ffmpeg/libavformat/vocdec.c

111 lines
3.4 KiB
C

/*
* Creative Voice File demuxer.
* Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org>
*
* 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/intreadwrite.h"
#include "voc.h"
#include "internal.h"
static int voc_probe(const AVProbeData *p)
{
int version, check;
if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
return 0;
version = AV_RL16(p->buf + 22);
check = AV_RL16(p->buf + 24);
if (~version + 0x1234 != check)
return 10;
return AVPROBE_SCORE_MAX;
}
static int voc_read_header(AVFormatContext *s)
{
VocDecContext *voc = s->priv_data;
AVIOContext *pb = s->pb;
int header_size;
avio_skip(pb, 20);
header_size = avio_rl16(pb) - 22;
if (header_size != 4) {
av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
return AVERROR(ENOSYS);
}
avio_skip(pb, header_size);
s->ctx_flags |= AVFMTCTX_NOHEADER;
voc->remaining_size = 0;
return 0;
}
static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
{
if (!s->nb_streams) {
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
}
return ff_voc_get_packet(s, pkt, s->streams[0], 0);
}
static int voc_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
VocDecContext *voc = s->priv_data;
AVStream *st;
int index;
if (s->nb_streams < 1) {
av_log(s, AV_LOG_ERROR, "cannot seek while no stream was found yet\n");
return AVERROR(EINVAL);
}
st = s->streams[stream_index];
index = av_index_search_timestamp(st, timestamp, flags);
if (index >= 0 && index < st->internal->nb_index_entries - 1) {
AVIndexEntry *e = &st->internal->index_entries[index];
avio_seek(s->pb, e->pos, SEEK_SET);
voc->pts = e->timestamp;
voc->remaining_size = e->size;
return 0;
} else if (st->internal->nb_index_entries && st->internal->index_entries[0].timestamp <= timestamp) {
AVIndexEntry *e = &st->internal->index_entries[st->internal->nb_index_entries - 1];
// prepare context for seek_frame_generic()
voc->pts = e->timestamp;
voc->remaining_size = e->size;
}
return -1;
}
AVInputFormat ff_voc_demuxer = {
.name = "voc",
.long_name = NULL_IF_CONFIG_SMALL("Creative Voice"),
.priv_data_size = sizeof(VocDecContext),
.read_probe = voc_probe,
.read_header = voc_read_header,
.read_packet = voc_read_packet,
.read_seek = voc_read_seek,
.codec_tag = (const AVCodecTag* const []){ ff_voc_codec_tags, 0 },
};