xref: /third_party/ffmpeg/libavcodec/atrac9dec.c (revision cabdff1a)
1/*
2 * ATRAC9 decoder
3 * Copyright (c) 2018 Rostislav Pehlivanov <atomnuker@gmail.com>
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#include "libavutil/channel_layout.h"
23#include "libavutil/thread.h"
24
25#include "codec_internal.h"
26#include "internal.h"
27#include "get_bits.h"
28#include "fft.h"
29#include "atrac9tab.h"
30#include "libavutil/lfg.h"
31#include "libavutil/float_dsp.h"
32#include "libavutil/mem_internal.h"
33
34#define ATRAC9_SF_VLC_BITS 8
35#define ATRAC9_COEFF_VLC_BITS 9
36
37typedef struct ATRAC9ChannelData {
38    int band_ext;
39    int q_unit_cnt;
40    int band_ext_data[4];
41    int32_t scalefactors[31];
42    int32_t scalefactors_prev[31];
43
44    int precision_coarse[30];
45    int precision_fine[30];
46    int precision_mask[30];
47
48    int codebookset[30];
49
50    int32_t q_coeffs_coarse[256];
51    int32_t q_coeffs_fine[256];
52
53    DECLARE_ALIGNED(32, float, coeffs  )[256];
54    DECLARE_ALIGNED(32, float, prev_win)[128];
55} ATRAC9ChannelData;
56
57typedef struct ATRAC9BlockData {
58    ATRAC9ChannelData channel[2];
59
60    /* Base */
61    int band_count;
62    int q_unit_cnt;
63    int q_unit_cnt_prev;
64
65    /* Stereo block only */
66    int stereo_q_unit;
67
68    /* Band extension only */
69    int has_band_ext;
70    int has_band_ext_data;
71    int band_ext_q_unit;
72
73    /* Gradient */
74    int grad_mode;
75    int grad_boundary;
76    int gradient[31];
77
78    /* Stereo */
79    int cpe_base_channel;
80    int is_signs[30];
81
82    int reuseable;
83
84} ATRAC9BlockData;
85
86typedef struct ATRAC9Context {
87    AVCodecContext *avctx;
88    AVFloatDSPContext *fdsp;
89    FFTContext imdct;
90    ATRAC9BlockData block[5];
91    AVLFG lfg;
92
93    /* Set on init */
94    int frame_log2;
95    int avg_frame_size;
96    int frame_count;
97    int samplerate_idx;
98    const ATRAC9BlockConfig *block_config;
99
100    /* Generated on init */
101    uint8_t alloc_curve[48][48];
102    DECLARE_ALIGNED(32, float, imdct_win)[256];
103
104    DECLARE_ALIGNED(32, float, temp)[256];
105} ATRAC9Context;
106
107static VLC sf_vlc[2][8];            /* Signed/unsigned, length */
108static VLC coeff_vlc[2][8][4];      /* Cookbook, precision, cookbook index */
109
110static inline int parse_gradient(ATRAC9Context *s, ATRAC9BlockData *b,
111                                 GetBitContext *gb)
112{
113    int grad_range[2];
114    int grad_value[2];
115    int values, sign, base;
116    uint8_t *curve;
117    float scale;
118
119    b->grad_mode = get_bits(gb, 2);
120    if (b->grad_mode) {
121        grad_range[0] = get_bits(gb, 5);
122        grad_range[1] = 31;
123        grad_value[0] = get_bits(gb, 5);
124        grad_value[1] = 31;
125    } else {
126        grad_range[0] = get_bits(gb, 6);
127        grad_range[1] = get_bits(gb, 6) + 1;
128        grad_value[0] = get_bits(gb, 5);
129        grad_value[1] = get_bits(gb, 5);
130    }
131    b->grad_boundary = get_bits(gb, 4);
132
133    if (grad_range[0] >= grad_range[1] || grad_range[1] > 31)
134        return AVERROR_INVALIDDATA;
135
136    if (b->grad_boundary > b->q_unit_cnt)
137        return AVERROR_INVALIDDATA;
138
139    values    = grad_value[1] - grad_value[0];
140    sign      = 1 - 2*(values < 0);
141    base      = grad_value[0] + sign;
142    scale     = (FFABS(values) - 1) / 31.0f;
143    curve     = s->alloc_curve[grad_range[1] - grad_range[0] - 1];
144
145    for (int i = 0; i <= b->q_unit_cnt; i++)
146        b->gradient[i] = grad_value[i >= grad_range[0]];
147
148    for (int i = grad_range[0]; i < grad_range[1]; i++)
149        b->gradient[i] = base + sign*((int)(scale*curve[i - grad_range[0]]));
150
151    return 0;
152}
153
154static inline void calc_precision(ATRAC9Context *s, ATRAC9BlockData *b,
155                                  ATRAC9ChannelData *c)
156{
157    memset(c->precision_mask, 0, sizeof(c->precision_mask));
158    for (int i = 1; i < b->q_unit_cnt; i++) {
159        const int delta = FFABS(c->scalefactors[i] - c->scalefactors[i - 1]) - 1;
160        if (delta > 0) {
161            const int neg = c->scalefactors[i - 1] > c->scalefactors[i];
162            c->precision_mask[i - neg] += FFMIN(delta, 5);
163        }
164    }
165
166    if (b->grad_mode) {
167        for (int i = 0; i < b->q_unit_cnt; i++) {
168            c->precision_coarse[i] = c->scalefactors[i];
169            c->precision_coarse[i] += c->precision_mask[i] - b->gradient[i];
170            if (c->precision_coarse[i] < 0)
171                continue;
172            switch (b->grad_mode) {
173            case 1:
174                c->precision_coarse[i] >>= 1;
175                break;
176            case 2:
177                c->precision_coarse[i] = (3 * c->precision_coarse[i]) >> 3;
178                break;
179            case 3:
180                c->precision_coarse[i] >>= 2;
181                break;
182            }
183        }
184    } else {
185        for (int i = 0; i < b->q_unit_cnt; i++)
186            c->precision_coarse[i] = c->scalefactors[i] - b->gradient[i];
187    }
188
189
190    for (int i = 0; i < b->q_unit_cnt; i++)
191        c->precision_coarse[i] = FFMAX(c->precision_coarse[i], 1);
192
193    for (int i = 0; i < b->grad_boundary; i++)
194        c->precision_coarse[i]++;
195
196    for (int i = 0; i < b->q_unit_cnt; i++) {
197        c->precision_fine[i] = 0;
198        if (c->precision_coarse[i] > 15) {
199            c->precision_fine[i] = FFMIN(c->precision_coarse[i], 30) - 15;
200            c->precision_coarse[i] = 15;
201        }
202    }
203}
204
205static inline int parse_band_ext(ATRAC9Context *s, ATRAC9BlockData *b,
206                                 GetBitContext *gb, int stereo)
207{
208    int ext_band = 0;
209
210    if (b->has_band_ext) {
211        if (b->q_unit_cnt < 13 || b->q_unit_cnt > 20)
212            return AVERROR_INVALIDDATA;
213        ext_band = at9_tab_band_ext_group[b->q_unit_cnt - 13][2];
214        if (stereo) {
215            b->channel[1].band_ext = get_bits(gb, 2);
216            b->channel[1].band_ext = ext_band > 2 ? b->channel[1].band_ext : 4;
217        } else {
218            skip_bits1(gb);
219        }
220    }
221
222    b->has_band_ext_data = get_bits1(gb);
223    if (!b->has_band_ext_data)
224        return 0;
225
226    if (!b->has_band_ext) {
227        skip_bits(gb, 2);
228        skip_bits_long(gb, get_bits(gb, 5));
229        return 0;
230    }
231
232    b->channel[0].band_ext = get_bits(gb, 2);
233    b->channel[0].band_ext = ext_band > 2 ? b->channel[0].band_ext : 4;
234
235    if (!get_bits(gb, 5)) {
236        for (int i = 0; i <= stereo; i++) {
237            ATRAC9ChannelData *c = &b->channel[i];
238            const int count = at9_tab_band_ext_cnt[c->band_ext][ext_band];
239            for (int j = 0; j < count; j++) {
240                int len = at9_tab_band_ext_lengths[c->band_ext][ext_band][j];
241                c->band_ext_data[j] = av_clip_uintp2_c(c->band_ext_data[j], len);
242            }
243        }
244
245        return 0;
246    }
247
248    for (int i = 0; i <= stereo; i++) {
249        ATRAC9ChannelData *c = &b->channel[i];
250        const int count = at9_tab_band_ext_cnt[c->band_ext][ext_band];
251        for (int j = 0; j < count; j++) {
252            int len = at9_tab_band_ext_lengths[c->band_ext][ext_band][j];
253            c->band_ext_data[j] = get_bits(gb, len);
254        }
255    }
256
257    return 0;
258}
259
260static inline int read_scalefactors(ATRAC9Context *s, ATRAC9BlockData *b,
261                                    ATRAC9ChannelData *c, GetBitContext *gb,
262                                    int channel_idx, int first_in_pkt)
263{
264    static const uint8_t mode_map[2][4] = { { 0, 1, 2, 3 }, { 0, 2, 3, 4 } };
265    const int mode = mode_map[channel_idx][get_bits(gb, 2)];
266
267    memset(c->scalefactors, 0, sizeof(c->scalefactors));
268
269    if (first_in_pkt && (mode == 4 || ((mode == 3) && !channel_idx))) {
270        av_log(s->avctx, AV_LOG_ERROR, "Invalid scalefactor coding mode!\n");
271        return AVERROR_INVALIDDATA;
272    }
273
274    switch (mode) {
275    case 0: { /* VLC delta offset */
276        const uint8_t *sf_weights = at9_tab_sf_weights[get_bits(gb, 3)];
277        const int base = get_bits(gb, 5);
278        const int len = get_bits(gb, 2) + 3;
279        const VLC *tab = &sf_vlc[0][len];
280
281        c->scalefactors[0] = get_bits(gb, len);
282
283        for (int i = 1; i < b->band_ext_q_unit; i++) {
284            int val = c->scalefactors[i - 1] + get_vlc2(gb, tab->table,
285                                                        ATRAC9_SF_VLC_BITS, 1);
286            c->scalefactors[i] = val & ((1 << len) - 1);
287        }
288
289        for (int i = 0; i < b->band_ext_q_unit; i++)
290            c->scalefactors[i] += base - sf_weights[i];
291
292        break;
293    }
294    case 1: { /* CLC offset */
295        const int len = get_bits(gb, 2) + 2;
296        const int base = len < 5 ? get_bits(gb, 5) : 0;
297        for (int i = 0; i < b->band_ext_q_unit; i++)
298            c->scalefactors[i] = base + get_bits(gb, len);
299        break;
300    }
301    case 2:
302    case 4: { /* VLC dist to baseline */
303        const int *baseline = mode == 4 ? c->scalefactors_prev :
304                              channel_idx ? b->channel[0].scalefactors :
305                              c->scalefactors_prev;
306        const int baseline_len = mode == 4 ? b->q_unit_cnt_prev :
307                                 channel_idx ? b->band_ext_q_unit :
308                                 b->q_unit_cnt_prev;
309
310        const int len = get_bits(gb, 2) + 2;
311        const int unit_cnt = FFMIN(b->band_ext_q_unit, baseline_len);
312        const VLC *tab = &sf_vlc[1][len];
313
314        for (int i = 0; i < unit_cnt; i++) {
315            int dist = get_vlc2(gb, tab->table, ATRAC9_SF_VLC_BITS, 1);
316            c->scalefactors[i] = baseline[i] + dist;
317        }
318
319        for (int i = unit_cnt; i < b->band_ext_q_unit; i++)
320            c->scalefactors[i] = get_bits(gb, 5);
321
322        break;
323    }
324    case 3: { /* VLC offset with baseline */
325        const int *baseline = channel_idx ? b->channel[0].scalefactors :
326                              c->scalefactors_prev;
327        const int baseline_len = channel_idx ? b->band_ext_q_unit :
328                                 b->q_unit_cnt_prev;
329
330        const int base = get_bits(gb, 5) - (1 << (5 - 1));
331        const int len = get_bits(gb, 2) + 1;
332        const int unit_cnt = FFMIN(b->band_ext_q_unit, baseline_len);
333        const VLC *tab = &sf_vlc[0][len];
334
335        c->scalefactors[0] = get_bits(gb, len);
336
337        for (int i = 1; i < unit_cnt; i++) {
338            int val = c->scalefactors[i - 1] + get_vlc2(gb, tab->table,
339                                                        ATRAC9_SF_VLC_BITS, 1);
340            c->scalefactors[i] = val & ((1 << len) - 1);
341        }
342
343        for (int i = 0; i < unit_cnt; i++)
344            c->scalefactors[i] += base + baseline[i];
345
346        for (int i = unit_cnt; i < b->band_ext_q_unit; i++)
347            c->scalefactors[i] = get_bits(gb, 5);
348        break;
349    }
350    }
351
352    for (int i = 0; i < b->band_ext_q_unit; i++)
353        if (c->scalefactors[i] < 0 || c->scalefactors[i] > 31)
354            return AVERROR_INVALIDDATA;
355
356    memcpy(c->scalefactors_prev, c->scalefactors, sizeof(c->scalefactors));
357
358    return 0;
359}
360
361static inline void calc_codebook_idx(ATRAC9Context *s, ATRAC9BlockData *b,
362                                     ATRAC9ChannelData *c)
363{
364    int avg = 0;
365    const int last_sf = c->scalefactors[c->q_unit_cnt];
366
367    memset(c->codebookset, 0, sizeof(c->codebookset));
368
369    if (c->q_unit_cnt <= 1)
370        return;
371    if (s->samplerate_idx > 7)
372        return;
373
374    c->scalefactors[c->q_unit_cnt] = c->scalefactors[c->q_unit_cnt - 1];
375
376    if (c->q_unit_cnt > 12) {
377        for (int i = 0; i < 12; i++)
378            avg += c->scalefactors[i];
379        avg = (avg + 6) / 12;
380    }
381
382    for (int i = 8; i < c->q_unit_cnt; i++) {
383        const int prev = c->scalefactors[i - 1];
384        const int cur  = c->scalefactors[i    ];
385        const int next = c->scalefactors[i + 1];
386        const int min  = FFMIN(prev, next);
387        if ((cur - min >= 3 || 2*cur - prev - next >= 3))
388            c->codebookset[i] = 1;
389    }
390
391
392    for (int i = 12; i < c->q_unit_cnt; i++) {
393        const int cur = c->scalefactors[i];
394        const int cnd = at9_q_unit_to_coeff_cnt[i] == 16;
395        const int min = FFMIN(c->scalefactors[i + 1], c->scalefactors[i - 1]);
396        if (c->codebookset[i])
397            continue;
398
399        c->codebookset[i] = (((cur - min) >= 2) && (cur >= (avg - cnd)));
400    }
401
402    c->scalefactors[c->q_unit_cnt] = last_sf;
403}
404
405static inline void read_coeffs_coarse(ATRAC9Context *s, ATRAC9BlockData *b,
406                                      ATRAC9ChannelData *c, GetBitContext *gb)
407{
408    const int max_prec = s->samplerate_idx > 7 ? 1 : 7;
409
410    memset(c->q_coeffs_coarse, 0, sizeof(c->q_coeffs_coarse));
411
412    for (int i = 0; i < c->q_unit_cnt; i++) {
413        int *coeffs = &c->q_coeffs_coarse[at9_q_unit_to_coeff_idx[i]];
414        const int bands = at9_q_unit_to_coeff_cnt[i];
415        const int prec = c->precision_coarse[i] + 1;
416
417        if (prec <= max_prec) {
418            const int cb = c->codebookset[i];
419            const int cbi = at9_q_unit_to_codebookidx[i];
420            const VLC *tab = &coeff_vlc[cb][prec][cbi];
421            const HuffmanCodebook *huff = &at9_huffman_coeffs[cb][prec][cbi];
422            const int groups = bands >> huff->value_cnt_pow;
423
424            for (int j = 0; j < groups; j++) {
425                uint16_t val = get_vlc2(gb, tab->table, ATRAC9_COEFF_VLC_BITS, 2);
426
427                for (int k = 0; k < huff->value_cnt; k++) {
428                    coeffs[k] = sign_extend(val, huff->value_bits);
429                    val >>= huff->value_bits;
430                }
431
432                coeffs += huff->value_cnt;
433            }
434        } else {
435            for (int j = 0; j < bands; j++)
436                coeffs[j] = sign_extend(get_bits(gb, prec), prec);
437        }
438    }
439}
440
441static inline void read_coeffs_fine(ATRAC9Context *s, ATRAC9BlockData *b,
442                                    ATRAC9ChannelData *c, GetBitContext *gb)
443{
444    memset(c->q_coeffs_fine, 0, sizeof(c->q_coeffs_fine));
445
446    for (int i = 0; i < c->q_unit_cnt; i++) {
447        const int start = at9_q_unit_to_coeff_idx[i + 0];
448        const int end   = at9_q_unit_to_coeff_idx[i + 1];
449        const int len   = c->precision_fine[i] + 1;
450
451        if (c->precision_fine[i] <= 0)
452            continue;
453
454        for (int j = start; j < end; j++)
455            c->q_coeffs_fine[j] = sign_extend(get_bits(gb, len), len);
456    }
457}
458
459static inline void dequantize(ATRAC9Context *s, ATRAC9BlockData *b,
460                              ATRAC9ChannelData *c)
461{
462    memset(c->coeffs, 0, sizeof(c->coeffs));
463
464    for (int i = 0; i < c->q_unit_cnt; i++) {
465        const int start = at9_q_unit_to_coeff_idx[i + 0];
466        const int end   = at9_q_unit_to_coeff_idx[i + 1];
467
468        const float coarse_c = at9_quant_step_coarse[c->precision_coarse[i]];
469        const float fine_c   = at9_quant_step_fine[c->precision_fine[i]];
470
471        for (int j = start; j < end; j++) {
472            const float vc = c->q_coeffs_coarse[j] * coarse_c;
473            const float vf = c->q_coeffs_fine[j]   * fine_c;
474            c->coeffs[j] = vc + vf;
475        }
476    }
477}
478
479static inline void apply_intensity_stereo(ATRAC9Context *s, ATRAC9BlockData *b,
480                                          const int stereo)
481{
482    float *src = b->channel[ b->cpe_base_channel].coeffs;
483    float *dst = b->channel[!b->cpe_base_channel].coeffs;
484
485    if (!stereo)
486        return;
487
488    if (b->q_unit_cnt <= b->stereo_q_unit)
489        return;
490
491    for (int i = b->stereo_q_unit; i < b->q_unit_cnt; i++) {
492        const int sign  = b->is_signs[i];
493        const int start = at9_q_unit_to_coeff_idx[i + 0];
494        const int end   = at9_q_unit_to_coeff_idx[i + 1];
495        for (int j = start; j < end; j++)
496            dst[j] = sign*src[j];
497    }
498}
499
500static inline void apply_scalefactors(ATRAC9Context *s, ATRAC9BlockData *b,
501                                      const int stereo)
502{
503    for (int i = 0; i <= stereo; i++) {
504        float *coeffs = b->channel[i].coeffs;
505        for (int j = 0; j < b->q_unit_cnt; j++) {
506            const int start = at9_q_unit_to_coeff_idx[j + 0];
507            const int end   = at9_q_unit_to_coeff_idx[j + 1];
508            const int scalefactor = b->channel[i].scalefactors[j];
509            const float scale = at9_scalefactor_c[scalefactor];
510            for (int k = start; k < end; k++)
511                coeffs[k] *= scale;
512        }
513    }
514}
515
516static inline void fill_with_noise(ATRAC9Context *s, ATRAC9ChannelData *c,
517                                   int start, int count)
518{
519    float maxval = 0.0f;
520    for (int i = 0; i < count; i += 2) {
521        double tmp[2];
522        av_bmg_get(&s->lfg, tmp);
523        c->coeffs[start + i + 0] = tmp[0];
524        c->coeffs[start + i + 1] = tmp[1];
525        maxval = FFMAX(FFMAX(FFABS(tmp[0]), FFABS(tmp[1])), maxval);
526    }
527    /* Normalize */
528    for (int i = 0; i < count; i++)
529        c->coeffs[start + i] /= maxval;
530}
531
532static inline void scale_band_ext_coeffs(ATRAC9ChannelData *c, float sf[6],
533                                         const int s_unit, const int e_unit)
534{
535    for (int i = s_unit; i < e_unit; i++) {
536        const int start = at9_q_unit_to_coeff_idx[i + 0];
537        const int end   = at9_q_unit_to_coeff_idx[i + 1];
538        for (int j = start; j < end; j++)
539            c->coeffs[j] *= sf[i - s_unit];
540    }
541}
542
543static inline void apply_band_extension(ATRAC9Context *s, ATRAC9BlockData *b,
544                                       const int stereo)
545{
546    const int g_units[4] = { /* A, B, C, total units */
547        b->q_unit_cnt,
548        at9_tab_band_ext_group[b->q_unit_cnt - 13][0],
549        at9_tab_band_ext_group[b->q_unit_cnt - 13][1],
550        FFMAX(g_units[2], 22),
551    };
552
553    const int g_bins[4] = { /* A, B, C, total bins */
554        at9_q_unit_to_coeff_idx[g_units[0]],
555        at9_q_unit_to_coeff_idx[g_units[1]],
556        at9_q_unit_to_coeff_idx[g_units[2]],
557        at9_q_unit_to_coeff_idx[g_units[3]],
558    };
559
560    for (int ch = 0; ch <= stereo; ch++) {
561        ATRAC9ChannelData *c = &b->channel[ch];
562
563        /* Mirror the spectrum */
564        for (int i = 0; i < 3; i++)
565            for (int j = 0; j < (g_bins[i + 1] - g_bins[i + 0]); j++)
566                c->coeffs[g_bins[i] + j] = c->coeffs[g_bins[i] - j - 1];
567
568        switch (c->band_ext) {
569        case 0: {
570            float sf[6] = { 0.0f };
571            const int l = g_units[3] - g_units[0] - 1;
572            const int n_start = at9_q_unit_to_coeff_idx[g_units[3] - 1];
573            const int n_cnt   = at9_q_unit_to_coeff_cnt[g_units[3] - 1];
574            switch (at9_tab_band_ext_group[b->q_unit_cnt - 13][2]) {
575            case 3:
576                sf[0] = at9_band_ext_scales_m0[0][0][c->band_ext_data[0]];
577                sf[1] = at9_band_ext_scales_m0[0][1][c->band_ext_data[0]];
578                sf[2] = at9_band_ext_scales_m0[0][2][c->band_ext_data[1]];
579                sf[3] = at9_band_ext_scales_m0[0][3][c->band_ext_data[2]];
580                sf[4] = at9_band_ext_scales_m0[0][4][c->band_ext_data[3]];
581                break;
582            case 4:
583                sf[0] = at9_band_ext_scales_m0[1][0][c->band_ext_data[0]];
584                sf[1] = at9_band_ext_scales_m0[1][1][c->band_ext_data[0]];
585                sf[2] = at9_band_ext_scales_m0[1][2][c->band_ext_data[1]];
586                sf[3] = at9_band_ext_scales_m0[1][3][c->band_ext_data[2]];
587                sf[4] = at9_band_ext_scales_m0[1][4][c->band_ext_data[3]];
588                break;
589            case 5:
590                sf[0] = at9_band_ext_scales_m0[2][0][c->band_ext_data[0]];
591                sf[1] = at9_band_ext_scales_m0[2][1][c->band_ext_data[1]];
592                sf[2] = at9_band_ext_scales_m0[2][2][c->band_ext_data[1]];
593                break;
594            }
595
596            sf[l] = at9_scalefactor_c[c->scalefactors[g_units[0]]];
597
598            fill_with_noise(s, c, n_start, n_cnt);
599            scale_band_ext_coeffs(c, sf, g_units[0], g_units[3]);
600            break;
601        }
602        case 1: {
603            float sf[6];
604            for (int i = g_units[0]; i < g_units[3]; i++)
605                sf[i - g_units[0]] = at9_scalefactor_c[c->scalefactors[i]];
606
607            fill_with_noise(s, c, g_bins[0], g_bins[3] - g_bins[0]);
608            scale_band_ext_coeffs(c, sf, g_units[0], g_units[3]);
609            break;
610        }
611        case 2: {
612            const float g_sf[2] = {
613                at9_band_ext_scales_m2[c->band_ext_data[0]],
614                at9_band_ext_scales_m2[c->band_ext_data[1]],
615            };
616
617            for (int i = 0; i < 2; i++)
618                for (int j = g_bins[i + 0]; j < g_bins[i + 1]; j++)
619                    c->coeffs[j] *= g_sf[i];
620            break;
621        }
622        case 3: {
623            float scale = at9_band_ext_scales_m3[c->band_ext_data[0]][0];
624            float rate  = at9_band_ext_scales_m3[c->band_ext_data[1]][1];
625            rate = pow(2, rate);
626            for (int i = g_bins[0]; i < g_bins[3]; i++) {
627                scale *= rate;
628                c->coeffs[i] *= scale;
629            }
630            break;
631        }
632        case 4: {
633            const float m = at9_band_ext_scales_m4[c->band_ext_data[0]];
634            const float g_sf[3] = { 0.7079468f*m, 0.5011902f*m, 0.3548279f*m };
635
636            for (int i = 0; i < 3; i++)
637                for (int j = g_bins[i + 0]; j < g_bins[i + 1]; j++)
638                    c->coeffs[j] *= g_sf[i];
639            break;
640        }
641        }
642    }
643}
644
645static int atrac9_decode_block(ATRAC9Context *s, GetBitContext *gb,
646                               ATRAC9BlockData *b, AVFrame *frame,
647                               int frame_idx, int block_idx)
648{
649    const int first_in_pkt = !get_bits1(gb);
650    const int reuse_params =  get_bits1(gb);
651    const int stereo = s->block_config->type[block_idx] == ATRAC9_BLOCK_TYPE_CPE;
652
653    if (s->block_config->type[block_idx] == ATRAC9_BLOCK_TYPE_LFE) {
654        ATRAC9ChannelData *c = &b->channel[0];
655        const int precision = reuse_params ? 8 : 4;
656        c->q_unit_cnt = b->q_unit_cnt = 2;
657
658        memset(c->scalefactors, 0, sizeof(c->scalefactors));
659        memset(c->q_coeffs_fine, 0, sizeof(c->q_coeffs_fine));
660        memset(c->q_coeffs_coarse, 0, sizeof(c->q_coeffs_coarse));
661
662        for (int i = 0; i < b->q_unit_cnt; i++) {
663            c->scalefactors[i] = get_bits(gb, 5);
664            c->precision_coarse[i] = precision;
665            c->precision_fine[i] = 0;
666        }
667
668        for (int i = 0; i < c->q_unit_cnt; i++) {
669            const int start = at9_q_unit_to_coeff_idx[i + 0];
670            const int end   = at9_q_unit_to_coeff_idx[i + 1];
671            for (int j = start; j < end; j++)
672                c->q_coeffs_coarse[j] = get_bits(gb, c->precision_coarse[i] + 1);
673        }
674
675        dequantize        (s, b, c);
676        apply_scalefactors(s, b, 0);
677
678        goto imdct;
679    }
680
681    if (first_in_pkt && reuse_params) {
682        av_log(s->avctx, AV_LOG_ERROR, "Invalid block flags!\n");
683        return AVERROR_INVALIDDATA;
684    }
685
686    /* Band parameters */
687    if (!reuse_params) {
688        int stereo_band, ext_band;
689        const int min_band_count = s->samplerate_idx > 7 ? 1 : 3;
690        b->reuseable = 0;
691        b->band_count = get_bits(gb, 4) + min_band_count;
692        b->q_unit_cnt = at9_tab_band_q_unit_map[b->band_count];
693
694        b->band_ext_q_unit = b->stereo_q_unit = b->q_unit_cnt;
695
696        if (b->band_count > at9_tab_sri_max_bands[s->samplerate_idx]) {
697            av_log(s->avctx, AV_LOG_ERROR, "Invalid band count %i!\n",
698                   b->band_count);
699            return AVERROR_INVALIDDATA;
700        }
701
702        if (stereo) {
703            stereo_band = get_bits(gb, 4) + min_band_count;
704            if (stereo_band > b->band_count) {
705                av_log(s->avctx, AV_LOG_ERROR, "Invalid stereo band %i!\n",
706                       stereo_band);
707                return AVERROR_INVALIDDATA;
708            }
709            b->stereo_q_unit = at9_tab_band_q_unit_map[stereo_band];
710        }
711
712        b->has_band_ext = get_bits1(gb);
713        if (b->has_band_ext) {
714            ext_band = get_bits(gb, 4) + min_band_count;
715            if (ext_band < b->band_count) {
716                av_log(s->avctx, AV_LOG_ERROR, "Invalid extension band %i!\n",
717                       ext_band);
718                return AVERROR_INVALIDDATA;
719            }
720            b->band_ext_q_unit = at9_tab_band_q_unit_map[ext_band];
721        }
722        b->reuseable = 1;
723    }
724    if (!b->reuseable) {
725        av_log(s->avctx, AV_LOG_ERROR, "invalid block reused!\n");
726        return AVERROR_INVALIDDATA;
727    }
728
729    /* Calculate bit alloc gradient */
730    if (parse_gradient(s, b, gb))
731        return AVERROR_INVALIDDATA;
732
733    /* IS data */
734    b->cpe_base_channel = 0;
735    if (stereo) {
736        b->cpe_base_channel = get_bits1(gb);
737        if (get_bits1(gb)) {
738            for (int i = b->stereo_q_unit; i < b->q_unit_cnt; i++)
739                b->is_signs[i] = 1 - 2*get_bits1(gb);
740        } else {
741            for (int i = 0; i < FF_ARRAY_ELEMS(b->is_signs); i++)
742                b->is_signs[i] = 1;
743        }
744    }
745
746    /* Band extension */
747    if (parse_band_ext(s, b, gb, stereo))
748        return AVERROR_INVALIDDATA;
749
750    /* Scalefactors */
751    for (int i = 0; i <= stereo; i++) {
752        ATRAC9ChannelData *c = &b->channel[i];
753        c->q_unit_cnt = i == b->cpe_base_channel ? b->q_unit_cnt :
754                                                   b->stereo_q_unit;
755        if (read_scalefactors(s, b, c, gb, i, first_in_pkt))
756            return AVERROR_INVALIDDATA;
757
758        calc_precision    (s, b, c);
759        calc_codebook_idx (s, b, c);
760        read_coeffs_coarse(s, b, c, gb);
761        read_coeffs_fine  (s, b, c, gb);
762        dequantize        (s, b, c);
763    }
764
765    b->q_unit_cnt_prev = b->has_band_ext ? b->band_ext_q_unit : b->q_unit_cnt;
766
767    apply_intensity_stereo(s, b, stereo);
768    apply_scalefactors    (s, b, stereo);
769
770    if (b->has_band_ext && b->has_band_ext_data)
771        apply_band_extension  (s, b, stereo);
772
773imdct:
774    for (int i = 0; i <= stereo; i++) {
775        ATRAC9ChannelData *c = &b->channel[i];
776        const int dst_idx = s->block_config->plane_map[block_idx][i];
777        const int wsize = 1 << s->frame_log2;
778        const ptrdiff_t offset = wsize*frame_idx*sizeof(float);
779        float *dst = (float *)(frame->extended_data[dst_idx] + offset);
780
781        s->imdct.imdct_half(&s->imdct, s->temp, c->coeffs);
782        s->fdsp->vector_fmul_window(dst, c->prev_win, s->temp,
783                                    s->imdct_win, wsize >> 1);
784        memcpy(c->prev_win, s->temp + (wsize >> 1), sizeof(float)*wsize >> 1);
785    }
786
787    return 0;
788}
789
790static int atrac9_decode_frame(AVCodecContext *avctx, AVFrame *frame,
791                               int *got_frame_ptr, AVPacket *avpkt)
792{
793    int ret;
794    GetBitContext gb;
795    ATRAC9Context *s = avctx->priv_data;
796    const int frames = FFMIN(avpkt->size / s->avg_frame_size, s->frame_count);
797
798    frame->nb_samples = (1 << s->frame_log2) * frames;
799    ret = ff_get_buffer(avctx, frame, 0);
800    if (ret < 0)
801        return ret;
802
803    init_get_bits8(&gb, avpkt->data, avpkt->size);
804
805    for (int i = 0; i < frames; i++) {
806        for (int j = 0; j < s->block_config->count; j++) {
807            ret = atrac9_decode_block(s, &gb, &s->block[j], frame, i, j);
808            if (ret)
809                return ret;
810            align_get_bits(&gb);
811        }
812    }
813
814    *got_frame_ptr = 1;
815
816    return avctx->block_align;
817}
818
819static void atrac9_decode_flush(AVCodecContext *avctx)
820{
821    ATRAC9Context *s = avctx->priv_data;
822
823    for (int j = 0; j < s->block_config->count; j++) {
824        ATRAC9BlockData *b = &s->block[j];
825        const int stereo = s->block_config->type[j] == ATRAC9_BLOCK_TYPE_CPE;
826        for (int i = 0; i <= stereo; i++) {
827            ATRAC9ChannelData *c = &b->channel[i];
828            memset(c->prev_win, 0, sizeof(c->prev_win));
829        }
830    }
831}
832
833static av_cold int atrac9_decode_close(AVCodecContext *avctx)
834{
835    ATRAC9Context *s = avctx->priv_data;
836
837    ff_mdct_end(&s->imdct);
838    av_freep(&s->fdsp);
839
840    return 0;
841}
842
843static av_cold void atrac9_init_vlc(VLC *vlc, int nb_bits, int nb_codes,
844                                    const uint8_t (**tab)[2],
845                                    unsigned *buf_offset, int offset)
846{
847    static VLCElem vlc_buf[24812];
848
849    vlc->table           = &vlc_buf[*buf_offset];
850    vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *buf_offset;
851    ff_init_vlc_from_lengths(vlc, nb_bits, nb_codes,
852                             &(*tab)[0][1], 2, &(*tab)[0][0], 2, 1,
853                             offset, INIT_VLC_STATIC_OVERLONG, NULL);
854    *buf_offset += vlc->table_size;
855    *tab        += nb_codes;
856}
857
858static av_cold void atrac9_init_static(void)
859{
860    const uint8_t (*tab)[2];
861    unsigned offset = 0;
862
863    /* Unsigned scalefactor VLCs */
864    tab = at9_sfb_a_tab;
865    for (int i = 1; i < 7; i++) {
866        const HuffmanCodebook *hf = &at9_huffman_sf_unsigned[i];
867
868        atrac9_init_vlc(&sf_vlc[0][i], ATRAC9_SF_VLC_BITS,
869                        hf->size, &tab, &offset, 0);
870    }
871
872    /* Signed scalefactor VLCs */
873    tab = at9_sfb_b_tab;
874    for (int i = 2; i < 6; i++) {
875        const HuffmanCodebook *hf = &at9_huffman_sf_signed[i];
876
877        /* The symbols are signed integers in the range -16..15;
878         * the values in the source table are offset by 16 to make
879         * them fit into an uint8_t; the -16 reverses this shift. */
880        atrac9_init_vlc(&sf_vlc[1][i], ATRAC9_SF_VLC_BITS,
881                        hf->size, &tab, &offset, -16);
882    }
883
884    /* Coefficient VLCs */
885    tab = at9_coeffs_tab;
886    for (int i = 0; i < 2; i++) {
887        for (int j = 2; j < 8; j++) {
888            for (int k = i; k < 4; k++) {
889                const HuffmanCodebook *hf = &at9_huffman_coeffs[i][j][k];
890                atrac9_init_vlc(&coeff_vlc[i][j][k], ATRAC9_COEFF_VLC_BITS,
891                                hf->size, &tab, &offset, 0);
892            }
893        }
894    }
895}
896
897static av_cold int atrac9_decode_init(AVCodecContext *avctx)
898{
899    static AVOnce static_table_init = AV_ONCE_INIT;
900    GetBitContext gb;
901    ATRAC9Context *s = avctx->priv_data;
902    int version, block_config_idx, superframe_idx, alloc_c_len;
903
904    s->avctx = avctx;
905
906    av_lfg_init(&s->lfg, 0xFBADF00D);
907
908    if (avctx->block_align <= 0) {
909        av_log(avctx, AV_LOG_ERROR, "Invalid block align\n");
910        return AVERROR_INVALIDDATA;
911    }
912
913    if (avctx->extradata_size != 12) {
914        av_log(avctx, AV_LOG_ERROR, "Invalid extradata length!\n");
915        return AVERROR_INVALIDDATA;
916    }
917
918    version = AV_RL32(avctx->extradata);
919    if (version > 2) {
920        av_log(avctx, AV_LOG_ERROR, "Unsupported version (%i)!\n", version);
921        return AVERROR_INVALIDDATA;
922    }
923
924    init_get_bits8(&gb, avctx->extradata + 4, avctx->extradata_size);
925
926    if (get_bits(&gb, 8) != 0xFE) {
927        av_log(avctx, AV_LOG_ERROR, "Incorrect magic byte!\n");
928        return AVERROR_INVALIDDATA;
929    }
930
931    s->samplerate_idx = get_bits(&gb, 4);
932    avctx->sample_rate = at9_tab_samplerates[s->samplerate_idx];
933
934    block_config_idx = get_bits(&gb, 3);
935    if (block_config_idx > 5) {
936        av_log(avctx, AV_LOG_ERROR, "Incorrect block config!\n");
937        return AVERROR_INVALIDDATA;
938    }
939    s->block_config = &at9_block_layout[block_config_idx];
940
941    av_channel_layout_uninit(&avctx->ch_layout);
942    avctx->ch_layout      = s->block_config->channel_layout;
943    avctx->sample_fmt     = AV_SAMPLE_FMT_FLTP;
944
945    if (get_bits1(&gb)) {
946        av_log(avctx, AV_LOG_ERROR, "Incorrect verification bit!\n");
947        return AVERROR_INVALIDDATA;
948    }
949
950    /* Average frame size in bytes */
951    s->avg_frame_size = get_bits(&gb, 11) + 1;
952
953    superframe_idx = get_bits(&gb, 2);
954    if (superframe_idx & 1) {
955        av_log(avctx, AV_LOG_ERROR, "Invalid superframe index!\n");
956        return AVERROR_INVALIDDATA;
957    }
958
959    s->frame_count = 1 << superframe_idx;
960    s->frame_log2  = at9_tab_sri_frame_log2[s->samplerate_idx];
961
962    if (ff_mdct_init(&s->imdct, s->frame_log2 + 1, 1, 1.0f / 32768.0f))
963        return AVERROR(ENOMEM);
964
965    s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
966    if (!s->fdsp)
967        return AVERROR(ENOMEM);
968
969    /* iMDCT window */
970    for (int i = 0; i < (1 << s->frame_log2); i++) {
971        const int   len  = 1 << s->frame_log2;
972        const float sidx = (      i + 0.5f) / len;
973        const float eidx = (len - i - 0.5f) / len;
974        const float s_c  = sinf(sidx*M_PI - M_PI_2)*0.5f + 0.5f;
975        const float e_c  = sinf(eidx*M_PI - M_PI_2)*0.5f + 0.5f;
976        s->imdct_win[i]  = s_c / ((s_c * s_c) + (e_c * e_c));
977    }
978
979    /* Allocation curve */
980    alloc_c_len = FF_ARRAY_ELEMS(at9_tab_b_dist);
981    for (int i = 1; i <= alloc_c_len; i++)
982        for (int j = 0; j < i; j++)
983            s->alloc_curve[i - 1][j] = at9_tab_b_dist[(j * alloc_c_len) / i];
984
985    ff_thread_once(&static_table_init, atrac9_init_static);
986
987    return 0;
988}
989
990const FFCodec ff_atrac9_decoder = {
991    .p.name         = "atrac9",
992    .p.long_name    = NULL_IF_CONFIG_SMALL("ATRAC9 (Adaptive TRansform Acoustic Coding 9)"),
993    .p.type         = AVMEDIA_TYPE_AUDIO,
994    .p.id           = AV_CODEC_ID_ATRAC9,
995    .priv_data_size = sizeof(ATRAC9Context),
996    .init           = atrac9_decode_init,
997    .close          = atrac9_decode_close,
998    FF_CODEC_DECODE_CB(atrac9_decode_frame),
999    .flush          = atrac9_decode_flush,
1000    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
1001    .p.capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
1002};
1003