Libav 0.7.1
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00001 /* 00002 * raw ADTS AAC demuxer 00003 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> 00004 * Copyright (c) 2009 Robert Swain ( rob opendot cl ) 00005 * 00006 * This file is part of Libav. 00007 * 00008 * Libav is free software; you can redistribute it and/or 00009 * modify it under the terms of the GNU Lesser General Public 00010 * License as published by the Free Software Foundation; either 00011 * version 2.1 of the License, or (at your option) any later version. 00012 * 00013 * Libav is distributed in the hope that it will be useful, 00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00016 * Lesser General Public License for more details. 00017 * 00018 * You should have received a copy of the GNU Lesser General Public 00019 * License along with Libav; if not, write to the Free Software 00020 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00021 */ 00022 00023 #include "libavutil/intreadwrite.h" 00024 #include "avformat.h" 00025 #include "rawdec.h" 00026 #include "id3v1.h" 00027 00028 00029 static int adts_aac_probe(AVProbeData *p) 00030 { 00031 int max_frames = 0, first_frames = 0; 00032 int fsize, frames; 00033 uint8_t *buf0 = p->buf; 00034 uint8_t *buf2; 00035 uint8_t *buf; 00036 uint8_t *end = buf0 + p->buf_size - 7; 00037 00038 buf = buf0; 00039 00040 for(; buf < end; buf= buf2+1) { 00041 buf2 = buf; 00042 00043 for(frames = 0; buf2 < end; frames++) { 00044 uint32_t header = AV_RB16(buf2); 00045 if((header&0xFFF6) != 0xFFF0) 00046 break; 00047 fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF; 00048 if(fsize < 7) 00049 break; 00050 buf2 += fsize; 00051 } 00052 max_frames = FFMAX(max_frames, frames); 00053 if(buf == buf0) 00054 first_frames= frames; 00055 } 00056 if (first_frames>=3) return AVPROBE_SCORE_MAX/2+1; 00057 else if(max_frames>500)return AVPROBE_SCORE_MAX/2; 00058 else if(max_frames>=3) return AVPROBE_SCORE_MAX/4; 00059 else if(max_frames>=1) return 1; 00060 else return 0; 00061 } 00062 00063 static int adts_aac_read_header(AVFormatContext *s, 00064 AVFormatParameters *ap) 00065 { 00066 AVStream *st; 00067 00068 st = av_new_stream(s, 0); 00069 if (!st) 00070 return AVERROR(ENOMEM); 00071 00072 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 00073 st->codec->codec_id = s->iformat->value; 00074 st->need_parsing = AVSTREAM_PARSE_FULL; 00075 00076 ff_id3v1_read(s); 00077 00078 //LCM of all possible ADTS sample rates 00079 av_set_pts_info(st, 64, 1, 28224000); 00080 00081 return 0; 00082 } 00083 00084 AVInputFormat ff_aac_demuxer = { 00085 "aac", 00086 NULL_IF_CONFIG_SMALL("raw ADTS AAC"), 00087 0, 00088 adts_aac_probe, 00089 adts_aac_read_header, 00090 ff_raw_read_partial_packet, 00091 .flags= AVFMT_GENERIC_INDEX, 00092 .extensions = "aac", 00093 .value = CODEC_ID_AAC, 00094 };