xref: /third_party/ffmpeg/libavcodec/alsdec.c (revision cabdff1a)
1/*
2 * MPEG-4 ALS decoder
3 * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ mail.de>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * MPEG-4 ALS decoder
25 * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
26 */
27
28#include <inttypes.h>
29
30#include "avcodec.h"
31#include "get_bits.h"
32#include "unary.h"
33#include "mpeg4audio.h"
34#include "bgmc.h"
35#include "bswapdsp.h"
36#include "codec_internal.h"
37#include "internal.h"
38#include "mlz.h"
39#include "libavutil/samplefmt.h"
40#include "libavutil/crc.h"
41#include "libavutil/softfloat_ieee754.h"
42#include "libavutil/intfloat.h"
43#include "libavutil/intreadwrite.h"
44
45#include <stdint.h>
46
47/** Rice parameters and corresponding index offsets for decoding the
48 *  indices of scaled PARCOR values. The table chosen is set globally
49 *  by the encoder and stored in ALSSpecificConfig.
50 */
51static const int8_t parcor_rice_table[3][20][2] = {
52    { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},
53      { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},
54      { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},
55      {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },
56    { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},
57      { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},
58      {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},
59      {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },
60    { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},
61      { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},
62      {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},
63      {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }
64};
65
66
67/** Scaled PARCOR values used for the first two PARCOR coefficients.
68 *  To be indexed by the Rice coded indices.
69 *  Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)
70 *  Actual values are divided by 32 in order to be stored in 16 bits.
71 */
72static const int16_t parcor_scaled_values[] = {
73    -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,
74    -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,
75    -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,
76    -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,
77    -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,
78     -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,
79     -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,
80     -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,
81     -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,
82     -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,
83     -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,
84     -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,
85     -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,
86     -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,
87     -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,
88     -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,
89     -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,
90     -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,
91     -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,
92     -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,
93     -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,
94     -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,
95      -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,
96       46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,
97      143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,
98      244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,
99      349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,
100      458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,
101      571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,
102      688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,
103      810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,
104      935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32
105};
106
107
108/** Gain values of p(0) for long-term prediction.
109 *  To be indexed by the Rice coded indices.
110 */
111static const uint8_t ltp_gain_values [4][4] = {
112    { 0,  8, 16,  24},
113    {32, 40, 48,  56},
114    {64, 70, 76,  82},
115    {88, 92, 96, 100}
116};
117
118
119/** Inter-channel weighting factors for multi-channel correlation.
120 *  To be indexed by the Rice coded indices.
121 */
122static const int16_t mcc_weightings[] = {
123    204,  192,  179,  166,  153,  140,  128,  115,
124    102,   89,   76,   64,   51,   38,   25,   12,
125      0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,
126   -102, -115, -128, -140, -153, -166, -179, -192
127};
128
129
130/** Tail codes used in arithmetic coding using block Gilbert-Moore codes.
131 */
132static const uint8_t tail_code[16][6] = {
133    { 74, 44, 25, 13,  7, 3},
134    { 68, 42, 24, 13,  7, 3},
135    { 58, 39, 23, 13,  7, 3},
136    {126, 70, 37, 19, 10, 5},
137    {132, 70, 37, 20, 10, 5},
138    {124, 70, 38, 20, 10, 5},
139    {120, 69, 37, 20, 11, 5},
140    {116, 67, 37, 20, 11, 5},
141    {108, 66, 36, 20, 10, 5},
142    {102, 62, 36, 20, 10, 5},
143    { 88, 58, 34, 19, 10, 5},
144    {162, 89, 49, 25, 13, 7},
145    {156, 87, 49, 26, 14, 7},
146    {150, 86, 47, 26, 14, 7},
147    {142, 84, 47, 26, 14, 7},
148    {131, 79, 46, 26, 14, 7}
149};
150
151
152enum RA_Flag {
153    RA_FLAG_NONE,
154    RA_FLAG_FRAMES,
155    RA_FLAG_HEADER
156};
157
158
159typedef struct ALSSpecificConfig {
160    uint32_t samples;         ///< number of samples, 0xFFFFFFFF if unknown
161    int resolution;           ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
162    int floating;             ///< 1 = IEEE 32-bit floating-point, 0 = integer
163    int msb_first;            ///< 1 = original CRC calculated on big-endian system, 0 = little-endian
164    int frame_length;         ///< frame length for each frame (last frame may differ)
165    int ra_distance;          ///< distance between RA frames (in frames, 0...255)
166    enum RA_Flag ra_flag;     ///< indicates where the size of ra units is stored
167    int adapt_order;          ///< adaptive order: 1 = on, 0 = off
168    int coef_table;           ///< table index of Rice code parameters
169    int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
170    int max_order;            ///< maximum prediction order (0..1023)
171    int block_switching;      ///< number of block switching levels
172    int bgmc;                 ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
173    int sb_part;              ///< sub-block partition
174    int joint_stereo;         ///< joint stereo: 1 = on, 0 = off
175    int mc_coding;            ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
176    int chan_config;          ///< indicates that a chan_config_info field is present
177    int chan_sort;            ///< channel rearrangement: 1 = on, 0 = off
178    int rlslms;               ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
179    int chan_config_info;     ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
180    int *chan_pos;            ///< original channel positions
181    int crc_enabled;          ///< enable Cyclic Redundancy Checksum
182} ALSSpecificConfig;
183
184
185typedef struct ALSChannelData {
186    int stop_flag;
187    int master_channel;
188    int time_diff_flag;
189    int time_diff_sign;
190    int time_diff_index;
191    int weighting[6];
192} ALSChannelData;
193
194
195typedef struct ALSDecContext {
196    AVCodecContext *avctx;
197    ALSSpecificConfig sconf;
198    GetBitContext gb;
199    BswapDSPContext bdsp;
200    const AVCRC *crc_table;
201    uint32_t crc_org;               ///< CRC value of the original input data
202    uint32_t crc;                   ///< CRC value calculated from decoded data
203    unsigned int cur_frame_length;  ///< length of the current frame to decode
204    unsigned int frame_id;          ///< the frame ID / number of the current frame
205    unsigned int js_switch;         ///< if true, joint-stereo decoding is enforced
206    unsigned int cs_switch;         ///< if true, channel rearrangement is done
207    unsigned int num_blocks;        ///< number of blocks used in the current frame
208    unsigned int s_max;             ///< maximum Rice parameter allowed in entropy coding
209    uint8_t *bgmc_lut;              ///< pointer at lookup tables used for BGMC
210    int *bgmc_lut_status;           ///< pointer at lookup table status flags used for BGMC
211    int ltp_lag_length;             ///< number of bits used for ltp lag value
212    int *const_block;               ///< contains const_block flags for all channels
213    unsigned int *shift_lsbs;       ///< contains shift_lsbs flags for all channels
214    unsigned int *opt_order;        ///< contains opt_order flags for all channels
215    int *store_prev_samples;        ///< contains store_prev_samples flags for all channels
216    int *use_ltp;                   ///< contains use_ltp flags for all channels
217    int *ltp_lag;                   ///< contains ltp lag values for all channels
218    int **ltp_gain;                 ///< gain values for ltp 5-tap filter for a channel
219    int *ltp_gain_buffer;           ///< contains all gain values for ltp 5-tap filter
220    int32_t **quant_cof;            ///< quantized parcor coefficients for a channel
221    int32_t *quant_cof_buffer;      ///< contains all quantized parcor coefficients
222    int32_t **lpc_cof;              ///< coefficients of the direct form prediction filter for a channel
223    int32_t *lpc_cof_buffer;        ///< contains all coefficients of the direct form prediction filter
224    int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer
225    ALSChannelData **chan_data;     ///< channel data for multi-channel correlation
226    ALSChannelData *chan_data_buffer; ///< contains channel data for all channels
227    int *reverted_channels;         ///< stores a flag for each reverted channel
228    int32_t *prev_raw_samples;      ///< contains unshifted raw samples from the previous block
229    int32_t **raw_samples;          ///< decoded raw samples for each channel
230    int32_t *raw_buffer;            ///< contains all decoded raw samples including carryover samples
231    uint8_t *crc_buffer;            ///< buffer of byte order corrected samples used for CRC check
232    MLZ* mlz;                       ///< masked lz decompression structure
233    SoftFloat_IEEE754 *acf;         ///< contains common multiplier for all channels
234    int *last_acf_mantissa;         ///< contains the last acf mantissa data of common multiplier for all channels
235    int *shift_value;               ///< value by which the binary point is to be shifted for all channels
236    int *last_shift_value;          ///< contains last shift value for all channels
237    int **raw_mantissa;             ///< decoded mantissa bits of the difference signal
238    unsigned char *larray;          ///< buffer to store the output of masked lz decompression
239    int *nbits;                     ///< contains the number of bits to read for masked lz decompression for all samples
240    int highest_decoded_channel;
241} ALSDecContext;
242
243
244typedef struct ALSBlockData {
245    unsigned int block_length;      ///< number of samples within the block
246    unsigned int ra_block;          ///< if true, this is a random access block
247    int          *const_block;      ///< if true, this is a constant value block
248    int          js_blocks;         ///< true if this block contains a difference signal
249    unsigned int *shift_lsbs;       ///< shift of values for this block
250    unsigned int *opt_order;        ///< prediction order of this block
251    int          *store_prev_samples;///< if true, carryover samples have to be stored
252    int          *use_ltp;          ///< if true, long-term prediction is used
253    int          *ltp_lag;          ///< lag value for long-term prediction
254    int          *ltp_gain;         ///< gain values for ltp 5-tap filter
255    int32_t      *quant_cof;        ///< quantized parcor coefficients
256    int32_t      *lpc_cof;          ///< coefficients of the direct form prediction
257    int32_t      *raw_samples;      ///< decoded raw samples / residuals for this block
258    int32_t      *prev_raw_samples; ///< contains unshifted raw samples from the previous block
259    int32_t      *raw_other;        ///< decoded raw samples of the other channel of a channel pair
260} ALSBlockData;
261
262
263static av_cold void dprint_specific_config(ALSDecContext *ctx)
264{
265#ifdef DEBUG
266    AVCodecContext *avctx    = ctx->avctx;
267    ALSSpecificConfig *sconf = &ctx->sconf;
268
269    ff_dlog(avctx, "resolution = %i\n",           sconf->resolution);
270    ff_dlog(avctx, "floating = %i\n",             sconf->floating);
271    ff_dlog(avctx, "frame_length = %i\n",         sconf->frame_length);
272    ff_dlog(avctx, "ra_distance = %i\n",          sconf->ra_distance);
273    ff_dlog(avctx, "ra_flag = %i\n",              sconf->ra_flag);
274    ff_dlog(avctx, "adapt_order = %i\n",          sconf->adapt_order);
275    ff_dlog(avctx, "coef_table = %i\n",           sconf->coef_table);
276    ff_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
277    ff_dlog(avctx, "max_order = %i\n",            sconf->max_order);
278    ff_dlog(avctx, "block_switching = %i\n",      sconf->block_switching);
279    ff_dlog(avctx, "bgmc = %i\n",                 sconf->bgmc);
280    ff_dlog(avctx, "sb_part = %i\n",              sconf->sb_part);
281    ff_dlog(avctx, "joint_stereo = %i\n",         sconf->joint_stereo);
282    ff_dlog(avctx, "mc_coding = %i\n",            sconf->mc_coding);
283    ff_dlog(avctx, "chan_config = %i\n",          sconf->chan_config);
284    ff_dlog(avctx, "chan_sort = %i\n",            sconf->chan_sort);
285    ff_dlog(avctx, "RLSLMS = %i\n",               sconf->rlslms);
286    ff_dlog(avctx, "chan_config_info = %i\n",     sconf->chan_config_info);
287#endif
288}
289
290
291/** Read an ALSSpecificConfig from a buffer into the output struct.
292 */
293static av_cold int read_specific_config(ALSDecContext *ctx)
294{
295    GetBitContext gb;
296    uint64_t ht_size;
297    int i, config_offset;
298    MPEG4AudioConfig m4ac = {0};
299    ALSSpecificConfig *sconf = &ctx->sconf;
300    AVCodecContext *avctx    = ctx->avctx;
301    uint32_t als_id, header_size, trailer_size;
302    int ret;
303
304    if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0)
305        return ret;
306
307    config_offset = avpriv_mpeg4audio_get_config2(&m4ac, avctx->extradata,
308                                                  avctx->extradata_size, 1, avctx);
309
310    if (config_offset < 0)
311        return AVERROR_INVALIDDATA;
312
313    skip_bits_long(&gb, config_offset);
314
315    if (get_bits_left(&gb) < (30 << 3))
316        return AVERROR_INVALIDDATA;
317
318    // read the fixed items
319    als_id                      = get_bits_long(&gb, 32);
320    avctx->sample_rate          = m4ac.sample_rate;
321    skip_bits_long(&gb, 32); // sample rate already known
322    sconf->samples              = get_bits_long(&gb, 32);
323
324    if (avctx->ch_layout.nb_channels != m4ac.channels) {
325        av_channel_layout_uninit(&avctx->ch_layout);
326        avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
327        avctx->ch_layout.nb_channels = m4ac.channels;
328    }
329
330    skip_bits(&gb, 16);      // number of channels already known
331    skip_bits(&gb, 3);       // skip file_type
332    sconf->resolution           = get_bits(&gb, 3);
333    sconf->floating             = get_bits1(&gb);
334    sconf->msb_first            = get_bits1(&gb);
335    sconf->frame_length         = get_bits(&gb, 16) + 1;
336    sconf->ra_distance          = get_bits(&gb, 8);
337    sconf->ra_flag              = get_bits(&gb, 2);
338    sconf->adapt_order          = get_bits1(&gb);
339    sconf->coef_table           = get_bits(&gb, 2);
340    sconf->long_term_prediction = get_bits1(&gb);
341    sconf->max_order            = get_bits(&gb, 10);
342    sconf->block_switching      = get_bits(&gb, 2);
343    sconf->bgmc                 = get_bits1(&gb);
344    sconf->sb_part              = get_bits1(&gb);
345    sconf->joint_stereo         = get_bits1(&gb);
346    sconf->mc_coding            = get_bits1(&gb);
347    sconf->chan_config          = get_bits1(&gb);
348    sconf->chan_sort            = get_bits1(&gb);
349    sconf->crc_enabled          = get_bits1(&gb);
350    sconf->rlslms               = get_bits1(&gb);
351    skip_bits(&gb, 5);       // skip 5 reserved bits
352    skip_bits1(&gb);         // skip aux_data_enabled
353
354
355    // check for ALSSpecificConfig struct
356    if (als_id != MKBETAG('A','L','S','\0'))
357        return AVERROR_INVALIDDATA;
358
359    if (avctx->ch_layout.nb_channels > FF_SANE_NB_CHANNELS) {
360        avpriv_request_sample(avctx, "Huge number of channels");
361        return AVERROR_PATCHWELCOME;
362    }
363
364    if (avctx->ch_layout.nb_channels == 0)
365        return AVERROR_INVALIDDATA;
366
367    ctx->cur_frame_length = sconf->frame_length;
368
369    // read channel config
370    if (sconf->chan_config)
371        sconf->chan_config_info = get_bits(&gb, 16);
372    // TODO: use this to set avctx->channel_layout
373
374
375    // read channel sorting
376    if (sconf->chan_sort && avctx->ch_layout.nb_channels > 1) {
377        int chan_pos_bits = av_ceil_log2(avctx->ch_layout.nb_channels);
378        int bits_needed  = avctx->ch_layout.nb_channels * chan_pos_bits + 7;
379        if (get_bits_left(&gb) < bits_needed)
380            return AVERROR_INVALIDDATA;
381
382        if (!(sconf->chan_pos = av_malloc_array(avctx->ch_layout.nb_channels, sizeof(*sconf->chan_pos))))
383            return AVERROR(ENOMEM);
384
385        ctx->cs_switch = 1;
386
387        for (i = 0; i < avctx->ch_layout.nb_channels; i++) {
388            sconf->chan_pos[i] = -1;
389        }
390
391        for (i = 0; i < avctx->ch_layout.nb_channels; i++) {
392            int idx;
393
394            idx = get_bits(&gb, chan_pos_bits);
395            if (idx >= avctx->ch_layout.nb_channels || sconf->chan_pos[idx] != -1) {
396                av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");
397                ctx->cs_switch = 0;
398                break;
399            }
400            sconf->chan_pos[idx] = i;
401        }
402
403        align_get_bits(&gb);
404    }
405
406
407    // read fixed header and trailer sizes,
408    // if size = 0xFFFFFFFF then there is no data field!
409    if (get_bits_left(&gb) < 64)
410        return AVERROR_INVALIDDATA;
411
412    header_size  = get_bits_long(&gb, 32);
413    trailer_size = get_bits_long(&gb, 32);
414    if (header_size  == 0xFFFFFFFF)
415        header_size  = 0;
416    if (trailer_size == 0xFFFFFFFF)
417        trailer_size = 0;
418
419    ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;
420
421
422    // skip the header and trailer data
423    if (get_bits_left(&gb) < ht_size)
424        return AVERROR_INVALIDDATA;
425
426    if (ht_size > INT32_MAX)
427        return AVERROR_PATCHWELCOME;
428
429    skip_bits_long(&gb, ht_size);
430
431
432    // initialize CRC calculation
433    if (sconf->crc_enabled) {
434        if (get_bits_left(&gb) < 32)
435            return AVERROR_INVALIDDATA;
436
437        if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
438            ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
439            ctx->crc       = 0xFFFFFFFF;
440            ctx->crc_org   = ~get_bits_long(&gb, 32);
441        } else
442            skip_bits_long(&gb, 32);
443    }
444
445
446    // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
447
448    dprint_specific_config(ctx);
449
450    return 0;
451}
452
453
454/** Check the ALSSpecificConfig for unsupported features.
455 */
456static int check_specific_config(ALSDecContext *ctx)
457{
458    ALSSpecificConfig *sconf = &ctx->sconf;
459    int error = 0;
460
461    // report unsupported feature and set error value
462    #define MISSING_ERR(cond, str, errval)              \
463    {                                                   \
464        if (cond) {                                     \
465            avpriv_report_missing_feature(ctx->avctx,   \
466                                          str);         \
467            error = errval;                             \
468        }                                               \
469    }
470
471    MISSING_ERR(sconf->rlslms,    "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);
472
473    return error;
474}
475
476
477/** Parse the bs_info field to extract the block partitioning used in
478 *  block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
479 */
480static void parse_bs_info(const uint32_t bs_info, unsigned int n,
481                          unsigned int div, unsigned int **div_blocks,
482                          unsigned int *num_blocks)
483{
484    if (n < 31 && ((bs_info << n) & 0x40000000)) {
485        // if the level is valid and the investigated bit n is set
486        // then recursively check both children at bits (2n+1) and (2n+2)
487        n   *= 2;
488        div += 1;
489        parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
490        parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
491    } else {
492        // else the bit is not set or the last level has been reached
493        // (bit implicitly not set)
494        **div_blocks = div;
495        (*div_blocks)++;
496        (*num_blocks)++;
497    }
498}
499
500
501/** Read and decode a Rice codeword.
502 */
503static int32_t decode_rice(GetBitContext *gb, unsigned int k)
504{
505    int max = get_bits_left(gb) - k;
506    unsigned q = get_unary(gb, 0, max);
507    int r   = k ? get_bits1(gb) : !(q & 1);
508
509    if (k > 1) {
510        q <<= (k - 1);
511        q  += get_bits_long(gb, k - 1);
512    } else if (!k) {
513        q >>= 1;
514    }
515    return r ? q : ~q;
516}
517
518
519/** Convert PARCOR coefficient k to direct filter coefficient.
520 */
521static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
522{
523    int i, j;
524
525    for (i = 0, j = k - 1; i < j; i++, j--) {
526        unsigned tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
527        cof[j]  += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
528        cof[i]  += tmp1;
529    }
530    if (i == j)
531        cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
532
533    cof[k] = par[k];
534}
535
536
537/** Read block switching field if necessary and set actual block sizes.
538 *  Also assure that the block sizes of the last frame correspond to the
539 *  actual number of samples.
540 */
541static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
542                            uint32_t *bs_info)
543{
544    ALSSpecificConfig *sconf     = &ctx->sconf;
545    GetBitContext *gb            = &ctx->gb;
546    unsigned int *ptr_div_blocks = div_blocks;
547    unsigned int b;
548
549    if (sconf->block_switching) {
550        unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
551        *bs_info = get_bits_long(gb, bs_info_len);
552        *bs_info <<= (32 - bs_info_len);
553    }
554
555    ctx->num_blocks = 0;
556    parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
557
558    // The last frame may have an overdetermined block structure given in
559    // the bitstream. In that case the defined block structure would need
560    // more samples than available to be consistent.
561    // The block structure is actually used but the block sizes are adapted
562    // to fit the actual number of available samples.
563    // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
564    // This results in the actual block sizes:    2 2 1 0.
565    // This is not specified in 14496-3 but actually done by the reference
566    // codec RM22 revision 2.
567    // This appears to happen in case of an odd number of samples in the last
568    // frame which is actually not allowed by the block length switching part
569    // of 14496-3.
570    // The ALS conformance files feature an odd number of samples in the last
571    // frame.
572
573    for (b = 0; b < ctx->num_blocks; b++)
574        div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
575
576    if (ctx->cur_frame_length != ctx->sconf.frame_length) {
577        unsigned int remaining = ctx->cur_frame_length;
578
579        for (b = 0; b < ctx->num_blocks; b++) {
580            if (remaining <= div_blocks[b]) {
581                div_blocks[b] = remaining;
582                ctx->num_blocks = b + 1;
583                break;
584            }
585
586            remaining -= div_blocks[b];
587        }
588    }
589}
590
591
592/** Read the block data for a constant block
593 */
594static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
595{
596    ALSSpecificConfig *sconf = &ctx->sconf;
597    AVCodecContext *avctx    = ctx->avctx;
598    GetBitContext *gb        = &ctx->gb;
599
600    if (bd->block_length <= 0)
601        return AVERROR_INVALIDDATA;
602
603    *bd->raw_samples = 0;
604    *bd->const_block = get_bits1(gb);    // 1 = constant value, 0 = zero block (silence)
605    bd->js_blocks    = get_bits1(gb);
606
607    // skip 5 reserved bits
608    skip_bits(gb, 5);
609
610    if (*bd->const_block) {
611        unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
612        *bd->raw_samples = get_sbits_long(gb, const_val_bits);
613    }
614
615    // ensure constant block decoding by reusing this field
616    *bd->const_block = 1;
617
618    return 0;
619}
620
621
622/** Decode the block data for a constant block
623 */
624static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
625{
626    int      smp = bd->block_length - 1;
627    int32_t  val = *bd->raw_samples;
628    int32_t *dst = bd->raw_samples + 1;
629
630    // write raw samples into buffer
631    for (; smp; smp--)
632        *dst++ = val;
633}
634
635
636/** Read the block data for a non-constant block
637 */
638static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
639{
640    ALSSpecificConfig *sconf = &ctx->sconf;
641    AVCodecContext *avctx    = ctx->avctx;
642    GetBitContext *gb        = &ctx->gb;
643    unsigned int k;
644    unsigned int s[8];
645    unsigned int sx[8];
646    unsigned int sub_blocks, log2_sub_blocks, sb_length;
647    unsigned int start      = 0;
648    unsigned int opt_order;
649    int          sb;
650    int32_t      *quant_cof = bd->quant_cof;
651    int32_t      *current_res;
652
653
654    // ensure variable block decoding by reusing this field
655    *bd->const_block = 0;
656
657    *bd->opt_order  = 1;
658    bd->js_blocks   = get_bits1(gb);
659
660    opt_order       = *bd->opt_order;
661
662    // determine the number of subblocks for entropy decoding
663    if (!sconf->bgmc && !sconf->sb_part) {
664        log2_sub_blocks = 0;
665    } else {
666        if (sconf->bgmc && sconf->sb_part)
667            log2_sub_blocks = get_bits(gb, 2);
668        else
669            log2_sub_blocks = 2 * get_bits1(gb);
670    }
671
672    sub_blocks = 1 << log2_sub_blocks;
673
674    // do not continue in case of a damaged stream since
675    // block_length must be evenly divisible by sub_blocks
676    if (bd->block_length & (sub_blocks - 1) || bd->block_length <= 0) {
677        av_log(avctx, AV_LOG_WARNING,
678               "Block length is not evenly divisible by the number of subblocks.\n");
679        return AVERROR_INVALIDDATA;
680    }
681
682    sb_length = bd->block_length >> log2_sub_blocks;
683
684    if (sconf->bgmc) {
685        s[0] = get_bits(gb, 8 + (sconf->resolution > 1));
686        for (k = 1; k < sub_blocks; k++)
687            s[k] = s[k - 1] + decode_rice(gb, 2);
688
689        for (k = 0; k < sub_blocks; k++) {
690            sx[k]   = s[k] & 0x0F;
691            s [k] >>= 4;
692        }
693    } else {
694        s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
695        for (k = 1; k < sub_blocks; k++)
696            s[k] = s[k - 1] + decode_rice(gb, 0);
697    }
698    for (k = 1; k < sub_blocks; k++)
699        if (s[k] > 32) {
700            av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
701            return AVERROR_INVALIDDATA;
702        }
703
704    if (get_bits1(gb))
705        *bd->shift_lsbs = get_bits(gb, 4) + 1;
706
707    *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;
708
709
710    if (!sconf->rlslms) {
711        if (sconf->adapt_order && sconf->max_order) {
712            int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
713                                                2, sconf->max_order + 1));
714            *bd->opt_order       = get_bits(gb, opt_order_length);
715            if (*bd->opt_order > sconf->max_order) {
716                *bd->opt_order = sconf->max_order;
717                av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
718                return AVERROR_INVALIDDATA;
719            }
720        } else {
721            *bd->opt_order = sconf->max_order;
722        }
723        opt_order = *bd->opt_order;
724
725        if (opt_order) {
726            int add_base;
727
728            if (sconf->coef_table == 3) {
729                add_base = 0x7F;
730
731                // read coefficient 0
732                quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
733
734                // read coefficient 1
735                if (opt_order > 1)
736                    quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
737
738                // read coefficients 2 to opt_order
739                for (k = 2; k < opt_order; k++)
740                    quant_cof[k] = get_bits(gb, 7);
741            } else {
742                int k_max;
743                add_base = 1;
744
745                // read coefficient 0 to 19
746                k_max = FFMIN(opt_order, 20);
747                for (k = 0; k < k_max; k++) {
748                    int rice_param = parcor_rice_table[sconf->coef_table][k][1];
749                    int offset     = parcor_rice_table[sconf->coef_table][k][0];
750                    quant_cof[k] = decode_rice(gb, rice_param) + offset;
751                    if (quant_cof[k] < -64 || quant_cof[k] > 63) {
752                        av_log(avctx, AV_LOG_ERROR,
753                               "quant_cof %"PRId32" is out of range.\n",
754                               quant_cof[k]);
755                        return AVERROR_INVALIDDATA;
756                    }
757                }
758
759                // read coefficients 20 to 126
760                k_max = FFMIN(opt_order, 127);
761                for (; k < k_max; k++)
762                    quant_cof[k] = decode_rice(gb, 2) + (k & 1);
763
764                // read coefficients 127 to opt_order
765                for (; k < opt_order; k++)
766                    quant_cof[k] = decode_rice(gb, 1);
767
768                quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
769
770                if (opt_order > 1)
771                    quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
772            }
773
774            for (k = 2; k < opt_order; k++)
775                quant_cof[k] = (quant_cof[k] * (1U << 14)) + (add_base << 13);
776        }
777    }
778
779    // read LTP gain and lag values
780    if (sconf->long_term_prediction) {
781        *bd->use_ltp = get_bits1(gb);
782
783        if (*bd->use_ltp) {
784            int r, c;
785
786            bd->ltp_gain[0]   = decode_rice(gb, 1) * 8;
787            bd->ltp_gain[1]   = decode_rice(gb, 2) * 8;
788
789            r                 = get_unary(gb, 0, 4);
790            c                 = get_bits(gb, 2);
791            if (r >= 4) {
792                av_log(avctx, AV_LOG_ERROR, "r overflow\n");
793                return AVERROR_INVALIDDATA;
794            }
795
796            bd->ltp_gain[2]   = ltp_gain_values[r][c];
797
798            bd->ltp_gain[3]   = decode_rice(gb, 2) * 8;
799            bd->ltp_gain[4]   = decode_rice(gb, 1) * 8;
800
801            *bd->ltp_lag      = get_bits(gb, ctx->ltp_lag_length);
802            *bd->ltp_lag     += FFMAX(4, opt_order + 1);
803        }
804    }
805
806    // read first value and residuals in case of a random access block
807    if (bd->ra_block) {
808        start = FFMIN(opt_order, 3);
809        av_assert0(sb_length <= sconf->frame_length);
810        if (sb_length <= start) {
811            // opt_order or sb_length may be corrupted, either way this is unsupported and not well defined in the specification
812            av_log(avctx, AV_LOG_ERROR, "Sub block length smaller or equal start\n");
813            return AVERROR_PATCHWELCOME;
814        }
815
816        if (opt_order)
817            bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
818        if (opt_order > 1)
819            bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
820        if (opt_order > 2)
821            bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
822    }
823
824    // read all residuals
825    if (sconf->bgmc) {
826        int          delta[8];
827        unsigned int k    [8];
828        unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);
829
830        // read most significant bits
831        unsigned int high;
832        unsigned int low;
833        unsigned int value;
834
835        int ret = ff_bgmc_decode_init(gb, &high, &low, &value);
836        if (ret < 0)
837            return ret;
838
839        current_res = bd->raw_samples + start;
840
841        for (sb = 0; sb < sub_blocks; sb++) {
842            unsigned int sb_len  = sb_length - (sb ? 0 : start);
843
844            k    [sb] = s[sb] > b ? s[sb] - b : 0;
845            delta[sb] = 5 - s[sb] + k[sb];
846
847            if (k[sb] >= 32)
848                return AVERROR_INVALIDDATA;
849
850            ff_bgmc_decode(gb, sb_len, current_res,
851                        delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);
852
853            current_res += sb_len;
854        }
855
856        ff_bgmc_decode_end(gb);
857
858
859        // read least significant bits and tails
860        current_res = bd->raw_samples + start;
861
862        for (sb = 0; sb < sub_blocks; sb++, start = 0) {
863            unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];
864            unsigned int cur_k         = k[sb];
865            unsigned int cur_s         = s[sb];
866
867            for (; start < sb_length; start++) {
868                int32_t res = *current_res;
869
870                if (res == cur_tail_code) {
871                    unsigned int max_msb =   (2 + (sx[sb] > 2) + (sx[sb] > 10))
872                                          << (5 - delta[sb]);
873
874                    res = decode_rice(gb, cur_s);
875
876                    if (res >= 0) {
877                        res += (max_msb    ) << cur_k;
878                    } else {
879                        res -= (max_msb - 1) << cur_k;
880                    }
881                } else {
882                    if (res > cur_tail_code)
883                        res--;
884
885                    if (res & 1)
886                        res = -res;
887
888                    res >>= 1;
889
890                    if (cur_k) {
891                        res  *= 1U << cur_k;
892                        res  |= get_bits_long(gb, cur_k);
893                    }
894                }
895
896                *current_res++ = res;
897            }
898        }
899    } else {
900        current_res = bd->raw_samples + start;
901
902        for (sb = 0; sb < sub_blocks; sb++, start = 0)
903            for (; start < sb_length; start++)
904                *current_res++ = decode_rice(gb, s[sb]);
905     }
906
907    return 0;
908}
909
910
911/** Decode the block data for a non-constant block
912 */
913static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
914{
915    ALSSpecificConfig *sconf = &ctx->sconf;
916    unsigned int block_length = bd->block_length;
917    unsigned int smp = 0;
918    unsigned int k;
919    int opt_order             = *bd->opt_order;
920    int sb;
921    int64_t y;
922    int32_t *quant_cof        = bd->quant_cof;
923    int32_t *lpc_cof          = bd->lpc_cof;
924    int32_t *raw_samples      = bd->raw_samples;
925    int32_t *raw_samples_end  = bd->raw_samples + bd->block_length;
926    int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;
927
928    // reverse long-term prediction
929    if (*bd->use_ltp) {
930        int ltp_smp;
931
932        for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
933            int center = ltp_smp - *bd->ltp_lag;
934            int begin  = FFMAX(0, center - 2);
935            int end    = center + 3;
936            int tab    = 5 - (end - begin);
937            int base;
938
939            y = 1 << 6;
940
941            for (base = begin; base < end; base++, tab++)
942                y += (uint64_t)MUL64(bd->ltp_gain[tab], raw_samples[base]);
943
944            raw_samples[ltp_smp] += y >> 7;
945        }
946    }
947
948    // reconstruct all samples from residuals
949    if (bd->ra_block) {
950        for (smp = 0; smp < FFMIN(opt_order, block_length); smp++) {
951            y = 1 << 19;
952
953            for (sb = 0; sb < smp; sb++)
954                y += (uint64_t)MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
955
956            *raw_samples++ -= y >> 20;
957            parcor_to_lpc(smp, quant_cof, lpc_cof);
958        }
959    } else {
960        for (k = 0; k < opt_order; k++)
961            parcor_to_lpc(k, quant_cof, lpc_cof);
962
963        // store previous samples in case that they have to be altered
964        if (*bd->store_prev_samples)
965            memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
966                   sizeof(*bd->prev_raw_samples) * sconf->max_order);
967
968        // reconstruct difference signal for prediction (joint-stereo)
969        if (bd->js_blocks && bd->raw_other) {
970            uint32_t *left, *right;
971
972            if (bd->raw_other > raw_samples) {  // D = R - L
973                left  = raw_samples;
974                right = bd->raw_other;
975            } else {                                // D = R - L
976                left  = bd->raw_other;
977                right = raw_samples;
978            }
979
980            for (sb = -1; sb >= -sconf->max_order; sb--)
981                raw_samples[sb] = right[sb] - left[sb];
982        }
983
984        // reconstruct shifted signal
985        if (*bd->shift_lsbs)
986            for (sb = -1; sb >= -sconf->max_order; sb--)
987                raw_samples[sb] >>= *bd->shift_lsbs;
988    }
989
990    // reverse linear prediction coefficients for efficiency
991    lpc_cof = lpc_cof + opt_order;
992
993    for (sb = 0; sb < opt_order; sb++)
994        lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
995
996    // reconstruct raw samples
997    raw_samples = bd->raw_samples + smp;
998    lpc_cof     = lpc_cof_reversed + opt_order;
999
1000    for (; raw_samples < raw_samples_end; raw_samples++) {
1001        y = 1 << 19;
1002
1003        for (sb = -opt_order; sb < 0; sb++)
1004            y += (uint64_t)MUL64(lpc_cof[sb], raw_samples[sb]);
1005
1006        *raw_samples -= y >> 20;
1007    }
1008
1009    raw_samples = bd->raw_samples;
1010
1011    // restore previous samples in case that they have been altered
1012    if (*bd->store_prev_samples)
1013        memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
1014               sizeof(*raw_samples) * sconf->max_order);
1015
1016    return 0;
1017}
1018
1019
1020/** Read the block data.
1021 */
1022static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
1023{
1024    int ret;
1025    GetBitContext *gb        = &ctx->gb;
1026    ALSSpecificConfig *sconf = &ctx->sconf;
1027
1028    *bd->shift_lsbs = 0;
1029
1030    if (get_bits_left(gb) < 7)
1031        return AVERROR_INVALIDDATA;
1032
1033    // read block type flag and read the samples accordingly
1034    if (get_bits1(gb)) {
1035        ret = read_var_block_data(ctx, bd);
1036    } else {
1037        ret = read_const_block_data(ctx, bd);
1038    }
1039
1040    if (!sconf->mc_coding || ctx->js_switch)
1041        align_get_bits(gb);
1042
1043    return ret;
1044}
1045
1046
1047/** Decode the block data.
1048 */
1049static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1050{
1051    unsigned int smp;
1052    int ret = 0;
1053
1054    // read block type flag and read the samples accordingly
1055    if (*bd->const_block)
1056        decode_const_block_data(ctx, bd);
1057    else
1058        ret = decode_var_block_data(ctx, bd); // always return 0
1059
1060    if (ret < 0)
1061        return ret;
1062
1063    // TODO: read RLSLMS extension data
1064
1065    if (*bd->shift_lsbs)
1066        for (smp = 0; smp < bd->block_length; smp++)
1067            bd->raw_samples[smp] = (unsigned)bd->raw_samples[smp] << *bd->shift_lsbs;
1068
1069    return 0;
1070}
1071
1072
1073/** Read and decode block data successively.
1074 */
1075static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1076{
1077    int ret;
1078
1079    if ((ret = read_block(ctx, bd)) < 0)
1080        return ret;
1081
1082    return decode_block(ctx, bd);
1083}
1084
1085
1086/** Compute the number of samples left to decode for the current frame and
1087 *  sets these samples to zero.
1088 */
1089static void zero_remaining(unsigned int b, unsigned int b_max,
1090                           const unsigned int *div_blocks, int32_t *buf)
1091{
1092    unsigned int count = 0;
1093
1094    while (b < b_max)
1095        count += div_blocks[b++];
1096
1097    if (count)
1098        memset(buf, 0, sizeof(*buf) * count);
1099}
1100
1101
1102/** Decode blocks independently.
1103 */
1104static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
1105                             unsigned int c, const unsigned int *div_blocks,
1106                             unsigned int *js_blocks)
1107{
1108    int ret;
1109    unsigned int b;
1110    ALSBlockData bd = { 0 };
1111
1112    bd.ra_block         = ra_frame;
1113    bd.const_block      = ctx->const_block;
1114    bd.shift_lsbs       = ctx->shift_lsbs;
1115    bd.opt_order        = ctx->opt_order;
1116    bd.store_prev_samples = ctx->store_prev_samples;
1117    bd.use_ltp          = ctx->use_ltp;
1118    bd.ltp_lag          = ctx->ltp_lag;
1119    bd.ltp_gain         = ctx->ltp_gain[0];
1120    bd.quant_cof        = ctx->quant_cof[0];
1121    bd.lpc_cof          = ctx->lpc_cof[0];
1122    bd.prev_raw_samples = ctx->prev_raw_samples;
1123    bd.raw_samples      = ctx->raw_samples[c];
1124
1125
1126    for (b = 0; b < ctx->num_blocks; b++) {
1127        bd.block_length     = div_blocks[b];
1128
1129        if ((ret = read_decode_block(ctx, &bd)) < 0) {
1130            // damaged block, write zero for the rest of the frame
1131            zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
1132            return ret;
1133        }
1134        bd.raw_samples += div_blocks[b];
1135        bd.ra_block     = 0;
1136    }
1137
1138    return 0;
1139}
1140
1141
1142/** Decode blocks dependently.
1143 */
1144static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
1145                         unsigned int c, const unsigned int *div_blocks,
1146                         unsigned int *js_blocks)
1147{
1148    ALSSpecificConfig *sconf = &ctx->sconf;
1149    unsigned int offset = 0;
1150    unsigned int b;
1151    int ret;
1152    ALSBlockData bd[2] = { { 0 } };
1153
1154    bd[0].ra_block         = ra_frame;
1155    bd[0].const_block      = ctx->const_block;
1156    bd[0].shift_lsbs       = ctx->shift_lsbs;
1157    bd[0].opt_order        = ctx->opt_order;
1158    bd[0].store_prev_samples = ctx->store_prev_samples;
1159    bd[0].use_ltp          = ctx->use_ltp;
1160    bd[0].ltp_lag          = ctx->ltp_lag;
1161    bd[0].ltp_gain         = ctx->ltp_gain[0];
1162    bd[0].quant_cof        = ctx->quant_cof[0];
1163    bd[0].lpc_cof          = ctx->lpc_cof[0];
1164    bd[0].prev_raw_samples = ctx->prev_raw_samples;
1165    bd[0].js_blocks        = *js_blocks;
1166
1167    bd[1].ra_block         = ra_frame;
1168    bd[1].const_block      = ctx->const_block;
1169    bd[1].shift_lsbs       = ctx->shift_lsbs;
1170    bd[1].opt_order        = ctx->opt_order;
1171    bd[1].store_prev_samples = ctx->store_prev_samples;
1172    bd[1].use_ltp          = ctx->use_ltp;
1173    bd[1].ltp_lag          = ctx->ltp_lag;
1174    bd[1].ltp_gain         = ctx->ltp_gain[0];
1175    bd[1].quant_cof        = ctx->quant_cof[0];
1176    bd[1].lpc_cof          = ctx->lpc_cof[0];
1177    bd[1].prev_raw_samples = ctx->prev_raw_samples;
1178    bd[1].js_blocks        = *(js_blocks + 1);
1179
1180    // decode all blocks
1181    for (b = 0; b < ctx->num_blocks; b++) {
1182        unsigned int s;
1183
1184        bd[0].block_length = div_blocks[b];
1185        bd[1].block_length = div_blocks[b];
1186
1187        bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;
1188        bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;
1189
1190        bd[0].raw_other    = bd[1].raw_samples;
1191        bd[1].raw_other    = bd[0].raw_samples;
1192
1193        if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||
1194            (ret = read_decode_block(ctx, &bd[1])) < 0)
1195            goto fail;
1196
1197        // reconstruct joint-stereo blocks
1198        if (bd[0].js_blocks) {
1199            if (bd[1].js_blocks)
1200                av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
1201
1202            for (s = 0; s < div_blocks[b]; s++)
1203                bd[0].raw_samples[s] = bd[1].raw_samples[s] - (unsigned)bd[0].raw_samples[s];
1204        } else if (bd[1].js_blocks) {
1205            for (s = 0; s < div_blocks[b]; s++)
1206                bd[1].raw_samples[s] = bd[1].raw_samples[s] + (unsigned)bd[0].raw_samples[s];
1207        }
1208
1209        offset  += div_blocks[b];
1210        bd[0].ra_block = 0;
1211        bd[1].ra_block = 0;
1212    }
1213
1214    // store carryover raw samples,
1215    // the others channel raw samples are stored by the calling function.
1216    memmove(ctx->raw_samples[c] - sconf->max_order,
1217            ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1218            sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1219
1220    return 0;
1221fail:
1222    // damaged block, write zero for the rest of the frame
1223    zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
1224    zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
1225    return ret;
1226}
1227
1228static inline int als_weighting(GetBitContext *gb, int k, int off)
1229{
1230    int idx = av_clip(decode_rice(gb, k) + off,
1231                      0, FF_ARRAY_ELEMS(mcc_weightings) - 1);
1232    return mcc_weightings[idx];
1233}
1234
1235/** Read the channel data.
1236  */
1237static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)
1238{
1239    GetBitContext *gb       = &ctx->gb;
1240    ALSChannelData *current = cd;
1241    unsigned int channels   = ctx->avctx->ch_layout.nb_channels;
1242    int entries             = 0;
1243
1244    while (entries < channels && !(current->stop_flag = get_bits1(gb))) {
1245        current->master_channel = get_bits_long(gb, av_ceil_log2(channels));
1246
1247        if (current->master_channel >= channels) {
1248            av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");
1249            return AVERROR_INVALIDDATA;
1250        }
1251
1252        if (current->master_channel != c) {
1253            current->time_diff_flag = get_bits1(gb);
1254            current->weighting[0]   = als_weighting(gb, 1, 16);
1255            current->weighting[1]   = als_weighting(gb, 2, 14);
1256            current->weighting[2]   = als_weighting(gb, 1, 16);
1257
1258            if (current->time_diff_flag) {
1259                current->weighting[3] = als_weighting(gb, 1, 16);
1260                current->weighting[4] = als_weighting(gb, 1, 16);
1261                current->weighting[5] = als_weighting(gb, 1, 16);
1262
1263                current->time_diff_sign  = get_bits1(gb);
1264                current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;
1265            }
1266        }
1267
1268        current++;
1269        entries++;
1270    }
1271
1272    if (entries == channels) {
1273        av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");
1274        return AVERROR_INVALIDDATA;
1275    }
1276
1277    align_get_bits(gb);
1278    return 0;
1279}
1280
1281
1282/** Recursively reverts the inter-channel correlation for a block.
1283 */
1284static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
1285                                       ALSChannelData **cd, int *reverted,
1286                                       unsigned int offset, int c)
1287{
1288    ALSChannelData *ch = cd[c];
1289    unsigned int   dep = 0;
1290    unsigned int channels = ctx->avctx->ch_layout.nb_channels;
1291    unsigned int channel_size = ctx->sconf.frame_length + ctx->sconf.max_order;
1292
1293    if (reverted[c])
1294        return 0;
1295
1296    reverted[c] = 1;
1297
1298    while (dep < channels && !ch[dep].stop_flag) {
1299        revert_channel_correlation(ctx, bd, cd, reverted, offset,
1300                                   ch[dep].master_channel);
1301
1302        dep++;
1303    }
1304
1305    if (dep == channels) {
1306        av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");
1307        return AVERROR_INVALIDDATA;
1308    }
1309
1310    bd->const_block = ctx->const_block + c;
1311    bd->shift_lsbs  = ctx->shift_lsbs + c;
1312    bd->opt_order   = ctx->opt_order + c;
1313    bd->store_prev_samples = ctx->store_prev_samples + c;
1314    bd->use_ltp     = ctx->use_ltp + c;
1315    bd->ltp_lag     = ctx->ltp_lag + c;
1316    bd->ltp_gain    = ctx->ltp_gain[c];
1317    bd->lpc_cof     = ctx->lpc_cof[c];
1318    bd->quant_cof   = ctx->quant_cof[c];
1319    bd->raw_samples = ctx->raw_samples[c] + offset;
1320
1321    for (dep = 0; !ch[dep].stop_flag; dep++) {
1322        ptrdiff_t smp;
1323        ptrdiff_t begin = 1;
1324        ptrdiff_t end   = bd->block_length - 1;
1325        int64_t y;
1326        int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;
1327
1328        if (ch[dep].master_channel == c)
1329            continue;
1330
1331        if (ch[dep].time_diff_flag) {
1332            int t = ch[dep].time_diff_index;
1333
1334            if (ch[dep].time_diff_sign) {
1335                t      = -t;
1336                if (begin < t) {
1337                    av_log(ctx->avctx, AV_LOG_ERROR, "begin %"PTRDIFF_SPECIFIER" smaller than time diff index %d.\n", begin, t);
1338                    return AVERROR_INVALIDDATA;
1339                }
1340                begin -= t;
1341            } else {
1342                if (end < t) {
1343                    av_log(ctx->avctx, AV_LOG_ERROR, "end %"PTRDIFF_SPECIFIER" smaller than time diff index %d.\n", end, t);
1344                    return AVERROR_INVALIDDATA;
1345                }
1346                end   -= t;
1347            }
1348
1349            if (FFMIN(begin - 1, begin - 1 + t) < ctx->raw_buffer - master ||
1350                FFMAX(end   + 1,   end + 1 + t) > ctx->raw_buffer + channels * channel_size - master) {
1351                av_log(ctx->avctx, AV_LOG_ERROR,
1352                       "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",
1353                       master + FFMIN(begin - 1, begin - 1 + t), master + FFMAX(end + 1,   end + 1 + t),
1354                       ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);
1355                return AVERROR_INVALIDDATA;
1356            }
1357
1358            for (smp = begin; smp < end; smp++) {
1359                y  = (1 << 6) +
1360                     MUL64(ch[dep].weighting[0], master[smp - 1    ]) +
1361                     MUL64(ch[dep].weighting[1], master[smp        ]) +
1362                     MUL64(ch[dep].weighting[2], master[smp + 1    ]) +
1363                     MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +
1364                     MUL64(ch[dep].weighting[4], master[smp     + t]) +
1365                     MUL64(ch[dep].weighting[5], master[smp + 1 + t]);
1366
1367                bd->raw_samples[smp] += y >> 7;
1368            }
1369        } else {
1370
1371            if (begin - 1 < ctx->raw_buffer - master ||
1372                end   + 1 > ctx->raw_buffer + channels * channel_size - master) {
1373                av_log(ctx->avctx, AV_LOG_ERROR,
1374                       "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",
1375                       master + begin - 1, master + end + 1,
1376                       ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);
1377                return AVERROR_INVALIDDATA;
1378            }
1379
1380            for (smp = begin; smp < end; smp++) {
1381                y  = (1 << 6) +
1382                     MUL64(ch[dep].weighting[0], master[smp - 1]) +
1383                     MUL64(ch[dep].weighting[1], master[smp    ]) +
1384                     MUL64(ch[dep].weighting[2], master[smp + 1]);
1385
1386                bd->raw_samples[smp] += y >> 7;
1387            }
1388        }
1389    }
1390
1391    return 0;
1392}
1393
1394
1395/** multiply two softfloats and handle the rounding off
1396 */
1397static SoftFloat_IEEE754 multiply(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
1398    uint64_t mantissa_temp;
1399    uint64_t mask_64;
1400    int cutoff_bit_count;
1401    unsigned char last_2_bits;
1402    unsigned int mantissa;
1403    int32_t sign;
1404    uint32_t return_val = 0;
1405    int bit_count       = 48;
1406
1407    sign = a.sign ^ b.sign;
1408
1409    // Multiply mantissa bits in a 64-bit register
1410    mantissa_temp = (uint64_t)a.mant * (uint64_t)b.mant;
1411    mask_64       = (uint64_t)0x1 << 47;
1412
1413    if (!mantissa_temp)
1414        return FLOAT_0;
1415
1416    // Count the valid bit count
1417    while (!(mantissa_temp & mask_64) && mask_64) {
1418        bit_count--;
1419        mask_64 >>= 1;
1420    }
1421
1422    // Round off
1423    cutoff_bit_count = bit_count - 24;
1424    if (cutoff_bit_count > 0) {
1425        last_2_bits = (unsigned char)(((unsigned int)mantissa_temp >> (cutoff_bit_count - 1)) & 0x3 );
1426        if ((last_2_bits == 0x3) || ((last_2_bits == 0x1) && ((unsigned int)mantissa_temp & ((0x1UL << (cutoff_bit_count - 1)) - 1)))) {
1427            // Need to round up
1428            mantissa_temp += (uint64_t)0x1 << cutoff_bit_count;
1429        }
1430    }
1431
1432    if (cutoff_bit_count >= 0) {
1433        mantissa = (unsigned int)(mantissa_temp >> cutoff_bit_count);
1434    } else {
1435        mantissa = (unsigned int)(mantissa_temp <<-cutoff_bit_count);
1436    }
1437
1438    // Need one more shift?
1439    if (mantissa & 0x01000000ul) {
1440        bit_count++;
1441        mantissa >>= 1;
1442    }
1443
1444    if (!sign) {
1445        return_val = 0x80000000U;
1446    }
1447
1448    return_val |= ((unsigned)av_clip(a.exp + b.exp + bit_count - 47, -126, 127) << 23) & 0x7F800000;
1449    return_val |= mantissa;
1450    return av_bits2sf_ieee754(return_val);
1451}
1452
1453
1454/** Read and decode the floating point sample data
1455 */
1456static int read_diff_float_data(ALSDecContext *ctx, unsigned int ra_frame) {
1457    AVCodecContext *avctx   = ctx->avctx;
1458    GetBitContext *gb       = &ctx->gb;
1459    SoftFloat_IEEE754 *acf  = ctx->acf;
1460    int *shift_value        = ctx->shift_value;
1461    int *last_shift_value   = ctx->last_shift_value;
1462    int *last_acf_mantissa  = ctx->last_acf_mantissa;
1463    int **raw_mantissa      = ctx->raw_mantissa;
1464    int *nbits              = ctx->nbits;
1465    unsigned char *larray   = ctx->larray;
1466    int frame_length        = ctx->cur_frame_length;
1467    SoftFloat_IEEE754 scale = av_int2sf_ieee754(0x1u, 23);
1468    unsigned int partA_flag;
1469    unsigned int highest_byte;
1470    unsigned int shift_amp;
1471    uint32_t tmp_32;
1472    int use_acf;
1473    int nchars;
1474    int i;
1475    int c;
1476    long k;
1477    long nbits_aligned;
1478    unsigned long acc;
1479    unsigned long j;
1480    uint32_t sign;
1481    uint32_t e;
1482    uint32_t mantissa;
1483
1484    skip_bits_long(gb, 32); //num_bytes_diff_float
1485    use_acf = get_bits1(gb);
1486
1487    if (ra_frame) {
1488        memset(last_acf_mantissa, 0, avctx->ch_layout.nb_channels * sizeof(*last_acf_mantissa));
1489        memset(last_shift_value,  0, avctx->ch_layout.nb_channels * sizeof(*last_shift_value) );
1490        ff_mlz_flush_dict(ctx->mlz);
1491    }
1492
1493    if (avctx->ch_layout.nb_channels * 8 > get_bits_left(gb))
1494        return AVERROR_INVALIDDATA;
1495
1496    for (c = 0; c < avctx->ch_layout.nb_channels; ++c) {
1497        if (use_acf) {
1498            //acf_flag
1499            if (get_bits1(gb)) {
1500                tmp_32 = get_bits(gb, 23);
1501                last_acf_mantissa[c] = tmp_32;
1502            } else {
1503                tmp_32 = last_acf_mantissa[c];
1504            }
1505            acf[c] = av_bits2sf_ieee754(tmp_32);
1506        } else {
1507            acf[c] = FLOAT_1;
1508        }
1509
1510        highest_byte = get_bits(gb, 2);
1511        partA_flag   = get_bits1(gb);
1512        shift_amp    = get_bits1(gb);
1513
1514        if (shift_amp) {
1515            shift_value[c] = get_bits(gb, 8);
1516            last_shift_value[c] = shift_value[c];
1517        } else {
1518            shift_value[c] = last_shift_value[c];
1519        }
1520
1521        if (partA_flag) {
1522            if (!get_bits1(gb)) { //uncompressed
1523                for (i = 0; i < frame_length; ++i) {
1524                    if (ctx->raw_samples[c][i] == 0) {
1525                        ctx->raw_mantissa[c][i] = get_bits_long(gb, 32);
1526                    }
1527                }
1528            } else { //compressed
1529                nchars = 0;
1530                for (i = 0; i < frame_length; ++i) {
1531                    if (ctx->raw_samples[c][i] == 0) {
1532                        nchars += 4;
1533                    }
1534                }
1535
1536                tmp_32 = ff_mlz_decompression(ctx->mlz, gb, nchars, larray);
1537                if(tmp_32 != nchars) {
1538                    av_log(ctx->avctx, AV_LOG_ERROR, "Error in MLZ decompression (%"PRId32", %d).\n", tmp_32, nchars);
1539                    return AVERROR_INVALIDDATA;
1540                }
1541
1542                for (i = 0; i < frame_length; ++i) {
1543                    ctx->raw_mantissa[c][i] = AV_RB32(larray);
1544                }
1545            }
1546        }
1547
1548        //decode part B
1549        if (highest_byte) {
1550            for (i = 0; i < frame_length; ++i) {
1551                if (ctx->raw_samples[c][i] != 0) {
1552                    //The following logic is taken from Tabel 14.45 and 14.46 from the ISO spec
1553                    if (av_cmp_sf_ieee754(acf[c], FLOAT_1)) {
1554                        nbits[i] = 23 - av_log2(abs(ctx->raw_samples[c][i]));
1555                    } else {
1556                        nbits[i] = 23;
1557                    }
1558                    nbits[i] = FFMIN(nbits[i], highest_byte*8);
1559                }
1560            }
1561
1562            if (!get_bits1(gb)) { //uncompressed
1563                for (i = 0; i < frame_length; ++i) {
1564                    if (ctx->raw_samples[c][i] != 0) {
1565                        raw_mantissa[c][i] = get_bitsz(gb, nbits[i]);
1566                    }
1567                }
1568            } else { //compressed
1569                nchars = 0;
1570                for (i = 0; i < frame_length; ++i) {
1571                    if (ctx->raw_samples[c][i]) {
1572                        nchars += (int) nbits[i] / 8;
1573                        if (nbits[i] & 7) {
1574                            ++nchars;
1575                        }
1576                    }
1577                }
1578
1579                tmp_32 = ff_mlz_decompression(ctx->mlz, gb, nchars, larray);
1580                if(tmp_32 != nchars) {
1581                    av_log(ctx->avctx, AV_LOG_ERROR, "Error in MLZ decompression (%"PRId32", %d).\n", tmp_32, nchars);
1582                    return AVERROR_INVALIDDATA;
1583                }
1584
1585                j = 0;
1586                for (i = 0; i < frame_length; ++i) {
1587                    if (ctx->raw_samples[c][i]) {
1588                        if (nbits[i] & 7) {
1589                            nbits_aligned = 8 * ((unsigned int)(nbits[i] / 8) + 1);
1590                        } else {
1591                            nbits_aligned = nbits[i];
1592                        }
1593                        acc = 0;
1594                        for (k = 0; k < nbits_aligned/8; ++k) {
1595                            acc = (acc << 8) + larray[j++];
1596                        }
1597                        acc >>= (nbits_aligned - nbits[i]);
1598                        raw_mantissa[c][i] = acc;
1599                    }
1600                }
1601            }
1602        }
1603
1604        for (i = 0; i < frame_length; ++i) {
1605            SoftFloat_IEEE754 pcm_sf = av_int2sf_ieee754(ctx->raw_samples[c][i], 0);
1606            pcm_sf = av_div_sf_ieee754(pcm_sf, scale);
1607
1608            if (ctx->raw_samples[c][i] != 0) {
1609                if (!av_cmp_sf_ieee754(acf[c], FLOAT_1)) {
1610                    pcm_sf = multiply(acf[c], pcm_sf);
1611                }
1612
1613                sign = pcm_sf.sign;
1614                e = pcm_sf.exp;
1615                mantissa = (pcm_sf.mant | 0x800000) + raw_mantissa[c][i];
1616
1617                while(mantissa >= 0x1000000) {
1618                    e++;
1619                    mantissa >>= 1;
1620                }
1621
1622                if (mantissa) e += (shift_value[c] - 127);
1623                mantissa &= 0x007fffffUL;
1624
1625                tmp_32 = (sign << 31) | ((e + EXP_BIAS) << 23) | (mantissa);
1626                ctx->raw_samples[c][i] = tmp_32;
1627            } else {
1628                ctx->raw_samples[c][i] = raw_mantissa[c][i] & 0x007fffffUL;
1629            }
1630        }
1631        align_get_bits(gb);
1632    }
1633    return 0;
1634}
1635
1636
1637/** Read the frame data.
1638 */
1639static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1640{
1641    ALSSpecificConfig *sconf = &ctx->sconf;
1642    AVCodecContext *avctx    = ctx->avctx;
1643    GetBitContext *gb = &ctx->gb;
1644    unsigned int div_blocks[32];                ///< block sizes.
1645    int c;
1646    unsigned int js_blocks[2];
1647    int channels = avctx->ch_layout.nb_channels;
1648    uint32_t bs_info = 0;
1649    int ret;
1650
1651    // skip the size of the ra unit if present in the frame
1652    if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1653        skip_bits_long(gb, 32);
1654
1655    if (sconf->mc_coding && sconf->joint_stereo) {
1656        ctx->js_switch = get_bits1(gb);
1657        align_get_bits(gb);
1658    }
1659
1660    if (!sconf->mc_coding || ctx->js_switch) {
1661        int independent_bs = !sconf->joint_stereo;
1662        if (get_bits_left(gb) < 7*channels*ctx->num_blocks)
1663            return AVERROR_INVALIDDATA;
1664        for (c = 0; c < channels; c++) {
1665            js_blocks[0] = 0;
1666            js_blocks[1] = 0;
1667
1668            get_block_sizes(ctx, div_blocks, &bs_info);
1669
1670            // if joint_stereo and block_switching is set, independent decoding
1671            // is signaled via the first bit of bs_info
1672            if (sconf->joint_stereo && sconf->block_switching)
1673                if (bs_info >> 31)
1674                    independent_bs = 2;
1675
1676            // if this is the last channel, it has to be decoded independently
1677            if (c == channels - 1 || (c & 1))
1678                independent_bs = 1;
1679
1680            if (independent_bs) {
1681                ret = decode_blocks_ind(ctx, ra_frame, c,
1682                                        div_blocks, js_blocks);
1683                if (ret < 0)
1684                    return ret;
1685                independent_bs--;
1686            } else {
1687                ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);
1688                if (ret < 0)
1689                    return ret;
1690
1691                c++;
1692            }
1693
1694            // store carryover raw samples
1695            memmove(ctx->raw_samples[c] - sconf->max_order,
1696                    ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1697                    sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1698            ctx->highest_decoded_channel = c;
1699        }
1700    } else { // multi-channel coding
1701        ALSBlockData   bd = { 0 };
1702        int            b, ret;
1703        int            *reverted_channels = ctx->reverted_channels;
1704        unsigned int   offset             = 0;
1705
1706        for (c = 0; c < channels; c++)
1707            if (ctx->chan_data[c] < ctx->chan_data_buffer) {
1708                av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");
1709                return AVERROR_INVALIDDATA;
1710            }
1711
1712        memset(reverted_channels, 0, sizeof(*reverted_channels) * channels);
1713
1714        bd.ra_block         = ra_frame;
1715        bd.prev_raw_samples = ctx->prev_raw_samples;
1716
1717        get_block_sizes(ctx, div_blocks, &bs_info);
1718
1719        for (b = 0; b < ctx->num_blocks; b++) {
1720            bd.block_length = div_blocks[b];
1721            if (bd.block_length <= 0) {
1722                av_log(ctx->avctx, AV_LOG_WARNING,
1723                       "Invalid block length %u in channel data!\n",
1724                       bd.block_length);
1725                continue;
1726            }
1727
1728            for (c = 0; c < channels; c++) {
1729                bd.const_block = ctx->const_block + c;
1730                bd.shift_lsbs  = ctx->shift_lsbs + c;
1731                bd.opt_order   = ctx->opt_order + c;
1732                bd.store_prev_samples = ctx->store_prev_samples + c;
1733                bd.use_ltp     = ctx->use_ltp + c;
1734                bd.ltp_lag     = ctx->ltp_lag + c;
1735                bd.ltp_gain    = ctx->ltp_gain[c];
1736                bd.lpc_cof     = ctx->lpc_cof[c];
1737                bd.quant_cof   = ctx->quant_cof[c];
1738                bd.raw_samples = ctx->raw_samples[c] + offset;
1739                bd.raw_other   = NULL;
1740
1741                if ((ret = read_block(ctx, &bd)) < 0)
1742                    return ret;
1743                if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)
1744                    return ret;
1745            }
1746
1747            for (c = 0; c < channels; c++) {
1748                ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,
1749                                                 reverted_channels, offset, c);
1750                if (ret < 0)
1751                    return ret;
1752            }
1753            for (c = 0; c < channels; c++) {
1754                bd.const_block = ctx->const_block + c;
1755                bd.shift_lsbs  = ctx->shift_lsbs + c;
1756                bd.opt_order   = ctx->opt_order + c;
1757                bd.store_prev_samples = ctx->store_prev_samples + c;
1758                bd.use_ltp     = ctx->use_ltp + c;
1759                bd.ltp_lag     = ctx->ltp_lag + c;
1760                bd.ltp_gain    = ctx->ltp_gain[c];
1761                bd.lpc_cof     = ctx->lpc_cof[c];
1762                bd.quant_cof   = ctx->quant_cof[c];
1763                bd.raw_samples = ctx->raw_samples[c] + offset;
1764
1765                if ((ret = decode_block(ctx, &bd)) < 0)
1766                    return ret;
1767
1768                ctx->highest_decoded_channel = FFMAX(ctx->highest_decoded_channel, c);
1769            }
1770
1771            memset(reverted_channels, 0, channels * sizeof(*reverted_channels));
1772            offset      += div_blocks[b];
1773            bd.ra_block  = 0;
1774        }
1775
1776        // store carryover raw samples
1777        for (c = 0; c < channels; c++)
1778            memmove(ctx->raw_samples[c] - sconf->max_order,
1779                    ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1780                    sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1781    }
1782
1783    if (sconf->floating) {
1784        read_diff_float_data(ctx, ra_frame);
1785    }
1786
1787    if (get_bits_left(gb) < 0) {
1788        av_log(ctx->avctx, AV_LOG_ERROR, "Overread %d\n", -get_bits_left(gb));
1789        return AVERROR_INVALIDDATA;
1790    }
1791
1792    return 0;
1793}
1794
1795
1796/** Decode an ALS frame.
1797 */
1798static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
1799                        int *got_frame_ptr, AVPacket *avpkt)
1800{
1801    ALSDecContext *ctx       = avctx->priv_data;
1802    ALSSpecificConfig *sconf = &ctx->sconf;
1803    const uint8_t *buffer    = avpkt->data;
1804    int buffer_size          = avpkt->size;
1805    int invalid_frame, ret;
1806    int channels = avctx->ch_layout.nb_channels;
1807    unsigned int c, sample, ra_frame, bytes_read, shift;
1808
1809    if ((ret = init_get_bits8(&ctx->gb, buffer, buffer_size)) < 0)
1810        return ret;
1811
1812    // In the case that the distance between random access frames is set to zero
1813    // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1814    // For the first frame, if prediction is used, all samples used from the
1815    // previous frame are assumed to be zero.
1816    ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1817
1818    // the last frame to decode might have a different length
1819    if (sconf->samples != 0xFFFFFFFF)
1820        ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1821                                      sconf->frame_length);
1822    else
1823        ctx->cur_frame_length = sconf->frame_length;
1824
1825    ctx->highest_decoded_channel = -1;
1826    // decode the frame data
1827    if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)
1828        av_log(ctx->avctx, AV_LOG_WARNING,
1829               "Reading frame data failed. Skipping RA unit.\n");
1830
1831    if (ctx->highest_decoded_channel == -1) {
1832        av_log(ctx->avctx, AV_LOG_WARNING,
1833               "No channel data decoded.\n");
1834        return AVERROR_INVALIDDATA;
1835    }
1836
1837    ctx->frame_id++;
1838
1839    /* get output buffer */
1840    frame->nb_samples = ctx->cur_frame_length;
1841    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1842        return ret;
1843
1844    // transform decoded frame into output format
1845    #define INTERLEAVE_OUTPUT(bps)                                                   \
1846    {                                                                                \
1847        int##bps##_t *dest = (int##bps##_t*)frame->data[0];                          \
1848        int32_t *raw_samples = ctx->raw_samples[0];                                  \
1849        int raw_step = channels > 1 ? ctx->raw_samples[1] - raw_samples : 1;         \
1850        shift = bps - ctx->avctx->bits_per_raw_sample;                               \
1851        if (!ctx->cs_switch) {                                                       \
1852            for (sample = 0; sample < ctx->cur_frame_length; sample++)               \
1853                for (c = 0; c < channels; c++)                                       \
1854                    *dest++ = raw_samples[c*raw_step + sample] * (1U << shift);      \
1855        } else {                                                                     \
1856            for (sample = 0; sample < ctx->cur_frame_length; sample++)               \
1857                for (c = 0; c < channels; c++)                                       \
1858                    *dest++ = raw_samples[sconf->chan_pos[c]*raw_step + sample] * (1U << shift);\
1859        }                                                                            \
1860    }
1861
1862    if (ctx->avctx->bits_per_raw_sample <= 16) {
1863        INTERLEAVE_OUTPUT(16)
1864    } else {
1865        INTERLEAVE_OUTPUT(32)
1866    }
1867
1868    // update CRC
1869    if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1870        int swap = HAVE_BIGENDIAN != sconf->msb_first;
1871
1872        if (ctx->avctx->bits_per_raw_sample == 24) {
1873            int32_t *src = (int32_t *)frame->data[0];
1874
1875            for (sample = 0;
1876                 sample < ctx->cur_frame_length * channels;
1877                 sample++) {
1878                int32_t v;
1879
1880                if (swap)
1881                    v = av_bswap32(src[sample]);
1882                else
1883                    v = src[sample];
1884                if (!HAVE_BIGENDIAN)
1885                    v >>= 8;
1886
1887                ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
1888            }
1889        } else {
1890            uint8_t *crc_source;
1891
1892            if (swap) {
1893                if (ctx->avctx->bits_per_raw_sample <= 16) {
1894                    int16_t *src  = (int16_t*) frame->data[0];
1895                    int16_t *dest = (int16_t*) ctx->crc_buffer;
1896                    for (sample = 0;
1897                         sample < ctx->cur_frame_length * channels;
1898                         sample++)
1899                        *dest++ = av_bswap16(src[sample]);
1900                } else {
1901                    ctx->bdsp.bswap_buf((uint32_t *) ctx->crc_buffer,
1902                                        (uint32_t *) frame->data[0],
1903                                        ctx->cur_frame_length * channels);
1904                }
1905                crc_source = ctx->crc_buffer;
1906            } else {
1907                crc_source = frame->data[0];
1908            }
1909
1910            ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,
1911                              ctx->cur_frame_length * channels *
1912                              av_get_bytes_per_sample(avctx->sample_fmt));
1913        }
1914
1915
1916        // check CRC sums if this is the last frame
1917        if (ctx->cur_frame_length != sconf->frame_length &&
1918            ctx->crc_org != ctx->crc) {
1919            av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
1920            if (avctx->err_recognition & AV_EF_EXPLODE)
1921                return AVERROR_INVALIDDATA;
1922        }
1923    }
1924
1925    *got_frame_ptr = 1;
1926
1927    bytes_read = invalid_frame ? buffer_size :
1928                                 (get_bits_count(&ctx->gb) + 7) >> 3;
1929
1930    return bytes_read;
1931}
1932
1933
1934/** Uninitialize the ALS decoder.
1935 */
1936static av_cold int decode_end(AVCodecContext *avctx)
1937{
1938    ALSDecContext *ctx = avctx->priv_data;
1939    int i;
1940
1941    av_freep(&ctx->sconf.chan_pos);
1942
1943    ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);
1944
1945    av_freep(&ctx->const_block);
1946    av_freep(&ctx->shift_lsbs);
1947    av_freep(&ctx->opt_order);
1948    av_freep(&ctx->store_prev_samples);
1949    av_freep(&ctx->use_ltp);
1950    av_freep(&ctx->ltp_lag);
1951    av_freep(&ctx->ltp_gain);
1952    av_freep(&ctx->ltp_gain_buffer);
1953    av_freep(&ctx->quant_cof);
1954    av_freep(&ctx->lpc_cof);
1955    av_freep(&ctx->quant_cof_buffer);
1956    av_freep(&ctx->lpc_cof_buffer);
1957    av_freep(&ctx->lpc_cof_reversed_buffer);
1958    av_freep(&ctx->prev_raw_samples);
1959    av_freep(&ctx->raw_samples);
1960    av_freep(&ctx->raw_buffer);
1961    av_freep(&ctx->chan_data);
1962    av_freep(&ctx->chan_data_buffer);
1963    av_freep(&ctx->reverted_channels);
1964    av_freep(&ctx->crc_buffer);
1965    if (ctx->mlz) {
1966        av_freep(&ctx->mlz->dict);
1967        av_freep(&ctx->mlz);
1968    }
1969    av_freep(&ctx->acf);
1970    av_freep(&ctx->last_acf_mantissa);
1971    av_freep(&ctx->shift_value);
1972    av_freep(&ctx->last_shift_value);
1973    if (ctx->raw_mantissa) {
1974        for (i = 0; i < avctx->ch_layout.nb_channels; i++) {
1975            av_freep(&ctx->raw_mantissa[i]);
1976        }
1977        av_freep(&ctx->raw_mantissa);
1978    }
1979    av_freep(&ctx->larray);
1980    av_freep(&ctx->nbits);
1981
1982    return 0;
1983}
1984
1985
1986/** Initialize the ALS decoder.
1987 */
1988static av_cold int decode_init(AVCodecContext *avctx)
1989{
1990    unsigned int c;
1991    unsigned int channel_size;
1992    int num_buffers, ret;
1993    int channels;
1994    ALSDecContext *ctx = avctx->priv_data;
1995    ALSSpecificConfig *sconf = &ctx->sconf;
1996    ctx->avctx = avctx;
1997
1998    if (!avctx->extradata) {
1999        av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
2000        return AVERROR_INVALIDDATA;
2001    }
2002
2003    if ((ret = read_specific_config(ctx)) < 0) {
2004        av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
2005        return ret;
2006    }
2007    channels = avctx->ch_layout.nb_channels;
2008
2009    if ((ret = check_specific_config(ctx)) < 0) {
2010        return ret;
2011    }
2012
2013    if (sconf->bgmc) {
2014        ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);
2015        if (ret < 0)
2016            return ret;
2017    }
2018    if (sconf->floating) {
2019        avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;
2020        avctx->bits_per_raw_sample = 32;
2021    } else {
2022        avctx->sample_fmt          = sconf->resolution > 1
2023                                     ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
2024        avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
2025        if (avctx->bits_per_raw_sample > 32) {
2026            av_log(avctx, AV_LOG_ERROR, "Bits per raw sample %d larger than 32.\n",
2027                   avctx->bits_per_raw_sample);
2028            return AVERROR_INVALIDDATA;
2029        }
2030    }
2031
2032    // set maximum Rice parameter for progressive decoding based on resolution
2033    // This is not specified in 14496-3 but actually done by the reference
2034    // codec RM22 revision 2.
2035    ctx->s_max = sconf->resolution > 1 ? 31 : 15;
2036
2037    // set lag value for long-term prediction
2038    ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +
2039                              (avctx->sample_rate >= 192000);
2040
2041    // allocate quantized parcor coefficient buffer
2042    num_buffers = sconf->mc_coding ? channels : 1;
2043    if (num_buffers * (uint64_t)num_buffers > INT_MAX) // protect chan_data_buffer allocation
2044        return AVERROR_INVALIDDATA;
2045
2046    ctx->quant_cof        = av_malloc_array(num_buffers, sizeof(*ctx->quant_cof));
2047    ctx->lpc_cof          = av_malloc_array(num_buffers, sizeof(*ctx->lpc_cof));
2048    ctx->quant_cof_buffer = av_malloc_array(num_buffers * sconf->max_order,
2049                                            sizeof(*ctx->quant_cof_buffer));
2050    ctx->lpc_cof_buffer   = av_malloc_array(num_buffers * sconf->max_order,
2051                                            sizeof(*ctx->lpc_cof_buffer));
2052    ctx->lpc_cof_reversed_buffer = av_malloc_array(sconf->max_order,
2053                                                   sizeof(*ctx->lpc_cof_buffer));
2054
2055    if (!ctx->quant_cof              || !ctx->lpc_cof        ||
2056        !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||
2057        !ctx->lpc_cof_reversed_buffer) {
2058        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2059        return AVERROR(ENOMEM);
2060    }
2061
2062    // assign quantized parcor coefficient buffers
2063    for (c = 0; c < num_buffers; c++) {
2064        ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;
2065        ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;
2066    }
2067
2068    // allocate and assign lag and gain data buffer for ltp mode
2069    ctx->const_block     = av_malloc_array(num_buffers, sizeof(*ctx->const_block));
2070    ctx->shift_lsbs      = av_malloc_array(num_buffers, sizeof(*ctx->shift_lsbs));
2071    ctx->opt_order       = av_malloc_array(num_buffers, sizeof(*ctx->opt_order));
2072    ctx->store_prev_samples = av_malloc_array(num_buffers, sizeof(*ctx->store_prev_samples));
2073    ctx->use_ltp         = av_calloc(num_buffers, sizeof(*ctx->use_ltp));
2074    ctx->ltp_lag         = av_malloc_array(num_buffers, sizeof(*ctx->ltp_lag));
2075    ctx->ltp_gain        = av_malloc_array(num_buffers, sizeof(*ctx->ltp_gain));
2076    ctx->ltp_gain_buffer = av_malloc_array(num_buffers * 5, sizeof(*ctx->ltp_gain_buffer));
2077
2078    if (!ctx->const_block || !ctx->shift_lsbs ||
2079        !ctx->opt_order || !ctx->store_prev_samples ||
2080        !ctx->use_ltp  || !ctx->ltp_lag ||
2081        !ctx->ltp_gain || !ctx->ltp_gain_buffer) {
2082        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2083        return AVERROR(ENOMEM);
2084    }
2085
2086    for (c = 0; c < num_buffers; c++)
2087        ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;
2088
2089    // allocate and assign channel data buffer for mcc mode
2090    if (sconf->mc_coding) {
2091        ctx->chan_data_buffer  = av_calloc(num_buffers * num_buffers,
2092                                           sizeof(*ctx->chan_data_buffer));
2093        ctx->chan_data         = av_calloc(num_buffers, sizeof(*ctx->chan_data));
2094        ctx->reverted_channels = av_malloc_array(num_buffers,
2095                                                 sizeof(*ctx->reverted_channels));
2096
2097        if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {
2098            av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2099            return AVERROR(ENOMEM);
2100        }
2101
2102        for (c = 0; c < num_buffers; c++)
2103            ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;
2104    } else {
2105        ctx->chan_data         = NULL;
2106        ctx->chan_data_buffer  = NULL;
2107        ctx->reverted_channels = NULL;
2108    }
2109
2110    if (sconf->floating) {
2111        ctx->acf               = av_malloc_array(channels, sizeof(*ctx->acf));
2112        ctx->shift_value       = av_malloc_array(channels, sizeof(*ctx->shift_value));
2113        ctx->last_shift_value  = av_malloc_array(channels, sizeof(*ctx->last_shift_value));
2114        ctx->last_acf_mantissa = av_malloc_array(channels, sizeof(*ctx->last_acf_mantissa));
2115        ctx->raw_mantissa      = av_calloc(channels, sizeof(*ctx->raw_mantissa));
2116
2117        ctx->larray = av_malloc_array(ctx->cur_frame_length * 4, sizeof(*ctx->larray));
2118        ctx->nbits  = av_malloc_array(ctx->cur_frame_length, sizeof(*ctx->nbits));
2119        ctx->mlz    = av_mallocz(sizeof(*ctx->mlz));
2120
2121        if (!ctx->mlz || !ctx->acf || !ctx->shift_value || !ctx->last_shift_value
2122            || !ctx->last_acf_mantissa || !ctx->raw_mantissa) {
2123            av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2124            return AVERROR(ENOMEM);
2125        }
2126
2127        ret = ff_mlz_init_dict(avctx, ctx->mlz);
2128        if (ret < 0)
2129            return ret;
2130        ff_mlz_flush_dict(ctx->mlz);
2131
2132        for (c = 0; c < channels; ++c) {
2133            ctx->raw_mantissa[c] = av_calloc(ctx->cur_frame_length, sizeof(**ctx->raw_mantissa));
2134        }
2135    }
2136
2137    channel_size      = sconf->frame_length + sconf->max_order;
2138
2139    // allocate previous raw sample buffer
2140    ctx->prev_raw_samples = av_malloc_array(sconf->max_order, sizeof(*ctx->prev_raw_samples));
2141    ctx->raw_buffer       = av_calloc(channels * channel_size, sizeof(*ctx->raw_buffer));
2142    ctx->raw_samples      = av_malloc_array(channels, sizeof(*ctx->raw_samples));
2143    if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
2144        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2145        return AVERROR(ENOMEM);
2146    }
2147
2148    // assign raw samples buffers
2149    ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
2150    for (c = 1; c < channels; c++)
2151        ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
2152
2153    // allocate crc buffer
2154    if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&
2155        (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
2156        ctx->crc_buffer = av_malloc_array(ctx->cur_frame_length *
2157                                          channels *
2158                                          av_get_bytes_per_sample(avctx->sample_fmt),
2159                                          sizeof(*ctx->crc_buffer));
2160        if (!ctx->crc_buffer) {
2161            av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
2162            return AVERROR(ENOMEM);
2163        }
2164    }
2165
2166    ff_bswapdsp_init(&ctx->bdsp);
2167
2168    return 0;
2169}
2170
2171
2172/** Flush (reset) the frame ID after seeking.
2173 */
2174static av_cold void flush(AVCodecContext *avctx)
2175{
2176    ALSDecContext *ctx = avctx->priv_data;
2177
2178    ctx->frame_id = 0;
2179}
2180
2181
2182const FFCodec ff_als_decoder = {
2183    .p.name         = "als",
2184    .p.long_name    = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
2185    .p.type         = AVMEDIA_TYPE_AUDIO,
2186    .p.id           = AV_CODEC_ID_MP4ALS,
2187    .priv_data_size = sizeof(ALSDecContext),
2188    .init           = decode_init,
2189    .close          = decode_end,
2190    FF_CODEC_DECODE_CB(decode_frame),
2191    .flush          = flush,
2192    .p.capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
2193    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
2194};
2195