diff options
Diffstat (limited to 'libavformat/astdec.c')
| -rw-r--r-- | libavformat/astdec.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/libavformat/astdec.c b/libavformat/astdec.c new file mode 100644 index 0000000000..92c208d044 --- /dev/null +++ b/libavformat/astdec.c @@ -0,0 +1,122 @@ +/* + * AST demuxer + * Copyright (c) 2012 Paul B Mahol + * + * 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/channel_layout.h" +#include "libavutil/intreadwrite.h" +#include "avformat.h" +#include "internal.h" +#include "ast.h" + +static int ast_probe(AVProbeData *p) +{ + if (AV_RL32(p->buf) != MKTAG('S','T','R','M')) + return 0; + + if (!AV_RB16(p->buf + 10) || + !AV_RB16(p->buf + 12) || AV_RB16(p->buf + 12) > 256 || + !AV_RB32(p->buf + 16) || AV_RB32(p->buf + 16) > 8*48000) + return AVPROBE_SCORE_MAX / 8; + + return AVPROBE_SCORE_MAX / 3 * 2; +} + +static int ast_read_header(AVFormatContext *s) +{ + int depth; + AVStream *st; + + st = avformat_new_stream(s, NULL); + if (!st) + return AVERROR(ENOMEM); + + avio_skip(s->pb, 8); + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb)); + + depth = avio_rb16(s->pb); + if (depth != 16) { + avpriv_request_sample(s, "depth %d", depth); + return AVERROR_INVALIDDATA; + } + + st->codec->channels = avio_rb16(s->pb); + if (!st->codec->channels) + return AVERROR_INVALIDDATA; + + if (st->codec->channels == 2) + st->codec->channel_layout = AV_CH_LAYOUT_STEREO; + else if (st->codec->channels == 4) + st->codec->channel_layout = AV_CH_LAYOUT_4POINT0; + + avio_skip(s->pb, 2); + st->codec->sample_rate = avio_rb32(s->pb); + if (st->codec->sample_rate <= 0) + return AVERROR_INVALIDDATA; + st->start_time = 0; + st->duration = avio_rb32(s->pb); + avio_skip(s->pb, 40); + avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate); + + return 0; +} + +static int ast_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + uint32_t type, size; + int64_t pos; + int ret; + + if (avio_feof(s->pb)) + return AVERROR_EOF; + + pos = avio_tell(s->pb); + type = avio_rl32(s->pb); + size = avio_rb32(s->pb); + if (size > INT_MAX / s->streams[0]->codec->channels) + return AVERROR_INVALIDDATA; + + size *= s->streams[0]->codec->channels; + if ((ret = avio_skip(s->pb, 24)) < 0) // padding + return ret; + + if (type == MKTAG('B','L','C','K')) { + ret = av_get_packet(s->pb, pkt, size); + pkt->stream_index = 0; + pkt->pos = pos; + } else { + av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type); + avio_skip(s->pb, size); + ret = AVERROR_INVALIDDATA; + } + + return ret; +} + +AVInputFormat ff_ast_demuxer = { + .name = "ast", + .long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"), + .read_probe = ast_probe, + .read_header = ast_read_header, + .read_packet = ast_read_packet, + .extensions = "ast", + .flags = AVFMT_GENERIC_INDEX, + .codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0}, +}; |