| /* |
| * RAW AC-3 and E-AC-3 demuxer |
| * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com> |
| * |
| * 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 "libavutil/crc.h" |
| #include "libavcodec/ac3_parser.h" |
| #include "avformat.h" |
| #include "rawdec.h" |
| |
| static int ac3_eac3_probe(AVProbeData *p, enum AVCodecID expected_codec_id) |
| { |
| int max_frames, first_frames = 0, frames; |
| const uint8_t *buf, *buf2, *end; |
| AC3HeaderInfo *phdr = NULL; |
| GetBitContext gbc; |
| enum AVCodecID codec_id = AV_CODEC_ID_AC3; |
| |
| max_frames = 0; |
| buf = p->buf; |
| end = buf + p->buf_size; |
| |
| for(; buf < end; buf++) { |
| if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77) |
| && !(buf[0] == 0x77 && buf[1] == 0x0B) ) |
| continue; |
| buf2 = buf; |
| |
| for(frames = 0; buf2 < end; frames++) { |
| uint8_t buf3[4096]; |
| int i; |
| if(!memcmp(buf2, "\x1\x10\0\0\0\0\0\0", 8)) |
| buf2+=16; |
| if (buf[0] == 0x77 && buf[1] == 0x0B) { |
| for(i=0; i<8; i+=2) { |
| buf3[i ] = buf[i+1]; |
| buf3[i+1] = buf[i ]; |
| } |
| init_get_bits(&gbc, buf3, 54); |
| }else |
| init_get_bits(&gbc, buf2, 54); |
| if(avpriv_ac3_parse_header(&gbc, &phdr) < 0) |
| break; |
| if(buf2 + phdr->frame_size > end) |
| break; |
| if (buf[0] == 0x77 && buf[1] == 0x0B) { |
| av_assert0(phdr->frame_size <= sizeof(buf3)); |
| for(i=8; i<phdr->frame_size; i+=2) { |
| buf3[i ] = buf[i+1]; |
| buf3[i+1] = buf[i ]; |
| } |
| } |
| if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, gbc.buffer + 2, phdr->frame_size - 2)) |
| break; |
| if (phdr->bitstream_id > 10) |
| codec_id = AV_CODEC_ID_EAC3; |
| buf2 += phdr->frame_size; |
| } |
| max_frames = FFMAX(max_frames, frames); |
| if(buf == p->buf) |
| first_frames = frames; |
| } |
| av_freep(&phdr); |
| if(codec_id != expected_codec_id) return 0; |
| // keep this in sync with mp3 probe, both need to avoid |
| // issues with MPEG-files! |
| if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1; |
| else if(max_frames>200)return AVPROBE_SCORE_EXTENSION; |
| else if(max_frames>=4) return AVPROBE_SCORE_EXTENSION/2; |
| else if(max_frames>=1) return 1; |
| else return 0; |
| } |
| |
| #if CONFIG_AC3_DEMUXER |
| static int ac3_probe(AVProbeData *p) |
| { |
| return ac3_eac3_probe(p, AV_CODEC_ID_AC3); |
| } |
| |
| AVInputFormat ff_ac3_demuxer = { |
| .name = "ac3", |
| .long_name = NULL_IF_CONFIG_SMALL("raw AC-3"), |
| .read_probe = ac3_probe, |
| .read_header = ff_raw_audio_read_header, |
| .read_packet = ff_raw_read_partial_packet, |
| .flags= AVFMT_GENERIC_INDEX, |
| .extensions = "ac3", |
| .raw_codec_id = AV_CODEC_ID_AC3, |
| }; |
| #endif |
| |
| #if CONFIG_EAC3_DEMUXER |
| static int eac3_probe(AVProbeData *p) |
| { |
| return ac3_eac3_probe(p, AV_CODEC_ID_EAC3); |
| } |
| |
| AVInputFormat ff_eac3_demuxer = { |
| .name = "eac3", |
| .long_name = NULL_IF_CONFIG_SMALL("raw E-AC-3"), |
| .read_probe = eac3_probe, |
| .read_header = ff_raw_audio_read_header, |
| .read_packet = ff_raw_read_partial_packet, |
| .flags = AVFMT_GENERIC_INDEX, |
| .extensions = "eac3", |
| .raw_codec_id = AV_CODEC_ID_EAC3, |
| }; |
| #endif |
