xref: /third_party/ffmpeg/libavcodec/ra144dec.c (revision cabdff1a)
1/*
2 * Real Audio 1.0 (14.4K)
3 *
4 * Copyright (c) 2008 Vitor Sessak
5 * Copyright (c) 2003 Nick Kurshev
6 *     Based on public domain decoder at http://www.honeypot.net/audio
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#include "libavutil/channel_layout.h"
26#include "avcodec.h"
27#include "codec_internal.h"
28#include "get_bits.h"
29#include "internal.h"
30#include "ra144.h"
31
32
33static av_cold int ra144_decode_init(AVCodecContext * avctx)
34{
35    RA144Context *ractx = avctx->priv_data;
36
37    ractx->avctx = avctx;
38    ff_audiodsp_init(&ractx->adsp);
39
40    ractx->lpc_coef[0] = ractx->lpc_tables[0];
41    ractx->lpc_coef[1] = ractx->lpc_tables[1];
42
43    av_channel_layout_uninit(&avctx->ch_layout);
44    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
45    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
46
47    return 0;
48}
49
50static void do_output_subblock(RA144Context *ractx, const int16_t  *lpc_coefs,
51                               int gval, GetBitContext *gb)
52{
53    int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
54    int gain    = get_bits(gb, 8);
55    int cb1_idx = get_bits(gb, 7);
56    int cb2_idx = get_bits(gb, 7);
57
58    ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval,
59                          gain);
60}
61
62/** Uncompress one block (20 bytes -> 160*2 bytes). */
63static int ra144_decode_frame(AVCodecContext * avctx, AVFrame *frame,
64                              int *got_frame_ptr, AVPacket *avpkt)
65{
66    const uint8_t *buf = avpkt->data;
67    int buf_size = avpkt->size;
68    static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
69    unsigned int refl_rms[NBLOCKS];           // RMS of the reflection coefficients
70    int16_t block_coefs[NBLOCKS][LPC_ORDER];  // LPC coefficients of each sub-block
71    unsigned int lpc_refl[LPC_ORDER];         // LPC reflection coefficients of the frame
72    int i, j;
73    int ret;
74    int16_t *samples;
75    unsigned int energy;
76
77    RA144Context *ractx = avctx->priv_data;
78    GetBitContext gb;
79
80    if (buf_size < FRAME_SIZE) {
81        av_log(avctx, AV_LOG_ERROR,
82               "Frame too small (%d bytes). Truncated file?\n", buf_size);
83        *got_frame_ptr = 0;
84        return AVERROR_INVALIDDATA;
85    }
86
87    /* get output buffer */
88    frame->nb_samples = NBLOCKS * BLOCKSIZE;
89    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
90        return ret;
91    samples = (int16_t *)frame->data[0];
92
93    init_get_bits8(&gb, buf, FRAME_SIZE);
94
95    for (i = 0; i < LPC_ORDER; i++)
96        lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])];
97
98    ff_eval_coefs(ractx->lpc_coef[0], lpc_refl);
99    ractx->lpc_refl_rms[0] = ff_rms(lpc_refl);
100
101    energy = ff_energy_tab[get_bits(&gb, 5)];
102
103    refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
104    refl_rms[1] = ff_interp(ractx, block_coefs[1], 2,
105                            energy <= ractx->old_energy,
106                            ff_t_sqrt(energy*ractx->old_energy) >> 12);
107    refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy);
108    refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy);
109
110    ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]);
111
112    for (i=0; i < NBLOCKS; i++) {
113        do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
114
115        for (j=0; j < BLOCKSIZE; j++)
116            *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] * (1 << 2));
117    }
118
119    ractx->old_energy = energy;
120    ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
121
122    FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
123
124    *got_frame_ptr = 1;
125
126    return FRAME_SIZE;
127}
128
129const FFCodec ff_ra_144_decoder = {
130    .p.name         = "real_144",
131    .p.long_name    = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
132    .p.type         = AVMEDIA_TYPE_AUDIO,
133    .p.id           = AV_CODEC_ID_RA_144,
134    .priv_data_size = sizeof(RA144Context),
135    .init           = ra144_decode_init,
136    FF_CODEC_DECODE_CB(ra144_decode_frame),
137    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
138    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
139};
140