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Diffstat (limited to 'contrib/ffmpeg/libavcodec/ac3dec.c')
| -rw-r--r-- | contrib/ffmpeg/libavcodec/ac3dec.c | 1173 |
1 files changed, 0 insertions, 1173 deletions
diff --git a/contrib/ffmpeg/libavcodec/ac3dec.c b/contrib/ffmpeg/libavcodec/ac3dec.c deleted file mode 100644 index 0ce75e769..000000000 --- a/contrib/ffmpeg/libavcodec/ac3dec.c +++ /dev/null @@ -1,1173 +0,0 @@ -/* - * AC-3 Audio Decoder - * This code is developed as part of Google Summer of Code 2006 Program. - * - * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com). - * Copyright (c) 2007 Justin Ruggles - * - * Portions of this code are derived from liba52 - * http://liba52.sourceforge.net - * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org> - * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca> - * - * This file is part of FFmpeg. - * - * FFmpeg is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * FFmpeg 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 - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with FFmpeg; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -#include <stdio.h> -#include <stddef.h> -#include <math.h> -#include <string.h> - -#include "avcodec.h" -#include "ac3_parser.h" -#include "bitstream.h" -#include "crc.h" -#include "dsputil.h" -#include "random.h" - -/** - * Table of bin locations for rematrixing bands - * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions - */ -static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 }; - -/** - * table for exponent to scale_factor mapping - * scale_factors[i] = 2 ^ -i - */ -static float scale_factors[25]; - -/** table for grouping exponents */ -static uint8_t exp_ungroup_tab[128][3]; - - -/** tables for ungrouping mantissas */ -static float b1_mantissas[32][3]; -static float b2_mantissas[128][3]; -static float b3_mantissas[8]; -static float b4_mantissas[128][2]; -static float b5_mantissas[16]; - -/** - * Quantization table: levels for symmetric. bits for asymmetric. - * reference: Table 7.18 Mapping of bap to Quantizer - */ -static const uint8_t quantization_tab[16] = { - 0, 3, 5, 7, 11, 15, - 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 -}; - -/** dynamic range table. converts codes to scale factors. */ -static float dynamic_range_tab[256]; - -/** Adjustments in dB gain */ -#define LEVEL_MINUS_3DB 0.7071067811865476 -#define LEVEL_MINUS_4POINT5DB 0.5946035575013605 -#define LEVEL_MINUS_6DB 0.5000000000000000 -#define LEVEL_MINUS_9DB 0.3535533905932738 -#define LEVEL_ZERO 0.0000000000000000 -#define LEVEL_ONE 1.0000000000000000 - -static const float gain_levels[6] = { - LEVEL_ZERO, - LEVEL_ONE, - LEVEL_MINUS_3DB, - LEVEL_MINUS_4POINT5DB, - LEVEL_MINUS_6DB, - LEVEL_MINUS_9DB -}; - -/** - * Table for center mix levels - * reference: Section 5.4.2.4 cmixlev - */ -static const uint8_t center_levels[4] = { 2, 3, 4, 3 }; - -/** - * Table for surround mix levels - * reference: Section 5.4.2.5 surmixlev - */ -static const uint8_t surround_levels[4] = { 2, 4, 0, 4 }; - -/** - * Table for default stereo downmixing coefficients - * reference: Section 7.8.2 Downmixing Into Two Channels - */ -static const uint8_t ac3_default_coeffs[8][5][2] = { - { { 1, 0 }, { 0, 1 }, }, - { { 2, 2 }, }, - { { 1, 0 }, { 0, 1 }, }, - { { 1, 0 }, { 3, 3 }, { 0, 1 }, }, - { { 1, 0 }, { 0, 1 }, { 4, 4 }, }, - { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 }, }, - { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, }, - { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, }, -}; - -/* override ac3.h to include coupling channel */ -#undef AC3_MAX_CHANNELS -#define AC3_MAX_CHANNELS 7 -#define CPL_CH 0 - -#define AC3_OUTPUT_LFEON 8 - -typedef struct { - int channel_mode; ///< channel mode (acmod) - int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags - int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags - int dither_all; ///< true if all channels are dithered - int cpl_in_use; ///< coupling in use - int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling - int phase_flags_in_use; ///< phase flags in use - int phase_flags[18]; ///< phase flags - int cpl_band_struct[18]; ///< coupling band structure - int num_rematrixing_bands; ///< number of rematrixing bands - int rematrixing_flags[4]; ///< rematrixing flags - int exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies - int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets - int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio) - int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode - int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments - uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets - uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths - uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment - - int sample_rate; ///< sample frequency, in Hz - int bit_rate; ///< stream bit rate, in bits-per-second - int frame_size; ///< current frame size, in bytes - - int channels; ///< number of total channels - int fbw_channels; ///< number of full-bandwidth channels - int lfe_on; ///< lfe channel in use - int lfe_ch; ///< index of LFE channel - int output_mode; ///< output channel configuration - int out_channels; ///< number of output channels - - int center_mix_level; ///< Center mix level index - int surround_mix_level; ///< Surround mix level index - float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients - float dynamic_range[2]; ///< dynamic range - float cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates - int num_cpl_bands; ///< number of coupling bands - int num_cpl_subbands; ///< number of coupling sub bands - int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin - int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin - AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters - - int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents - uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers - int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents - int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents - int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values - - DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients - - /* For IMDCT. */ - MDCTContext imdct_512; ///< for 512 sample IMDCT - MDCTContext imdct_256; ///< for 256 sample IMDCT - DSPContext dsp; ///< for optimization - float add_bias; ///< offset for float_to_int16 conversion - float mul_bias; ///< scaling for float_to_int16 conversion - - DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); ///< output after imdct transform and windowing - DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output - DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); ///< delay - added to the next block - DECLARE_ALIGNED_16(float, tmp_imdct[256]); ///< temporary storage for imdct transform - DECLARE_ALIGNED_16(float, tmp_output[512]); ///< temporary storage for output before windowing - DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients - - /* Miscellaneous. */ - GetBitContext gbc; ///< bitstream reader - AVRandomState dith_state; ///< for dither generation - AVCodecContext *avctx; ///< parent context -} AC3DecodeContext; - -/** - * Symmetrical Dequantization - * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization - * Tables 7.19 to 7.23 - */ -static inline float -symmetric_dequant(int code, int levels) -{ - return (code - (levels >> 1)) * (2.0f / levels); -} - -/* - * Initialize tables at runtime. - */ -static void ac3_tables_init(void) -{ - int i; - - /* generate grouped mantissa tables - reference: Section 7.3.5 Ungrouping of Mantissas */ - for(i=0; i<32; i++) { - /* bap=1 mantissas */ - b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3); - b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3); - b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3); - } - for(i=0; i<128; i++) { - /* bap=2 mantissas */ - b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5); - b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5); - b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5); - - /* bap=4 mantissas */ - b4_mantissas[i][0] = symmetric_dequant(i / 11, 11); - b4_mantissas[i][1] = symmetric_dequant(i % 11, 11); - } - /* generate ungrouped mantissa tables - reference: Tables 7.21 and 7.23 */ - for(i=0; i<7; i++) { - /* bap=3 mantissas */ - b3_mantissas[i] = symmetric_dequant(i, 7); - } - for(i=0; i<15; i++) { - /* bap=5 mantissas */ - b5_mantissas[i] = symmetric_dequant(i, 15); - } - - /* generate dynamic range table - reference: Section 7.7.1 Dynamic Range Control */ - for(i=0; i<256; i++) { - int v = (i >> 5) - ((i >> 7) << 3) - 5; - dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20); - } - - /* generate scale factors for exponents and asymmetrical dequantization - reference: Section 7.3.2 Expansion of Mantissas for Asymmetric Quantization */ - for (i = 0; i < 25; i++) - scale_factors[i] = pow(2.0, -i); - - /* generate exponent tables - reference: Section 7.1.3 Exponent Decoding */ - for(i=0; i<128; i++) { - exp_ungroup_tab[i][0] = i / 25; - exp_ungroup_tab[i][1] = (i % 25) / 5; - exp_ungroup_tab[i][2] = (i % 25) % 5; - } -} - - -/** - * AVCodec initialization - */ -static int ac3_decode_init(AVCodecContext *avctx) -{ - AC3DecodeContext *s = avctx->priv_data; - s->avctx = avctx; - - ac3_common_init(); - ac3_tables_init(); - ff_mdct_init(&s->imdct_256, 8, 1); - ff_mdct_init(&s->imdct_512, 9, 1); - ff_kbd_window_init(s->window, 5.0, 256); - dsputil_init(&s->dsp, avctx); - av_init_random(0, &s->dith_state); - - /* set bias values for float to int16 conversion */ - if(s->dsp.float_to_int16 == ff_float_to_int16_c) { - s->add_bias = 385.0f; - s->mul_bias = 1.0f; - } else { - s->add_bias = 0.0f; - s->mul_bias = 32767.0f; - } - - /* allow downmixing to stereo or mono */ - if (avctx->channels > 0 && avctx->request_channels > 0 && - avctx->request_channels < avctx->channels && - avctx->request_channels <= 2) { - avctx->channels = avctx->request_channels; - } - - return 0; -} - -/** - * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream. - * GetBitContext within AC3DecodeContext must point to - * start of the synchronized ac3 bitstream. - */ -static int ac3_parse_header(AC3DecodeContext *s) -{ - AC3HeaderInfo hdr; - GetBitContext *gbc = &s->gbc; - int err, i; - - err = ff_ac3_parse_header(gbc->buffer, &hdr); - if(err) - return err; - - if(hdr.bitstream_id > 10) - return AC3_PARSE_ERROR_BSID; - - /* get decoding parameters from header info */ - s->bit_alloc_params.sr_code = hdr.sr_code; - s->channel_mode = hdr.channel_mode; - s->lfe_on = hdr.lfe_on; - s->bit_alloc_params.sr_shift = hdr.sr_shift; - s->sample_rate = hdr.sample_rate; - s->bit_rate = hdr.bit_rate; - s->channels = hdr.channels; - s->fbw_channels = s->channels - s->lfe_on; - s->lfe_ch = s->fbw_channels + 1; - s->frame_size = hdr.frame_size; - - /* set default output to all source channels */ - s->out_channels = s->channels; - s->output_mode = s->channel_mode; - if(s->lfe_on) - s->output_mode |= AC3_OUTPUT_LFEON; - - /* set default mix levels */ - s->center_mix_level = 3; // -4.5dB - s->surround_mix_level = 4; // -6.0dB - - /* skip over portion of header which has already been read */ - skip_bits(gbc, 16); // skip the sync_word - skip_bits(gbc, 16); // skip crc1 - skip_bits(gbc, 8); // skip fscod and frmsizecod - skip_bits(gbc, 11); // skip bsid, bsmod, and acmod - if(s->channel_mode == AC3_CHMODE_STEREO) { - skip_bits(gbc, 2); // skip dsurmod - } else { - if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO) - s->center_mix_level = center_levels[get_bits(gbc, 2)]; - if(s->channel_mode & 4) - s->surround_mix_level = surround_levels[get_bits(gbc, 2)]; - } - skip_bits1(gbc); // skip lfeon - - /* read the rest of the bsi. read twice for dual mono mode. */ - i = !(s->channel_mode); - do { - skip_bits(gbc, 5); // skip dialog normalization - if (get_bits1(gbc)) - skip_bits(gbc, 8); //skip compression - if (get_bits1(gbc)) - skip_bits(gbc, 8); //skip language code - if (get_bits1(gbc)) - skip_bits(gbc, 7); //skip audio production information - } while (i--); - - skip_bits(gbc, 2); //skip copyright bit and original bitstream bit - - /* skip the timecodes (or extra bitstream information for Alternate Syntax) - TODO: read & use the xbsi1 downmix levels */ - if (get_bits1(gbc)) - skip_bits(gbc, 14); //skip timecode1 / xbsi1 - if (get_bits1(gbc)) - skip_bits(gbc, 14); //skip timecode2 / xbsi2 - - /* skip additional bitstream info */ - if (get_bits1(gbc)) { - i = get_bits(gbc, 6); - do { - skip_bits(gbc, 8); - } while(i--); - } - - return 0; -} - -/** - * Set stereo downmixing coefficients based on frame header info. - * reference: Section 7.8.2 Downmixing Into Two Channels - */ -static void set_downmix_coeffs(AC3DecodeContext *s) -{ - int i; - float cmix = gain_levels[s->center_mix_level]; - float smix = gain_levels[s->surround_mix_level]; - - for(i=0; i<s->fbw_channels; i++) { - s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]]; - s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]]; - } - if(s->channel_mode > 1 && s->channel_mode & 1) { - s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix; - } - if(s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) { - int nf = s->channel_mode - 2; - s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB; - } - if(s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) { - int nf = s->channel_mode - 4; - s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix; - } -} - -/** - * Decode the grouped exponents according to exponent strategy. - * reference: Section 7.1.3 Exponent Decoding - */ -static void decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps, - uint8_t absexp, int8_t *dexps) -{ - int i, j, grp, group_size; - int dexp[256]; - int expacc, prevexp; - - /* unpack groups */ - group_size = exp_strategy + (exp_strategy == EXP_D45); - for(grp=0,i=0; grp<ngrps; grp++) { - expacc = get_bits(gbc, 7); - dexp[i++] = exp_ungroup_tab[expacc][0]; - dexp[i++] = exp_ungroup_tab[expacc][1]; - dexp[i++] = exp_ungroup_tab[expacc][2]; - } - - /* convert to absolute exps and expand groups */ - prevexp = absexp; - for(i=0; i<ngrps*3; i++) { - prevexp = av_clip(prevexp + dexp[i]-2, 0, 24); - for(j=0; j<group_size; j++) { - dexps[(i*group_size)+j] = prevexp; - } - } -} - -/** - * Generate transform coefficients for each coupled channel in the coupling - * range using the coupling coefficients and coupling coordinates. - * reference: Section 7.4.3 Coupling Coordinate Format - */ -static void uncouple_channels(AC3DecodeContext *s) -{ - int i, j, ch, bnd, subbnd; - - subbnd = -1; - i = s->start_freq[CPL_CH]; - for(bnd=0; bnd<s->num_cpl_bands; bnd++) { - do { - subbnd++; - for(j=0; j<12; j++) { - for(ch=1; ch<=s->fbw_channels; ch++) { - if(s->channel_in_cpl[ch]) { - s->transform_coeffs[ch][i] = s->transform_coeffs[CPL_CH][i] * s->cpl_coords[ch][bnd] * 8.0f; - if (ch == 2 && s->phase_flags[bnd]) - s->transform_coeffs[ch][i] = -s->transform_coeffs[ch][i]; - } - } - i++; - } - } while(s->cpl_band_struct[subbnd]); - } -} - -/** - * Grouped mantissas for 3-level 5-level and 11-level quantization - */ -typedef struct { - float b1_mant[3]; - float b2_mant[3]; - float b4_mant[2]; - int b1ptr; - int b2ptr; - int b4ptr; -} mant_groups; - -/** - * Get the transform coefficients for a particular channel - * reference: Section 7.3 Quantization and Decoding of Mantissas - */ -static int get_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m) -{ - GetBitContext *gbc = &s->gbc; - int i, gcode, tbap, start, end; - uint8_t *exps; - uint8_t *bap; - float *coeffs; - - exps = s->dexps[ch_index]; - bap = s->bap[ch_index]; - coeffs = s->transform_coeffs[ch_index]; - start = s->start_freq[ch_index]; - end = s->end_freq[ch_index]; - - for (i = start; i < end; i++) { - tbap = bap[i]; - switch (tbap) { - case 0: - coeffs[i] = ((av_random(&s->dith_state) & 0xFFFF) / 65535.0f) - 0.5f; - break; - - case 1: - if(m->b1ptr > 2) { - gcode = get_bits(gbc, 5); - m->b1_mant[0] = b1_mantissas[gcode][0]; - m->b1_mant[1] = b1_mantissas[gcode][1]; - m->b1_mant[2] = b1_mantissas[gcode][2]; - m->b1ptr = 0; - } - coeffs[i] = m->b1_mant[m->b1ptr++]; - break; - - case 2: - if(m->b2ptr > 2) { - gcode = get_bits(gbc, 7); - m->b2_mant[0] = b2_mantissas[gcode][0]; - m->b2_mant[1] = b2_mantissas[gcode][1]; - m->b2_mant[2] = b2_mantissas[gcode][2]; - m->b2ptr = 0; - } - coeffs[i] = m->b2_mant[m->b2ptr++]; - break; - - case 3: - coeffs[i] = b3_mantissas[get_bits(gbc, 3)]; - break; - - case 4: - if(m->b4ptr > 1) { - gcode = get_bits(gbc, 7); - m->b4_mant[0] = b4_mantissas[gcode][0]; - m->b4_mant[1] = b4_mantissas[gcode][1]; - m->b4ptr = 0; - } - coeffs[i] = m->b4_mant[m->b4ptr++]; - break; - - case 5: - coeffs[i] = b5_mantissas[get_bits(gbc, 4)]; - break; - - default: - /* asymmetric dequantization */ - coeffs[i] = get_sbits(gbc, quantization_tab[tbap]) * scale_factors[quantization_tab[tbap]-1]; - break; - } - coeffs[i] *= scale_factors[exps[i]]; - } - - return 0; -} - -/** - * Remove random dithering from coefficients with zero-bit mantissas - * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0) - */ -static void remove_dithering(AC3DecodeContext *s) { - int ch, i; - int end=0; - float *coeffs; - uint8_t *bap; - - for(ch=1; ch<=s->fbw_channels; ch++) { - if(!s->dither_flag[ch]) { - coeffs = s->transform_coeffs[ch]; - bap = s->bap[ch]; - if(s->channel_in_cpl[ch]) - end = s->start_freq[CPL_CH]; - else - end = s->end_freq[ch]; - for(i=0; i<end; i++) { - if(!bap[i]) - coeffs[i] = 0.0f; - } - if(s->channel_in_cpl[ch]) { - bap = s->bap[CPL_CH]; - for(; i<s->end_freq[CPL_CH]; i++) { - if(!bap[i]) - coeffs[i] = 0.0f; - } - } - } - } -} - -/** - * Get the transform coefficients. - */ -static int get_transform_coeffs(AC3DecodeContext *s) -{ - int ch, end; - int got_cplchan = 0; - mant_groups m; - - m.b1ptr = m.b2ptr = m.b4ptr = 3; - - for (ch = 1; ch <= s->channels; ch++) { - /* transform coefficients for full-bandwidth channel */ - if (get_transform_coeffs_ch(s, ch, &m)) - return -1; - /* tranform coefficients for coupling channel come right after the - coefficients for the first coupled channel*/ - if (s->channel_in_cpl[ch]) { - if (!got_cplchan) { - if (get_transform_coeffs_ch(s, CPL_CH, &m)) { - av_log(s->avctx, AV_LOG_ERROR, "error in decoupling channels\n"); - return -1; - } - uncouple_channels(s); - got_cplchan = 1; - } - end = s->end_freq[CPL_CH]; - } else { - end = s->end_freq[ch]; - } - do - s->transform_coeffs[ch][end] = 0; - while(++end < 256); - } - - /* if any channel doesn't use dithering, zero appropriate coefficients */ - if(!s->dither_all) - remove_dithering(s); - - return 0; -} - -/** - * Stereo rematrixing. - * reference: Section 7.5.4 Rematrixing : Decoding Technique - */ -static void do_rematrixing(AC3DecodeContext *s) -{ - int bnd, i; - int end, bndend; - float tmp0, tmp1; - - end = FFMIN(s->end_freq[1], s->end_freq[2]); - - for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) { - if(s->rematrixing_flags[bnd]) { - bndend = FFMIN(end, rematrix_band_tab[bnd+1]); - for(i=rematrix_band_tab[bnd]; i<bndend; i++) { - tmp0 = s->transform_coeffs[1][i]; - tmp1 = s->transform_coeffs[2][i]; - s->transform_coeffs[1][i] = tmp0 + tmp1; - s->transform_coeffs[2][i] = tmp0 - tmp1; - } - } - } -} - -/** - * Perform the 256-point IMDCT - */ -static void do_imdct_256(AC3DecodeContext *s, int chindex) -{ - int i, k; - DECLARE_ALIGNED_16(float, x[128]); - FFTComplex z[2][64]; - float *o_ptr = s->tmp_output; - - for(i=0; i<2; i++) { - /* de-interleave coefficients */ - for(k=0; k<128; k++) { - x[k] = s->transform_coeffs[chindex][2*k+i]; - } - - /* run standard IMDCT */ - s->imdct_256.fft.imdct_calc(&s->imdct_256, o_ptr, x, s->tmp_imdct); - - /* reverse the post-rotation & reordering from standard IMDCT */ - for(k=0; k<32; k++) { - z[i][32+k].re = -o_ptr[128+2*k]; - z[i][32+k].im = -o_ptr[2*k]; - z[i][31-k].re = o_ptr[2*k+1]; - z[i][31-k].im = o_ptr[128+2*k+1]; - } - } - - /* apply AC-3 post-rotation & reordering */ - for(k=0; k<64; k++) { - o_ptr[ 2*k ] = -z[0][ k].im; - o_ptr[ 2*k+1] = z[0][63-k].re; - o_ptr[128+2*k ] = -z[0][ k].re; - o_ptr[128+2*k+1] = z[0][63-k].im; - o_ptr[256+2*k ] = -z[1][ k].re; - o_ptr[256+2*k+1] = z[1][63-k].im; - o_ptr[384+2*k ] = z[1][ k].im; - o_ptr[384+2*k+1] = -z[1][63-k].re; - } -} - -/** - * Inverse MDCT Transform. - * Convert frequency domain coefficients to time-domain audio samples. - * reference: Section 7.9.4 Transformation Equations - */ -static inline void do_imdct(AC3DecodeContext *s) -{ - int ch; - int channels; - - /* Don't perform the IMDCT on the LFE channel unless it's used in the output */ - channels = s->fbw_channels; - if(s->output_mode & AC3_OUTPUT_LFEON) - channels++; - - for (ch=1; ch<=channels; ch++) { - if (s->block_switch[ch]) { - do_imdct_256(s, ch); - } else { - s->imdct_512.fft.imdct_calc(&s->imdct_512, s->tmp_output, - s->transform_coeffs[ch], s->tmp_imdct); - } - /* For the first half of the block, apply the window, add the delay - from the previous block, and send to output */ - s->dsp.vector_fmul_add_add(s->output[ch-1], s->tmp_output, - s->window, s->delay[ch-1], 0, 256, 1); - /* For the second half of the block, apply the window and store the - samples to delay, to be combined with the next block */ - s->dsp.vector_fmul_reverse(s->delay[ch-1], s->tmp_output+256, - s->window, 256); - } -} - -/** - * Downmix the output to mono or stereo. - */ -static void ac3_downmix(AC3DecodeContext *s) -{ - int i, j; - float v0, v1, s0, s1; - - for(i=0; i<256; i++) { - v0 = v1 = s0 = s1 = 0.0f; - for(j=0; j<s->fbw_channels; j++) { - v0 += s->output[j][i] * s->downmix_coeffs[j][0]; - v1 += s->output[j][i] * s->downmix_coeffs[j][1]; - s0 += s->downmix_coeffs[j][0]; - s1 += s->downmix_coeffs[j][1]; - } - v0 /= s0; - v1 /= s1; - if(s->output_mode == AC3_CHMODE_MONO) { - s->output[0][i] = (v0 + v1) * LEVEL_MINUS_3DB; - } else if(s->output_mode == AC3_CHMODE_STEREO) { - s->output[0][i] = v0; - s->output[1][i] = v1; - } - } -} - -/** - * Parse an audio block from AC-3 bitstream. - */ -static int ac3_parse_audio_block(AC3DecodeContext *s, int blk) -{ - int fbw_channels = s->fbw_channels; - int channel_mode = s->channel_mode; - int i, bnd, seg, ch; - GetBitContext *gbc = &s->gbc; - uint8_t bit_alloc_stages[AC3_MAX_CHANNELS]; - - memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS); - - /* block switch flags */ - for (ch = 1; ch <= fbw_channels; ch++) - s->block_switch[ch] = get_bits1(gbc); - - /* dithering flags */ - s->dither_all = 1; - for (ch = 1; ch <= fbw_channels; ch++) { - s->dither_flag[ch] = get_bits1(gbc); - if(!s->dither_flag[ch]) - s->dither_all = 0; - } - - /* dynamic range */ - i = !(s->channel_mode); - do { - if(get_bits1(gbc)) { - s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) * - s->avctx->drc_scale)+1.0; - } else if(blk == 0) { - s->dynamic_range[i] = 1.0f; - } - } while(i--); - - /* coupling strategy */ - if (get_bits1(gbc)) { - memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS); - s->cpl_in_use = get_bits1(gbc); - if (s->cpl_in_use) { - /* coupling in use */ - int cpl_begin_freq, cpl_end_freq; - - /* determine which channels are coupled */ - for (ch = 1; ch <= fbw_channels; ch++) - s->channel_in_cpl[ch] = get_bits1(gbc); - - /* phase flags in use */ - if (channel_mode == AC3_CHMODE_STEREO) - s->phase_flags_in_use = get_bits1(gbc); - - /* coupling frequency range and band structure */ - cpl_begin_freq = get_bits(gbc, 4); - cpl_end_freq = get_bits(gbc, 4); - if (3 + cpl_end_freq - cpl_begin_freq < 0) { - av_log(s->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq); - return -1; - } - s->num_cpl_bands = s->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq; - s->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37; - s->end_freq[CPL_CH] = cpl_end_freq * 12 + 73; - for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) { - if (get_bits1(gbc)) { - s->cpl_band_struct[bnd] = 1; - s->num_cpl_bands--; - } - } - s->cpl_band_struct[s->num_cpl_subbands-1] = 0; - } else { - /* coupling not in use */ - for (ch = 1; ch <= fbw_channels; ch++) - s->channel_in_cpl[ch] = 0; - } - } - - /* coupling coordinates */ - if (s->cpl_in_use) { - int cpl_coords_exist = 0; - - for (ch = 1; ch <= fbw_channels; ch++) { - if (s->channel_in_cpl[ch]) { - if (get_bits1(gbc)) { - int master_cpl_coord, cpl_coord_exp, cpl_coord_mant; - cpl_coords_exist = 1; - master_cpl_coord = 3 * get_bits(gbc, 2); - for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { - cpl_coord_exp = get_bits(gbc, 4); - cpl_coord_mant = get_bits(gbc, 4); - if (cpl_coord_exp == 15) - s->cpl_coords[ch][bnd] = cpl_coord_mant / 16.0f; - else - s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16.0f) / 32.0f; - s->cpl_coords[ch][bnd] *= scale_factors[cpl_coord_exp + master_cpl_coord]; - } - } - } - } - /* phase flags */ - if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) { - for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { - s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0; - } - } - } - - /* stereo rematrixing strategy and band structure */ - if (channel_mode == AC3_CHMODE_STEREO) { - if (get_bits1(gbc)) { - s->num_rematrixing_bands = 4; - if(s->cpl_in_use && s->start_freq[CPL_CH] <= 61) - s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37); - for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) - s->rematrixing_flags[bnd] = get_bits1(gbc); - } - } - - /* exponent strategies for each channel */ - s->exp_strategy[CPL_CH] = EXP_REUSE; - s->exp_strategy[s->lfe_ch] = EXP_REUSE; - for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { - if(ch == s->lfe_ch) - s->exp_strategy[ch] = get_bits(gbc, 1); - else - s->exp_strategy[ch] = get_bits(gbc, 2); - if(s->exp_strategy[ch] != EXP_REUSE) - bit_alloc_stages[ch] = 3; - } - - /* channel bandwidth */ - for (ch = 1; ch <= fbw_channels; ch++) { - s->start_freq[ch] = 0; - if (s->exp_strategy[ch] != EXP_REUSE) { - int prev = s->end_freq[ch]; - if (s->channel_in_cpl[ch]) - s->end_freq[ch] = s->start_freq[CPL_CH]; - else { - int bandwidth_code = get_bits(gbc, 6); - if (bandwidth_code > 60) { - av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code); - return -1; - } - s->end_freq[ch] = bandwidth_code * 3 + 73; - } - if(blk > 0 && s->end_freq[ch] != prev) - memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS); - } - } - s->start_freq[s->lfe_ch] = 0; - s->end_freq[s->lfe_ch] = 7; - - /* decode exponents for each channel */ - for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { - if (s->exp_strategy[ch] != EXP_REUSE) { - int group_size, num_groups; - group_size = 3 << (s->exp_strategy[ch] - 1); - if(ch == CPL_CH) - num_groups = (s->end_freq[ch] - s->start_freq[ch]) / group_size; - else if(ch == s->lfe_ch) - num_groups = 2; - else - num_groups = (s->end_freq[ch] + group_size - 4) / group_size; - s->dexps[ch][0] = get_bits(gbc, 4) << !ch; - decode_exponents(gbc, s->exp_strategy[ch], num_groups, s->dexps[ch][0], - &s->dexps[ch][s->start_freq[ch]+!!ch]); - if(ch != CPL_CH && ch != s->lfe_ch) - skip_bits(gbc, 2); /* skip gainrng */ - } - } - - /* bit allocation information */ - if (get_bits1(gbc)) { - s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift; - s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift; - s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)]; - s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)]; - s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)]; - for(ch=!s->cpl_in_use; ch<=s->channels; ch++) { - bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); - } - } - - /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */ - if (get_bits1(gbc)) { - int csnr; - csnr = (get_bits(gbc, 6) - 15) << 4; - for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */ - s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2; - s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)]; - } - memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS); - } - - /* coupling leak information */ - if (s->cpl_in_use && get_bits1(gbc)) { - s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3); - s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3); - bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2); - } - - /* delta bit allocation information */ - if (get_bits1(gbc)) { - /* delta bit allocation exists (strategy) */ - for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) { - s->dba_mode[ch] = get_bits(gbc, 2); - if (s->dba_mode[ch] == DBA_RESERVED) { - av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n"); - return -1; - } - bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); - } - /* channel delta offset, len and bit allocation */ - for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) { - if (s->dba_mode[ch] == DBA_NEW) { - s->dba_nsegs[ch] = get_bits(gbc, 3); - for (seg = 0; seg <= s->dba_nsegs[ch]; seg++) { - s->dba_offsets[ch][seg] = get_bits(gbc, 5); - s->dba_lengths[ch][seg] = get_bits(gbc, 4); - s->dba_values[ch][seg] = get_bits(gbc, 3); - } - } - } - } else if(blk == 0) { - for(ch=0; ch<=s->channels; ch++) { - s->dba_mode[ch] = DBA_NONE; - } - } - - /* Bit allocation */ - for(ch=!s->cpl_in_use; ch<=s->channels; ch++) { - if(bit_alloc_stages[ch] > 2) { - /* Exponent mapping into PSD and PSD integration */ - ff_ac3_bit_alloc_calc_psd(s->dexps[ch], - s->start_freq[ch], s->end_freq[ch], - s->psd[ch], s->band_psd[ch]); - } - if(bit_alloc_stages[ch] > 1) { - /* Compute excitation function, Compute masking curve, and - Apply delta bit allocation */ - ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch], - s->start_freq[ch], s->end_freq[ch], - s->fast_gain[ch], (ch == s->lfe_ch), - s->dba_mode[ch], s->dba_nsegs[ch], - s->dba_offsets[ch], s->dba_lengths[ch], - s->dba_values[ch], s->mask[ch]); - } - if(bit_alloc_stages[ch] > 0) { - /* Compute bit allocation */ - ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch], - s->start_freq[ch], s->end_freq[ch], - s->snr_offset[ch], - s->bit_alloc_params.floor, - s->bap[ch]); - } - } - - /* unused dummy data */ - if (get_bits1(gbc)) { - int skipl = get_bits(gbc, 9); - while(skipl--) - skip_bits(gbc, 8); - } - - /* unpack the transform coefficients - this also uncouples channels if coupling is in use. */ - if (get_transform_coeffs(s)) { - av_log(s->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n"); - return -1; - } - - /* recover coefficients if rematrixing is in use */ - if(s->channel_mode == AC3_CHMODE_STEREO) - do_rematrixing(s); - - /* apply scaling to coefficients (headroom, dynrng) */ - for(ch=1; ch<=s->channels; ch++) { - float gain = 2.0f * s->mul_bias; - if(s->channel_mode == AC3_CHMODE_DUALMONO) { - gain *= s->dynamic_range[ch-1]; - } else { - gain *= s->dynamic_range[0]; - } - for(i=0; i<s->end_freq[ch]; i++) { - s->transform_coeffs[ch][i] *= gain; - } - } - - do_imdct(s); - - /* downmix output if needed */ - if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) && - s->fbw_channels == s->out_channels)) { - ac3_downmix(s); - } - - /* convert float to 16-bit integer */ - for(ch=0; ch<s->out_channels; ch++) { - for(i=0; i<256; i++) { - s->output[ch][i] += s->add_bias; - } - s->dsp.float_to_int16(s->int_output[ch], s->output[ch], 256); - } - - return 0; -} - -/** - * Decode a single AC-3 frame. - */ -static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size) -{ - AC3DecodeContext *s = avctx->priv_data; - int16_t *out_samples = (int16_t *)data; - int i, blk, ch, err; - - /* initialize the GetBitContext with the start of valid AC-3 Frame */ - init_get_bits(&s->gbc, buf, buf_size * 8); - - /* parse the syncinfo */ - err = ac3_parse_header(s); - if(err) { - switch(err) { - case AC3_PARSE_ERROR_SYNC: - av_log(avctx, AV_LOG_ERROR, "frame sync error\n"); - break; - case AC3_PARSE_ERROR_BSID: - av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n"); - break; - case AC3_PARSE_ERROR_SAMPLE_RATE: - av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n"); - break; - case AC3_PARSE_ERROR_FRAME_SIZE: - av_log(avctx, AV_LOG_ERROR, "invalid frame size\n"); - break; - default: - av_log(avctx, AV_LOG_ERROR, "invalid header\n"); - break; - } - return -1; - } - - /* check that reported frame size fits in input buffer */ - if(s->frame_size > buf_size) { - av_log(avctx, AV_LOG_ERROR, "incomplete frame\n"); - return -1; - } - - /* check for crc mismatch */ - if(avctx->error_resilience >= FF_ER_CAREFUL) { - if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) { - av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n"); - return -1; - } - /* TODO: error concealment */ - } - - avctx->sample_rate = s->sample_rate; - avctx->bit_rate = s->bit_rate; - - /* channel config */ - s->out_channels = s->channels; - if (avctx->request_channels > 0 && avctx->request_channels <= 2 && - avctx->request_channels < s->channels) { - s->out_channels = avctx->request_channels; - s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO; - } - avctx->channels = s->out_channels; - - /* set downmixing coefficients if needed */ - if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) && - s->fbw_channels == s->out_channels)) { - set_downmix_coeffs(s); - } - - /* parse the audio blocks */ - for (blk = 0; blk < NB_BLOCKS; blk++) { - if (ac3_parse_audio_block(s, blk)) { - av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n"); - *data_size = 0; - return s->frame_size; - } - for (i = 0; i < 256; i++) - for (ch = 0; ch < s->out_channels; ch++) - *(out_samples++) = s->int_output[ch][i]; - } - *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t); - return s->frame_size; -} - -/** - * Uninitialize the AC-3 decoder. - */ -static int ac3_decode_end(AVCodecContext *avctx) -{ - AC3DecodeContext *s = avctx->priv_data; - ff_mdct_end(&s->imdct_512); - ff_mdct_end(&s->imdct_256); - - return 0; -} - -AVCodec ac3_decoder = { - .name = "ac3", - .type = CODEC_TYPE_AUDIO, - .id = CODEC_ID_AC3, - .priv_data_size = sizeof (AC3DecodeContext), - .init = ac3_decode_init, - .close = ac3_decode_end, - .decode = ac3_decode_frame, -}; |