X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Feac3dec.c;h=baba454fd6d8fad1c2a5f29ee9ac7752acf35a0d;hb=01f6df01b6fdc2d71b82370374cde4bf102928c7;hp=388e2fc7ea5595853a87da270c3b419e05f62339;hpb=0c3021eade9cde6c3658df40b929452ed3c6de19;p=ffmpeg diff --git a/libavcodec/eac3dec.c b/libavcodec/eac3dec.c index 388e2fc7ea5..baba454fd6d 100644 --- a/libavcodec/eac3dec.c +++ b/libavcodec/eac3dec.c @@ -3,28 +3,55 @@ * Copyright (c) 2007 Bartlomiej Wolowiec * Copyright (c) 2008 Justin Ruggles * - * This file is part of FFmpeg. + * This file is part of Libav. * - * FFmpeg is free software; you can redistribute it and/or + * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * FFmpeg is distributed in the hope that it will be useful, + * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with FFmpeg; if not, write to the Free Software + * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +/* + * There are several features of E-AC-3 that this decoder does not yet support. + * + * Enhanced Coupling + * No known samples exist. If any ever surface, this feature should not be + * too difficult to implement. + * + * Reduced Sample Rates + * No known samples exist. The spec also does not give clear information + * on how this is to be implemented. + * + * Dependent Streams + * Only the independent stream is currently decoded. Any dependent + * streams are skipped. We have only come across two examples of this, and + * they are both just test streams, one for HD-DVD and the other for + * Blu-ray. + * + * Transient Pre-noise Processing + * This is side information which a decoder should use to reduce artifacts + * caused by transients. There are samples which are known to have this + * information, but this decoder currently ignores it. + */ + + #include "avcodec.h" +#include "internal.h" +#include "aac_ac3_parser.h" #include "ac3.h" #include "ac3_parser.h" #include "ac3dec.h" #include "ac3dec_data.h" +#include "eac3_data.h" /** gain adaptive quantization mode */ typedef enum { @@ -36,6 +63,95 @@ typedef enum { #define EAC3_SR_CODE_REDUCED 3 +void ff_eac3_apply_spectral_extension(AC3DecodeContext *s) +{ + int bin, bnd, ch, i; + uint8_t wrapflag[SPX_MAX_BANDS]={1,0,}, num_copy_sections, copy_sizes[SPX_MAX_BANDS]; + float rms_energy[SPX_MAX_BANDS]; + + /* Set copy index mapping table. Set wrap flags to apply a notch filter at + wrap points later on. */ + bin = s->spx_dst_start_freq; + num_copy_sections = 0; + for (bnd = 0; bnd < s->num_spx_bands; bnd++) { + int copysize; + int bandsize = s->spx_band_sizes[bnd]; + if (bin + bandsize > s->spx_src_start_freq) { + copy_sizes[num_copy_sections++] = bin - s->spx_dst_start_freq; + bin = s->spx_dst_start_freq; + wrapflag[bnd] = 1; + } + for (i = 0; i < bandsize; i += copysize) { + if (bin == s->spx_src_start_freq) { + copy_sizes[num_copy_sections++] = bin - s->spx_dst_start_freq; + bin = s->spx_dst_start_freq; + } + copysize = FFMIN(bandsize - i, s->spx_src_start_freq - bin); + bin += copysize; + } + } + copy_sizes[num_copy_sections++] = bin - s->spx_dst_start_freq; + + for (ch = 1; ch <= s->fbw_channels; ch++) { + if (!s->channel_uses_spx[ch]) + continue; + + /* Copy coeffs from normal bands to extension bands */ + bin = s->spx_src_start_freq; + for (i = 0; i < num_copy_sections; i++) { + memcpy(&s->transform_coeffs[ch][bin], + &s->transform_coeffs[ch][s->spx_dst_start_freq], + copy_sizes[i]*sizeof(float)); + bin += copy_sizes[i]; + } + + /* Calculate RMS energy for each SPX band. */ + bin = s->spx_src_start_freq; + for (bnd = 0; bnd < s->num_spx_bands; bnd++) { + int bandsize = s->spx_band_sizes[bnd]; + float accum = 0.0f; + for (i = 0; i < bandsize; i++) { + float coeff = s->transform_coeffs[ch][bin++]; + accum += coeff * coeff; + } + rms_energy[bnd] = sqrtf(accum / bandsize); + } + + /* Apply a notch filter at transitions between normal and extension + bands and at all wrap points. */ + if (s->spx_atten_code[ch] >= 0) { + const float *atten_tab = ff_eac3_spx_atten_tab[s->spx_atten_code[ch]]; + bin = s->spx_src_start_freq - 2; + for (bnd = 0; bnd < s->num_spx_bands; bnd++) { + if (wrapflag[bnd]) { + float *coeffs = &s->transform_coeffs[ch][bin]; + coeffs[0] *= atten_tab[0]; + coeffs[1] *= atten_tab[1]; + coeffs[2] *= atten_tab[2]; + coeffs[3] *= atten_tab[1]; + coeffs[4] *= atten_tab[0]; + } + bin += s->spx_band_sizes[bnd]; + } + } + + /* Apply noise-blended coefficient scaling based on previously + calculated RMS energy, blending factors, and SPX coordinates for + each band. */ + bin = s->spx_src_start_freq; + for (bnd = 0; bnd < s->num_spx_bands; bnd++) { + float nscale = s->spx_noise_blend[ch][bnd] * rms_energy[bnd] * (1.0f / INT32_MIN); + float sscale = s->spx_signal_blend[ch][bnd]; + for (i = 0; i < s->spx_band_sizes[bnd]; i++) { + float noise = nscale * (int32_t)av_lfg_get(&s->dith_state); + s->transform_coeffs[ch][bin] *= sscale; + s->transform_coeffs[ch][bin++] += noise; + } + } + } +} + + /** lrint(M_SQRT2*cos(2*M_PI/12)*(1<<23)) */ #define COEFF_0 10273905LL @@ -78,3 +194,414 @@ static void idct6(int pre_mant[6]) pre_mant[4] = even1 - odd1; pre_mant[5] = even0 - odd0; } + +void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch) +{ + int bin, blk, gs; + int end_bap, gaq_mode; + GetBitContext *gbc = &s->gbc; + int gaq_gain[AC3_MAX_COEFS]; + + gaq_mode = get_bits(gbc, 2); + end_bap = (gaq_mode < 2) ? 12 : 17; + + /* if GAQ gain is used, decode gain codes for bins with hebap between + 8 and end_bap */ + gs = 0; + if (gaq_mode == EAC3_GAQ_12 || gaq_mode == EAC3_GAQ_14) { + /* read 1-bit GAQ gain codes */ + for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) { + if (s->bap[ch][bin] > 7 && s->bap[ch][bin] < end_bap) + gaq_gain[gs++] = get_bits1(gbc) << (gaq_mode-1); + } + } else if (gaq_mode == EAC3_GAQ_124) { + /* read 1.67-bit GAQ gain codes (3 codes in 5 bits) */ + int gc = 2; + for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) { + if (s->bap[ch][bin] > 7 && s->bap[ch][bin] < 17) { + if (gc++ == 2) { + int group_code = get_bits(gbc, 5); + if (group_code > 26) { + av_log(s->avctx, AV_LOG_WARNING, "GAQ gain group code out-of-range\n"); + group_code = 26; + } + gaq_gain[gs++] = ff_ac3_ungroup_3_in_5_bits_tab[group_code][0]; + gaq_gain[gs++] = ff_ac3_ungroup_3_in_5_bits_tab[group_code][1]; + gaq_gain[gs++] = ff_ac3_ungroup_3_in_5_bits_tab[group_code][2]; + gc = 0; + } + } + } + } + + gs=0; + for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) { + int hebap = s->bap[ch][bin]; + int bits = ff_eac3_bits_vs_hebap[hebap]; + if (!hebap) { + /* zero-mantissa dithering */ + for (blk = 0; blk < 6; blk++) { + s->pre_mantissa[ch][bin][blk] = (av_lfg_get(&s->dith_state) & 0x7FFFFF) - 0x400000; + } + } else if (hebap < 8) { + /* Vector Quantization */ + int v = get_bits(gbc, bits); + for (blk = 0; blk < 6; blk++) { + s->pre_mantissa[ch][bin][blk] = ff_eac3_mantissa_vq[hebap][v][blk] << 8; + } + } else { + /* Gain Adaptive Quantization */ + int gbits, log_gain; + if (gaq_mode != EAC3_GAQ_NO && hebap < end_bap) { + log_gain = gaq_gain[gs++]; + } else { + log_gain = 0; + } + gbits = bits - log_gain; + + for (blk = 0; blk < 6; blk++) { + int mant = get_sbits(gbc, gbits); + if (log_gain && mant == -(1 << (gbits-1))) { + /* large mantissa */ + int b; + int mbits = bits - (2 - log_gain); + mant = get_sbits(gbc, mbits); + mant <<= (23 - (mbits - 1)); + /* remap mantissa value to correct for asymmetric quantization */ + if (mant >= 0) + b = 1 << (23 - log_gain); + else + b = ff_eac3_gaq_remap_2_4_b[hebap-8][log_gain-1] << 8; + mant += ((ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] * (int64_t)mant) >> 15) + b; + } else { + /* small mantissa, no GAQ, or Gk=1 */ + mant <<= 24 - bits; + if (!log_gain) { + /* remap mantissa value for no GAQ or Gk=1 */ + mant += (ff_eac3_gaq_remap_1[hebap-8] * (int64_t)mant) >> 15; + } + } + s->pre_mantissa[ch][bin][blk] = mant; + } + } + idct6(s->pre_mantissa[ch][bin]); + } +} + +int ff_eac3_parse_header(AC3DecodeContext *s) +{ + int i, blk, ch; + int ac3_exponent_strategy, parse_aht_info, parse_spx_atten_data; + int parse_transient_proc_info; + int num_cpl_blocks; + GetBitContext *gbc = &s->gbc; + + /* An E-AC-3 stream can have multiple independent streams which the + application can select from. each independent stream can also contain + dependent streams which are used to add or replace channels. */ + if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT) { + avpriv_request_sample(s->avctx, "Dependent substream decoding"); + return AAC_AC3_PARSE_ERROR_FRAME_TYPE; + } else if (s->frame_type == EAC3_FRAME_TYPE_RESERVED) { + av_log(s->avctx, AV_LOG_ERROR, "Reserved frame type\n"); + return AAC_AC3_PARSE_ERROR_FRAME_TYPE; + } + + /* The substream id indicates which substream this frame belongs to. each + independent stream has its own substream id, and the dependent streams + associated to an independent stream have matching substream id's. */ + if (s->substreamid) { + /* only decode substream with id=0. skip any additional substreams. */ + avpriv_request_sample(s->avctx, "Additional substreams"); + return AAC_AC3_PARSE_ERROR_FRAME_TYPE; + } + + if (s->bit_alloc_params.sr_code == EAC3_SR_CODE_REDUCED) { + /* The E-AC-3 specification does not tell how to handle reduced sample + rates in bit allocation. The best assumption would be that it is + handled like AC-3 DolbyNet, but we cannot be sure until we have a + sample which utilizes this feature. */ + avpriv_request_sample(s->avctx, "Reduced sampling rate"); + return AVERROR_PATCHWELCOME; + } + skip_bits(gbc, 5); // skip bitstream id + + /* volume control params */ + for (i = 0; i < (s->channel_mode ? 1 : 2); i++) { + skip_bits(gbc, 5); // skip dialog normalization + if (get_bits1(gbc)) { + skip_bits(gbc, 8); // skip compression gain word + } + } + + /* dependent stream channel map */ + if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT) { + if (get_bits1(gbc)) { + skip_bits(gbc, 16); // skip custom channel map + } + } + + /* mixing metadata */ + if (get_bits1(gbc)) { + /* center and surround mix levels */ + if (s->channel_mode > AC3_CHMODE_STEREO) { + skip_bits(gbc, 2); // skip preferred stereo downmix mode + if (s->channel_mode & 1) { + /* if three front channels exist */ + skip_bits(gbc, 3); //skip Lt/Rt center mix level + s->center_mix_level = get_bits(gbc, 3); + } + if (s->channel_mode & 4) { + /* if a surround channel exists */ + skip_bits(gbc, 3); //skip Lt/Rt surround mix level + s->surround_mix_level = get_bits(gbc, 3); + } + } + + /* lfe mix level */ + if (s->lfe_on && get_bits1(gbc)) { + // TODO: use LFE mix level + skip_bits(gbc, 5); // skip LFE mix level code + } + + /* info for mixing with other streams and substreams */ + if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT) { + for (i = 0; i < (s->channel_mode ? 1 : 2); i++) { + // TODO: apply program scale factor + if (get_bits1(gbc)) { + skip_bits(gbc, 6); // skip program scale factor + } + } + if (get_bits1(gbc)) { + skip_bits(gbc, 6); // skip external program scale factor + } + /* skip mixing parameter data */ + switch(get_bits(gbc, 2)) { + case 1: skip_bits(gbc, 5); break; + case 2: skip_bits(gbc, 12); break; + case 3: { + int mix_data_size = (get_bits(gbc, 5) + 2) << 3; + skip_bits_long(gbc, mix_data_size); + break; + } + } + /* skip pan information for mono or dual mono source */ + if (s->channel_mode < AC3_CHMODE_STEREO) { + for (i = 0; i < (s->channel_mode ? 1 : 2); i++) { + if (get_bits1(gbc)) { + /* note: this is not in the ATSC A/52B specification + reference: ETSI TS 102 366 V1.1.1 + section: E.1.3.1.25 */ + skip_bits(gbc, 8); // skip pan mean direction index + skip_bits(gbc, 6); // skip reserved paninfo bits + } + } + } + /* skip mixing configuration information */ + if (get_bits1(gbc)) { + for (blk = 0; blk < s->num_blocks; blk++) { + if (s->num_blocks == 1 || get_bits1(gbc)) { + skip_bits(gbc, 5); + } + } + } + } + } + + /* informational metadata */ + if (get_bits1(gbc)) { + s->bitstream_mode = get_bits(gbc, 3); + skip_bits(gbc, 2); // skip copyright bit and original bitstream bit + if (s->channel_mode == AC3_CHMODE_STEREO) { + skip_bits(gbc, 4); // skip Dolby surround and headphone mode + } + if (s->channel_mode >= AC3_CHMODE_2F2R) { + skip_bits(gbc, 2); // skip Dolby surround EX mode + } + for (i = 0; i < (s->channel_mode ? 1 : 2); i++) { + if (get_bits1(gbc)) { + skip_bits(gbc, 8); // skip mix level, room type, and A/D converter type + } + } + if (s->bit_alloc_params.sr_code != EAC3_SR_CODE_REDUCED) { + skip_bits1(gbc); // skip source sample rate code + } + } + + /* converter synchronization flag + If frames are less than six blocks, this bit should be turned on + once every 6 blocks to indicate the start of a frame set. + reference: RFC 4598, Section 2.1.3 Frame Sets */ + if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && s->num_blocks != 6) { + skip_bits1(gbc); // skip converter synchronization flag + } + + /* original frame size code if this stream was converted from AC-3 */ + if (s->frame_type == EAC3_FRAME_TYPE_AC3_CONVERT && + (s->num_blocks == 6 || get_bits1(gbc))) { + skip_bits(gbc, 6); // skip frame size code + } + + /* additional bitstream info */ + if (get_bits1(gbc)) { + int addbsil = get_bits(gbc, 6); + for (i = 0; i < addbsil + 1; i++) { + skip_bits(gbc, 8); // skip additional bit stream info + } + } + + /* audio frame syntax flags, strategy data, and per-frame data */ + + if (s->num_blocks == 6) { + ac3_exponent_strategy = get_bits1(gbc); + parse_aht_info = get_bits1(gbc); + } else { + /* less than 6 blocks, so use AC-3-style exponent strategy syntax, and + do not use AHT */ + ac3_exponent_strategy = 1; + parse_aht_info = 0; + } + + s->snr_offset_strategy = get_bits(gbc, 2); + parse_transient_proc_info = get_bits1(gbc); + + s->block_switch_syntax = get_bits1(gbc); + if (!s->block_switch_syntax) + memset(s->block_switch, 0, sizeof(s->block_switch)); + + s->dither_flag_syntax = get_bits1(gbc); + if (!s->dither_flag_syntax) { + for (ch = 1; ch <= s->fbw_channels; ch++) + s->dither_flag[ch] = 1; + } + s->dither_flag[CPL_CH] = s->dither_flag[s->lfe_ch] = 0; + + s->bit_allocation_syntax = get_bits1(gbc); + if (!s->bit_allocation_syntax) { + /* set default bit allocation parameters */ + s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[2]; + s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[1]; + s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab [1]; + s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[2]; + s->bit_alloc_params.floor = ff_ac3_floor_tab [7]; + } + + s->fast_gain_syntax = get_bits1(gbc); + s->dba_syntax = get_bits1(gbc); + s->skip_syntax = get_bits1(gbc); + parse_spx_atten_data = get_bits1(gbc); + + /* coupling strategy occurrence and coupling use per block */ + num_cpl_blocks = 0; + if (s->channel_mode > 1) { + for (blk = 0; blk < s->num_blocks; blk++) { + s->cpl_strategy_exists[blk] = (!blk || get_bits1(gbc)); + if (s->cpl_strategy_exists[blk]) { + s->cpl_in_use[blk] = get_bits1(gbc); + } else { + s->cpl_in_use[blk] = s->cpl_in_use[blk-1]; + } + num_cpl_blocks += s->cpl_in_use[blk]; + } + } else { + memset(s->cpl_in_use, 0, sizeof(s->cpl_in_use)); + } + + /* exponent strategy data */ + if (ac3_exponent_strategy) { + /* AC-3-style exponent strategy syntax */ + for (blk = 0; blk < s->num_blocks; blk++) { + for (ch = !s->cpl_in_use[blk]; ch <= s->fbw_channels; ch++) { + s->exp_strategy[blk][ch] = get_bits(gbc, 2); + } + } + } else { + /* LUT-based exponent strategy syntax */ + for (ch = !((s->channel_mode > 1) && num_cpl_blocks); ch <= s->fbw_channels; ch++) { + int frmchexpstr = get_bits(gbc, 5); + for (blk = 0; blk < 6; blk++) { + s->exp_strategy[blk][ch] = ff_eac3_frm_expstr[frmchexpstr][blk]; + } + } + } + /* LFE exponent strategy */ + if (s->lfe_on) { + for (blk = 0; blk < s->num_blocks; blk++) { + s->exp_strategy[blk][s->lfe_ch] = get_bits1(gbc); + } + } + /* original exponent strategies if this stream was converted from AC-3 */ + if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && + (s->num_blocks == 6 || get_bits1(gbc))) { + skip_bits(gbc, 5 * s->fbw_channels); // skip converter channel exponent strategy + } + + /* determine which channels use AHT */ + if (parse_aht_info) { + /* For AHT to be used, all non-zero blocks must reuse exponents from + the first block. Furthermore, for AHT to be used in the coupling + channel, all blocks must use coupling and use the same coupling + strategy. */ + s->channel_uses_aht[CPL_CH]=0; + for (ch = (num_cpl_blocks != 6); ch <= s->channels; ch++) { + int use_aht = 1; + for (blk = 1; blk < 6; blk++) { + if ((s->exp_strategy[blk][ch] != EXP_REUSE) || + (!ch && s->cpl_strategy_exists[blk])) { + use_aht = 0; + break; + } + } + s->channel_uses_aht[ch] = use_aht && get_bits1(gbc); + } + } else { + memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht)); + } + + /* per-frame SNR offset */ + if (!s->snr_offset_strategy) { + int csnroffst = (get_bits(gbc, 6) - 15) << 4; + int snroffst = (csnroffst + get_bits(gbc, 4)) << 2; + for (ch = 0; ch <= s->channels; ch++) + s->snr_offset[ch] = snroffst; + } + + /* transient pre-noise processing data */ + if (parse_transient_proc_info) { + for (ch = 1; ch <= s->fbw_channels; ch++) { + if (get_bits1(gbc)) { // channel in transient processing + skip_bits(gbc, 10); // skip transient processing location + skip_bits(gbc, 8); // skip transient processing length + } + } + } + + /* spectral extension attenuation data */ + for (ch = 1; ch <= s->fbw_channels; ch++) { + if (parse_spx_atten_data && get_bits1(gbc)) { + s->spx_atten_code[ch] = get_bits(gbc, 5); + } else { + s->spx_atten_code[ch] = -1; + } + } + + /* block start information */ + if (s->num_blocks > 1 && get_bits1(gbc)) { + /* reference: Section E2.3.2.27 + nblkstrtbits = (numblks - 1) * (4 + ceiling(log2(words_per_frame))) + The spec does not say what this data is or what it's used for. + It is likely the offset of each block within the frame. */ + int block_start_bits = (s->num_blocks-1) * (4 + av_log2(s->frame_size-2)); + skip_bits_long(gbc, block_start_bits); + avpriv_request_sample(s->avctx, "Block start info"); + } + + /* syntax state initialization */ + for (ch = 1; ch <= s->fbw_channels; ch++) { + s->first_spx_coords[ch] = 1; + s->first_cpl_coords[ch] = 1; + } + s->first_cpl_leak = 1; + + return 0; +}