/* AC3 Audio Decoder. * * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com). * * This library 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 of the License, or (at your option) any later version. * * This library 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 this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #define ALT_BITSTREAM_READER #include "ac3.h" #include "ac3tab.h" #include "ac3_decoder.h" #include "avcodec.h" #include "bitstream.h" #include "dsputil.h" #include "avutil.h" #include "common.h" /* Synchronization information. */ typedef struct { uint16_t sync_word; //synchronization word = always 0x0b77 uint16_t crc1; //crc for the first 5/8 of the frame uint8_t fscod; //sampling rate code uint8_t frmsizecod; //frame size code /* Derived Attributes */ int sampling_rate; //sampling rate - 48, 44.1 or 32 kHz (value in Hz) int bit_rate; //nominal bit rate (value in kbps) } ac3_sync_info; /* flags for the BSI. */ #define AC3_BSI_LFEON 0x00000001 //low frequency effects channel on #define AC3_BSI_COMPRE 0x00000002 //compression exists #define AC3_BSI_LANGCODE 0x00000004 //langcode exists #define AC3_BSI_AUDPRODIE 0x00000008 //audio production information exists #define AC3_BSI_COMPR2E 0x00000010 //compr2 exists #define AC3_BSI_LANGCOD2E 0x00000020 //langcod2 exists #define AC3_BSI_AUDPRODI2E 0x00000040 //audio production information 2 exists #define AC3_BSI_COPYRIGHTB 0x00000080 //copyright #define AC3_BSI_ORIGBS 0x00000100 //original bit stream #define AC3_BSI_TIMECOD1E 0x00000200 //timecod1 exists #define AC3_BSI_TIMECOD2E 0x00000400 //timecod2 exists #define AC3_BSI_ADDBSIE 0x00000800 //additional bit stream information exists /* Bit Stream Information. */ typedef struct { uint32_t flags; uint8_t bsid; //bit stream identification uint8_t bsmod; //bit stream mode - type of service uint8_t acmod; //audio coding mode - which channels are in use uint8_t cmixlev; //center mix level uint8_t surmixlev; //surround mix level uint8_t dsurmod; //dynamic surround encoded uint8_t dialnorm; //dialog normalization uint8_t compr; //compression gain word uint8_t langcod; //language code uint8_t mixlevel; //mixing level uint8_t roomtyp; //room type uint8_t dialnorm2; //dialogue normalization for 1+1 mode uint8_t compr2; //compression gain word for 1+1 mode uint8_t langcod2; //language code for 1+1 mode uint8_t mixlevel2; //mixing level for 1+1 mode uint8_t roomtyp2; //room type for 1+1 mode uint16_t timecod1; //timecode 1 uint16_t timecod2; //timecode 2 uint8_t addbsil; //additional bit stream information length /* Dervied Attributes */ int nfchans; //number of full bandwidth channels - derived from acmod } ac3_bsi; /* #defs relevant to Audio Block. */ #define MAX_FBW_CHANNELS 5 //maximum full bandwidth channels #define NUM_LFE_GROUPS 3 //number of LFE Groups #define MAX_NUM_SEGS 8 //maximum number of segments per delta bit allocation #define NUM_LFE_MANTS 7 //number of lfe mantissas #define MAX_CPL_SUBNDS 18 //maximum number of coupling sub bands #define MAX_CPL_BNDS 18 //maximum number of coupling bands #define MAX_CPL_GRPS 253 //maximum number of coupling groups #define MAX_CHNL_GRPS 88 //maximum number of channel groups #define MAX_NUM_MANTISSAS 256 //maximum number of mantissas /* flags for the Audio Block. */ #define AC3_AB_DYNRNGE 0x00000001 //dynamic range control exists #define AC3_AB_DYNRNG2E 0x00000002 //dynamic range control 2 exists #define AC3_AB_CPLSTRE 0x00000004 //coupling strategy exists #define AC3_AB_CPLINU 0x00000008 //coupling in use #define AC3_AB_PHSFLGINU 0x00000010 //phase flag in use #define AC3_AB_REMATSTR 0x00000020 //rematrixing required #define AC3_AB_LFEEXPSTR 0x00000100 //lfe exponent strategy #define AC3_AB_BAIE 0x00000200 //bit allocation information exists #define AC3_AB_SNROFFSTE 0x00000400 //SNR offset exists #define AC3_AB_CPLLEAKE 0x00000800 //coupling leak initialization exists #define AC3_AB_DELTBAIE 0x00001000 //delta bit allocation information exists #define AC3_AB_SKIPLE 0x00002000 //skip length exists /* Exponent strategies. */ #define AC3_EXPSTR_D15 0x01 #define AC3_EXPSTR_D25 0x02 #define AC3_EXPSTR_D45 0x03 #define AC3_EXPSTR_REUSE 0x00 /* Bit allocation strategies */ #define AC3_DBASTR_NEW 0x01 #define AC3_DBASTR_NONE 0x02 #define AC3_DBASTR_RESERVED 0x03 #define AC3_DBASTR_REUSE 0x00 /* Audio Block */ typedef struct { uint32_t flags; uint8_t blksw; //block switch flags for channels in use uint8_t dithflag; //dithering flags for channels in use int8_t dynrng; //dynamic range word int8_t dynrng2; //dynamic range word for 1+1 mode uint8_t chincpl; //channel in coupling flags for channels in use uint8_t cplbegf; //coupling begin frequency code uint8_t cplendf; //coupling end frequency code uint32_t cplbndstrc; //coupling band structure uint8_t cplcoe; //coupling co-ordinates exists for the channel in use uint8_t mstrcplco[5]; //master coupling co-ordinate for channels in use uint8_t cplcoexp[5][18]; //coupling co-ordinate exponenets uint8_t cplcomant[5][18]; //coupling co-ordinate mantissas uint32_t phsflg; //phase flag per band uint8_t rematflg; //rematrixing flag uint8_t cplexpstr; //coupling exponent strategy uint8_t chexpstr[5]; //channel exponent strategy uint8_t lfeexpstr; //lfe exponent strategy uint8_t chbwcod[5]; //channel bandwdith code for channels in use uint8_t cplabsexp; //coupling absolute exponent uint8_t cplexps[72]; //coupling exponents uint8_t exps[5][88]; //channel exponents uint8_t gainrng[5]; //gain range uint8_t lfeexps[3]; //LFE exponents uint8_t sdcycod; //slow decay code uint8_t fdcycod; //fast decay code uint8_t sgaincod; //slow gain code uint8_t dbpbcod; //dB per bit code uint8_t floorcod; //masking floor code uint8_t csnroffst; //coarse SNR offset uint8_t cplfsnroffst; //coupling fine SNR offset uint8_t cplfgaincod; //coupling fast gain code uint8_t fsnroffst[5]; //fine SNR offset for channels in use uint8_t fgaincod[5]; //fast gain code for channels in use uint8_t lfefsnroffst; //lfe fine SNR offset uint8_t lfefgaincod; //lfe fast gain code uint8_t cplfleak; //coupling fast leak initialization value uint8_t cplsleak; //coupling slow leak initialization value uint8_t cpldeltbae; //coupling delta bit allocation exists uint8_t deltbae[5]; //delta bit allocation exists for channels in use uint8_t cpldeltnseg; //coupling delta bit allocation number of segments uint8_t cpldeltoffst[8]; //coupling delta offset uint8_t cpldeltlen[8]; //coupling delta len uint8_t cpldeltba[8]; //coupling delta bit allocation uint8_t deltnseg[5]; //delta bit allocation number of segments per channel uint8_t deltoffst[5][8]; //delta offset for channels in use uint8_t deltlen[5][8]; //delta len for channels in use uint8_t deltba[5][8]; //delta bit allocation uint16_t skipl; //skip length /* Derived Attributes */ int ncplsubnd; //number of active coupling sub bands = 3 + cplendf - cplbegf int ncplbnd; //derived from ncplsubnd and cplbndstrc int ncplgrps; //derived from ncplsubnd, cplexpstr int nchgrps[5]; //derived from chexpstr, and cplbegf or chbwcod int nchmant[5]; //derived from cplbegf or chbwcod int ncplmant; //derived from ncplsubnd = 12 * ncplsubnd uint8_t cplstrtbnd; //coupling start band for bit allocation uint8_t cplstrtmant; //coupling start mantissa uint8_t cplendmant; //coupling end mantissa uint8_t endmant[5]; //channel end mantissas uint8_t dcplexps[256]; //decoded coupling exponents uint8_t dexps[5][256]; //decoded fbw channel exponents uint8_t dlfeexps[256]; //decoded lfe exponents uint8_t cplbap[256]; //coupling bit allocation parameters table uint8_t bap[5][256]; //fbw channels bit allocation parameters table uint8_t lfebap[256]; //lfe bit allocaiton parameters table float cplcoeffs[256]; //temporary storage for coupling transform coefficients float cplco[5][18]; //coupling co-ordinates float chcoeffs[6]; //channel coefficients for downmix } ac3_audio_block; #define AC3_OUTPUT_UNMODIFIED 0x00 #define AC3_OUTPUT_MONO 0x01 #define AC3_OUTPUT_STEREO 0x02 #define AC3_OUTPUT_DOLBY 0x03 #define AC3_INPUT_DUALMONO 0x00 #define AC3_INPUT_MONO 0x01 #define AC3_INPUT_STEREO 0x02 #define AC3_INPUT_3F 0x03 #define AC3_INPUT_2F_1R 0x04 #define AC3_INPUT_3F_1R 0x05 #define AC3_INPUT_2F_2R 0x06 #define AC3_INPUT_3F_2R 0x07 /* BEGIN Mersenne Twister Code. */ #define N 624 #define M 397 #define MATRIX_A 0x9908b0df #define UPPER_MASK 0x80000000 #define LOWER_MASK 0x7fffffff typedef struct { uint32_t mt[N]; int mti; } dither_state; static void dither_seed(dither_state *state, uint32_t seed) { if (seed == 0) seed = 0x1f2e3d4c; state->mt[0] = seed; for (state->mti = 1; state->mti < N; state->mti++) state->mt[state->mti] = ((69069 * state->mt[state->mti - 1]) + 1); } static uint32_t dither_uint32(dither_state *state) { uint32_t y; static const uint32_t mag01[2] = { 0x00, MATRIX_A }; int kk; if (state->mti >= N) { for (kk = 0; kk < N - M; kk++) { y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK); state->mt[kk] = state->mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x01]; } for (;kk < N - 1; kk++) { y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK); state->mt[kk] = state->mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x01]; } y = (state->mt[N - 1] & UPPER_MASK) | (state->mt[0] & LOWER_MASK); state->mt[N - 1] = state->mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x01]; state->mti = 0; } y = state->mt[state->mti++]; y ^= (y >> 11); y ^= ((y << 7) & 0x9d2c5680); y ^= ((y << 15) & 0xefc60000); y ^= (y >> 18); return y; } static inline int16_t dither_int16(dither_state *state) { return ((dither_uint32(state) << 16) >> 16); } /* END Mersenne Twister */ /* AC3 Context. */ typedef struct { ac3_sync_info sync_info; ac3_bsi bsi; ac3_audio_block audio_block; float *samples; int output; dither_state state; MDCTContext imdct_ctx_256; MDCTContext imdct_ctx_512; GetBitContext gb; } AC3DecodeContext; static int ac3_decode_init(AVCodecContext *avctx) { AC3DecodeContext *ctx = avctx->priv_data; ac3_common_init(); ff_mdct_init(&ctx->imdct_ctx_256, 8, 1); ff_mdct_init(&ctx->imdct_ctx_512, 9, 1); ctx->samples = av_mallocz(6 * 256 * sizeof (float)); if (!ctx->samples) { av_log(avctx, AV_LOG_ERROR, "Cannot allocate memory for samples\n"); return -1; } dither_seed(&ctx->state, 0); return 0; } static int ac3_synchronize(uint8_t *buf, int buf_size) { int i; for (i = 0; i < buf_size - 1; i++) if (buf[i] == 0x0b && buf[i + 1] == 0x77) return i; return -1; } //Returns -1 when 'fscod' is not valid; static int ac3_parse_sync_info(AC3DecodeContext *ctx) { ac3_sync_info *sync_info = &ctx->sync_info; GetBitContext *gb = &ctx->gb; sync_info->sync_word = get_bits(gb, 16); sync_info->crc1 = get_bits(gb, 16); sync_info->fscod = get_bits(gb, 2); if (sync_info->fscod == 0x03) return -1; sync_info->frmsizecod = get_bits(gb, 6); if (sync_info->frmsizecod >= 0x38) return -1; sync_info->sampling_rate = ac3_freqs[sync_info->fscod]; sync_info->bit_rate = ac3_bitratetab[sync_info->frmsizecod >> 1]; return 0; } //Returns -1 when static int ac3_parse_bsi(AC3DecodeContext *ctx) { ac3_bsi *bsi = &ctx->bsi; uint32_t *flags = &bsi->flags; GetBitContext *gb = &ctx->gb; *flags = 0; bsi->cmixlev = 0; bsi->surmixlev = 0; bsi->dsurmod = 0; bsi->bsid = get_bits(gb, 5); if (bsi->bsid > 0x08) return -1; bsi->bsmod = get_bits(gb, 3); bsi->acmod = get_bits(gb, 3); if (bsi->acmod & 0x01 && bsi->acmod != 0x01) bsi->cmixlev = get_bits(gb, 2); if (bsi->acmod & 0x04) bsi->surmixlev = get_bits(gb, 2); if (bsi->acmod == 0x02) bsi->dsurmod = get_bits(gb, 2); if (get_bits(gb, 1)) *flags |= AC3_BSI_LFEON; bsi->dialnorm = get_bits(gb, 5); if (get_bits(gb, 1)) { *flags |= AC3_BSI_COMPRE; bsi->compr = get_bits(gb, 5); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_LANGCODE; bsi->langcod = get_bits(gb, 8); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_AUDPRODIE; bsi->mixlevel = get_bits(gb, 5); bsi->roomtyp = get_bits(gb, 2); } if (bsi->acmod == 0x00) { bsi->dialnorm2 = get_bits(gb, 5); if (get_bits(gb, 1)) { *flags |= AC3_BSI_COMPR2E; bsi->compr2 = get_bits(gb, 5); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_LANGCOD2E; bsi->langcod2 = get_bits(gb, 8); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_AUDPRODIE; bsi->mixlevel2 = get_bits(gb, 5); bsi->roomtyp2 = get_bits(gb, 2); } } if (get_bits(gb, 1)) *flags |= AC3_BSI_COPYRIGHTB; if (get_bits(gb, 1)) *flags |= AC3_BSI_ORIGBS; if (get_bits(gb, 1)) { *flags |= AC3_BSI_TIMECOD1E; bsi->timecod1 = get_bits(gb, 14); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_TIMECOD2E; bsi->timecod2 = get_bits(gb, 14); } if (get_bits(gb, 1)) { *flags |= AC3_BSI_ADDBSIE; bsi->addbsil = get_bits(gb, 6); do { get_bits(gb, 8); } while (bsi->addbsil--); } bsi->nfchans = nfchans_tbl[bsi->acmod]; return 0; } /* Decodes the grouped exponents (gexps) and stores them * in decoded exponents (dexps). * The code is derived from liba52. * Uses liba52 tables. */ static int _decode_exponents(int expstr, int ngrps, uint8_t absexp, uint8_t *gexps, uint8_t *dexps) { int exps; int i = 0; while (ngrps--) { exps = gexps[i++]; absexp += exp_1[exps]; assert(absexp <= 24); switch (expstr) { case AC3_EXPSTR_D45: *(dexps++) = absexp; *(dexps++) = absexp; case AC3_EXPSTR_D25: *(dexps++) = absexp; case AC3_EXPSTR_D15: *(dexps++) = absexp; } absexp += exp_2[exps]; assert(absexp <= 24); switch (expstr) { case AC3_EXPSTR_D45: *(dexps++) = absexp; *(dexps++) = absexp; case AC3_EXPSTR_D25: *(dexps++) = absexp; case AC3_EXPSTR_D15: *(dexps++) = absexp; } absexp += exp_3[exps]; assert(absexp <= 24); switch (expstr) { case AC3_EXPSTR_D45: *(dexps++) = absexp; *(dexps++) = absexp; case AC3_EXPSTR_D25: *(dexps++) = absexp; case AC3_EXPSTR_D15: *(dexps++) = absexp; } } return 0; } static int decode_exponents(AC3DecodeContext *ctx) { ac3_audio_block *ab = &ctx->audio_block; int i; uint8_t *exps; uint8_t *dexps; if (ab->flags & AC3_AB_CPLINU && ab->cplexpstr != AC3_EXPSTR_REUSE) if (_decode_exponents(ab->cplexpstr, ab->ncplgrps, ab->cplabsexp, ab->cplexps, ab->dcplexps + ab->cplstrtmant)) return -1; for (i = 0; i < ctx->bsi.nfchans; i++) if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) { exps = ab->exps[i]; dexps = ab->dexps[i]; if (_decode_exponents(ab->chexpstr[i], ab->nchgrps[i], exps[0], exps + 1, dexps + 1)) return -1; } if (ctx->bsi.flags & AC3_BSI_LFEON && ab->lfeexpstr != AC3_EXPSTR_REUSE) if (_decode_exponents(ab->lfeexpstr, 2, ab->lfeexps[0], ab->lfeexps + 1, ab->dlfeexps)) return -1; return 0; } static inline int16_t logadd(int16_t a, int16_t b) { int16_t c = a - b; uint8_t address = FFMIN((ABS(c) >> 1), 255); return ((c >= 0) ? (a + latab[address]) : (b + latab[address])); } static inline int16_t calc_lowcomp(int16_t a, int16_t b0, int16_t b1, uint8_t bin) { if (bin < 7) { if ((b0 + 256) == b1) a = 384; else if (b0 > b1) a = FFMAX(0, a - 64); } else if (bin < 20) { if ((b0 + 256) == b1) a = 320; else if (b0 > b1) a = FFMAX(0, a - 64); } else { a = FFMAX(0, a - 128); } return a; } /* do the bit allocation for chnl. * chnl = 0 to 4 - fbw channel * chnl = 5 coupling channel * chnl = 6 lfe channel */ static int _do_bit_allocation(AC3DecodeContext *ctx, int chnl) { ac3_audio_block *ab = &ctx->audio_block; int16_t sdecay, fdecay, sgain, dbknee, floor; int16_t lowcomp, fgain, snroffset, fastleak, slowleak; int16_t psd[256], bndpsd[50], excite[50], mask[50], delta; uint8_t start, end, bin, i, j, k, lastbin, bndstrt, bndend, begin, deltnseg, band, seg, address; uint8_t fscod = ctx->sync_info.fscod; uint8_t *exps, *deltoffst, *deltlen, *deltba; uint8_t *baps; int do_delta = 0; /* initialization */ sdecay = sdecaytab[ab->sdcycod]; fdecay = fdecaytab[ab->fdcycod]; sgain = sgaintab[ab->sgaincod]; dbknee = dbkneetab[ab->dbpbcod]; floor = floortab[ab->floorcod]; if (chnl == 5) { start = ab->cplstrtmant; end = ab->cplendmant; fgain = fgaintab[ab->cplfgaincod]; snroffset = (((ab->csnroffst - 15) << 4) + ab->cplfsnroffst) << 2; fastleak = (ab->cplfleak << 8) + 768; slowleak = (ab->cplsleak << 8) + 768; exps = ab->dcplexps; baps = ab->cplbap; if (ab->cpldeltbae == 0 || ab->cpldeltbae == 1) { do_delta = 1; deltnseg = ab->cpldeltnseg; deltoffst = ab->cpldeltoffst; deltlen = ab->cpldeltlen; deltba = ab->cpldeltba; } } else if (chnl == 6) { start = 0; end = 7; lowcomp = 0; fgain = fgaintab[ab->lfefgaincod]; snroffset = (((ab->csnroffst - 15) << 4) + ab->lfefsnroffst) << 2; exps = ab->dlfeexps; baps = ab->lfebap; } else { start = 0; end = ab->endmant[chnl]; lowcomp = 0; fgain = fgaintab[ab->fgaincod[chnl]]; snroffset = (((ab->csnroffst - 15) << 4) + ab->fsnroffst[chnl]) << 2; exps = ab->dexps[chnl]; baps = ab->bap[chnl]; if (ab->deltbae[chnl] == 0 || ab->deltbae[chnl] == 1) { do_delta = 1; deltnseg = ab->deltnseg[chnl]; deltoffst = ab->deltoffst[chnl]; deltlen = ab->deltlen[chnl]; deltba = ab->deltba[chnl]; } } for (bin = start; bin < end; bin++) /* exponent mapping into psd */ psd[bin] = (3072 - ((int16_t) (exps[bin] << 7))); /* psd integration */ j = start; k = masktab[start]; do { lastbin = FFMIN(bndtab[k] + bndsz[k], end); bndpsd[k] = psd[j]; j++; for (i = j; i < lastbin; i++) { bndpsd[k] = logadd(bndpsd[k], psd[j]); j++; } k++; } while (end > lastbin); /* compute the excite function */ bndstrt = masktab[start]; bndend = masktab[end - 1] + 1; if (bndstrt == 0) { lowcomp = calc_lowcomp(lowcomp, bndpsd[0], bndpsd[1], 0); excite[0] = bndpsd[0] - fgain - lowcomp; lowcomp = calc_lowcomp(lowcomp, bndpsd[1], bndpsd[2], 1); excite[1] = bndpsd[1] - fgain - lowcomp; begin = 7; for (bin = 2; bin < 7; bin++) { if (bndend != 7 || bin != 6) lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin + 1], bin); fastleak = bndpsd[bin] - fgain; slowleak = bndpsd[bin] - sgain; excite[bin] = fastleak - lowcomp; if (bndend != 7 || bin != 6) if (bndpsd[bin] <= bndpsd[bin + 1]) { begin = bin + 1; break; } } for (bin = begin; bin < (FFMIN(bndend, 22)); bin++) { if (bndend != 7 || bin != 6) lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin + 1], bin); fastleak -= fdecay; fastleak = FFMAX(fastleak, bndpsd[bin] - fgain); slowleak -= sdecay; slowleak = FFMAX(slowleak, bndpsd[bin] - sgain); excite[bin] = FFMAX(fastleak - lowcomp, slowleak); } begin = 22; } else { begin = bndstrt; } for (bin = begin; bin < bndend; bin++) { fastleak -= fdecay; fastleak = FFMAX(fastleak, bndpsd[bin] - fgain); slowleak -= sdecay; slowleak = FFMAX(slowleak, bndpsd[bin] - sgain); excite[bin] = FFMAX(fastleak, slowleak); } /* compute the masking curve */ for (bin = bndstrt; bin < bndend; bin++) { if (bndpsd[bin] < dbknee) excite[bin] += ((dbknee - bndpsd[bin]) >> 2); mask[bin] = FFMAX(excite[bin], hth[bin][fscod]); } /* apply the delta bit allocation */ if (do_delta) { band = 0; for (seg = 0; seg < deltnseg + 1; seg++) { band += deltoffst[seg]; if (deltba[seg] >= 4) delta = (deltba[seg] - 3) << 7; else delta = (deltba[seg] - 4) << 7; for (k = 0; k < deltlen[seg]; k++) { mask[band] += delta; band++; } } } /*compute the bit allocation */ i = start; j = masktab[start]; do { lastbin = FFMIN(bndtab[j] + bndsz[j], end); mask[j] -= snroffset; mask[j] -= floor; if (mask[j] < 0) mask[j] = 0; mask[j] &= 0x1fe0; mask[j] += floor; for (k = i; k < lastbin; k++) { address = (psd[i] - mask[j]) >> 5; address = FFMIN(63, (FFMAX(0, address))); baps[i] = baptab[address]; i++; } j++; } while (end > lastbin); return 0; } static int do_bit_allocation(AC3DecodeContext *ctx, int flags) { ac3_audio_block *ab = &ctx->audio_block; int i, snroffst = 0; if (!flags) /* bit allocation is not required */ return 0; if (ab->flags & AC3_AB_SNROFFSTE) { /* check whether snroffsts are zero */ snroffst += ab->csnroffst; if (ab->flags & AC3_AB_CPLINU) snroffst += ab->cplfsnroffst; for (i = 0; i < ctx->bsi.nfchans; i++) snroffst += ab->fsnroffst[i]; if (ctx->bsi.flags & AC3_BSI_LFEON) snroffst += ab->lfefsnroffst; if (!snroffst) { memset(ab->cplbap, 0, sizeof (ab->cplbap)); for (i = 0; i < ctx->bsi.nfchans; i++) memset(ab->bap[i], 0, sizeof (ab->bap[i])); memset(ab->lfebap, 0, sizeof (ab->lfebap)); return 0; } } /* perform bit allocation */ if ((ab->flags & AC3_AB_CPLINU) && (flags & 64)) if (_do_bit_allocation(ctx, 5)) return -1; for (i = 0; i < ctx->bsi.nfchans; i++) if (flags & (1 << i)) if (_do_bit_allocation(ctx, i)) return -1; if ((ctx->bsi.flags & AC3_BSI_LFEON) && (flags & 32)) if (_do_bit_allocation(ctx, 6)) return -1; return 0; } static inline float to_float(uint8_t exp, int16_t mantissa) { return ((float) (mantissa * scale_factors[exp])); } typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */ uint8_t gcodes[3]; uint8_t gcptr; } mant_group; /* Get the transform coefficients for particular channel */ static int _get_transform_coeffs(uint8_t *exps, uint8_t *bap, float chcoeff, float *samples, int start, int end, int dith_flag, GetBitContext *gb, dither_state *state) { int16_t mantissa; int i; int gcode; mant_group l3_grp, l5_grp, l11_grp; for (i = 0; i < 3; i++) l3_grp.gcodes[i] = l5_grp.gcodes[i] = l11_grp.gcodes[i] = -1; l3_grp.gcptr = l5_grp.gcptr = 3; l11_grp.gcptr = 2; i = 0; while (i < start) samples[i++] = 0; for (i = start; i < end; i++) { switch (bap[i]) { case 0: if (!dith_flag) mantissa = 0; else mantissa = dither_int16(state); samples[i] = to_float(exps[i], mantissa) * chcoeff; break; case 1: if (l3_grp.gcptr > 2) { gcode = get_bits(gb, qntztab[1]); if (gcode > 26) return -1; l3_grp.gcodes[0] = gcode / 9; l3_grp.gcodes[1] = (gcode % 9) / 3; l3_grp.gcodes[2] = (gcode % 9) % 3; l3_grp.gcptr = 0; } mantissa = l3_q_tab[l3_grp.gcodes[l3_grp.gcptr++]]; samples[i] = to_float(exps[i], mantissa) * chcoeff; break; case 2: if (l5_grp.gcptr > 2) { gcode = get_bits(gb, qntztab[2]); if (gcode > 124) return -1; l5_grp.gcodes[0] = gcode / 25; l5_grp.gcodes[1] = (gcode % 25) / 5; l5_grp.gcodes[2] = (gcode % 25) % 5; l5_grp.gcptr = 0; } mantissa = l5_q_tab[l5_grp.gcodes[l5_grp.gcptr++]]; samples[i] = to_float(exps[i], mantissa) * chcoeff; break; case 3: mantissa = get_bits(gb, qntztab[3]); if (mantissa > 6) return -1; mantissa = l7_q_tab[mantissa]; samples[i] = to_float(exps[i], mantissa); break; case 4: if (l11_grp.gcptr > 1) { gcode = get_bits(gb, qntztab[4]); if (gcode > 120) return -1; l11_grp.gcodes[0] = gcode / 11; l11_grp.gcodes[1] = gcode % 11; } mantissa = l11_q_tab[l11_grp.gcodes[l11_grp.gcptr++]]; samples[i] = to_float(exps[i], mantissa) * chcoeff; break; case 5: mantissa = get_bits(gb, qntztab[5]); if (mantissa > 14) return -1; mantissa = l15_q_tab[mantissa]; samples[i] = to_float(exps[i], mantissa) * chcoeff; break; default: mantissa = get_bits(gb, qntztab[bap[i]]) << (16 - qntztab[bap[i]]); samples[i] = to_float(exps[i], mantissa) * chcoeff; break; } } i = end; while (i < 256) samples[i++] = 0; return 0; } static int uncouple_channels(AC3DecodeContext * ctx) { ac3_audio_block *ab = &ctx->audio_block; int ch, sbnd, bin; int index; float (*samples)[256]; int16_t mantissa; samples = (float (*)[256])((ctx->bsi.flags & AC3_BSI_LFEON) ? (ctx->samples + 256) : (ctx->samples)); /* uncouple channels */ for (ch = 0; ch < ctx->bsi.nfchans; ch++) if (ab->chincpl & (1 << ch)) for (sbnd = ab->cplbegf; sbnd < 3 + ab->cplendf; sbnd++) for (bin = 0; bin < 12; bin++) { index = sbnd * 12 + bin + 37; samples[ch][index] = ab->cplcoeffs[index] * ab->cplco[ch][sbnd] * ab->chcoeffs[ch]; } /* generate dither if required */ for (ch = 0; ch < ctx->bsi.nfchans; ch++) if ((ab->chincpl & (1 << ch)) && (ab->dithflag & (1 << ch))) for (index = 0; index < ab->endmant[ch]; index++) if (!ab->bap[ch][index]) { mantissa = dither_int16(&ctx->state); samples[ch][index] = to_float(ab->dexps[ch][index], mantissa) * ab->chcoeffs[ch]; } return 0; } static int get_transform_coeffs(AC3DecodeContext * ctx) { int i; ac3_audio_block *ab = &ctx->audio_block; float *samples = ctx->samples; int got_cplchan = 0; int dithflag = 0; samples += (ctx->bsi.flags & AC3_BSI_LFEON) ? 256 : 0; for (i = 0; i < ctx->bsi.nfchans; i++) { if ((ab->flags & AC3_AB_CPLINU) && (ab->chincpl & (1 << i))) dithflag = 0; /* don't generate dither until channels are decoupled */ else dithflag = ab->dithflag & (1 << i); /* transform coefficients for individual channel */ if (_get_transform_coeffs(ab->dexps[i], ab->bap[i], ab->chcoeffs[i], samples + (i * 256), 0, ab->endmant[i], dithflag, &ctx->gb, &ctx->state)) return -1; /* tranform coefficients for coupling channels */ if ((ab->flags & AC3_AB_CPLINU) && (ab->chincpl & (1 << i)) && !got_cplchan) { if (_get_transform_coeffs(ab->dcplexps, ab->cplbap, 1.0f, ab->cplcoeffs, ab->cplstrtmant, ab->cplendmant, 0, &ctx->gb, &ctx->state)) return -1; got_cplchan = 1; } } if (ctx->bsi.flags & AC3_BSI_LFEON) if (_get_transform_coeffs(ab->lfeexps, ab->lfebap, 1.0f, samples - 256, 0, 7, 0, &ctx->gb, &ctx->state)) return -1; /* uncouple the channels from the coupling channel */ if (ab->flags & AC3_AB_CPLINU) if (uncouple_channels(ctx)) return -1; return 0; } /* generate coupling co-ordinates for each coupling subband * from coupling co-ordinates of each band and coupling band * structure information */ static int generate_coupling_coordinates(AC3DecodeContext * ctx) { ac3_audio_block *ab = &ctx->audio_block; uint8_t exp, mstrcplco; int16_t mant; uint32_t cplbndstrc = (1 << ab->ncplsubnd) >> 1; int ch, bnd, sbnd; float cplco; if (ab->cplcoe) for (ch = 0; ch < ctx->bsi.nfchans; ch++) if (ab->cplcoe & (1 << ch)) { mstrcplco = 3 * ab->mstrcplco[ch]; sbnd = ab->cplbegf; for (bnd = 0; bnd < ab->ncplbnd; bnd++) { exp = ab->cplcoexp[ch][bnd]; if (exp == 15) mant = ab->cplcomant[ch][bnd] <<= 14; else mant = (ab->cplcomant[ch][bnd] | 0x10) << 13; cplco = to_float(exp + mstrcplco, mant); if (ctx->bsi.acmod == 0x02 && (ab->flags & AC3_AB_PHSFLGINU) && ch == 1 && (ab->phsflg & (1 << bnd))) cplco = -cplco; /* invert the right channel */ ab->cplco[ch][sbnd++] = cplco; while (cplbndstrc & ab->cplbndstrc) { cplbndstrc >>= 1; ab->cplco[ch][sbnd++] = cplco; } cplbndstrc >>= 1; } } return 0; } static int _do_rematrixing(AC3DecodeContext *ctx, int start, int end) { float tmp0, tmp1; while (start < end) { tmp0 = ctx->samples[start]; tmp1 = (ctx->samples + 256)[start]; ctx->samples[start] = tmp0 + tmp1; (ctx->samples + 256)[start] = tmp0 - tmp1; start++; } return 0; } static void do_rematrixing(AC3DecodeContext *ctx) { ac3_audio_block *ab = &ctx->audio_block; uint8_t bnd1 = 13, bnd2 = 25, bnd3 = 37, bnd4 = 61; uint8_t bndend; bndend = FFMIN(ab->endmant[0], ab->endmant[1]); if (ab->rematflg & 1) _do_rematrixing(ctx, bnd1, bnd2); if (ab->rematflg & 2) _do_rematrixing(ctx, bnd2, bnd3); if (ab->rematflg & 4) { if (ab->cplbegf > 0 && ab->cplbegf <= 2 && (ab->flags & AC3_AB_CPLINU)) _do_rematrixing(ctx, bnd3, bndend); else { _do_rematrixing(ctx, bnd3, bnd4); if (ab->rematflg & 8) _do_rematrixing(ctx, bnd4, bndend); } } } static void get_downmix_coeffs(AC3DecodeContext *ctx) { int from = ctx->bsi.acmod; int to = ctx->output; float clev = clevs[ctx->bsi.cmixlev]; float slev = slevs[ctx->bsi.surmixlev]; ac3_audio_block *ab = &ctx->audio_block; if (to == AC3_OUTPUT_UNMODIFIED) return 0; switch (from) { case AC3_INPUT_DUALMONO: switch (to) { case AC3_OUTPUT_MONO: case AC3_OUTPUT_STEREO: /* We Assume that sum of both mono channels is requested */ ab->chcoeffs[0] *= LEVEL_MINUS_6DB; ab->chcoeffs[1] *= LEVEL_MINUS_6DB; break; } break; case AC3_INPUT_MONO: switch (to) { case AC3_OUTPUT_STEREO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; break; } break; case AC3_INPUT_STEREO: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= LEVEL_MINUS_3DB; break; } break; case AC3_INPUT_3F: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[2] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB; break; case AC3_OUTPUT_STEREO: ab->chcoeffs[1] *= clev; break; } break; case AC3_INPUT_2F_1R: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= LEVEL_MINUS_3DB; ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_STEREO: ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_DOLBY: ab->chcoeffs[2] *= LEVEL_MINUS_3DB; break; } break; case AC3_INPUT_3F_1R: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[2] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB; ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_STEREO: ab->chcoeffs[1] *= clev; ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_DOLBY: ab->chcoeffs[1] *= LEVEL_MINUS_3DB; ab->chcoeffs[3] *= LEVEL_MINUS_3DB; break; } break; case AC3_INPUT_2F_2R: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= LEVEL_MINUS_3DB; ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB; ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_STEREO: ab->chcoeffs[2] *= slev; ab->chcoeffs[3] *= slev; break; case AC3_OUTPUT_DOLBY: ab->chcoeffs[2] *= LEVEL_MINUS_3DB; ab->chcoeffs[3] *= LEVEL_MINUS_3DB; break; } break; case AC3_INPUT_3F_2R: switch (to) { case AC3_OUTPUT_MONO: ab->chcoeffs[0] *= LEVEL_MINUS_3DB; ab->chcoeffs[2] *= LEVEL_MINUS_3DB; ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB; ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB; ab->chcoeffs[4] *= slev * LEVEL_MINUS_3DB; break; case AC3_OUTPUT_STEREO: ab->chcoeffs[1] *= clev; ab->chcoeffs[3] *= slev; ab->chcoeffs[4] *= slev; break; case AC3_OUTPUT_DOLBY: ab->chcoeffs[1] *= LEVEL_MINUS_3DB; ab->chcoeffs[3] *= LEVEL_MINUS_3DB; ab->chcoeffs[4] *= LEVEL_MINUS_3DB; break; } break; } } static inline void downmix_dualmono_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += samples[i + 256]; samples[i + 256] = 0; } } static inline void downmix_dualmono_to_stereo(float *samples) { int i; float tmp; for (i = 0; i < 256; i++) { tmp = samples[i] + samples[i + 256]; samples[i] = samples[i + 256] = tmp; } } static inline void downmix_mono_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) samples[i + 256] = samples[i]; } static inline void downmix_stereo_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += samples[i + 256]; samples[i + 256] = 0; } } static inline void downmix_3f_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 512]); samples[i + 256] = samples[i + 512] = 0; } } static inline void downmix_3f_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += samples[i + 256]; samples[i + 256] = samples[i + 512]; samples[i + 512] = 0; } } static inline void downmix_2f_1r_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 512]); samples[i + 256] = samples[i + 512] = 0; } } static inline void downmix_2f_1r_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += samples[i + 512]; samples[i + 256] += samples[i + 512]; samples[i + 512] = 0; } } static inline void downmix_2f_1r_to_dolby(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] -= samples[i + 512]; samples[i + 256] += samples[i + 512]; samples[i + 512] = 0; } } static inline void downmix_3f_1r_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 512] + samples[i + 768]); samples[i + 256] = samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_3f_1r_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 768]); samples[i + 256] += (samples[i + 512] + samples[i + 768]); samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_3f_1r_to_dolby(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] - samples[i + 768]); samples[i + 256] += (samples[i + 512] + samples[i + 768]); samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_2f_2r_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 512] + samples[i + 768]); samples[i + 256] = samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_2f_2r_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += samples[i + 512]; samples[i + 256] = samples[i + 768]; samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_2f_2r_to_dolby(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] -= samples[i + 512]; samples[i + 256] += samples[i + 768]; samples[i + 512] = samples[i + 768] = 0; } } static inline void downmix_3f_2r_to_mono(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 512] + samples[i + 768] + samples[i + 1024]); samples[i + 256] = samples[i + 512] = samples[i + 768] = samples[i + 1024] = 0; } } static inline void downmix_3f_2r_to_stereo(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] + samples[i + 768]); samples[i + 256] = (samples[i + 512] + samples[i + 1024]); samples[i + 512] = samples[i + 768] = samples[i + 1024] = 0; } } static inline void downmix_3f_2r_to_dolby(float *samples) { int i; for (i = 0; i < 256; i++) { samples[i] += (samples[i + 256] - samples[i + 768]); samples[i + 256] = (samples[i + 512] + samples[i + 1024]); samples[i + 512] = samples[i + 768] = samples[i + 1024] = 0; } } static void do_downmix(AC3DecodeContext *ctx) { int from = ctx->bsi.acmod; int to = ctx->output; float *samples = ctx->samples + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 256 : 0); switch (from) { case AC3_INPUT_DUALMONO: switch (to) { case AC3_OUTPUT_MONO: downmix_dualmono_to_mono(samples); break; case AC3_OUTPUT_STEREO: /* We Assume that sum of both mono channels is requested */ downmix_dualmono_to_stereo(samples); break; } break; case AC3_INPUT_MONO: switch (to) { case AC3_OUTPUT_STEREO: downmix_mono_to_stereo(samples); break; } break; case AC3_INPUT_STEREO: switch (to) { case AC3_OUTPUT_MONO: downmix_stereo_to_mono(samples); break; } break; case AC3_INPUT_3F: switch (to) { case AC3_OUTPUT_MONO: downmix_3f_to_mono(samples); break; case AC3_OUTPUT_STEREO: downmix_3f_to_stereo(samples); break; } break; case AC3_INPUT_2F_1R: switch (to) { case AC3_OUTPUT_MONO: downmix_2f_1r_to_mono(samples); break; case AC3_OUTPUT_STEREO: downmix_2f_1r_to_stereo(samples); break; case AC3_OUTPUT_DOLBY: downmix_2f_1r_to_dolby(samples); break; } break; case AC3_INPUT_3F_1R: switch (to) { case AC3_OUTPUT_MONO: downmix_3f_1r_to_mono(samples); break; case AC3_OUTPUT_STEREO: downmix_3f_1r_to_stereo(samples); break; case AC3_OUTPUT_DOLBY: downmix_3f_1r_to_dolby(samples); break; } break; case AC3_INPUT_2F_2R: switch (to) { case AC3_OUTPUT_MONO: downmix_2f_2r_to_mono(samples); break; case AC3_OUTPUT_STEREO: downmix_2f_2r_to_stereo(samples); break; case AC3_OUTPUT_DOLBY: downmix_2f_2r_to_dolby(samples); break; } break; case AC3_INPUT_3F_2R: switch (to) { case AC3_OUTPUT_MONO: downmix_3f_2r_to_mono(samples); break; case AC3_OUTPUT_STEREO: downmix_3f_2r_to_stereo(samples); break; case AC3_OUTPUT_DOLBY: downmix_3f_2r_to_dolby(samples); break; } break; } } static int ac3_parse_audio_block(AC3DecodeContext * ctx, int index) { ac3_audio_block *ab = &ctx->audio_block; int nfchans = ctx->bsi.nfchans; int acmod = ctx->bsi.acmod; int i, bnd, rbnd, grp, seg; GetBitContext *gb = &ctx->gb; uint32_t *flags = &ab->flags; int bit_alloc_flags = 0; float drange; *flags = 0; ab->blksw = 0; for (i = 0; i < 5; i++) ab->chcoeffs[i] = 1.0; for (i = 0; i < nfchans; i++) /*block switch flag */ ab->blksw |= get_bits(gb, 1) << i; ab->dithflag = 0; for (i = 0; i < nfchans; i++) /* dithering flag */ ab->dithflag |= get_bits(gb, 1) << i; if (get_bits(gb, 1)) { /* dynamic range */ *flags |= AC3_AB_DYNRNGE; ab->dynrng = get_bits(gb, 8); drange = ((((ab->dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (ab->dynrng >> 5)]); for (i = 0; i < nfchans; i++) ab->chcoeffs[i] *= drange; } if (acmod == 0x00) { /* dynamic range 1+1 mode */ if (get_bits(gb, 1)) { *flags |= AC3_AB_DYNRNG2E; ab->dynrng2 = get_bits(gb, 8); drange = ((((ab->dynrng2 & 0x1f) | 0x20) << 13) * scale_factors[3 - (ab->dynrng2 >> 5)]); ab->chcoeffs[1] *= drange; } } get_downmix_coeffs(ctx); ab->chincpl = 0; if (get_bits(gb, 1)) { /* coupling strategy */ *flags |= AC3_AB_CPLSTRE; ab->cplbndstrc = 0; if (get_bits(gb, 1)) { /* coupling in use */ *flags |= AC3_AB_CPLINU; for (i = 0; i < nfchans; i++) ab->chincpl |= get_bits(gb, 1) << i; if (acmod == 0x02) if (get_bits(gb, 1)) /* phase flag in use */ *flags |= AC3_AB_PHSFLGINU; ab->cplbegf = get_bits(gb, 4); ab->cplendf = get_bits(gb, 4); assert((ab->ncplsubnd = 3 + ab->cplendf - ab->cplbegf) > 0); ab->ncplbnd = ab->ncplsubnd; for (i = 0; i < ab->ncplsubnd - 1; i++) /* coupling band structure */ if (get_bits(gb, 1)) { ab->cplbndstrc |= 1 << i; ab->ncplbnd--; } } } if (*flags & AC3_AB_CPLINU) { ab->cplcoe = 0; for (i = 0; i < nfchans; i++) if (ab->chincpl & (1 << i)) if (get_bits(gb, 1)) { /* coupling co-ordinates */ ab->cplcoe |= 1 << i; ab->mstrcplco[i] = get_bits(gb, 2); for (bnd = 0; bnd < ab->ncplbnd; bnd++) { ab->cplcoexp[i][bnd] = get_bits(gb, 4); ab->cplcomant[i][bnd] = get_bits(gb, 4); } } } ab->phsflg = 0; if ((acmod == 0x02) && (*flags & AC3_AB_PHSFLGINU) && (ab->cplcoe & 1 || ab->cplcoe & (1 << 1))) { for (bnd = 0; bnd < ab->ncplbnd; bnd++) if (get_bits(gb, 1)) ab->phsflg |= 1 << bnd; } generate_coupling_coordinates(ctx); ab->rematflg = 0; if (acmod == 0x02) /* rematrixing */ if (get_bits(gb, 1)) { *flags |= AC3_AB_REMATSTR; if (ab->cplbegf > 2 || !(*flags & AC3_AB_CPLINU)) for (rbnd = 0; rbnd < 4; rbnd++) ab->rematflg |= get_bits(gb, 1) << bnd; else if (ab->cplbegf > 0 && ab->cplbegf <= 2 && *flags & AC3_AB_CPLINU) for (rbnd = 0; rbnd < 3; rbnd++) ab->rematflg |= get_bits(gb, 1) << bnd; else if (!(ab->cplbegf) && *flags & AC3_AB_CPLINU) for (rbnd = 0; rbnd < 2; rbnd++) ab->rematflg |= get_bits(gb, 1) << bnd; } if (*flags & AC3_AB_CPLINU) /* coupling exponent strategy */ ab->cplexpstr = get_bits(gb, 2); for (i = 0; i < nfchans; i++) /* channel exponent strategy */ ab->chexpstr[i] = get_bits(gb, 2); if (ctx->bsi.flags & AC3_BSI_LFEON) /* lfe exponent strategy */ ab->lfeexpstr = get_bits(gb, 1); for (i = 0; i < nfchans; i++) /* channel bandwidth code */ if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) if (!(ab->chincpl & (1 << i))) { ab->chbwcod[i] = get_bits(gb, 6); assert (ab->chbwcod[i] <= 60); } if (*flags & AC3_AB_CPLINU) if (ab->cplexpstr != AC3_EXPSTR_REUSE) {/* coupling exponents */ bit_alloc_flags |= 64; ab->cplabsexp = get_bits(gb, 4) << 1; ab->cplstrtmant = (ab->cplbegf * 12) + 37; ab->cplendmant = ((ab->cplendmant + 3) * 12) + 37; ab->ncplgrps = (ab->cplendmant - ab->cplstrtmant) / (3 << (ab->cplexpstr - 1)); for (grp = 0; grp < ab->ncplgrps; grp++) ab->cplexps[grp] = get_bits(gb, 7); } for (i = 0; i < nfchans; i++) /* fbw channel exponents */ if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) { bit_alloc_flags |= 1 << i; if (ab->chincpl & (1 << i)) ab->endmant[i] = (ab->cplbegf * 12) + 37; else ab->endmant[i] = ((ab->chbwcod[i] + 3) * 12) + 37; ab->nchgrps[i] = (ab->endmant[i] + (3 << (ab->chexpstr[i] - 1)) - 4) / (3 << (ab->chexpstr[i] - 1)); ab->exps[i][0] = ab->dexps[i][0] = get_bits(gb, 4); for (grp = 1; grp <= ab->nchgrps[i]; grp++) ab->exps[i][grp] = get_bits(gb, 7); ab->gainrng[i] = get_bits(gb, 2); } if (ctx->bsi.flags & AC3_BSI_LFEON) /* lfe exponents */ if (ab->lfeexpstr != AC3_EXPSTR_REUSE) { bit_alloc_flags |= 32; ab->lfeexps[0] = ab->dlfeexps[0] = get_bits(gb, 4); ab->lfeexps[1] = get_bits(gb, 7); ab->lfeexps[2] = get_bits(gb, 7); } if (decode_exponents(ctx)) {/* decode the exponents for this block */ av_log(NULL, AV_LOG_ERROR, "Error parsing exponents\n"); return -1; } if (get_bits(gb, 1)) { /* bit allocation information */ *flags |= AC3_AB_BAIE; bit_alloc_flags |= 127; ab->sdcycod = get_bits(gb, 2); ab->fdcycod = get_bits(gb, 2); ab->sgaincod = get_bits(gb, 2); ab->dbpbcod = get_bits(gb, 2); ab->floorcod = get_bits(gb, 3); } if (get_bits(gb, 1)) { /* snroffset */ *flags |= AC3_AB_SNROFFSTE; bit_alloc_flags |= 127; ab->csnroffst = get_bits(gb, 6); if (*flags & AC3_AB_CPLINU) { /* couling fine snr offset and fast gain code */ ab->cplfsnroffst = get_bits(gb, 4); ab->cplfgaincod = get_bits(gb, 3); } for (i = 0; i < nfchans; i++) { /* channel fine snr offset and fast gain code */ ab->fsnroffst[i] = get_bits(gb, 4); ab->fgaincod[i] = get_bits(gb, 3); } if (ctx->bsi.flags & AC3_BSI_LFEON) { /* lfe fine snr offset and fast gain code */ ab->lfefsnroffst = get_bits(gb, 4); ab->lfefgaincod = get_bits(gb, 3); } } if (*flags & AC3_AB_CPLINU) if (get_bits(gb, 1)) { /* coupling leak information */ bit_alloc_flags |= 64; *flags |= AC3_AB_CPLLEAKE; ab->cplfleak = get_bits(gb, 3); ab->cplsleak = get_bits(gb, 3); } if (get_bits(gb, 1)) { /* delta bit allocation information */ *flags |= AC3_AB_DELTBAIE; bit_alloc_flags |= 127; if (*flags & AC3_AB_CPLINU) { ab->cpldeltbae = get_bits(gb, 2); if (ab->cpldeltbae == AC3_DBASTR_RESERVED) { av_log(NULL, AV_LOG_ERROR, "coupling delta bit allocation strategy reserved\n"); return -1; } } for (i = 0; i < nfchans; i++) { ab->deltbae[i] = get_bits(gb, 2); if (ab->deltbae[i] == AC3_DBASTR_RESERVED) { av_log(NULL, AV_LOG_ERROR, "delta bit allocation strategy reserved\n"); return -1; } } if (*flags & AC3_AB_CPLINU) if (ab->cpldeltbae == AC3_DBASTR_NEW) { /*coupling delta offset, len and bit allocation */ ab->cpldeltnseg = get_bits(gb, 3); for (seg = 0; seg <= ab->cpldeltnseg; seg++) { ab->cpldeltoffst[seg] = get_bits(gb, 5); ab->cpldeltlen[seg] = get_bits(gb, 4); ab->cpldeltba[seg] = get_bits(gb, 3); } } for (i = 0; i < nfchans; i++) if (ab->deltbae[i] == AC3_DBASTR_NEW) {/*channel delta offset, len and bit allocation */ ab->deltnseg[i] = get_bits(gb, 3); for (seg = 0; seg <= ab->deltnseg[i]; seg++) { ab->deltoffst[i][seg] = get_bits(gb, 5); ab->deltlen[i][seg] = get_bits(gb, 4); ab->deltba[i][seg] = get_bits(gb, 3); } } } if (do_bit_allocation (ctx, bit_alloc_flags)) /* perform the bit allocation */ { av_log(NULL, AV_LOG_ERROR, "Error in bit allocation routine\n"); return -1; } if (get_bits(gb, 1)) { /* unused dummy data */ *flags |= AC3_AB_SKIPLE; ab->skipl = get_bits(gb, 9); while (ab->skipl) { get_bits(gb, 8); ab->skipl--; } } /* unpack the transform coefficients * * this also uncouples channels if coupling is in use. */ if (get_transform_coeffs(ctx)) { av_log(NULL, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n"); return -1; } /* recover coefficients if rematrixing is in use */ if (*flags & AC3_AB_REMATSTR) do_rematrixing(ctx); if (ctx->output != AC3_OUTPUT_UNMODIFIED) do_downmix(ctx); return 0; } /**** the following two functions comes from ac3dec */ static inline int blah (int32_t i) { if (i > 0x43c07fff) return 32767; else if (i < 0x43bf8000) return -32768; else return i - 0x43c00000; } static inline void float_to_int (float * _f, int16_t * s16, int samples) { int32_t * f = (int32_t *) _f; // XXX assumes IEEE float format int i; for (i = 0; i < samples; i++) { s16[i] = blah (f[i]); } } /**** end */ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t * buf, int buf_size) { AC3DecodeContext *ctx = avctx->priv_data; int frame_start; int i, j, k, l; float tmp0[128], tmp1[128], tmp[512]; short *out_samples = (short *)data; float *samples = ctx->samples; //Synchronize the frame. frame_start = ac3_synchronize(buf, buf_size); if (frame_start == -1) { av_log(avctx, AV_LOG_ERROR, "frame is not synchronized\n"); *data_size = 0; return -1; } //Initialize the GetBitContext with the start of valid AC3 Frame. init_get_bits(&(ctx->gb), buf + frame_start, (buf_size - frame_start) * 8); //Parse the syncinfo. ////If 'fscod' is not valid the decoder shall mute as per the standard. if (ac3_parse_sync_info(ctx)) { av_log(avctx, AV_LOG_ERROR, "fscod is not valid\n"); *data_size = 0; return -1; } //Check for the errors. /* if (ac3_error_check(ctx)) { *data_size = 0; return -1; } */ //Parse the BSI. //If 'bsid' is not valid decoder shall not decode the audio as per the standard. if (ac3_parse_bsi(ctx)) { av_log(avctx, AV_LOG_ERROR, "bsid is not valid\n"); *data_size = 0; return -1; } avctx->sample_rate = ctx->sync_info.sampling_rate; if (avctx->channels == 0) { avctx->channels = ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0); ctx->output = AC3_OUTPUT_UNMODIFIED; } else if ((ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0)) < avctx->channels) { av_log(avctx, AV_LOG_INFO, "ac3_decoder: AC3 Source Channels Are Less Then Specified %d: Output to %d Channels\n", avctx->channels, (ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0))); avctx->channels = ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0); ctx->output = AC3_OUTPUT_UNMODIFIED; } else if (avctx->channels == 1) { ctx->output = AC3_OUTPUT_MONO; } else if (avctx->channels == 2) { if (ctx->bsi.dsurmod == 0x02) ctx->output = AC3_OUTPUT_DOLBY; else ctx->output = AC3_OUTPUT_STEREO; } avctx->bit_rate = ctx->sync_info.bit_rate; av_log(avctx, AV_LOG_INFO, "channels = %d \t bit rate = %d \t sampling rate = %d \n", avctx->channels, avctx->sample_rate, avctx->bit_rate); //Parse the Audio Blocks. for (i = 0; i < 6; i++) { if (ac3_parse_audio_block(ctx, i)) { av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n"); *data_size = 0; return -1; } samples = ctx->samples; if (ctx->bsi.flags & AC3_BSI_LFEON) { ff_imdct_calc(&ctx->imdct_ctx_512, ctx->samples + 1536, samples, tmp); for (l = 0; l < 256; l++) samples[l] = (ctx->samples + 1536)[l]; float_to_int(samples, out_samples, 256); samples += 256; out_samples += 256; } for (j = 0; j < ctx->bsi.nfchans; j++) { if (ctx->audio_block.blksw & (1 << j)) { for (k = 0; k < 128; k++) { tmp0[k] = samples[2 * k]; tmp1[k] = samples[2 * k + 1]; } ff_imdct_calc(&ctx->imdct_ctx_256, ctx->samples + 1536, tmp0, tmp); for (l = 0; l < 256; l++) samples[l] = (ctx->samples + 1536)[l] * window[l] + (ctx->samples + 2048)[l] * window[255 - l]; ff_imdct_calc(&ctx->imdct_ctx_256, ctx->samples + 2048, tmp1, tmp); float_to_int(samples, out_samples, 256); samples += 256; out_samples += 256; } else { ff_imdct_calc(&ctx->imdct_ctx_512, ctx->samples + 1536, samples, tmp); for (l = 0; l < 256; l++) samples[l] = (ctx->samples + 1536)[l] * window[l] + (ctx->samples + 2048)[l] * window[255 - l]; float_to_int(samples, out_samples, 256); memcpy(ctx->samples + 2048, ctx->samples + 1792, 256 * sizeof (float)); samples += 256; out_samples += 256; } } } *data_size = 6 * ctx->bsi.nfchans * 256 * sizeof (int16_t); return (buf_size - frame_start); } static int ac3_decode_end(AVCodecContext *ctx) { return 0; } AVCodec lgpl_ac3_decoder = { "ac3", CODEC_TYPE_AUDIO, CODEC_ID_AC3, sizeof (AC3DecodeContext), ac3_decode_init, NULL, ac3_decode_end, ac3_decode_frame, };