3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2009 Robert Swain ( rob opendot cl )
6 * This file is part of FFmpeg.
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.
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.
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
23 #include "libavutil/intreadwrite.h"
29 #define ADTS_HEADER_SIZE 7
31 static int adts_aac_probe(AVProbeData *p)
33 int max_frames = 0, first_frames = 0;
35 const uint8_t *buf0 = p->buf;
38 const uint8_t *end = buf0 + p->buf_size - 7;
42 for (; buf < end; buf = buf2 + 1) {
45 for (frames = 0; buf2 < end; frames++) {
46 uint32_t header = AV_RB16(buf2);
47 if ((header & 0xFFF6) != 0xFFF0) {
49 // Found something that isn't an ADTS header, starting
50 // from a position other than the start of the buffer.
51 // Discard the count we've accumulated so far since it
52 // probably was a false positive.
57 fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF;
60 fsize = FFMIN(fsize, end - buf2);
63 max_frames = FFMAX(max_frames, frames);
65 first_frames = frames;
68 if (first_frames >= 3)
69 return AVPROBE_SCORE_EXTENSION + 1;
70 else if (max_frames > 100)
71 return AVPROBE_SCORE_EXTENSION;
72 else if (max_frames >= 3)
73 return AVPROBE_SCORE_EXTENSION / 2;
74 else if (first_frames >= 1)
80 static int adts_aac_read_header(AVFormatContext *s)
85 st = avformat_new_stream(s, NULL);
87 return AVERROR(ENOMEM);
89 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
90 st->codecpar->codec_id = s->iformat->raw_codec_id;
91 st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
94 if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
95 !av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
96 int64_t cur = avio_tell(s->pb);
98 avio_seek(s->pb, cur, SEEK_SET);
101 // skip data until the first ADTS frame is found
102 state = avio_r8(s->pb);
103 while (!avio_feof(s->pb) && avio_tell(s->pb) < s->probesize) {
104 state = (state << 8) | avio_r8(s->pb);
105 if ((state >> 4) != 0xFFF)
107 avio_seek(s->pb, -2, SEEK_CUR);
110 if ((state >> 4) != 0xFFF)
111 return AVERROR_INVALIDDATA;
113 // LCM of all possible ADTS sample rates
114 avpriv_set_pts_info(st, 64, 1, 28224000);
119 static int adts_aac_read_packet(AVFormatContext *s, AVPacket *pkt)
123 ret = av_get_packet(s->pb, pkt, ADTS_HEADER_SIZE);
126 if (ret < ADTS_HEADER_SIZE) {
127 av_packet_unref(pkt);
131 if ((AV_RB16(pkt->data) >> 4) != 0xfff) {
132 av_packet_unref(pkt);
133 return AVERROR_INVALIDDATA;
136 fsize = (AV_RB32(pkt->data + 3) >> 13) & 0x1FFF;
137 if (fsize < ADTS_HEADER_SIZE) {
138 av_packet_unref(pkt);
139 return AVERROR_INVALIDDATA;
142 ret = av_append_packet(s->pb, pkt, fsize - ADTS_HEADER_SIZE);
144 av_packet_unref(pkt);
149 AVInputFormat ff_aac_demuxer = {
151 .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"),
152 .read_probe = adts_aac_probe,
153 .read_header = adts_aac_read_header,
154 .read_packet = adts_aac_read_packet,
155 .flags = AVFMT_GENERIC_INDEX,
157 .mime_type = "audio/aac,audio/aacp,audio/x-aac",
158 .raw_codec_id = AV_CODEC_ID_AAC,