3 * This code was developed as part of Google Summer of Code 2006.
4 * E-AC-3 support was added as part of Google Summer of Code 2007.
6 * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com)
7 * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
8 * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
10 * This file is part of FFmpeg.
12 * FFmpeg is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public
14 * License as published by the Free Software Foundation; either
15 * version 2.1 of the License, or (at your option) any later version.
17 * FFmpeg is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with FFmpeg; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
32 #include "libavutil/crc.h"
33 #include "libavutil/opt.h"
35 #include "aac_ac3_parser.h"
36 #include "ac3_parser.h"
38 #include "ac3dec_data.h"
42 * table for ungrouping 3 values in 7 bits.
43 * used for exponents and bap=2 mantissas
45 static uint8_t ungroup_3_in_7_bits_tab[128][3];
47 /** tables for ungrouping mantissas */
48 static int b1_mantissas[32][3];
49 static int b2_mantissas[128][3];
50 static int b3_mantissas[8];
51 static int b4_mantissas[128][2];
52 static int b5_mantissas[16];
55 * Quantization table: levels for symmetric. bits for asymmetric.
56 * reference: Table 7.18 Mapping of bap to Quantizer
58 static const uint8_t quantization_tab[16] = {
60 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
63 /** dynamic range table. converts codes to scale factors. */
64 static float dynamic_range_tab[256];
66 /** Adjustments in dB gain */
67 static const float gain_levels[9] = {
71 LEVEL_MINUS_1POINT5DB,
73 LEVEL_MINUS_4POINT5DB,
80 * Table for default stereo downmixing coefficients
81 * reference: Section 7.8.2 Downmixing Into Two Channels
83 static const uint8_t ac3_default_coeffs[8][5][2] = {
84 { { 2, 7 }, { 7, 2 }, },
86 { { 2, 7 }, { 7, 2 }, },
87 { { 2, 7 }, { 5, 5 }, { 7, 2 }, },
88 { { 2, 7 }, { 7, 2 }, { 6, 6 }, },
89 { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, },
90 { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
91 { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
95 * Symmetrical Dequantization
96 * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
100 symmetric_dequant(int code, int levels)
102 return ((code - (levels >> 1)) << 24) / levels;
106 * Initialize tables at runtime.
108 static av_cold void ac3_tables_init(void)
112 /* generate table for ungrouping 3 values in 7 bits
113 reference: Section 7.1.3 Exponent Decoding */
114 for (i = 0; i < 128; i++) {
115 ungroup_3_in_7_bits_tab[i][0] = i / 25;
116 ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
117 ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
120 /* generate grouped mantissa tables
121 reference: Section 7.3.5 Ungrouping of Mantissas */
122 for (i = 0; i < 32; i++) {
123 /* bap=1 mantissas */
124 b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
125 b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
126 b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
128 for (i = 0; i < 128; i++) {
129 /* bap=2 mantissas */
130 b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5);
131 b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5);
132 b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5);
134 /* bap=4 mantissas */
135 b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
136 b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
138 /* generate ungrouped mantissa tables
139 reference: Tables 7.21 and 7.23 */
140 for (i = 0; i < 7; i++) {
141 /* bap=3 mantissas */
142 b3_mantissas[i] = symmetric_dequant(i, 7);
144 for (i = 0; i < 15; i++) {
145 /* bap=5 mantissas */
146 b5_mantissas[i] = symmetric_dequant(i, 15);
149 /* generate dynamic range table
150 reference: Section 7.7.1 Dynamic Range Control */
151 for (i = 0; i < 256; i++) {
152 int v = (i >> 5) - ((i >> 7) << 3) - 5;
153 dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
158 * AVCodec initialization
160 static av_cold int ac3_decode_init(AVCodecContext *avctx)
162 AC3DecodeContext *s = avctx->priv_data;
167 ff_ac3_common_init();
169 ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
170 ff_mdct_init(&s->imdct_512, 9, 1, 1.0);
171 ff_kbd_window_init(s->window, 5.0, 256);
172 ff_dsputil_init(&s->dsp, avctx);
173 avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
174 ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT);
175 ff_fmt_convert_init(&s->fmt_conv, avctx);
176 av_lfg_init(&s->dith_state, 0);
178 avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
180 /* allow downmixing to stereo or mono */
181 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
182 avctx->request_channels < avctx->channels) {
183 avctx->channels = avctx->request_channels;
187 for (i = 0; i < AC3_MAX_CHANNELS; i++) {
188 s->xcfptr[i] = s->transform_coeffs[i];
189 s->dlyptr[i] = s->delay[i];
196 * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
197 * GetBitContext within AC3DecodeContext must point to
198 * the start of the synchronized AC-3 bitstream.
200 static int ac3_parse_header(AC3DecodeContext *s)
202 GetBitContext *gbc = &s->gbc;
205 /* read the rest of the bsi. read twice for dual mono mode. */
206 i = !s->channel_mode;
208 skip_bits(gbc, 5); // skip dialog normalization
210 skip_bits(gbc, 8); //skip compression
212 skip_bits(gbc, 8); //skip language code
214 skip_bits(gbc, 7); //skip audio production information
217 skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
219 /* skip the timecodes (or extra bitstream information for Alternate Syntax)
220 TODO: read & use the xbsi1 downmix levels */
222 skip_bits(gbc, 14); //skip timecode1 / xbsi1
224 skip_bits(gbc, 14); //skip timecode2 / xbsi2
226 /* skip additional bitstream info */
227 if (get_bits1(gbc)) {
228 i = get_bits(gbc, 6);
238 * Common function to parse AC-3 or E-AC-3 frame header
240 static int parse_frame_header(AC3DecodeContext *s)
245 err = avpriv_ac3_parse_header(&s->gbc, &hdr);
249 /* get decoding parameters from header info */
250 s->bit_alloc_params.sr_code = hdr.sr_code;
251 s->bitstream_mode = hdr.bitstream_mode;
252 s->channel_mode = hdr.channel_mode;
253 s->channel_layout = hdr.channel_layout;
254 s->lfe_on = hdr.lfe_on;
255 s->bit_alloc_params.sr_shift = hdr.sr_shift;
256 s->sample_rate = hdr.sample_rate;
257 s->bit_rate = hdr.bit_rate;
258 s->channels = hdr.channels;
259 s->fbw_channels = s->channels - s->lfe_on;
260 s->lfe_ch = s->fbw_channels + 1;
261 s->frame_size = hdr.frame_size;
262 s->center_mix_level = hdr.center_mix_level;
263 s->surround_mix_level = hdr.surround_mix_level;
264 s->num_blocks = hdr.num_blocks;
265 s->frame_type = hdr.frame_type;
266 s->substreamid = hdr.substreamid;
269 s->start_freq[s->lfe_ch] = 0;
270 s->end_freq[s->lfe_ch] = 7;
271 s->num_exp_groups[s->lfe_ch] = 2;
272 s->channel_in_cpl[s->lfe_ch] = 0;
275 if (hdr.bitstream_id <= 10) {
277 s->snr_offset_strategy = 2;
278 s->block_switch_syntax = 1;
279 s->dither_flag_syntax = 1;
280 s->bit_allocation_syntax = 1;
281 s->fast_gain_syntax = 0;
282 s->first_cpl_leak = 0;
285 memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
286 return ac3_parse_header(s);
287 } else if (CONFIG_EAC3_DECODER) {
289 return ff_eac3_parse_header(s);
291 av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n");
292 return AVERROR(ENOSYS);
297 * Set stereo downmixing coefficients based on frame header info.
298 * reference: Section 7.8.2 Downmixing Into Two Channels
300 static void set_downmix_coeffs(AC3DecodeContext *s)
303 float cmix = gain_levels[s-> center_mix_level];
304 float smix = gain_levels[s->surround_mix_level];
307 for (i = 0; i < s->fbw_channels; i++) {
308 s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
309 s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
311 if (s->channel_mode > 1 && s->channel_mode & 1) {
312 s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix;
314 if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
315 int nf = s->channel_mode - 2;
316 s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
318 if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
319 int nf = s->channel_mode - 4;
320 s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix;
325 for (i = 0; i < s->fbw_channels; i++) {
326 norm0 += s->downmix_coeffs[i][0];
327 norm1 += s->downmix_coeffs[i][1];
329 norm0 = 1.0f / norm0;
330 norm1 = 1.0f / norm1;
331 for (i = 0; i < s->fbw_channels; i++) {
332 s->downmix_coeffs[i][0] *= norm0;
333 s->downmix_coeffs[i][1] *= norm1;
336 if (s->output_mode == AC3_CHMODE_MONO) {
337 for (i = 0; i < s->fbw_channels; i++)
338 s->downmix_coeffs[i][0] = (s->downmix_coeffs[i][0] +
339 s->downmix_coeffs[i][1]) * LEVEL_MINUS_3DB;
344 * Decode the grouped exponents according to exponent strategy.
345 * reference: Section 7.1.3 Exponent Decoding
347 static int decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps,
348 uint8_t absexp, int8_t *dexps)
350 int i, j, grp, group_size;
355 group_size = exp_strategy + (exp_strategy == EXP_D45);
356 for (grp = 0, i = 0; grp < ngrps; grp++) {
357 expacc = get_bits(gbc, 7);
358 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
359 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
360 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
363 /* convert to absolute exps and expand groups */
365 for (i = 0, j = 0; i < ngrps * 3; i++) {
366 prevexp += dexp[i] - 2;
369 switch (group_size) {
370 case 4: dexps[j++] = prevexp;
371 dexps[j++] = prevexp;
372 case 2: dexps[j++] = prevexp;
373 case 1: dexps[j++] = prevexp;
380 * Generate transform coefficients for each coupled channel in the coupling
381 * range using the coupling coefficients and coupling coordinates.
382 * reference: Section 7.4.3 Coupling Coordinate Format
384 static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
388 bin = s->start_freq[CPL_CH];
389 for (band = 0; band < s->num_cpl_bands; band++) {
390 int band_start = bin;
391 int band_end = bin + s->cpl_band_sizes[band];
392 for (ch = 1; ch <= s->fbw_channels; ch++) {
393 if (s->channel_in_cpl[ch]) {
394 int cpl_coord = s->cpl_coords[ch][band] << 5;
395 for (bin = band_start; bin < band_end; bin++) {
396 s->fixed_coeffs[ch][bin] =
397 MULH(s->fixed_coeffs[CPL_CH][bin] << 4, cpl_coord);
399 if (ch == 2 && s->phase_flags[band]) {
400 for (bin = band_start; bin < band_end; bin++)
401 s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin];
410 * Grouped mantissas for 3-level 5-level and 11-level quantization
422 * Decode the transform coefficients for a particular channel
423 * reference: Section 7.3 Quantization and Decoding of Mantissas
425 static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
427 int start_freq = s->start_freq[ch_index];
428 int end_freq = s->end_freq[ch_index];
429 uint8_t *baps = s->bap[ch_index];
430 int8_t *exps = s->dexps[ch_index];
431 int32_t *coeffs = s->fixed_coeffs[ch_index];
432 int dither = (ch_index == CPL_CH) || s->dither_flag[ch_index];
433 GetBitContext *gbc = &s->gbc;
436 for (freq = start_freq; freq < end_freq; freq++) {
437 int bap = baps[freq];
441 /* random noise with approximate range of -0.707 to 0.707 */
443 mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008;
450 mantissa = m->b1_mant[m->b1];
452 int bits = get_bits(gbc, 5);
453 mantissa = b1_mantissas[bits][0];
454 m->b1_mant[1] = b1_mantissas[bits][1];
455 m->b1_mant[0] = b1_mantissas[bits][2];
462 mantissa = m->b2_mant[m->b2];
464 int bits = get_bits(gbc, 7);
465 mantissa = b2_mantissas[bits][0];
466 m->b2_mant[1] = b2_mantissas[bits][1];
467 m->b2_mant[0] = b2_mantissas[bits][2];
472 mantissa = b3_mantissas[get_bits(gbc, 3)];
477 mantissa = m->b4_mant;
479 int bits = get_bits(gbc, 7);
480 mantissa = b4_mantissas[bits][0];
481 m->b4_mant = b4_mantissas[bits][1];
486 mantissa = b5_mantissas[get_bits(gbc, 4)];
488 default: /* 6 to 15 */
489 /* Shift mantissa and sign-extend it. */
490 mantissa = get_sbits(gbc, quantization_tab[bap]);
491 mantissa <<= 24 - quantization_tab[bap];
494 coeffs[freq] = mantissa >> exps[freq];
499 * Remove random dithering from coupling range coefficients with zero-bit
500 * mantissas for coupled channels which do not use dithering.
501 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
503 static void remove_dithering(AC3DecodeContext *s) {
506 for (ch = 1; ch <= s->fbw_channels; ch++) {
507 if (!s->dither_flag[ch] && s->channel_in_cpl[ch]) {
508 for (i = s->start_freq[CPL_CH]; i < s->end_freq[CPL_CH]; i++) {
509 if (!s->bap[CPL_CH][i])
510 s->fixed_coeffs[ch][i] = 0;
516 static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
519 if (!s->channel_uses_aht[ch]) {
520 ac3_decode_transform_coeffs_ch(s, ch, m);
522 /* if AHT is used, mantissas for all blocks are encoded in the first
523 block of the frame. */
525 if (!blk && CONFIG_EAC3_DECODER)
526 ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
527 for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
528 s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
534 * Decode the transform coefficients.
536 static void decode_transform_coeffs(AC3DecodeContext *s, int blk)
542 m.b1 = m.b2 = m.b4 = 0;
544 for (ch = 1; ch <= s->channels; ch++) {
545 /* transform coefficients for full-bandwidth channel */
546 decode_transform_coeffs_ch(s, blk, ch, &m);
547 /* transform coefficients for coupling channel come right after the
548 coefficients for the first coupled channel*/
549 if (s->channel_in_cpl[ch]) {
551 decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
552 calc_transform_coeffs_cpl(s);
555 end = s->end_freq[CPL_CH];
557 end = s->end_freq[ch];
560 s->fixed_coeffs[ch][end] = 0;
564 /* zero the dithered coefficients for appropriate channels */
569 * Stereo rematrixing.
570 * reference: Section 7.5.4 Rematrixing : Decoding Technique
572 static void do_rematrixing(AC3DecodeContext *s)
577 end = FFMIN(s->end_freq[1], s->end_freq[2]);
579 for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
580 if (s->rematrixing_flags[bnd]) {
581 bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd + 1]);
582 for (i = ff_ac3_rematrix_band_tab[bnd]; i < bndend; i++) {
583 int tmp0 = s->fixed_coeffs[1][i];
584 s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i];
585 s->fixed_coeffs[2][i] = tmp0 - s->fixed_coeffs[2][i];
592 * Inverse MDCT Transform.
593 * Convert frequency domain coefficients to time-domain audio samples.
594 * reference: Section 7.9.4 Transformation Equations
596 static inline void do_imdct(AC3DecodeContext *s, int channels)
600 for (ch = 1; ch <= channels; ch++) {
601 if (s->block_switch[ch]) {
603 float *x = s->tmp_output + 128;
604 for (i = 0; i < 128; i++)
605 x[i] = s->transform_coeffs[ch][2 * i];
606 s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
607 s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
608 s->tmp_output, s->window, 128);
609 for (i = 0; i < 128; i++)
610 x[i] = s->transform_coeffs[ch][2 * i + 1];
611 s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1], x);
613 s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
614 s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
615 s->tmp_output, s->window, 128);
616 memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(float));
622 * Upmix delay samples from stereo to original channel layout.
624 static void ac3_upmix_delay(AC3DecodeContext *s)
626 int channel_data_size = sizeof(s->delay[0]);
627 switch (s->channel_mode) {
628 case AC3_CHMODE_DUALMONO:
629 case AC3_CHMODE_STEREO:
630 /* upmix mono to stereo */
631 memcpy(s->delay[1], s->delay[0], channel_data_size);
633 case AC3_CHMODE_2F2R:
634 memset(s->delay[3], 0, channel_data_size);
635 case AC3_CHMODE_2F1R:
636 memset(s->delay[2], 0, channel_data_size);
638 case AC3_CHMODE_3F2R:
639 memset(s->delay[4], 0, channel_data_size);
640 case AC3_CHMODE_3F1R:
641 memset(s->delay[3], 0, channel_data_size);
643 memcpy(s->delay[2], s->delay[1], channel_data_size);
644 memset(s->delay[1], 0, channel_data_size);
650 * Decode band structure for coupling, spectral extension, or enhanced coupling.
651 * The band structure defines how many subbands are in each band. For each
652 * subband in the range, 1 means it is combined with the previous band, and 0
653 * means that it starts a new band.
655 * @param[in] gbc bit reader context
656 * @param[in] blk block number
657 * @param[in] eac3 flag to indicate E-AC-3
658 * @param[in] ecpl flag to indicate enhanced coupling
659 * @param[in] start_subband subband number for start of range
660 * @param[in] end_subband subband number for end of range
661 * @param[in] default_band_struct default band structure table
662 * @param[out] num_bands number of bands (optionally NULL)
663 * @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
665 static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
666 int ecpl, int start_subband, int end_subband,
667 const uint8_t *default_band_struct,
668 int *num_bands, uint8_t *band_sizes)
670 int subbnd, bnd, n_subbands, n_bands=0;
672 uint8_t coded_band_struct[22];
673 const uint8_t *band_struct;
675 n_subbands = end_subband - start_subband;
677 /* decode band structure from bitstream or use default */
678 if (!eac3 || get_bits1(gbc)) {
679 for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
680 coded_band_struct[subbnd] = get_bits1(gbc);
682 band_struct = coded_band_struct;
684 band_struct = &default_band_struct[start_subband+1];
686 /* no change in band structure */
690 /* calculate number of bands and band sizes based on band structure.
691 note that the first 4 subbands in enhanced coupling span only 6 bins
693 if (num_bands || band_sizes ) {
694 n_bands = n_subbands;
695 bnd_sz[0] = ecpl ? 6 : 12;
696 for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) {
697 int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12;
698 if (band_struct[subbnd - 1]) {
700 bnd_sz[bnd] += subbnd_size;
702 bnd_sz[++bnd] = subbnd_size;
707 /* set optional output params */
709 *num_bands = n_bands;
711 memcpy(band_sizes, bnd_sz, n_bands);
715 * Decode a single audio block from the AC-3 bitstream.
717 static int decode_audio_block(AC3DecodeContext *s, int blk)
719 int fbw_channels = s->fbw_channels;
720 int channel_mode = s->channel_mode;
722 int different_transforms;
725 GetBitContext *gbc = &s->gbc;
726 uint8_t bit_alloc_stages[AC3_MAX_CHANNELS] = { 0 };
728 /* block switch flags */
729 different_transforms = 0;
730 if (s->block_switch_syntax) {
731 for (ch = 1; ch <= fbw_channels; ch++) {
732 s->block_switch[ch] = get_bits1(gbc);
733 if (ch > 1 && s->block_switch[ch] != s->block_switch[1])
734 different_transforms = 1;
738 /* dithering flags */
739 if (s->dither_flag_syntax) {
740 for (ch = 1; ch <= fbw_channels; ch++) {
741 s->dither_flag[ch] = get_bits1(gbc);
746 i = !s->channel_mode;
748 if (get_bits1(gbc)) {
749 s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)] - 1.0) *
751 } else if (blk == 0) {
752 s->dynamic_range[i] = 1.0f;
756 /* spectral extension strategy */
757 if (s->eac3 && (!blk || get_bits1(gbc))) {
758 s->spx_in_use = get_bits1(gbc);
760 int dst_start_freq, dst_end_freq, src_start_freq,
761 start_subband, end_subband;
763 /* determine which channels use spx */
764 if (s->channel_mode == AC3_CHMODE_MONO) {
765 s->channel_uses_spx[1] = 1;
767 for (ch = 1; ch <= fbw_channels; ch++)
768 s->channel_uses_spx[ch] = get_bits1(gbc);
771 /* get the frequency bins of the spx copy region and the spx start
773 dst_start_freq = get_bits(gbc, 2);
774 start_subband = get_bits(gbc, 3) + 2;
775 if (start_subband > 7)
776 start_subband += start_subband - 7;
777 end_subband = get_bits(gbc, 3) + 5;
779 end_subband += end_subband - 7;
780 dst_start_freq = dst_start_freq * 12 + 25;
781 src_start_freq = start_subband * 12 + 25;
782 dst_end_freq = end_subband * 12 + 25;
784 /* check validity of spx ranges */
785 if (start_subband >= end_subband) {
786 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
787 "range (%d >= %d)\n", start_subband, end_subband);
788 return AVERROR_INVALIDDATA;
790 if (dst_start_freq >= src_start_freq) {
791 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
792 "copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
793 return AVERROR_INVALIDDATA;
796 s->spx_dst_start_freq = dst_start_freq;
797 s->spx_src_start_freq = src_start_freq;
798 s->spx_dst_end_freq = dst_end_freq;
800 decode_band_structure(gbc, blk, s->eac3, 0,
801 start_subband, end_subband,
802 ff_eac3_default_spx_band_struct,
806 for (ch = 1; ch <= fbw_channels; ch++) {
807 s->channel_uses_spx[ch] = 0;
808 s->first_spx_coords[ch] = 1;
813 /* spectral extension coordinates */
815 for (ch = 1; ch <= fbw_channels; ch++) {
816 if (s->channel_uses_spx[ch]) {
817 if (s->first_spx_coords[ch] || get_bits1(gbc)) {
819 int bin, master_spx_coord;
821 s->first_spx_coords[ch] = 0;
822 spx_blend = get_bits(gbc, 5) * (1.0f/32);
823 master_spx_coord = get_bits(gbc, 2) * 3;
825 bin = s->spx_src_start_freq;
826 for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
828 int spx_coord_exp, spx_coord_mant;
829 float nratio, sblend, nblend, spx_coord;
831 /* calculate blending factors */
832 bandsize = s->spx_band_sizes[bnd];
833 nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
834 nratio = av_clipf(nratio, 0.0f, 1.0f);
835 nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
836 // to give unity variance
837 sblend = sqrtf(1.0f - nratio);
840 /* decode spx coordinates */
841 spx_coord_exp = get_bits(gbc, 4);
842 spx_coord_mant = get_bits(gbc, 2);
843 if (spx_coord_exp == 15) spx_coord_mant <<= 1;
844 else spx_coord_mant += 4;
845 spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
846 spx_coord = spx_coord_mant * (1.0f / (1 << 23));
848 /* multiply noise and signal blending factors by spx coordinate */
849 s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
850 s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
854 s->first_spx_coords[ch] = 1;
859 /* coupling strategy */
860 if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
861 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
863 s->cpl_in_use[blk] = get_bits1(gbc);
864 if (s->cpl_in_use[blk]) {
865 /* coupling in use */
866 int cpl_start_subband, cpl_end_subband;
868 if (channel_mode < AC3_CHMODE_STEREO) {
869 av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
870 return AVERROR_INVALIDDATA;
873 /* check for enhanced coupling */
874 if (s->eac3 && get_bits1(gbc)) {
875 /* TODO: parse enhanced coupling strategy info */
876 avpriv_request_sample(s->avctx, "Enhanced coupling");
877 return AVERROR_PATCHWELCOME;
880 /* determine which channels are coupled */
881 if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
882 s->channel_in_cpl[1] = 1;
883 s->channel_in_cpl[2] = 1;
885 for (ch = 1; ch <= fbw_channels; ch++)
886 s->channel_in_cpl[ch] = get_bits1(gbc);
889 /* phase flags in use */
890 if (channel_mode == AC3_CHMODE_STEREO)
891 s->phase_flags_in_use = get_bits1(gbc);
893 /* coupling frequency range */
894 cpl_start_subband = get_bits(gbc, 4);
895 cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 :
896 get_bits(gbc, 4) + 3;
897 if (cpl_start_subband >= cpl_end_subband) {
898 av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
899 cpl_start_subband, cpl_end_subband);
900 return AVERROR_INVALIDDATA;
902 s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37;
903 s->end_freq[CPL_CH] = cpl_end_subband * 12 + 37;
905 decode_band_structure(gbc, blk, s->eac3, 0, cpl_start_subband,
907 ff_eac3_default_cpl_band_struct,
908 &s->num_cpl_bands, s->cpl_band_sizes);
910 /* coupling not in use */
911 for (ch = 1; ch <= fbw_channels; ch++) {
912 s->channel_in_cpl[ch] = 0;
913 s->first_cpl_coords[ch] = 1;
915 s->first_cpl_leak = s->eac3;
916 s->phase_flags_in_use = 0;
918 } else if (!s->eac3) {
920 av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must "
921 "be present in block 0\n");
922 return AVERROR_INVALIDDATA;
924 s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
927 cpl_in_use = s->cpl_in_use[blk];
929 /* coupling coordinates */
931 int cpl_coords_exist = 0;
933 for (ch = 1; ch <= fbw_channels; ch++) {
934 if (s->channel_in_cpl[ch]) {
935 if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) {
936 int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
937 s->first_cpl_coords[ch] = 0;
938 cpl_coords_exist = 1;
939 master_cpl_coord = 3 * get_bits(gbc, 2);
940 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
941 cpl_coord_exp = get_bits(gbc, 4);
942 cpl_coord_mant = get_bits(gbc, 4);
943 if (cpl_coord_exp == 15)
944 s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
946 s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
947 s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
950 av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must "
951 "be present in block 0\n");
952 return AVERROR_INVALIDDATA;
955 /* channel not in coupling */
956 s->first_cpl_coords[ch] = 1;
960 if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
961 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
962 s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
967 /* stereo rematrixing strategy and band structure */
968 if (channel_mode == AC3_CHMODE_STEREO) {
969 if ((s->eac3 && !blk) || get_bits1(gbc)) {
970 s->num_rematrixing_bands = 4;
971 if (cpl_in_use && s->start_freq[CPL_CH] <= 61) {
972 s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
973 } else if (s->spx_in_use && s->spx_src_start_freq <= 61) {
974 s->num_rematrixing_bands--;
976 for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++)
977 s->rematrixing_flags[bnd] = get_bits1(gbc);
979 av_log(s->avctx, AV_LOG_WARNING, "Warning: "
980 "new rematrixing strategy not present in block 0\n");
981 s->num_rematrixing_bands = 0;
985 /* exponent strategies for each channel */
986 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
988 s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
989 if (s->exp_strategy[blk][ch] != EXP_REUSE)
990 bit_alloc_stages[ch] = 3;
993 /* channel bandwidth */
994 for (ch = 1; ch <= fbw_channels; ch++) {
995 s->start_freq[ch] = 0;
996 if (s->exp_strategy[blk][ch] != EXP_REUSE) {
998 int prev = s->end_freq[ch];
999 if (s->channel_in_cpl[ch])
1000 s->end_freq[ch] = s->start_freq[CPL_CH];
1001 else if (s->channel_uses_spx[ch])
1002 s->end_freq[ch] = s->spx_src_start_freq;
1004 int bandwidth_code = get_bits(gbc, 6);
1005 if (bandwidth_code > 60) {
1006 av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
1007 return AVERROR_INVALIDDATA;
1009 s->end_freq[ch] = bandwidth_code * 3 + 73;
1011 group_size = 3 << (s->exp_strategy[blk][ch] - 1);
1012 s->num_exp_groups[ch] = (s->end_freq[ch] + group_size-4) / group_size;
1013 if (blk > 0 && s->end_freq[ch] != prev)
1014 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
1017 if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
1018 s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
1019 (3 << (s->exp_strategy[blk][CPL_CH] - 1));
1022 /* decode exponents for each channel */
1023 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1024 if (s->exp_strategy[blk][ch] != EXP_REUSE) {
1025 s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
1026 if (decode_exponents(gbc, s->exp_strategy[blk][ch],
1027 s->num_exp_groups[ch], s->dexps[ch][0],
1028 &s->dexps[ch][s->start_freq[ch]+!!ch])) {
1029 av_log(s->avctx, AV_LOG_ERROR, "exponent out-of-range\n");
1030 return AVERROR_INVALIDDATA;
1032 if (ch != CPL_CH && ch != s->lfe_ch)
1033 skip_bits(gbc, 2); /* skip gainrng */
1037 /* bit allocation information */
1038 if (s->bit_allocation_syntax) {
1039 if (get_bits1(gbc)) {
1040 s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
1041 s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
1042 s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
1043 s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
1044 s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
1045 for (ch = !cpl_in_use; ch <= s->channels; ch++)
1046 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1048 av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must "
1049 "be present in block 0\n");
1050 return AVERROR_INVALIDDATA;
1054 /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
1055 if (!s->eac3 || !blk) {
1056 if (s->snr_offset_strategy && get_bits1(gbc)) {
1059 csnr = (get_bits(gbc, 6) - 15) << 4;
1060 for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
1062 if (ch == i || s->snr_offset_strategy == 2)
1063 snr = (csnr + get_bits(gbc, 4)) << 2;
1064 /* run at least last bit allocation stage if snr offset changes */
1065 if (blk && s->snr_offset[ch] != snr) {
1066 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
1068 s->snr_offset[ch] = snr;
1070 /* fast gain (normal AC-3 only) */
1072 int prev = s->fast_gain[ch];
1073 s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1074 /* run last 2 bit allocation stages if fast gain changes */
1075 if (blk && prev != s->fast_gain[ch])
1076 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1079 } else if (!s->eac3 && !blk) {
1080 av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
1081 return AVERROR_INVALIDDATA;
1085 /* fast gain (E-AC-3 only) */
1086 if (s->fast_gain_syntax && get_bits1(gbc)) {
1087 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1088 int prev = s->fast_gain[ch];
1089 s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1090 /* run last 2 bit allocation stages if fast gain changes */
1091 if (blk && prev != s->fast_gain[ch])
1092 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1094 } else if (s->eac3 && !blk) {
1095 for (ch = !cpl_in_use; ch <= s->channels; ch++)
1096 s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
1099 /* E-AC-3 to AC-3 converter SNR offset */
1100 if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
1101 skip_bits(gbc, 10); // skip converter snr offset
1104 /* coupling leak information */
1106 if (s->first_cpl_leak || get_bits1(gbc)) {
1107 int fl = get_bits(gbc, 3);
1108 int sl = get_bits(gbc, 3);
1109 /* run last 2 bit allocation stages for coupling channel if
1110 coupling leak changes */
1111 if (blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
1112 sl != s->bit_alloc_params.cpl_slow_leak)) {
1113 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
1115 s->bit_alloc_params.cpl_fast_leak = fl;
1116 s->bit_alloc_params.cpl_slow_leak = sl;
1117 } else if (!s->eac3 && !blk) {
1118 av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must "
1119 "be present in block 0\n");
1120 return AVERROR_INVALIDDATA;
1122 s->first_cpl_leak = 0;
1125 /* delta bit allocation information */
1126 if (s->dba_syntax && get_bits1(gbc)) {
1127 /* delta bit allocation exists (strategy) */
1128 for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
1129 s->dba_mode[ch] = get_bits(gbc, 2);
1130 if (s->dba_mode[ch] == DBA_RESERVED) {
1131 av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
1132 return AVERROR_INVALIDDATA;
1134 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1136 /* channel delta offset, len and bit allocation */
1137 for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
1138 if (s->dba_mode[ch] == DBA_NEW) {
1139 s->dba_nsegs[ch] = get_bits(gbc, 3) + 1;
1140 for (seg = 0; seg < s->dba_nsegs[ch]; seg++) {
1141 s->dba_offsets[ch][seg] = get_bits(gbc, 5);
1142 s->dba_lengths[ch][seg] = get_bits(gbc, 4);
1143 s->dba_values[ch][seg] = get_bits(gbc, 3);
1145 /* run last 2 bit allocation stages if new dba values */
1146 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1149 } else if (blk == 0) {
1150 for (ch = 0; ch <= s->channels; ch++) {
1151 s->dba_mode[ch] = DBA_NONE;
1155 /* Bit allocation */
1156 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1157 if (bit_alloc_stages[ch] > 2) {
1158 /* Exponent mapping into PSD and PSD integration */
1159 ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
1160 s->start_freq[ch], s->end_freq[ch],
1161 s->psd[ch], s->band_psd[ch]);
1163 if (bit_alloc_stages[ch] > 1) {
1164 /* Compute excitation function, Compute masking curve, and
1165 Apply delta bit allocation */
1166 if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
1167 s->start_freq[ch], s->end_freq[ch],
1168 s->fast_gain[ch], (ch == s->lfe_ch),
1169 s->dba_mode[ch], s->dba_nsegs[ch],
1170 s->dba_offsets[ch], s->dba_lengths[ch],
1171 s->dba_values[ch], s->mask[ch])) {
1172 av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n");
1173 return AVERROR_INVALIDDATA;
1176 if (bit_alloc_stages[ch] > 0) {
1177 /* Compute bit allocation */
1178 const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
1179 ff_eac3_hebap_tab : ff_ac3_bap_tab;
1180 s->ac3dsp.bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
1181 s->start_freq[ch], s->end_freq[ch],
1183 s->bit_alloc_params.floor,
1184 bap_tab, s->bap[ch]);
1188 /* unused dummy data */
1189 if (s->skip_syntax && get_bits1(gbc)) {
1190 int skipl = get_bits(gbc, 9);
1195 /* unpack the transform coefficients
1196 this also uncouples channels if coupling is in use. */
1197 decode_transform_coeffs(s, blk);
1199 /* TODO: generate enhanced coupling coordinates and uncouple */
1201 /* recover coefficients if rematrixing is in use */
1202 if (s->channel_mode == AC3_CHMODE_STEREO)
1205 /* apply scaling to coefficients (headroom, dynrng) */
1206 for (ch = 1; ch <= s->channels; ch++) {
1207 float gain = 1.0 / 4194304.0f;
1208 if (s->channel_mode == AC3_CHMODE_DUALMONO) {
1209 gain *= s->dynamic_range[2 - ch];
1211 gain *= s->dynamic_range[0];
1213 s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch],
1214 s->fixed_coeffs[ch], gain, 256);
1217 /* apply spectral extension to high frequency bins */
1218 if (s->spx_in_use && CONFIG_EAC3_DECODER) {
1219 ff_eac3_apply_spectral_extension(s);
1222 /* downmix and MDCT. order depends on whether block switching is used for
1223 any channel in this block. this is because coefficients for the long
1224 and short transforms cannot be mixed. */
1225 downmix_output = s->channels != s->out_channels &&
1226 !((s->output_mode & AC3_OUTPUT_LFEON) &&
1227 s->fbw_channels == s->out_channels);
1228 if (different_transforms) {
1229 /* the delay samples have already been downmixed, so we upmix the delay
1230 samples in order to reconstruct all channels before downmixing. */
1236 do_imdct(s, s->channels);
1238 if (downmix_output) {
1239 s->ac3dsp.downmix(s->outptr, s->downmix_coeffs,
1240 s->out_channels, s->fbw_channels, 256);
1243 if (downmix_output) {
1244 s->ac3dsp.downmix(s->xcfptr + 1, s->downmix_coeffs,
1245 s->out_channels, s->fbw_channels, 256);
1248 if (downmix_output && !s->downmixed) {
1250 s->ac3dsp.downmix(s->dlyptr, s->downmix_coeffs, s->out_channels,
1251 s->fbw_channels, 128);
1254 do_imdct(s, s->out_channels);
1261 * Decode a single AC-3 frame.
1263 static int ac3_decode_frame(AVCodecContext * avctx, void *data,
1264 int *got_frame_ptr, AVPacket *avpkt)
1266 AVFrame *frame = data;
1267 const uint8_t *buf = avpkt->data;
1268 int buf_size = avpkt->size;
1269 AC3DecodeContext *s = avctx->priv_data;
1270 int blk, ch, err, ret;
1271 const uint8_t *channel_map;
1272 const float *output[AC3_MAX_CHANNELS];
1274 /* copy input buffer to decoder context to avoid reading past the end
1275 of the buffer, which can be caused by a damaged input stream. */
1276 if (buf_size >= 2 && AV_RB16(buf) == 0x770B) {
1277 // seems to be byte-swapped AC-3
1278 int cnt = FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE) >> 1;
1279 s->dsp.bswap16_buf((uint16_t *)s->input_buffer, (const uint16_t *)buf, cnt);
1281 memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
1282 buf = s->input_buffer;
1283 /* initialize the GetBitContext with the start of valid AC-3 Frame */
1284 init_get_bits(&s->gbc, buf, buf_size * 8);
1286 /* parse the syncinfo */
1287 err = parse_frame_header(s);
1291 case AAC_AC3_PARSE_ERROR_SYNC:
1292 av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
1293 return AVERROR_INVALIDDATA;
1294 case AAC_AC3_PARSE_ERROR_BSID:
1295 av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
1297 case AAC_AC3_PARSE_ERROR_SAMPLE_RATE:
1298 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1300 case AAC_AC3_PARSE_ERROR_FRAME_SIZE:
1301 av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
1303 case AAC_AC3_PARSE_ERROR_FRAME_TYPE:
1304 /* skip frame if CRC is ok. otherwise use error concealment. */
1305 /* TODO: add support for substreams and dependent frames */
1306 if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) {
1307 av_log(avctx, AV_LOG_WARNING, "unsupported frame type : "
1308 "skipping frame\n");
1312 av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
1315 case AAC_AC3_PARSE_ERROR_CRC:
1316 case AAC_AC3_PARSE_ERROR_CHANNEL_CFG:
1318 default: // Normal AVERROR do not try to recover.
1323 /* check that reported frame size fits in input buffer */
1324 if (s->frame_size > buf_size) {
1325 av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
1326 err = AAC_AC3_PARSE_ERROR_FRAME_SIZE;
1327 } else if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
1328 /* check for crc mismatch */
1329 if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2],
1330 s->frame_size - 2)) {
1331 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
1332 if (avctx->err_recognition & AV_EF_EXPLODE)
1333 return AVERROR_INVALIDDATA;
1334 err = AAC_AC3_PARSE_ERROR_CRC;
1339 /* if frame is ok, set audio parameters */
1341 avctx->sample_rate = s->sample_rate;
1342 avctx->bit_rate = s->bit_rate;
1345 /* channel config */
1346 if (!err || (s->channels && s->out_channels != s->channels)) {
1347 s->out_channels = s->channels;
1348 s->output_mode = s->channel_mode;
1350 s->output_mode |= AC3_OUTPUT_LFEON;
1351 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
1352 avctx->request_channels < s->channels) {
1353 s->out_channels = avctx->request_channels;
1354 s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
1355 s->channel_layout = avpriv_ac3_channel_layout_tab[s->output_mode];
1357 avctx->channels = s->out_channels;
1358 avctx->channel_layout = s->channel_layout;
1360 s->loro_center_mix_level = gain_levels[s-> center_mix_level];
1361 s->loro_surround_mix_level = gain_levels[s->surround_mix_level];
1362 s->ltrt_center_mix_level = LEVEL_MINUS_3DB;
1363 s->ltrt_surround_mix_level = LEVEL_MINUS_3DB;
1364 /* set downmixing coefficients if needed */
1365 if (s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
1366 s->fbw_channels == s->out_channels)) {
1367 set_downmix_coeffs(s);
1369 } else if (!s->channels) {
1370 av_log(avctx, AV_LOG_ERROR, "unable to determine channel mode\n");
1371 return AVERROR_INVALIDDATA;
1373 avctx->channels = s->out_channels;
1375 /* set audio service type based on bitstream mode for AC-3 */
1376 avctx->audio_service_type = s->bitstream_mode;
1377 if (s->bitstream_mode == 0x7 && s->channels > 1)
1378 avctx->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
1380 /* get output buffer */
1381 frame->nb_samples = s->num_blocks * AC3_BLOCK_SIZE;
1382 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1385 /* decode the audio blocks */
1386 channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on];
1387 for (ch = 0; ch < AC3_MAX_CHANNELS; ch++) {
1388 output[ch] = s->output[ch];
1389 s->outptr[ch] = s->output[ch];
1391 for (ch = 0; ch < s->channels; ch++) {
1392 if (ch < s->out_channels)
1393 s->outptr[channel_map[ch]] = (float *)frame->data[ch];
1395 for (blk = 0; blk < s->num_blocks; blk++) {
1396 if (!err && decode_audio_block(s, blk)) {
1397 av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
1401 for (ch = 0; ch < s->out_channels; ch++)
1402 memcpy(((float*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], sizeof(**output) * AC3_BLOCK_SIZE);
1403 for (ch = 0; ch < s->out_channels; ch++)
1404 output[ch] = s->outptr[channel_map[ch]];
1405 for (ch = 0; ch < s->out_channels; ch++) {
1406 if (!ch || channel_map[ch])
1407 s->outptr[channel_map[ch]] += AC3_BLOCK_SIZE;
1411 av_frame_set_decode_error_flags(frame, err ? FF_DECODE_ERROR_INVALID_BITSTREAM : 0);
1413 /* keep last block for error concealment in next frame */
1414 for (ch = 0; ch < s->out_channels; ch++)
1415 memcpy(s->output[ch], output[ch], sizeof(**output) * AC3_BLOCK_SIZE);
1419 return FFMIN(buf_size, s->frame_size);
1423 * Uninitialize the AC-3 decoder.
1425 static av_cold int ac3_decode_end(AVCodecContext *avctx)
1427 AC3DecodeContext *s = avctx->priv_data;
1428 ff_mdct_end(&s->imdct_512);
1429 ff_mdct_end(&s->imdct_256);
1434 #define OFFSET(x) offsetof(AC3DecodeContext, x)
1435 #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM)
1436 static const AVOption options[] = {
1437 { "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 1.0, PAR },
1439 {"dmix_mode", "Preferred Stereo Downmix Mode", OFFSET(preferred_stereo_downmix), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, 2, 0, "dmix_mode"},
1440 {"ltrt_cmixlev", "Lt/Rt Center Mix Level", OFFSET(ltrt_center_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0},
1441 {"ltrt_surmixlev", "Lt/Rt Surround Mix Level", OFFSET(ltrt_surround_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0},
1442 {"loro_cmixlev", "Lo/Ro Center Mix Level", OFFSET(loro_center_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0},
1443 {"loro_surmixlev", "Lo/Ro Surround Mix Level", OFFSET(loro_surround_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0},
1448 static const AVClass ac3_decoder_class = {
1449 .class_name = "AC3 decoder",
1450 .item_name = av_default_item_name,
1452 .version = LIBAVUTIL_VERSION_INT,
1455 AVCodec ff_ac3_decoder = {
1457 .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
1458 .type = AVMEDIA_TYPE_AUDIO,
1459 .id = AV_CODEC_ID_AC3,
1460 .priv_data_size = sizeof (AC3DecodeContext),
1461 .init = ac3_decode_init,
1462 .close = ac3_decode_end,
1463 .decode = ac3_decode_frame,
1464 .capabilities = CODEC_CAP_DR1,
1465 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1466 AV_SAMPLE_FMT_NONE },
1467 .priv_class = &ac3_decoder_class,
1470 #if CONFIG_EAC3_DECODER
1471 static const AVClass eac3_decoder_class = {
1472 .class_name = "E-AC3 decoder",
1473 .item_name = av_default_item_name,
1475 .version = LIBAVUTIL_VERSION_INT,
1478 AVCodec ff_eac3_decoder = {
1480 .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
1481 .type = AVMEDIA_TYPE_AUDIO,
1482 .id = AV_CODEC_ID_EAC3,
1483 .priv_data_size = sizeof (AC3DecodeContext),
1484 .init = ac3_decode_init,
1485 .close = ac3_decode_end,
1486 .decode = ac3_decode_frame,
1487 .capabilities = CODEC_CAP_DR1,
1488 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1489 AV_SAMPLE_FMT_NONE },
1490 .priv_class = &eac3_decoder_class,