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FFmpeg/libavformat/vocdec.c

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/*
* 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(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;
AVStream *st;
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);
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
voc->remaining_size = 0;
return 0;
}
int
ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
{
VocDecContext *voc = s->priv_data;
AVCodecContext *dec = st->codec;
AVIOContext *pb = s->pb;
VocType type;
int size, tmp_codec=-1;
int sample_rate = 0;
int channels = 1;
int64_t duration;
int ret;
av_add_index_entry(st,
avio_tell(pb),
voc->pts,
voc->remaining_size,
0,
AVINDEX_KEYFRAME);
while (!voc->remaining_size) {
type = avio_r8(pb);
if (type == VOC_TYPE_EOF)
return AVERROR_EOF;
voc->remaining_size = avio_rl24(pb);
if (!voc->remaining_size) {
if (!s->pb->seekable)
return AVERROR(EIO);
voc->remaining_size = avio_size(pb) - avio_tell(pb);
}
max_size -= 4;
switch (type) {
case VOC_TYPE_VOICE_DATA:
if (!dec->sample_rate) {
dec->sample_rate = 1000000 / (256 - avio_r8(pb));
if (sample_rate)
dec->sample_rate = sample_rate;
avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
dec->channels = channels;
dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);
} else
avio_skip(pb, 1);
tmp_codec = avio_r8(pb);
voc->remaining_size -= 2;
max_size -= 2;
channels = 1;
break;
case VOC_TYPE_VOICE_DATA_CONT:
break;
case VOC_TYPE_EXTENDED:
sample_rate = avio_rl16(pb);
avio_r8(pb);
channels = avio_r8(pb) + 1;
sample_rate = 256000000 / (channels * (65536 - sample_rate));
voc->remaining_size = 0;
max_size -= 4;
break;
case VOC_TYPE_NEW_VOICE_DATA:
if (!dec->sample_rate) {
dec->sample_rate = avio_rl32(pb);
avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
dec->bits_per_coded_sample = avio_r8(pb);
dec->channels = avio_r8(pb);
} else
avio_skip(pb, 6);
tmp_codec = avio_rl16(pb);
avio_skip(pb, 4);
voc->remaining_size -= 12;
max_size -= 12;
break;
default:
avio_skip(pb, voc->remaining_size);
max_size -= voc->remaining_size;
voc->remaining_size = 0;
break;
}
}
if (tmp_codec >= 0) {
tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec);
if (dec->codec_id == AV_CODEC_ID_NONE)
dec->codec_id = tmp_codec;
else if (dec->codec_id != tmp_codec)
av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n");
if (dec->codec_id == AV_CODEC_ID_NONE) {
if (s->audio_codec_id == AV_CODEC_ID_NONE) {
av_log(s, AV_LOG_ERROR, "unknown codec tag\n");
return AVERROR(EINVAL);
}
av_log(s, AV_LOG_WARNING, "unknown codec tag\n");
}
}
dec->bit_rate = dec->sample_rate * dec->channels * dec->bits_per_coded_sample;
if (max_size <= 0)
max_size = 2048;
size = FFMIN(voc->remaining_size, max_size);
voc->remaining_size -= size;
ret = av_get_packet(pb, pkt, size);
pkt->dts = pkt->pts = voc->pts;
duration = av_get_audio_frame_duration(st->codec, size);
if (duration > 0 && voc->pts != AV_NOPTS_VALUE)
voc->pts += duration;
else
voc->pts = AV_NOPTS_VALUE;
return ret;
}
static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
{
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 = s->streams[stream_index];
int index = av_index_search_timestamp(st, timestamp, flags);
if (index >= 0 && index < st->nb_index_entries - 1) {
AVIndexEntry *e = &st->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->nb_index_entries && st->index_entries[0].timestamp <= timestamp) {
AVIndexEntry *e = &st->index_entries[st->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 },
};