/* * 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 CodecID expected_codec_id) { int max_frames, first_frames = 0, frames; uint8_t *buf, *buf2, *end; AC3HeaderInfo hdr; GetBitContext gbc; enum CodecID codec_id = CODEC_ID_AC3; max_frames = 0; buf = p->buf; end = buf + p->buf_size; for(; buf < end; buf++) { buf2 = buf; for(frames = 0; buf2 < end; frames++) { init_get_bits(&gbc, buf2, 54); if(ff_ac3_parse_header(&gbc, &hdr) < 0) break; if(buf2 + hdr.frame_size > end || av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2)) break; if (hdr.bitstream_id > 10) codec_id = CODEC_ID_EAC3; buf2 += hdr.frame_size; } max_frames = FFMAX(max_frames, frames); if(buf == p->buf) first_frames = frames; } 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>=4) return AVPROBE_SCORE_MAX/2+1; else if(max_frames>500)return AVPROBE_SCORE_MAX/2; else if(max_frames>=4) return AVPROBE_SCORE_MAX/4; 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, CODEC_ID_AC3); } AVInputFormat ac3_demuxer = { "ac3", NULL_IF_CONFIG_SMALL("raw AC-3"), 0, ac3_probe, ff_raw_audio_read_header, ff_raw_read_partial_packet, .flags= AVFMT_GENERIC_INDEX, .extensions = "ac3", .value = CODEC_ID_AC3, }; #endif #if CONFIG_EAC3_DEMUXER static int eac3_probe(AVProbeData *p) { return ac3_eac3_probe(p, CODEC_ID_EAC3); } AVInputFormat eac3_demuxer = { "eac3", NULL_IF_CONFIG_SMALL("raw E-AC-3"), 0, eac3_probe, ff_raw_audio_read_header, ff_raw_read_partial_packet, .flags= AVFMT_GENERIC_INDEX, .extensions = "eac3", .value = CODEC_ID_EAC3, }; #endif