mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-12 19:18:44 +02:00
134 lines
4.0 KiB
C
134 lines
4.0 KiB
C
/*
|
|
* RAW GSM demuxer
|
|
* Copyright (c) 2011 Justin Ruggles
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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.
|
|
*
|
|
* Libav 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 Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "libavutil/mathematics.h"
|
|
#include "libavutil/opt.h"
|
|
#include "avformat.h"
|
|
#include "internal.h"
|
|
|
|
#define GSM_BLOCK_SIZE 33
|
|
#define GSM_BLOCK_SAMPLES 160
|
|
#define GSM_SAMPLE_RATE 8000
|
|
|
|
typedef struct {
|
|
AVClass *class;
|
|
int sample_rate;
|
|
} GSMDemuxerContext;
|
|
|
|
static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
|
|
{
|
|
int ret, size;
|
|
|
|
size = GSM_BLOCK_SIZE * 32;
|
|
|
|
pkt->pos = avio_tell(s->pb);
|
|
pkt->stream_index = 0;
|
|
|
|
ret = av_get_packet(s->pb, pkt, size);
|
|
if (ret < GSM_BLOCK_SIZE) {
|
|
av_free_packet(pkt);
|
|
return ret < 0 ? ret : AVERROR(EIO);
|
|
}
|
|
pkt->size = ret;
|
|
pkt->duration = ret / GSM_BLOCK_SIZE;
|
|
pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gsm_read_header(AVFormatContext *s, AVFormatParameters *ap)
|
|
{
|
|
GSMDemuxerContext *c = s->priv_data;
|
|
AVStream *st = avformat_new_stream(s, NULL);
|
|
if (!st)
|
|
return AVERROR(ENOMEM);
|
|
|
|
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
|
|
st->codec->codec_id = s->iformat->value;
|
|
st->codec->channels = 1;
|
|
st->codec->sample_rate = c->sample_rate;
|
|
st->codec->block_align = GSM_BLOCK_SIZE;
|
|
st->codec->bit_rate = GSM_BLOCK_SIZE * 8 * c->sample_rate / GSM_BLOCK_SAMPLES;
|
|
|
|
avpriv_set_pts_info(st, 64, GSM_BLOCK_SAMPLES, GSM_SAMPLE_RATE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gsm_read_seek2(AVFormatContext *s, int stream_index, int64_t min_ts,
|
|
int64_t ts, int64_t max_ts, int flags)
|
|
{
|
|
GSMDemuxerContext *c = s->priv_data;
|
|
|
|
/* convert timestamps to file positions */
|
|
if (!(flags & AVSEEK_FLAG_BYTE)) {
|
|
if (stream_index < 0) {
|
|
AVRational bitrate_q = { GSM_BLOCK_SAMPLES, c->sample_rate * GSM_BLOCK_SIZE };
|
|
ts = av_rescale_q(ts, AV_TIME_BASE_Q, bitrate_q);
|
|
min_ts = av_rescale_q(min_ts, AV_TIME_BASE_Q, bitrate_q);
|
|
max_ts = av_rescale_q(max_ts, AV_TIME_BASE_Q, bitrate_q);
|
|
} else {
|
|
ts *= GSM_BLOCK_SIZE;
|
|
min_ts *= GSM_BLOCK_SIZE;
|
|
max_ts *= GSM_BLOCK_SIZE;
|
|
}
|
|
}
|
|
/* round to nearest block boundary */
|
|
ts = (ts + GSM_BLOCK_SIZE / 2) / GSM_BLOCK_SIZE * GSM_BLOCK_SIZE;
|
|
ts = FFMAX(0, ts);
|
|
|
|
/* handle min/max */
|
|
while (ts < min_ts)
|
|
ts += GSM_BLOCK_SIZE;
|
|
while (ts > max_ts)
|
|
ts -= GSM_BLOCK_SIZE;
|
|
if (ts < min_ts || ts > max_ts)
|
|
return -1;
|
|
|
|
return avio_seek(s->pb, ts, SEEK_SET);
|
|
}
|
|
|
|
static const AVOption options[] = {
|
|
{ "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
|
|
AV_OPT_TYPE_INT, {.dbl = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
|
|
AV_OPT_FLAG_DECODING_PARAM },
|
|
{ NULL },
|
|
};
|
|
|
|
static const AVClass class = {
|
|
.class_name = "gsm demuxer",
|
|
.item_name = av_default_item_name,
|
|
.option = options,
|
|
.version = LIBAVUTIL_VERSION_INT,
|
|
};
|
|
|
|
AVInputFormat ff_gsm_demuxer = {
|
|
.name = "gsm",
|
|
.long_name = NULL_IF_CONFIG_SMALL("raw GSM"),
|
|
.priv_data_size = sizeof(GSMDemuxerContext),
|
|
.read_header = gsm_read_header,
|
|
.read_packet = gsm_read_packet,
|
|
.read_seek2 = gsm_read_seek2,
|
|
.extensions = "gsm",
|
|
.value = CODEC_ID_GSM,
|
|
.priv_class = &class,
|
|
};
|