1/* 2 * raw ADTS AAC demuxer 3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> 4 * Copyright (c) 2009 Robert Swain ( rob opendot cl ) 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "libavutil/intreadwrite.h" 24#include "avformat.h" 25#include "internal.h" 26#include "rawdec.h" 27#include "id3v1.h" 28#include "apetag.h" 29 30static int adts_aac_probe(AVProbeData *p) 31{ 32 int max_frames = 0, first_frames = 0; 33 int fsize, frames; 34 const uint8_t *buf0 = p->buf; 35 const uint8_t *buf2; 36 const uint8_t *buf; 37 const uint8_t *end = buf0 + p->buf_size - 7; 38 39 buf = buf0; 40 41 for (; buf < end; buf = buf2 + 1) { 42 buf2 = buf; 43 44 for (frames = 0; buf2 < end; frames++) { 45 uint32_t header = AV_RB16(buf2); 46 if ((header & 0xFFF6) != 0xFFF0) { 47 if (buf != buf0) { 48 // Found something that isn't an ADTS header, starting 49 // from a position other than the start of the buffer. 50 // Discard the count we've accumulated so far since it 51 // probably was a false positive. 52 frames = 0; 53 } 54 break; 55 } 56 fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF; 57 if (fsize < 7) 58 break; 59 fsize = FFMIN(fsize, end - buf2); 60 buf2 += fsize; 61 } 62 max_frames = FFMAX(max_frames, frames); 63 if (buf == buf0) 64 first_frames = frames; 65 } 66 67 if (first_frames >= 3) 68 return AVPROBE_SCORE_EXTENSION + 1; 69 else if (max_frames > 100) 70 return AVPROBE_SCORE_EXTENSION; 71 else if (max_frames >= 3) 72 return AVPROBE_SCORE_EXTENSION / 2; 73 else if (max_frames >= 1) 74 return 1; 75 else 76 return 0; 77} 78 79static int adts_aac_read_header(AVFormatContext *s) 80{ 81 AVStream *st; 82 83 st = avformat_new_stream(s, NULL); 84 if (!st) 85 return AVERROR(ENOMEM); 86 87 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 88 st->codec->codec_id = s->iformat->raw_codec_id; 89 st->need_parsing = AVSTREAM_PARSE_FULL_RAW; 90 91 ff_id3v1_read(s); 92 if (s->pb->seekable && 93 !av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX)) { 94 int64_t cur = avio_tell(s->pb); 95 ff_ape_parse_tag(s); 96 avio_seek(s->pb, cur, SEEK_SET); 97 } 98 99 // LCM of all possible ADTS sample rates 100 avpriv_set_pts_info(st, 64, 1, 28224000); 101 102 return 0; 103} 104 105AVInputFormat ff_aac_demuxer = { 106 .name = "aac", 107 .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"), 108 .read_probe = adts_aac_probe, 109 .read_header = adts_aac_read_header, 110 .read_packet = ff_raw_read_partial_packet, 111 .flags = AVFMT_GENERIC_INDEX, 112 .extensions = "aac", 113 .raw_codec_id = AV_CODEC_ID_AAC, 114}; 115