| /* |
| * AC-3 parser |
| * Copyright (c) 2003 Fabrice Bellard |
| * Copyright (c) 2003 Michael Niedermayer |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "config_components.h" |
| |
| #include "libavutil/channel_layout.h" |
| #include "libavutil/mem.h" |
| #include "parser.h" |
| #include "ac3defs.h" |
| #include "ac3tab.h" |
| #include "ac3_parser.h" |
| #include "ac3_parser_internal.h" |
| #include "aac_ac3_parser.h" |
| #include "get_bits.h" |
| |
| |
| #define AC3_HEADER_SIZE 7 |
| |
| #if CONFIG_AC3_PARSER |
| |
| static const uint8_t eac3_blocks[4] = { |
| 1, 2, 3, 6 |
| }; |
| |
| /** |
| * Table for center mix levels |
| * reference: Section 5.4.2.4 cmixlev |
| */ |
| static const uint8_t center_levels[4] = { 4, 5, 6, 5 }; |
| |
| /** |
| * Table for surround mix levels |
| * reference: Section 5.4.2.5 surmixlev |
| */ |
| static const uint8_t surround_levels[4] = { 4, 6, 7, 6 }; |
| |
| /*** Chromium: vvv end #if CONFIG_AC3_PARSER */ |
| #endif |
| /*** Chromium: ^^^ end #if CONFIG_AC3_PARSER */ |
| |
| int ff_ac3_find_syncword(const uint8_t *buf, int buf_size) |
| { |
| int i; |
| |
| for (i = 1; i < buf_size; i += 2) { |
| if (buf[i] == 0x77 || buf[i] == 0x0B) { |
| if ((buf[i] ^ buf[i-1]) == (0x77 ^ 0x0B)) { |
| i--; |
| break; |
| } else if ((buf[i] ^ buf[i+1]) == (0x77 ^ 0x0B)) { |
| break; |
| } |
| } |
| } |
| if (i >= buf_size) |
| return AVERROR_INVALIDDATA; |
| |
| return i; |
| } |
| |
| /*** Chromium: vvv restart #if CONFIG_AC3_PARSER */ |
| #if CONFIG_AC3_PARSER |
| /*** Chromium: ^^^ restart #if CONFIG_AC3_PARSER */ |
| |
| /** |
| * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream. |
| * GetBitContext within AC3DecodeContext must point to |
| * the start of the synchronized AC-3 bitstream. |
| */ |
| static int ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr) |
| { |
| /* read the rest of the bsi. read twice for dual mono mode. */ |
| for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) { |
| hdr->dialog_normalization[i] = -get_bits(gbc, 5); |
| hdr->compression_exists[i] = get_bits1(gbc); |
| if (hdr->compression_exists[i]) |
| hdr->heavy_dynamic_range[i] = get_bits(gbc, 8); |
| if (get_bits1(gbc)) |
| skip_bits(gbc, 8); //skip language code |
| if (get_bits1(gbc)) |
| skip_bits(gbc, 7); //skip audio production information |
| } |
| |
| skip_bits(gbc, 2); //skip copyright bit and original bitstream bit |
| |
| /* skip the timecodes or parse the Alternate Bit Stream Syntax */ |
| if (hdr->bitstream_id != 6) { |
| if (get_bits1(gbc)) |
| skip_bits(gbc, 14); //skip timecode1 |
| if (get_bits1(gbc)) |
| skip_bits(gbc, 14); //skip timecode2 |
| } else { |
| if (get_bits1(gbc)) { |
| hdr->preferred_downmix = get_bits(gbc, 2); |
| hdr->center_mix_level_ltrt = get_bits(gbc, 3); |
| hdr->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7); |
| hdr->center_mix_level = get_bits(gbc, 3); |
| hdr->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7); |
| } |
| if (get_bits1(gbc)) { |
| hdr->dolby_surround_ex_mode = get_bits(gbc, 2); |
| hdr->dolby_headphone_mode = get_bits(gbc, 2); |
| skip_bits(gbc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo (1) |
| } |
| } |
| |
| /* skip additional bitstream info */ |
| if (get_bits1(gbc)) { |
| int i = get_bits(gbc, 6); |
| do { |
| skip_bits(gbc, 8); |
| } while (i--); |
| } |
| |
| return 0; |
| } |
| |
| static int eac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr) |
| { |
| if (hdr->frame_type == EAC3_FRAME_TYPE_RESERVED) |
| return AC3_PARSE_ERROR_FRAME_TYPE; |
| if (hdr->substreamid) |
| return AC3_PARSE_ERROR_FRAME_TYPE; |
| |
| skip_bits(gbc, 5); // skip bitstream id |
| |
| /* volume control params */ |
| for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) { |
| hdr->dialog_normalization[i] = -get_bits(gbc, 5); |
| hdr->compression_exists[i] = get_bits1(gbc); |
| if (hdr->compression_exists[i]) |
| hdr->heavy_dynamic_range[i] = get_bits(gbc, 8); |
| } |
| |
| /* dependent stream channel map */ |
| if (hdr->frame_type == EAC3_FRAME_TYPE_DEPENDENT) { |
| hdr->channel_map_present = get_bits1(gbc); |
| if (hdr->channel_map_present) { |
| int64_t channel_layout = 0; |
| int channel_map = get_bits(gbc, 16); |
| |
| for (int i = 0; i < 16; i++) |
| if (channel_map & (1 << (EAC3_MAX_CHANNELS - i - 1))) |
| channel_layout |= ff_eac3_custom_channel_map_locations[i][1]; |
| |
| if (av_popcount64(channel_layout) > EAC3_MAX_CHANNELS) { |
| return AC3_PARSE_ERROR_CHANNEL_MAP; |
| } |
| hdr->channel_map = channel_map; |
| } |
| } |
| |
| /* mixing metadata */ |
| if (get_bits1(gbc)) { |
| /* center and surround mix levels */ |
| if (hdr->channel_mode > AC3_CHMODE_STEREO) { |
| hdr->preferred_downmix = get_bits(gbc, 2); |
| if (hdr->channel_mode & 1) { |
| /* if three front channels exist */ |
| hdr->center_mix_level_ltrt = get_bits(gbc, 3); |
| hdr->center_mix_level = get_bits(gbc, 3); |
| } |
| if (hdr->channel_mode & 4) { |
| /* if a surround channel exists */ |
| hdr->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7); |
| hdr->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7); |
| } |
| } |
| |
| /* lfe mix level */ |
| if (hdr->lfe_on && (hdr->lfe_mix_level_exists = get_bits1(gbc))) { |
| hdr->lfe_mix_level = get_bits(gbc, 5); |
| } |
| |
| /* info for mixing with other streams and substreams */ |
| if (hdr->frame_type == EAC3_FRAME_TYPE_INDEPENDENT) { |
| for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) { |
| // TODO: apply program scale factor |
| if (get_bits1(gbc)) { |
| skip_bits(gbc, 6); // skip program scale factor |
| } |
| } |
| if (get_bits1(gbc)) { |
| skip_bits(gbc, 6); // skip external program scale factor |
| } |
| /* skip mixing parameter data */ |
| switch(get_bits(gbc, 2)) { |
| case 1: skip_bits(gbc, 5); break; |
| case 2: skip_bits(gbc, 12); break; |
| case 3: { |
| int mix_data_size = (get_bits(gbc, 5) + 2) << 3; |
| skip_bits_long(gbc, mix_data_size); |
| break; |
| } |
| } |
| /* skip pan information for mono or dual mono source */ |
| if (hdr->channel_mode < AC3_CHMODE_STEREO) { |
| for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) { |
| if (get_bits1(gbc)) { |
| /* note: this is not in the ATSC A/52B specification |
| reference: ETSI TS 102 366 V1.1.1 |
| section: E.1.3.1.25 */ |
| skip_bits(gbc, 8); // skip pan mean direction index |
| skip_bits(gbc, 6); // skip reserved paninfo bits |
| } |
| } |
| } |
| /* skip mixing configuration information */ |
| if (get_bits1(gbc)) { |
| for (int i = 0; i < hdr->num_blocks; i++) { |
| if (hdr->num_blocks == 1 || get_bits1(gbc)) { |
| skip_bits(gbc, 5); |
| } |
| } |
| } |
| } |
| } |
| |
| /* informational metadata */ |
| if (get_bits1(gbc)) { |
| hdr->bitstream_mode = get_bits(gbc, 3); |
| skip_bits(gbc, 2); // skip copyright bit and original bitstream bit |
| if (hdr->channel_mode == AC3_CHMODE_STEREO) { |
| hdr->dolby_surround_mode = get_bits(gbc, 2); |
| hdr->dolby_headphone_mode = get_bits(gbc, 2); |
| } |
| if (hdr->channel_mode >= AC3_CHMODE_2F2R) { |
| hdr->dolby_surround_ex_mode = get_bits(gbc, 2); |
| } |
| for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) { |
| if (get_bits1(gbc)) { |
| skip_bits(gbc, 8); // skip mix level, room type, and A/D converter type |
| } |
| } |
| if (hdr->sr_code != EAC3_SR_CODE_REDUCED) { |
| skip_bits1(gbc); // skip source sample rate code |
| } |
| } |
| |
| /* converter synchronization flag |
| If frames are less than six blocks, this bit should be turned on |
| once every 6 blocks to indicate the start of a frame set. |
| reference: RFC 4598, Section 2.1.3 Frame Sets */ |
| if (hdr->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && hdr->num_blocks != 6) { |
| skip_bits1(gbc); // skip converter synchronization flag |
| } |
| |
| /* original frame size code if this stream was converted from AC-3 */ |
| if (hdr->frame_type == EAC3_FRAME_TYPE_AC3_CONVERT && |
| (hdr->num_blocks == 6 || get_bits1(gbc))) { |
| skip_bits(gbc, 6); // skip frame size code |
| } |
| |
| /* additional bitstream info */ |
| if (get_bits1(gbc)) { |
| int addbsil = get_bits(gbc, 6); |
| for (int i = 0; i < addbsil + 1; i++) { |
| if (i == 0) { |
| /* In this 8 bit chunk, the LSB is equal to flag_ec3_extension_type_a |
| which can be used to detect Atmos presence */ |
| skip_bits(gbc, 7); |
| hdr->eac3_extension_type_a = get_bits1(gbc); |
| if (hdr->eac3_extension_type_a) { |
| hdr->complexity_index_type_a = get_bits(gbc, 8); |
| i++; |
| } |
| } else { |
| skip_bits(gbc, 8); // skip additional bit stream info |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr) |
| { |
| int frame_size_code; |
| |
| memset(hdr, 0, sizeof(*hdr)); |
| |
| hdr->sync_word = get_bits(gbc, 16); |
| if(hdr->sync_word != 0x0B77) |
| return AC3_PARSE_ERROR_SYNC; |
| |
| /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */ |
| hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F; |
| if(hdr->bitstream_id > 16) |
| return AC3_PARSE_ERROR_BSID; |
| |
| hdr->num_blocks = 6; |
| hdr->ac3_bit_rate_code = -1; |
| |
| /* set default mix levels */ |
| hdr->center_mix_level = 5; // -4.5dB |
| hdr->surround_mix_level = 6; // -6.0dB |
| |
| /* set default dolby surround mode */ |
| hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED; |
| |
| if(hdr->bitstream_id <= 10) { |
| /* Normal AC-3 */ |
| hdr->crc1 = get_bits(gbc, 16); |
| hdr->sr_code = get_bits(gbc, 2); |
| if(hdr->sr_code == 3) |
| return AC3_PARSE_ERROR_SAMPLE_RATE; |
| |
| frame_size_code = get_bits(gbc, 6); |
| if(frame_size_code > 37) |
| return AC3_PARSE_ERROR_FRAME_SIZE; |
| |
| hdr->ac3_bit_rate_code = (frame_size_code >> 1); |
| |
| skip_bits(gbc, 5); // skip bsid, already got it |
| |
| hdr->bitstream_mode = get_bits(gbc, 3); |
| hdr->channel_mode = get_bits(gbc, 3); |
| |
| if(hdr->channel_mode == AC3_CHMODE_STEREO) { |
| hdr->dolby_surround_mode = get_bits(gbc, 2); |
| } else { |
| if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO) |
| hdr-> center_mix_level = center_levels[get_bits(gbc, 2)]; |
| if(hdr->channel_mode & 4) |
| hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)]; |
| } |
| hdr->lfe_on = get_bits1(gbc); |
| |
| hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8; |
| hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift; |
| hdr->bit_rate = (ff_ac3_bitrate_tab[hdr->ac3_bit_rate_code] * 1000) >> hdr->sr_shift; |
| hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on; |
| hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2; |
| hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT; |
| hdr->substreamid = 0; |
| |
| int ret = ac3_parse_header(gbc, hdr); |
| if (ret < 0) |
| return ret; |
| } else { |
| /* Enhanced AC-3 */ |
| hdr->crc1 = 0; |
| hdr->frame_type = get_bits(gbc, 2); |
| if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED) |
| return AC3_PARSE_ERROR_FRAME_TYPE; |
| |
| hdr->substreamid = get_bits(gbc, 3); |
| |
| hdr->frame_size = (get_bits(gbc, 11) + 1) << 1; |
| if(hdr->frame_size < AC3_HEADER_SIZE) |
| return AC3_PARSE_ERROR_FRAME_SIZE; |
| |
| hdr->sr_code = get_bits(gbc, 2); |
| if (hdr->sr_code == 3) { |
| int sr_code2 = get_bits(gbc, 2); |
| if(sr_code2 == 3) |
| return AC3_PARSE_ERROR_SAMPLE_RATE; |
| hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2; |
| hdr->sr_shift = 1; |
| } else { |
| hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)]; |
| hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code]; |
| hdr->sr_shift = 0; |
| } |
| |
| hdr->channel_mode = get_bits(gbc, 3); |
| hdr->lfe_on = get_bits1(gbc); |
| |
| hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate / |
| (hdr->num_blocks * 256); |
| hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on; |
| |
| int ret = eac3_parse_header(gbc, hdr); |
| if (ret < 0) |
| return ret; |
| } |
| hdr->channel_layout = ff_ac3_channel_layout_tab[hdr->channel_mode]; |
| if (hdr->lfe_on) |
| hdr->channel_layout |= AV_CH_LOW_FREQUENCY; |
| |
| return 0; |
| } |
| |
| // TODO: Better way to pass AC3HeaderInfo fields to mov muxer. |
| int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf, |
| size_t size) |
| { |
| GetBitContext gb; |
| AC3HeaderInfo *hdr; |
| int err; |
| |
| if (!*phdr) |
| *phdr = av_mallocz(sizeof(AC3HeaderInfo)); |
| if (!*phdr) |
| return AVERROR(ENOMEM); |
| hdr = *phdr; |
| |
| err = init_get_bits8(&gb, buf, size); |
| if (err < 0) |
| return AVERROR_INVALIDDATA; |
| err = ff_ac3_parse_header(&gb, hdr); |
| if (err < 0) |
| return AVERROR_INVALIDDATA; |
| |
| return get_bits_count(&gb); |
| } |
| |
| int av_ac3_parse_header(const uint8_t *buf, size_t size, |
| uint8_t *bitstream_id, uint16_t *frame_size) |
| { |
| GetBitContext gb; |
| AC3HeaderInfo hdr; |
| uint8_t tmp[32 + AV_INPUT_BUFFER_PADDING_SIZE]; |
| int err; |
| |
| size = FFMIN(32, size); |
| memcpy(tmp, buf, size); |
| memset(tmp + size, 0, AV_INPUT_BUFFER_PADDING_SIZE); |
| err = init_get_bits8(&gb, tmp, size); |
| if (err < 0) |
| return AVERROR_INVALIDDATA; |
| err = ff_ac3_parse_header(&gb, &hdr); |
| if (err < 0) |
| return AVERROR_INVALIDDATA; |
| |
| *bitstream_id = hdr.bitstream_id; |
| *frame_size = hdr.frame_size; |
| |
| return 0; |
| } |
| |
| static int ac3_sync(uint64_t state, int *need_next_header, int *new_frame_start) |
| { |
| int err; |
| union { |
| uint64_t u64; |
| uint8_t u8[8 + AV_INPUT_BUFFER_PADDING_SIZE]; |
| } tmp = { av_be2ne64(state) }; |
| AC3HeaderInfo hdr; |
| GetBitContext gbc; |
| |
| if (tmp.u8[1] == 0x77 && tmp.u8[2] == 0x0b) { |
| FFSWAP(uint8_t, tmp.u8[1], tmp.u8[2]); |
| FFSWAP(uint8_t, tmp.u8[3], tmp.u8[4]); |
| FFSWAP(uint8_t, tmp.u8[5], tmp.u8[6]); |
| } |
| |
| init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54); |
| err = ff_ac3_parse_header(&gbc, &hdr); |
| |
| if(err < 0) |
| return 0; |
| |
| *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT); |
| *need_next_header = *new_frame_start || (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT); |
| return hdr.frame_size; |
| } |
| |
| static av_cold int ac3_parse_init(AVCodecParserContext *s1) |
| { |
| AACAC3ParseContext *s = s1->priv_data; |
| s->header_size = AC3_HEADER_SIZE; |
| s->crc_ctx = av_crc_get_table(AV_CRC_16_ANSI); |
| s->sync = ac3_sync; |
| return 0; |
| } |
| |
| |
| const AVCodecParser ff_ac3_parser = { |
| .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 }, |
| .priv_data_size = sizeof(AACAC3ParseContext), |
| .parser_init = ac3_parse_init, |
| .parser_parse = ff_aac_ac3_parse, |
| .parser_close = ff_parse_close, |
| }; |
| |
| #else |
| |
| int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf, |
| size_t size) |
| { |
| return AVERROR(ENOSYS); |
| } |
| |
| int av_ac3_parse_header(const uint8_t *buf, size_t size, |
| uint8_t *bitstream_id, uint16_t *frame_size) |
| { |
| return AVERROR(ENOSYS); |
| } |
| #endif |
