yading@10: /* yading@10: * AC-3 Audio Decoder yading@10: * This code was developed as part of Google Summer of Code 2006. yading@10: * E-AC-3 support was added as part of Google Summer of Code 2007. yading@10: * yading@10: * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com) yading@10: * Copyright (c) 2007-2008 Bartlomiej Wolowiec yading@10: * Copyright (c) 2007 Justin Ruggles yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: #include yading@10: #include yading@10: #include yading@10: #include yading@10: yading@10: #include "libavutil/crc.h" yading@10: #include "libavutil/opt.h" yading@10: #include "internal.h" yading@10: #include "aac_ac3_parser.h" yading@10: #include "ac3_parser.h" yading@10: #include "ac3dec.h" yading@10: #include "ac3dec_data.h" yading@10: #include "kbdwin.h" yading@10: yading@10: /** yading@10: * table for ungrouping 3 values in 7 bits. yading@10: * used for exponents and bap=2 mantissas yading@10: */ yading@10: static uint8_t ungroup_3_in_7_bits_tab[128][3]; yading@10: yading@10: /** tables for ungrouping mantissas */ yading@10: static int b1_mantissas[32][3]; yading@10: static int b2_mantissas[128][3]; yading@10: static int b3_mantissas[8]; yading@10: static int b4_mantissas[128][2]; yading@10: static int b5_mantissas[16]; yading@10: yading@10: /** yading@10: * Quantization table: levels for symmetric. bits for asymmetric. yading@10: * reference: Table 7.18 Mapping of bap to Quantizer yading@10: */ yading@10: static const uint8_t quantization_tab[16] = { yading@10: 0, 3, 5, 7, 11, 15, yading@10: 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 yading@10: }; yading@10: yading@10: /** dynamic range table. converts codes to scale factors. */ yading@10: static float dynamic_range_tab[256]; yading@10: yading@10: /** Adjustments in dB gain */ yading@10: static const float gain_levels[9] = { yading@10: LEVEL_PLUS_3DB, yading@10: LEVEL_PLUS_1POINT5DB, yading@10: LEVEL_ONE, yading@10: LEVEL_MINUS_1POINT5DB, yading@10: LEVEL_MINUS_3DB, yading@10: LEVEL_MINUS_4POINT5DB, yading@10: LEVEL_MINUS_6DB, yading@10: LEVEL_ZERO, yading@10: LEVEL_MINUS_9DB yading@10: }; yading@10: yading@10: /** yading@10: * Table for default stereo downmixing coefficients yading@10: * reference: Section 7.8.2 Downmixing Into Two Channels yading@10: */ yading@10: static const uint8_t ac3_default_coeffs[8][5][2] = { yading@10: { { 2, 7 }, { 7, 2 }, }, yading@10: { { 4, 4 }, }, yading@10: { { 2, 7 }, { 7, 2 }, }, yading@10: { { 2, 7 }, { 5, 5 }, { 7, 2 }, }, yading@10: { { 2, 7 }, { 7, 2 }, { 6, 6 }, }, yading@10: { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, }, yading@10: { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, }, yading@10: { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, }, yading@10: }; yading@10: yading@10: /** yading@10: * Symmetrical Dequantization yading@10: * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization yading@10: * Tables 7.19 to 7.23 yading@10: */ yading@10: static inline int yading@10: symmetric_dequant(int code, int levels) yading@10: { yading@10: return ((code - (levels >> 1)) << 24) / levels; yading@10: } yading@10: yading@10: /* yading@10: * Initialize tables at runtime. yading@10: */ yading@10: static av_cold void ac3_tables_init(void) yading@10: { yading@10: int i; yading@10: yading@10: /* generate table for ungrouping 3 values in 7 bits yading@10: reference: Section 7.1.3 Exponent Decoding */ yading@10: for (i = 0; i < 128; i++) { yading@10: ungroup_3_in_7_bits_tab[i][0] = i / 25; yading@10: ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5; yading@10: ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5; yading@10: } yading@10: yading@10: /* generate grouped mantissa tables yading@10: reference: Section 7.3.5 Ungrouping of Mantissas */ yading@10: for (i = 0; i < 32; i++) { yading@10: /* bap=1 mantissas */ yading@10: b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3); yading@10: b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3); yading@10: b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3); yading@10: } yading@10: for (i = 0; i < 128; i++) { yading@10: /* bap=2 mantissas */ yading@10: b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5); yading@10: b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5); yading@10: b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5); yading@10: yading@10: /* bap=4 mantissas */ yading@10: b4_mantissas[i][0] = symmetric_dequant(i / 11, 11); yading@10: b4_mantissas[i][1] = symmetric_dequant(i % 11, 11); yading@10: } yading@10: /* generate ungrouped mantissa tables yading@10: reference: Tables 7.21 and 7.23 */ yading@10: for (i = 0; i < 7; i++) { yading@10: /* bap=3 mantissas */ yading@10: b3_mantissas[i] = symmetric_dequant(i, 7); yading@10: } yading@10: for (i = 0; i < 15; i++) { yading@10: /* bap=5 mantissas */ yading@10: b5_mantissas[i] = symmetric_dequant(i, 15); yading@10: } yading@10: yading@10: /* generate dynamic range table yading@10: reference: Section 7.7.1 Dynamic Range Control */ yading@10: for (i = 0; i < 256; i++) { yading@10: int v = (i >> 5) - ((i >> 7) << 3) - 5; yading@10: dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20); yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * AVCodec initialization yading@10: */ yading@10: static av_cold int ac3_decode_init(AVCodecContext *avctx) yading@10: { yading@10: AC3DecodeContext *s = avctx->priv_data; yading@10: int i; yading@10: yading@10: s->avctx = avctx; yading@10: yading@10: ff_ac3_common_init(); yading@10: ac3_tables_init(); yading@10: ff_mdct_init(&s->imdct_256, 8, 1, 1.0); yading@10: ff_mdct_init(&s->imdct_512, 9, 1, 1.0); yading@10: ff_kbd_window_init(s->window, 5.0, 256); yading@10: ff_dsputil_init(&s->dsp, avctx); yading@10: avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT); yading@10: ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT); yading@10: ff_fmt_convert_init(&s->fmt_conv, avctx); yading@10: av_lfg_init(&s->dith_state, 0); yading@10: yading@10: avctx->sample_fmt = AV_SAMPLE_FMT_FLTP; yading@10: yading@10: /* allow downmixing to stereo or mono */ yading@10: if (avctx->channels > 0 && avctx->request_channels > 0 && yading@10: avctx->request_channels < avctx->channels && yading@10: avctx->request_channels <= 2) { yading@10: avctx->channels = avctx->request_channels; yading@10: } yading@10: s->downmixed = 1; yading@10: yading@10: for (i = 0; i < AC3_MAX_CHANNELS; i++) { yading@10: s->xcfptr[i] = s->transform_coeffs[i]; yading@10: s->dlyptr[i] = s->delay[i]; yading@10: } yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: /** yading@10: * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream. yading@10: * GetBitContext within AC3DecodeContext must point to yading@10: * the start of the synchronized AC-3 bitstream. yading@10: */ yading@10: static int ac3_parse_header(AC3DecodeContext *s) yading@10: { yading@10: GetBitContext *gbc = &s->gbc; yading@10: int i; yading@10: yading@10: /* read the rest of the bsi. read twice for dual mono mode. */ yading@10: i = !s->channel_mode; yading@10: do { yading@10: skip_bits(gbc, 5); // skip dialog normalization yading@10: if (get_bits1(gbc)) yading@10: skip_bits(gbc, 8); //skip compression yading@10: if (get_bits1(gbc)) yading@10: skip_bits(gbc, 8); //skip language code yading@10: if (get_bits1(gbc)) yading@10: skip_bits(gbc, 7); //skip audio production information yading@10: } while (i--); yading@10: yading@10: skip_bits(gbc, 2); //skip copyright bit and original bitstream bit yading@10: yading@10: /* skip the timecodes (or extra bitstream information for Alternate Syntax) yading@10: TODO: read & use the xbsi1 downmix levels */ yading@10: if (get_bits1(gbc)) yading@10: skip_bits(gbc, 14); //skip timecode1 / xbsi1 yading@10: if (get_bits1(gbc)) yading@10: skip_bits(gbc, 14); //skip timecode2 / xbsi2 yading@10: yading@10: /* skip additional bitstream info */ yading@10: if (get_bits1(gbc)) { yading@10: i = get_bits(gbc, 6); yading@10: do { yading@10: skip_bits(gbc, 8); yading@10: } while (i--); yading@10: } yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: /** yading@10: * Common function to parse AC-3 or E-AC-3 frame header yading@10: */ yading@10: static int parse_frame_header(AC3DecodeContext *s) yading@10: { yading@10: AC3HeaderInfo hdr; yading@10: int err; yading@10: yading@10: err = avpriv_ac3_parse_header(&s->gbc, &hdr); yading@10: if (err) yading@10: return err; yading@10: yading@10: /* get decoding parameters from header info */ yading@10: s->bit_alloc_params.sr_code = hdr.sr_code; yading@10: s->bitstream_mode = hdr.bitstream_mode; yading@10: s->channel_mode = hdr.channel_mode; yading@10: s->channel_layout = hdr.channel_layout; yading@10: s->lfe_on = hdr.lfe_on; yading@10: s->bit_alloc_params.sr_shift = hdr.sr_shift; yading@10: s->sample_rate = hdr.sample_rate; yading@10: s->bit_rate = hdr.bit_rate; yading@10: s->channels = hdr.channels; yading@10: s->fbw_channels = s->channels - s->lfe_on; yading@10: s->lfe_ch = s->fbw_channels + 1; yading@10: s->frame_size = hdr.frame_size; yading@10: s->center_mix_level = hdr.center_mix_level; yading@10: s->surround_mix_level = hdr.surround_mix_level; yading@10: s->num_blocks = hdr.num_blocks; yading@10: s->frame_type = hdr.frame_type; yading@10: s->substreamid = hdr.substreamid; yading@10: yading@10: if (s->lfe_on) { yading@10: s->start_freq[s->lfe_ch] = 0; yading@10: s->end_freq[s->lfe_ch] = 7; yading@10: s->num_exp_groups[s->lfe_ch] = 2; yading@10: s->channel_in_cpl[s->lfe_ch] = 0; yading@10: } yading@10: yading@10: if (hdr.bitstream_id <= 10) { yading@10: s->eac3 = 0; yading@10: s->snr_offset_strategy = 2; yading@10: s->block_switch_syntax = 1; yading@10: s->dither_flag_syntax = 1; yading@10: s->bit_allocation_syntax = 1; yading@10: s->fast_gain_syntax = 0; yading@10: s->first_cpl_leak = 0; yading@10: s->dba_syntax = 1; yading@10: s->skip_syntax = 1; yading@10: memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht)); yading@10: return ac3_parse_header(s); yading@10: } else if (CONFIG_EAC3_DECODER) { yading@10: s->eac3 = 1; yading@10: return ff_eac3_parse_header(s); yading@10: } else { yading@10: av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n"); yading@10: return -1; yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Set stereo downmixing coefficients based on frame header info. yading@10: * reference: Section 7.8.2 Downmixing Into Two Channels yading@10: */ yading@10: static void set_downmix_coeffs(AC3DecodeContext *s) yading@10: { yading@10: int i; yading@10: float cmix = gain_levels[s-> center_mix_level]; yading@10: float smix = gain_levels[s->surround_mix_level]; yading@10: float norm0, norm1; yading@10: yading@10: for (i = 0; i < s->fbw_channels; i++) { yading@10: s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]]; yading@10: s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]]; yading@10: } yading@10: if (s->channel_mode > 1 && s->channel_mode & 1) { yading@10: s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix; yading@10: } yading@10: if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) { yading@10: int nf = s->channel_mode - 2; yading@10: s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB; yading@10: } yading@10: if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) { yading@10: int nf = s->channel_mode - 4; yading@10: s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix; yading@10: } yading@10: yading@10: /* renormalize */ yading@10: norm0 = norm1 = 0.0; yading@10: for (i = 0; i < s->fbw_channels; i++) { yading@10: norm0 += s->downmix_coeffs[i][0]; yading@10: norm1 += s->downmix_coeffs[i][1]; yading@10: } yading@10: norm0 = 1.0f / norm0; yading@10: norm1 = 1.0f / norm1; yading@10: for (i = 0; i < s->fbw_channels; i++) { yading@10: s->downmix_coeffs[i][0] *= norm0; yading@10: s->downmix_coeffs[i][1] *= norm1; yading@10: } yading@10: yading@10: if (s->output_mode == AC3_CHMODE_MONO) { yading@10: for (i = 0; i < s->fbw_channels; i++) yading@10: s->downmix_coeffs[i][0] = (s->downmix_coeffs[i][0] + yading@10: s->downmix_coeffs[i][1]) * LEVEL_MINUS_3DB; yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Decode the grouped exponents according to exponent strategy. yading@10: * reference: Section 7.1.3 Exponent Decoding yading@10: */ yading@10: static int decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps, yading@10: uint8_t absexp, int8_t *dexps) yading@10: { yading@10: int i, j, grp, group_size; yading@10: int dexp[256]; yading@10: int expacc, prevexp; yading@10: yading@10: /* unpack groups */ yading@10: group_size = exp_strategy + (exp_strategy == EXP_D45); yading@10: for (grp = 0, i = 0; grp < ngrps; grp++) { yading@10: expacc = get_bits(gbc, 7); yading@10: dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0]; yading@10: dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1]; yading@10: dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2]; yading@10: } yading@10: yading@10: /* convert to absolute exps and expand groups */ yading@10: prevexp = absexp; yading@10: for (i = 0, j = 0; i < ngrps * 3; i++) { yading@10: prevexp += dexp[i] - 2; yading@10: if (prevexp > 24U) yading@10: return -1; yading@10: switch (group_size) { yading@10: case 4: dexps[j++] = prevexp; yading@10: dexps[j++] = prevexp; yading@10: case 2: dexps[j++] = prevexp; yading@10: case 1: dexps[j++] = prevexp; yading@10: } yading@10: } yading@10: return 0; yading@10: } yading@10: yading@10: /** yading@10: * Generate transform coefficients for each coupled channel in the coupling yading@10: * range using the coupling coefficients and coupling coordinates. yading@10: * reference: Section 7.4.3 Coupling Coordinate Format yading@10: */ yading@10: static void calc_transform_coeffs_cpl(AC3DecodeContext *s) yading@10: { yading@10: int bin, band, ch; yading@10: yading@10: bin = s->start_freq[CPL_CH]; yading@10: for (band = 0; band < s->num_cpl_bands; band++) { yading@10: int band_start = bin; yading@10: int band_end = bin + s->cpl_band_sizes[band]; yading@10: for (ch = 1; ch <= s->fbw_channels; ch++) { yading@10: if (s->channel_in_cpl[ch]) { yading@10: int cpl_coord = s->cpl_coords[ch][band] << 5; yading@10: for (bin = band_start; bin < band_end; bin++) { yading@10: s->fixed_coeffs[ch][bin] = yading@10: MULH(s->fixed_coeffs[CPL_CH][bin] << 4, cpl_coord); yading@10: } yading@10: if (ch == 2 && s->phase_flags[band]) { yading@10: for (bin = band_start; bin < band_end; bin++) yading@10: s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin]; yading@10: } yading@10: } yading@10: } yading@10: bin = band_end; yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Grouped mantissas for 3-level 5-level and 11-level quantization yading@10: */ yading@10: typedef struct { yading@10: int b1_mant[2]; yading@10: int b2_mant[2]; yading@10: int b4_mant; yading@10: int b1; yading@10: int b2; yading@10: int b4; yading@10: } mant_groups; yading@10: yading@10: /** yading@10: * Decode the transform coefficients for a particular channel yading@10: * reference: Section 7.3 Quantization and Decoding of Mantissas yading@10: */ yading@10: static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m) yading@10: { yading@10: int start_freq = s->start_freq[ch_index]; yading@10: int end_freq = s->end_freq[ch_index]; yading@10: uint8_t *baps = s->bap[ch_index]; yading@10: int8_t *exps = s->dexps[ch_index]; yading@10: int *coeffs = s->fixed_coeffs[ch_index]; yading@10: int dither = (ch_index == CPL_CH) || s->dither_flag[ch_index]; yading@10: GetBitContext *gbc = &s->gbc; yading@10: int freq; yading@10: yading@10: for (freq = start_freq; freq < end_freq; freq++) { yading@10: int bap = baps[freq]; yading@10: int mantissa; yading@10: switch (bap) { yading@10: case 0: yading@10: /* random noise with approximate range of -0.707 to 0.707 */ yading@10: if (dither) yading@10: mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008; yading@10: else yading@10: mantissa = 0; yading@10: break; yading@10: case 1: yading@10: if (m->b1) { yading@10: m->b1--; yading@10: mantissa = m->b1_mant[m->b1]; yading@10: } else { yading@10: int bits = get_bits(gbc, 5); yading@10: mantissa = b1_mantissas[bits][0]; yading@10: m->b1_mant[1] = b1_mantissas[bits][1]; yading@10: m->b1_mant[0] = b1_mantissas[bits][2]; yading@10: m->b1 = 2; yading@10: } yading@10: break; yading@10: case 2: yading@10: if (m->b2) { yading@10: m->b2--; yading@10: mantissa = m->b2_mant[m->b2]; yading@10: } else { yading@10: int bits = get_bits(gbc, 7); yading@10: mantissa = b2_mantissas[bits][0]; yading@10: m->b2_mant[1] = b2_mantissas[bits][1]; yading@10: m->b2_mant[0] = b2_mantissas[bits][2]; yading@10: m->b2 = 2; yading@10: } yading@10: break; yading@10: case 3: yading@10: mantissa = b3_mantissas[get_bits(gbc, 3)]; yading@10: break; yading@10: case 4: yading@10: if (m->b4) { yading@10: m->b4 = 0; yading@10: mantissa = m->b4_mant; yading@10: } else { yading@10: int bits = get_bits(gbc, 7); yading@10: mantissa = b4_mantissas[bits][0]; yading@10: m->b4_mant = b4_mantissas[bits][1]; yading@10: m->b4 = 1; yading@10: } yading@10: break; yading@10: case 5: yading@10: mantissa = b5_mantissas[get_bits(gbc, 4)]; yading@10: break; yading@10: default: /* 6 to 15 */ yading@10: /* Shift mantissa and sign-extend it. */ yading@10: mantissa = get_sbits(gbc, quantization_tab[bap]); yading@10: mantissa <<= 24 - quantization_tab[bap]; yading@10: break; yading@10: } yading@10: coeffs[freq] = mantissa >> exps[freq]; yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Remove random dithering from coupling range coefficients with zero-bit yading@10: * mantissas for coupled channels which do not use dithering. yading@10: * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0) yading@10: */ yading@10: static void remove_dithering(AC3DecodeContext *s) { yading@10: int ch, i; yading@10: yading@10: for (ch = 1; ch <= s->fbw_channels; ch++) { yading@10: if (!s->dither_flag[ch] && s->channel_in_cpl[ch]) { yading@10: for (i = s->start_freq[CPL_CH]; i < s->end_freq[CPL_CH]; i++) { yading@10: if (!s->bap[CPL_CH][i]) yading@10: s->fixed_coeffs[ch][i] = 0; yading@10: } yading@10: } yading@10: } yading@10: } yading@10: yading@10: static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch, yading@10: mant_groups *m) yading@10: { yading@10: if (!s->channel_uses_aht[ch]) { yading@10: ac3_decode_transform_coeffs_ch(s, ch, m); yading@10: } else { yading@10: /* if AHT is used, mantissas for all blocks are encoded in the first yading@10: block of the frame. */ yading@10: int bin; yading@10: if (!blk && CONFIG_EAC3_DECODER) yading@10: ff_eac3_decode_transform_coeffs_aht_ch(s, ch); yading@10: for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) { yading@10: s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin]; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Decode the transform coefficients. yading@10: */ yading@10: static void decode_transform_coeffs(AC3DecodeContext *s, int blk) yading@10: { yading@10: int ch, end; yading@10: int got_cplchan = 0; yading@10: mant_groups m; yading@10: yading@10: m.b1 = m.b2 = m.b4 = 0; yading@10: yading@10: for (ch = 1; ch <= s->channels; ch++) { yading@10: /* transform coefficients for full-bandwidth channel */ yading@10: decode_transform_coeffs_ch(s, blk, ch, &m); yading@10: /* transform coefficients for coupling channel come right after the yading@10: coefficients for the first coupled channel*/ yading@10: if (s->channel_in_cpl[ch]) { yading@10: if (!got_cplchan) { yading@10: decode_transform_coeffs_ch(s, blk, CPL_CH, &m); yading@10: calc_transform_coeffs_cpl(s); yading@10: got_cplchan = 1; yading@10: } yading@10: end = s->end_freq[CPL_CH]; yading@10: } else { yading@10: end = s->end_freq[ch]; yading@10: } yading@10: do yading@10: s->fixed_coeffs[ch][end] = 0; yading@10: while (++end < 256); yading@10: } yading@10: yading@10: /* zero the dithered coefficients for appropriate channels */ yading@10: remove_dithering(s); yading@10: } yading@10: yading@10: /** yading@10: * Stereo rematrixing. yading@10: * reference: Section 7.5.4 Rematrixing : Decoding Technique yading@10: */ yading@10: static void do_rematrixing(AC3DecodeContext *s) yading@10: { yading@10: int bnd, i; yading@10: int end, bndend; yading@10: yading@10: end = FFMIN(s->end_freq[1], s->end_freq[2]); yading@10: yading@10: for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) { yading@10: if (s->rematrixing_flags[bnd]) { yading@10: bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd + 1]); yading@10: for (i = ff_ac3_rematrix_band_tab[bnd]; i < bndend; i++) { yading@10: int tmp0 = s->fixed_coeffs[1][i]; yading@10: s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i]; yading@10: s->fixed_coeffs[2][i] = tmp0 - s->fixed_coeffs[2][i]; yading@10: } yading@10: } yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Inverse MDCT Transform. yading@10: * Convert frequency domain coefficients to time-domain audio samples. yading@10: * reference: Section 7.9.4 Transformation Equations yading@10: */ yading@10: static inline void do_imdct(AC3DecodeContext *s, int channels) yading@10: { yading@10: int ch; yading@10: yading@10: for (ch = 1; ch <= channels; ch++) { yading@10: if (s->block_switch[ch]) { yading@10: int i; yading@10: float *x = s->tmp_output + 128; yading@10: for (i = 0; i < 128; i++) yading@10: x[i] = s->transform_coeffs[ch][2 * i]; yading@10: s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x); yading@10: s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1], yading@10: s->tmp_output, s->window, 128); yading@10: for (i = 0; i < 128; i++) yading@10: x[i] = s->transform_coeffs[ch][2 * i + 1]; yading@10: s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1], x); yading@10: } else { yading@10: s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]); yading@10: s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1], yading@10: s->tmp_output, s->window, 128); yading@10: memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(float)); yading@10: } yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Upmix delay samples from stereo to original channel layout. yading@10: */ yading@10: static void ac3_upmix_delay(AC3DecodeContext *s) yading@10: { yading@10: int channel_data_size = sizeof(s->delay[0]); yading@10: switch (s->channel_mode) { yading@10: case AC3_CHMODE_DUALMONO: yading@10: case AC3_CHMODE_STEREO: yading@10: /* upmix mono to stereo */ yading@10: memcpy(s->delay[1], s->delay[0], channel_data_size); yading@10: break; yading@10: case AC3_CHMODE_2F2R: yading@10: memset(s->delay[3], 0, channel_data_size); yading@10: case AC3_CHMODE_2F1R: yading@10: memset(s->delay[2], 0, channel_data_size); yading@10: break; yading@10: case AC3_CHMODE_3F2R: yading@10: memset(s->delay[4], 0, channel_data_size); yading@10: case AC3_CHMODE_3F1R: yading@10: memset(s->delay[3], 0, channel_data_size); yading@10: case AC3_CHMODE_3F: yading@10: memcpy(s->delay[2], s->delay[1], channel_data_size); yading@10: memset(s->delay[1], 0, channel_data_size); yading@10: break; yading@10: } yading@10: } yading@10: yading@10: /** yading@10: * Decode band structure for coupling, spectral extension, or enhanced coupling. yading@10: * The band structure defines how many subbands are in each band. For each yading@10: * subband in the range, 1 means it is combined with the previous band, and 0 yading@10: * means that it starts a new band. yading@10: * yading@10: * @param[in] gbc bit reader context yading@10: * @param[in] blk block number yading@10: * @param[in] eac3 flag to indicate E-AC-3 yading@10: * @param[in] ecpl flag to indicate enhanced coupling yading@10: * @param[in] start_subband subband number for start of range yading@10: * @param[in] end_subband subband number for end of range yading@10: * @param[in] default_band_struct default band structure table yading@10: * @param[out] num_bands number of bands (optionally NULL) yading@10: * @param[out] band_sizes array containing the number of bins in each band (optionally NULL) yading@10: */ yading@10: static void decode_band_structure(GetBitContext *gbc, int blk, int eac3, yading@10: int ecpl, int start_subband, int end_subband, yading@10: const uint8_t *default_band_struct, yading@10: int *num_bands, uint8_t *band_sizes) yading@10: { yading@10: int subbnd, bnd, n_subbands, n_bands=0; yading@10: uint8_t bnd_sz[22]; yading@10: uint8_t coded_band_struct[22]; yading@10: const uint8_t *band_struct; yading@10: yading@10: n_subbands = end_subband - start_subband; yading@10: yading@10: /* decode band structure from bitstream or use default */ yading@10: if (!eac3 || get_bits1(gbc)) { yading@10: for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) { yading@10: coded_band_struct[subbnd] = get_bits1(gbc); yading@10: } yading@10: band_struct = coded_band_struct; yading@10: } else if (!blk) { yading@10: band_struct = &default_band_struct[start_subband+1]; yading@10: } else { yading@10: /* no change in band structure */ yading@10: return; yading@10: } yading@10: yading@10: /* calculate number of bands and band sizes based on band structure. yading@10: note that the first 4 subbands in enhanced coupling span only 6 bins yading@10: instead of 12. */ yading@10: if (num_bands || band_sizes ) { yading@10: n_bands = n_subbands; yading@10: bnd_sz[0] = ecpl ? 6 : 12; yading@10: for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) { yading@10: int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12; yading@10: if (band_struct[subbnd - 1]) { yading@10: n_bands--; yading@10: bnd_sz[bnd] += subbnd_size; yading@10: } else { yading@10: bnd_sz[++bnd] = subbnd_size; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /* set optional output params */ yading@10: if (num_bands) yading@10: *num_bands = n_bands; yading@10: if (band_sizes) yading@10: memcpy(band_sizes, bnd_sz, n_bands); yading@10: } yading@10: yading@10: /** yading@10: * Decode a single audio block from the AC-3 bitstream. yading@10: */ yading@10: static int decode_audio_block(AC3DecodeContext *s, int blk) yading@10: { yading@10: int fbw_channels = s->fbw_channels; yading@10: int channel_mode = s->channel_mode; yading@10: int i, bnd, seg, ch; yading@10: int different_transforms; yading@10: int downmix_output; yading@10: int cpl_in_use; yading@10: GetBitContext *gbc = &s->gbc; yading@10: uint8_t bit_alloc_stages[AC3_MAX_CHANNELS] = { 0 }; yading@10: yading@10: /* block switch flags */ yading@10: different_transforms = 0; yading@10: if (s->block_switch_syntax) { yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: s->block_switch[ch] = get_bits1(gbc); yading@10: if (ch > 1 && s->block_switch[ch] != s->block_switch[1]) yading@10: different_transforms = 1; yading@10: } yading@10: } yading@10: yading@10: /* dithering flags */ yading@10: if (s->dither_flag_syntax) { yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: s->dither_flag[ch] = get_bits1(gbc); yading@10: } yading@10: } yading@10: yading@10: /* dynamic range */ yading@10: i = !s->channel_mode; yading@10: do { yading@10: if (get_bits1(gbc)) { yading@10: s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)] - 1.0) * yading@10: s->drc_scale) + 1.0; yading@10: } else if (blk == 0) { yading@10: s->dynamic_range[i] = 1.0f; yading@10: } yading@10: } while (i--); yading@10: yading@10: /* spectral extension strategy */ yading@10: if (s->eac3 && (!blk || get_bits1(gbc))) { yading@10: s->spx_in_use = get_bits1(gbc); yading@10: if (s->spx_in_use) { yading@10: int dst_start_freq, dst_end_freq, src_start_freq, yading@10: start_subband, end_subband; yading@10: yading@10: /* determine which channels use spx */ yading@10: if (s->channel_mode == AC3_CHMODE_MONO) { yading@10: s->channel_uses_spx[1] = 1; yading@10: } else { yading@10: for (ch = 1; ch <= fbw_channels; ch++) yading@10: s->channel_uses_spx[ch] = get_bits1(gbc); yading@10: } yading@10: yading@10: /* get the frequency bins of the spx copy region and the spx start yading@10: and end subbands */ yading@10: dst_start_freq = get_bits(gbc, 2); yading@10: start_subband = get_bits(gbc, 3) + 2; yading@10: if (start_subband > 7) yading@10: start_subband += start_subband - 7; yading@10: end_subband = get_bits(gbc, 3) + 5; yading@10: if (end_subband > 7) yading@10: end_subband += end_subband - 7; yading@10: dst_start_freq = dst_start_freq * 12 + 25; yading@10: src_start_freq = start_subband * 12 + 25; yading@10: dst_end_freq = end_subband * 12 + 25; yading@10: yading@10: /* check validity of spx ranges */ yading@10: if (start_subband >= end_subband) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension " yading@10: "range (%d >= %d)\n", start_subband, end_subband); yading@10: return -1; yading@10: } yading@10: if (dst_start_freq >= src_start_freq) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension " yading@10: "copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq); yading@10: return -1; yading@10: } yading@10: yading@10: s->spx_dst_start_freq = dst_start_freq; yading@10: s->spx_src_start_freq = src_start_freq; yading@10: s->spx_dst_end_freq = dst_end_freq; yading@10: yading@10: decode_band_structure(gbc, blk, s->eac3, 0, yading@10: start_subband, end_subband, yading@10: ff_eac3_default_spx_band_struct, yading@10: &s->num_spx_bands, yading@10: s->spx_band_sizes); yading@10: } else { yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: s->channel_uses_spx[ch] = 0; yading@10: s->first_spx_coords[ch] = 1; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /* spectral extension coordinates */ yading@10: if (s->spx_in_use) { yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: if (s->channel_uses_spx[ch]) { yading@10: if (s->first_spx_coords[ch] || get_bits1(gbc)) { yading@10: float spx_blend; yading@10: int bin, master_spx_coord; yading@10: yading@10: s->first_spx_coords[ch] = 0; yading@10: spx_blend = get_bits(gbc, 5) * (1.0f/32); yading@10: master_spx_coord = get_bits(gbc, 2) * 3; yading@10: yading@10: bin = s->spx_src_start_freq; yading@10: for (bnd = 0; bnd < s->num_spx_bands; bnd++) { yading@10: int bandsize; yading@10: int spx_coord_exp, spx_coord_mant; yading@10: float nratio, sblend, nblend, spx_coord; yading@10: yading@10: /* calculate blending factors */ yading@10: bandsize = s->spx_band_sizes[bnd]; yading@10: nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend; yading@10: nratio = av_clipf(nratio, 0.0f, 1.0f); yading@10: nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3) yading@10: // to give unity variance yading@10: sblend = sqrtf(1.0f - nratio); yading@10: bin += bandsize; yading@10: yading@10: /* decode spx coordinates */ yading@10: spx_coord_exp = get_bits(gbc, 4); yading@10: spx_coord_mant = get_bits(gbc, 2); yading@10: if (spx_coord_exp == 15) spx_coord_mant <<= 1; yading@10: else spx_coord_mant += 4; yading@10: spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord); yading@10: spx_coord = spx_coord_mant * (1.0f / (1 << 23)); yading@10: yading@10: /* multiply noise and signal blending factors by spx coordinate */ yading@10: s->spx_noise_blend [ch][bnd] = nblend * spx_coord; yading@10: s->spx_signal_blend[ch][bnd] = sblend * spx_coord; yading@10: } yading@10: } yading@10: } else { yading@10: s->first_spx_coords[ch] = 1; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /* coupling strategy */ yading@10: if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) { yading@10: memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS); yading@10: if (!s->eac3) yading@10: s->cpl_in_use[blk] = get_bits1(gbc); yading@10: if (s->cpl_in_use[blk]) { yading@10: /* coupling in use */ yading@10: int cpl_start_subband, cpl_end_subband; yading@10: yading@10: if (channel_mode < AC3_CHMODE_STEREO) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n"); yading@10: return -1; yading@10: } yading@10: yading@10: /* check for enhanced coupling */ yading@10: if (s->eac3 && get_bits1(gbc)) { yading@10: /* TODO: parse enhanced coupling strategy info */ yading@10: avpriv_request_sample(s->avctx, "Enhanced coupling"); yading@10: return AVERROR_PATCHWELCOME; yading@10: } yading@10: yading@10: /* determine which channels are coupled */ yading@10: if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) { yading@10: s->channel_in_cpl[1] = 1; yading@10: s->channel_in_cpl[2] = 1; yading@10: } else { yading@10: for (ch = 1; ch <= fbw_channels; ch++) yading@10: s->channel_in_cpl[ch] = get_bits1(gbc); yading@10: } yading@10: yading@10: /* phase flags in use */ yading@10: if (channel_mode == AC3_CHMODE_STEREO) yading@10: s->phase_flags_in_use = get_bits1(gbc); yading@10: yading@10: /* coupling frequency range */ yading@10: cpl_start_subband = get_bits(gbc, 4); yading@10: cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 : yading@10: get_bits(gbc, 4) + 3; yading@10: if (cpl_start_subband >= cpl_end_subband) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n", yading@10: cpl_start_subband, cpl_end_subband); yading@10: return -1; yading@10: } yading@10: s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37; yading@10: s->end_freq[CPL_CH] = cpl_end_subband * 12 + 37; yading@10: yading@10: decode_band_structure(gbc, blk, s->eac3, 0, cpl_start_subband, yading@10: cpl_end_subband, yading@10: ff_eac3_default_cpl_band_struct, yading@10: &s->num_cpl_bands, s->cpl_band_sizes); yading@10: } else { yading@10: /* coupling not in use */ yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: s->channel_in_cpl[ch] = 0; yading@10: s->first_cpl_coords[ch] = 1; yading@10: } yading@10: s->first_cpl_leak = s->eac3; yading@10: s->phase_flags_in_use = 0; yading@10: } yading@10: } else if (!s->eac3) { yading@10: if (!blk) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must " yading@10: "be present in block 0\n"); yading@10: return -1; yading@10: } else { yading@10: s->cpl_in_use[blk] = s->cpl_in_use[blk-1]; yading@10: } yading@10: } yading@10: cpl_in_use = s->cpl_in_use[blk]; yading@10: yading@10: /* coupling coordinates */ yading@10: if (cpl_in_use) { yading@10: int cpl_coords_exist = 0; yading@10: yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: if (s->channel_in_cpl[ch]) { yading@10: if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) { yading@10: int master_cpl_coord, cpl_coord_exp, cpl_coord_mant; yading@10: s->first_cpl_coords[ch] = 0; yading@10: cpl_coords_exist = 1; yading@10: master_cpl_coord = 3 * get_bits(gbc, 2); yading@10: for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { yading@10: cpl_coord_exp = get_bits(gbc, 4); yading@10: cpl_coord_mant = get_bits(gbc, 4); yading@10: if (cpl_coord_exp == 15) yading@10: s->cpl_coords[ch][bnd] = cpl_coord_mant << 22; yading@10: else yading@10: s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21; yading@10: s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord); yading@10: } yading@10: } else if (!blk) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must " yading@10: "be present in block 0\n"); yading@10: return -1; yading@10: } yading@10: } else { yading@10: /* channel not in coupling */ yading@10: s->first_cpl_coords[ch] = 1; yading@10: } yading@10: } yading@10: /* phase flags */ yading@10: if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) { yading@10: for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { yading@10: s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /* stereo rematrixing strategy and band structure */ yading@10: if (channel_mode == AC3_CHMODE_STEREO) { yading@10: if ((s->eac3 && !blk) || get_bits1(gbc)) { yading@10: s->num_rematrixing_bands = 4; yading@10: if (cpl_in_use && s->start_freq[CPL_CH] <= 61) { yading@10: s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37); yading@10: } else if (s->spx_in_use && s->spx_src_start_freq <= 61) { yading@10: s->num_rematrixing_bands--; yading@10: } yading@10: for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) yading@10: s->rematrixing_flags[bnd] = get_bits1(gbc); yading@10: } else if (!blk) { yading@10: av_log(s->avctx, AV_LOG_WARNING, "Warning: " yading@10: "new rematrixing strategy not present in block 0\n"); yading@10: s->num_rematrixing_bands = 0; yading@10: } yading@10: } yading@10: yading@10: /* exponent strategies for each channel */ yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) { yading@10: if (!s->eac3) yading@10: s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch)); yading@10: if (s->exp_strategy[blk][ch] != EXP_REUSE) yading@10: bit_alloc_stages[ch] = 3; yading@10: } yading@10: yading@10: /* channel bandwidth */ yading@10: for (ch = 1; ch <= fbw_channels; ch++) { yading@10: s->start_freq[ch] = 0; yading@10: if (s->exp_strategy[blk][ch] != EXP_REUSE) { yading@10: int group_size; yading@10: int prev = s->end_freq[ch]; yading@10: if (s->channel_in_cpl[ch]) yading@10: s->end_freq[ch] = s->start_freq[CPL_CH]; yading@10: else if (s->channel_uses_spx[ch]) yading@10: s->end_freq[ch] = s->spx_src_start_freq; yading@10: else { yading@10: int bandwidth_code = get_bits(gbc, 6); yading@10: if (bandwidth_code > 60) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code); yading@10: return -1; yading@10: } yading@10: s->end_freq[ch] = bandwidth_code * 3 + 73; yading@10: } yading@10: group_size = 3 << (s->exp_strategy[blk][ch] - 1); yading@10: s->num_exp_groups[ch] = (s->end_freq[ch] + group_size-4) / group_size; yading@10: if (blk > 0 && s->end_freq[ch] != prev) yading@10: memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS); yading@10: } yading@10: } yading@10: if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) { yading@10: s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) / yading@10: (3 << (s->exp_strategy[blk][CPL_CH] - 1)); yading@10: } yading@10: yading@10: /* decode exponents for each channel */ yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) { yading@10: if (s->exp_strategy[blk][ch] != EXP_REUSE) { yading@10: s->dexps[ch][0] = get_bits(gbc, 4) << !ch; yading@10: if (decode_exponents(gbc, s->exp_strategy[blk][ch], yading@10: s->num_exp_groups[ch], s->dexps[ch][0], yading@10: &s->dexps[ch][s->start_freq[ch]+!!ch])) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "exponent out-of-range\n"); yading@10: return -1; yading@10: } yading@10: if (ch != CPL_CH && ch != s->lfe_ch) yading@10: skip_bits(gbc, 2); /* skip gainrng */ yading@10: } yading@10: } yading@10: yading@10: /* bit allocation information */ yading@10: if (s->bit_allocation_syntax) { yading@10: if (get_bits1(gbc)) { yading@10: s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift; yading@10: s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift; yading@10: s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)]; yading@10: s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)]; yading@10: s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)]; yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); yading@10: } else if (!blk) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must " yading@10: "be present in block 0\n"); yading@10: return -1; yading@10: } yading@10: } yading@10: yading@10: /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */ yading@10: if (!s->eac3 || !blk) { yading@10: if (s->snr_offset_strategy && get_bits1(gbc)) { yading@10: int snr = 0; yading@10: int csnr; yading@10: csnr = (get_bits(gbc, 6) - 15) << 4; yading@10: for (i = ch = !cpl_in_use; ch <= s->channels; ch++) { yading@10: /* snr offset */ yading@10: if (ch == i || s->snr_offset_strategy == 2) yading@10: snr = (csnr + get_bits(gbc, 4)) << 2; yading@10: /* run at least last bit allocation stage if snr offset changes */ yading@10: if (blk && s->snr_offset[ch] != snr) { yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1); yading@10: } yading@10: s->snr_offset[ch] = snr; yading@10: yading@10: /* fast gain (normal AC-3 only) */ yading@10: if (!s->eac3) { yading@10: int prev = s->fast_gain[ch]; yading@10: s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)]; yading@10: /* run last 2 bit allocation stages if fast gain changes */ yading@10: if (blk && prev != s->fast_gain[ch]) yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); yading@10: } yading@10: } yading@10: } else if (!s->eac3 && !blk) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n"); yading@10: return -1; yading@10: } yading@10: } yading@10: yading@10: /* fast gain (E-AC-3 only) */ yading@10: if (s->fast_gain_syntax && get_bits1(gbc)) { yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) { yading@10: int prev = s->fast_gain[ch]; yading@10: s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)]; yading@10: /* run last 2 bit allocation stages if fast gain changes */ yading@10: if (blk && prev != s->fast_gain[ch]) yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); yading@10: } yading@10: } else if (s->eac3 && !blk) { yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) yading@10: s->fast_gain[ch] = ff_ac3_fast_gain_tab[4]; yading@10: } yading@10: yading@10: /* E-AC-3 to AC-3 converter SNR offset */ yading@10: if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) { yading@10: skip_bits(gbc, 10); // skip converter snr offset yading@10: } yading@10: yading@10: /* coupling leak information */ yading@10: if (cpl_in_use) { yading@10: if (s->first_cpl_leak || get_bits1(gbc)) { yading@10: int fl = get_bits(gbc, 3); yading@10: int sl = get_bits(gbc, 3); yading@10: /* run last 2 bit allocation stages for coupling channel if yading@10: coupling leak changes */ yading@10: if (blk && (fl != s->bit_alloc_params.cpl_fast_leak || yading@10: sl != s->bit_alloc_params.cpl_slow_leak)) { yading@10: bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2); yading@10: } yading@10: s->bit_alloc_params.cpl_fast_leak = fl; yading@10: s->bit_alloc_params.cpl_slow_leak = sl; yading@10: } else if (!s->eac3 && !blk) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must " yading@10: "be present in block 0\n"); yading@10: return -1; yading@10: } yading@10: s->first_cpl_leak = 0; yading@10: } yading@10: yading@10: /* delta bit allocation information */ yading@10: if (s->dba_syntax && get_bits1(gbc)) { yading@10: /* delta bit allocation exists (strategy) */ yading@10: for (ch = !cpl_in_use; ch <= fbw_channels; ch++) { yading@10: s->dba_mode[ch] = get_bits(gbc, 2); yading@10: if (s->dba_mode[ch] == DBA_RESERVED) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n"); yading@10: return -1; yading@10: } yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); yading@10: } yading@10: /* channel delta offset, len and bit allocation */ yading@10: for (ch = !cpl_in_use; ch <= fbw_channels; ch++) { yading@10: if (s->dba_mode[ch] == DBA_NEW) { yading@10: s->dba_nsegs[ch] = get_bits(gbc, 3) + 1; yading@10: for (seg = 0; seg < s->dba_nsegs[ch]; seg++) { yading@10: s->dba_offsets[ch][seg] = get_bits(gbc, 5); yading@10: s->dba_lengths[ch][seg] = get_bits(gbc, 4); yading@10: s->dba_values[ch][seg] = get_bits(gbc, 3); yading@10: } yading@10: /* run last 2 bit allocation stages if new dba values */ yading@10: bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2); yading@10: } yading@10: } yading@10: } else if (blk == 0) { yading@10: for (ch = 0; ch <= s->channels; ch++) { yading@10: s->dba_mode[ch] = DBA_NONE; yading@10: } yading@10: } yading@10: yading@10: /* Bit allocation */ yading@10: for (ch = !cpl_in_use; ch <= s->channels; ch++) { yading@10: if (bit_alloc_stages[ch] > 2) { yading@10: /* Exponent mapping into PSD and PSD integration */ yading@10: ff_ac3_bit_alloc_calc_psd(s->dexps[ch], yading@10: s->start_freq[ch], s->end_freq[ch], yading@10: s->psd[ch], s->band_psd[ch]); yading@10: } yading@10: if (bit_alloc_stages[ch] > 1) { yading@10: /* Compute excitation function, Compute masking curve, and yading@10: Apply delta bit allocation */ yading@10: if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch], yading@10: s->start_freq[ch], s->end_freq[ch], yading@10: s->fast_gain[ch], (ch == s->lfe_ch), yading@10: s->dba_mode[ch], s->dba_nsegs[ch], yading@10: s->dba_offsets[ch], s->dba_lengths[ch], yading@10: s->dba_values[ch], s->mask[ch])) { yading@10: av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n"); yading@10: return -1; yading@10: } yading@10: } yading@10: if (bit_alloc_stages[ch] > 0) { yading@10: /* Compute bit allocation */ yading@10: const uint8_t *bap_tab = s->channel_uses_aht[ch] ? yading@10: ff_eac3_hebap_tab : ff_ac3_bap_tab; yading@10: s->ac3dsp.bit_alloc_calc_bap(s->mask[ch], s->psd[ch], yading@10: s->start_freq[ch], s->end_freq[ch], yading@10: s->snr_offset[ch], yading@10: s->bit_alloc_params.floor, yading@10: bap_tab, s->bap[ch]); yading@10: } yading@10: } yading@10: yading@10: /* unused dummy data */ yading@10: if (s->skip_syntax && get_bits1(gbc)) { yading@10: int skipl = get_bits(gbc, 9); yading@10: while (skipl--) yading@10: skip_bits(gbc, 8); yading@10: } yading@10: yading@10: /* unpack the transform coefficients yading@10: this also uncouples channels if coupling is in use. */ yading@10: decode_transform_coeffs(s, blk); yading@10: yading@10: /* TODO: generate enhanced coupling coordinates and uncouple */ yading@10: yading@10: /* recover coefficients if rematrixing is in use */ yading@10: if (s->channel_mode == AC3_CHMODE_STEREO) yading@10: do_rematrixing(s); yading@10: yading@10: /* apply scaling to coefficients (headroom, dynrng) */ yading@10: for (ch = 1; ch <= s->channels; ch++) { yading@10: float gain = 1.0 / 4194304.0f; yading@10: if (s->channel_mode == AC3_CHMODE_DUALMONO) { yading@10: gain *= s->dynamic_range[2 - ch]; yading@10: } else { yading@10: gain *= s->dynamic_range[0]; yading@10: } yading@10: s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch], yading@10: s->fixed_coeffs[ch], gain, 256); yading@10: } yading@10: yading@10: /* apply spectral extension to high frequency bins */ yading@10: if (s->spx_in_use && CONFIG_EAC3_DECODER) { yading@10: ff_eac3_apply_spectral_extension(s); yading@10: } yading@10: yading@10: /* downmix and MDCT. order depends on whether block switching is used for yading@10: any channel in this block. this is because coefficients for the long yading@10: and short transforms cannot be mixed. */ yading@10: downmix_output = s->channels != s->out_channels && yading@10: !((s->output_mode & AC3_OUTPUT_LFEON) && yading@10: s->fbw_channels == s->out_channels); yading@10: if (different_transforms) { yading@10: /* the delay samples have already been downmixed, so we upmix the delay yading@10: samples in order to reconstruct all channels before downmixing. */ yading@10: if (s->downmixed) { yading@10: s->downmixed = 0; yading@10: ac3_upmix_delay(s); yading@10: } yading@10: yading@10: do_imdct(s, s->channels); yading@10: yading@10: if (downmix_output) { yading@10: s->ac3dsp.downmix(s->outptr, s->downmix_coeffs, yading@10: s->out_channels, s->fbw_channels, 256); yading@10: } yading@10: } else { yading@10: if (downmix_output) { yading@10: s->ac3dsp.downmix(s->xcfptr + 1, s->downmix_coeffs, yading@10: s->out_channels, s->fbw_channels, 256); yading@10: } yading@10: yading@10: if (downmix_output && !s->downmixed) { yading@10: s->downmixed = 1; yading@10: s->ac3dsp.downmix(s->dlyptr, s->downmix_coeffs, s->out_channels, yading@10: s->fbw_channels, 128); yading@10: } yading@10: yading@10: do_imdct(s, s->out_channels); yading@10: } yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: /** yading@10: * Decode a single AC-3 frame. yading@10: */ yading@10: static int ac3_decode_frame(AVCodecContext * avctx, void *data, yading@10: int *got_frame_ptr, AVPacket *avpkt) yading@10: { yading@10: AVFrame *frame = data; yading@10: const uint8_t *buf = avpkt->data; yading@10: int buf_size = avpkt->size; yading@10: AC3DecodeContext *s = avctx->priv_data; yading@10: int blk, ch, err, ret; yading@10: const uint8_t *channel_map; yading@10: const float *output[AC3_MAX_CHANNELS]; yading@10: yading@10: /* copy input buffer to decoder context to avoid reading past the end yading@10: of the buffer, which can be caused by a damaged input stream. */ yading@10: if (buf_size >= 2 && AV_RB16(buf) == 0x770B) { yading@10: // seems to be byte-swapped AC-3 yading@10: int cnt = FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE) >> 1; yading@10: s->dsp.bswap16_buf((uint16_t *)s->input_buffer, (const uint16_t *)buf, cnt); yading@10: } else yading@10: memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE)); yading@10: buf = s->input_buffer; yading@10: /* initialize the GetBitContext with the start of valid AC-3 Frame */ yading@10: init_get_bits(&s->gbc, buf, buf_size * 8); yading@10: yading@10: /* parse the syncinfo */ yading@10: err = parse_frame_header(s); yading@10: yading@10: if (err) { yading@10: switch (err) { yading@10: case AAC_AC3_PARSE_ERROR_SYNC: yading@10: av_log(avctx, AV_LOG_ERROR, "frame sync error\n"); yading@10: return -1; yading@10: case AAC_AC3_PARSE_ERROR_BSID: yading@10: av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n"); yading@10: break; yading@10: case AAC_AC3_PARSE_ERROR_SAMPLE_RATE: yading@10: av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n"); yading@10: break; yading@10: case AAC_AC3_PARSE_ERROR_FRAME_SIZE: yading@10: av_log(avctx, AV_LOG_ERROR, "invalid frame size\n"); yading@10: break; yading@10: case AAC_AC3_PARSE_ERROR_FRAME_TYPE: yading@10: /* skip frame if CRC is ok. otherwise use error concealment. */ yading@10: /* TODO: add support for substreams and dependent frames */ yading@10: if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) { yading@10: av_log(avctx, AV_LOG_ERROR, "unsupported frame type : " yading@10: "skipping frame\n"); yading@10: *got_frame_ptr = 0; yading@10: return s->frame_size; yading@10: } else { yading@10: av_log(avctx, AV_LOG_ERROR, "invalid frame type\n"); yading@10: } yading@10: break; yading@10: default: yading@10: av_log(avctx, AV_LOG_ERROR, "invalid header\n"); yading@10: break; yading@10: } yading@10: } else { yading@10: /* check that reported frame size fits in input buffer */ yading@10: if (s->frame_size > buf_size) { yading@10: av_log(avctx, AV_LOG_ERROR, "incomplete frame\n"); yading@10: err = AAC_AC3_PARSE_ERROR_FRAME_SIZE; yading@10: } else if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) { yading@10: /* check for crc mismatch */ yading@10: if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], yading@10: s->frame_size - 2)) { yading@10: av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n"); yading@10: err = AAC_AC3_PARSE_ERROR_CRC; yading@10: } yading@10: } yading@10: } yading@10: yading@10: /* if frame is ok, set audio parameters */ yading@10: if (!err) { yading@10: avctx->sample_rate = s->sample_rate; yading@10: avctx->bit_rate = s->bit_rate; yading@10: } yading@10: yading@10: /* channel config */ yading@10: if (!err || (s->channels && s->out_channels != s->channels)) { yading@10: s->out_channels = s->channels; yading@10: s->output_mode = s->channel_mode; yading@10: if (s->lfe_on) yading@10: s->output_mode |= AC3_OUTPUT_LFEON; yading@10: if (avctx->request_channels > 0 && avctx->request_channels <= 2 && yading@10: avctx->request_channels < s->channels) { yading@10: s->out_channels = avctx->request_channels; yading@10: s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO; yading@10: s->channel_layout = avpriv_ac3_channel_layout_tab[s->output_mode]; yading@10: } yading@10: avctx->channels = s->out_channels; yading@10: avctx->channel_layout = s->channel_layout; yading@10: yading@10: s->loro_center_mix_level = gain_levels[s-> center_mix_level]; yading@10: s->loro_surround_mix_level = gain_levels[s->surround_mix_level]; yading@10: s->ltrt_center_mix_level = LEVEL_MINUS_3DB; yading@10: s->ltrt_surround_mix_level = LEVEL_MINUS_3DB; yading@10: /* set downmixing coefficients if needed */ yading@10: if (s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) && yading@10: s->fbw_channels == s->out_channels)) { yading@10: set_downmix_coeffs(s); yading@10: } yading@10: } else if (!s->channels) { yading@10: av_log(avctx, AV_LOG_ERROR, "unable to determine channel mode\n"); yading@10: return AVERROR_INVALIDDATA; yading@10: } yading@10: avctx->channels = s->out_channels; yading@10: yading@10: /* set audio service type based on bitstream mode for AC-3 */ yading@10: avctx->audio_service_type = s->bitstream_mode; yading@10: if (s->bitstream_mode == 0x7 && s->channels > 1) yading@10: avctx->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE; yading@10: yading@10: /* get output buffer */ yading@10: frame->nb_samples = s->num_blocks * 256; yading@10: if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) yading@10: return ret; yading@10: yading@10: /* decode the audio blocks */ yading@10: channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on]; yading@10: for (ch = 0; ch < AC3_MAX_CHANNELS; ch++) { yading@10: output[ch] = s->output[ch]; yading@10: s->outptr[ch] = s->output[ch]; yading@10: } yading@10: for (ch = 0; ch < s->channels; ch++) { yading@10: if (ch < s->out_channels) yading@10: s->outptr[channel_map[ch]] = (float *)frame->data[ch]; yading@10: } yading@10: for (blk = 0; blk < s->num_blocks; blk++) { yading@10: if (!err && decode_audio_block(s, blk)) { yading@10: av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n"); yading@10: err = 1; yading@10: } yading@10: if (err) yading@10: for (ch = 0; ch < s->out_channels; ch++) yading@10: memcpy(((float*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], 1024); yading@10: for (ch = 0; ch < s->out_channels; ch++) yading@10: output[ch] = s->outptr[channel_map[ch]]; yading@10: for (ch = 0; ch < s->out_channels; ch++) { yading@10: if (!ch || channel_map[ch]) yading@10: s->outptr[channel_map[ch]] += AC3_BLOCK_SIZE; yading@10: } yading@10: } yading@10: yading@10: av_frame_set_decode_error_flags(frame, err ? FF_DECODE_ERROR_INVALID_BITSTREAM : 0); yading@10: yading@10: /* keep last block for error concealment in next frame */ yading@10: for (ch = 0; ch < s->out_channels; ch++) yading@10: memcpy(s->output[ch], output[ch], 1024); yading@10: yading@10: *got_frame_ptr = 1; yading@10: yading@10: return FFMIN(buf_size, s->frame_size); yading@10: } yading@10: yading@10: /** yading@10: * Uninitialize the AC-3 decoder. yading@10: */ yading@10: static av_cold int ac3_decode_end(AVCodecContext *avctx) yading@10: { yading@10: AC3DecodeContext *s = avctx->priv_data; yading@10: ff_mdct_end(&s->imdct_512); yading@10: ff_mdct_end(&s->imdct_256); yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: #define OFFSET(x) offsetof(AC3DecodeContext, x) yading@10: #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM) yading@10: static const AVOption options[] = { yading@10: { "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 1.0, PAR }, yading@10: yading@10: {"dmix_mode", "Preferred Stereo Downmix Mode", OFFSET(preferred_stereo_downmix), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, 2, 0, "dmix_mode"}, yading@10: {"ltrt_cmixlev", "Lt/Rt Center Mix Level", OFFSET(ltrt_center_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0}, yading@10: {"ltrt_surmixlev", "Lt/Rt Surround Mix Level", OFFSET(ltrt_surround_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0}, yading@10: {"loro_cmixlev", "Lo/Ro Center Mix Level", OFFSET(loro_center_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0}, yading@10: {"loro_surmixlev", "Lo/Ro Surround Mix Level", OFFSET(loro_surround_mix_level), AV_OPT_TYPE_FLOAT, {.dbl = -1.0 }, -1.0, 2.0, 0}, yading@10: yading@10: { NULL}, yading@10: }; yading@10: yading@10: static const AVClass ac3_decoder_class = { yading@10: .class_name = "AC3 decoder", yading@10: .item_name = av_default_item_name, yading@10: .option = options, yading@10: .version = LIBAVUTIL_VERSION_INT, yading@10: }; yading@10: yading@10: AVCodec ff_ac3_decoder = { yading@10: .name = "ac3", yading@10: .type = AVMEDIA_TYPE_AUDIO, yading@10: .id = AV_CODEC_ID_AC3, yading@10: .priv_data_size = sizeof (AC3DecodeContext), yading@10: .init = ac3_decode_init, yading@10: .close = ac3_decode_end, yading@10: .decode = ac3_decode_frame, yading@10: .capabilities = CODEC_CAP_DR1, yading@10: .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"), yading@10: .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, yading@10: AV_SAMPLE_FMT_NONE }, yading@10: .priv_class = &ac3_decoder_class, yading@10: }; yading@10: yading@10: #if CONFIG_EAC3_DECODER yading@10: static const AVClass eac3_decoder_class = { yading@10: .class_name = "E-AC3 decoder", yading@10: .item_name = av_default_item_name, yading@10: .option = options, yading@10: .version = LIBAVUTIL_VERSION_INT, yading@10: }; yading@10: yading@10: AVCodec ff_eac3_decoder = { yading@10: .name = "eac3", yading@10: .type = AVMEDIA_TYPE_AUDIO, yading@10: .id = AV_CODEC_ID_EAC3, yading@10: .priv_data_size = sizeof (AC3DecodeContext), yading@10: .init = ac3_decode_init, yading@10: .close = ac3_decode_end, yading@10: .decode = ac3_decode_frame, yading@10: .capabilities = CODEC_CAP_DR1, yading@10: .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"), yading@10: .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, yading@10: AV_SAMPLE_FMT_NONE }, yading@10: .priv_class = &eac3_decoder_class, yading@10: }; yading@10: #endif