mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-23 12:43:46 +02:00
119 lines
3.3 KiB
C
119 lines
3.3 KiB
C
/*
|
|
* RAW GSM demuxer
|
|
* Copyright (c) 2011 Justin Ruggles
|
|
*
|
|
* 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/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 GSMDemuxerContext {
|
|
AVClass *class;
|
|
int sample_rate;
|
|
} GSMDemuxerContext;
|
|
|
|
static int gsm_probe(const AVProbeData *p)
|
|
{
|
|
int valid = 0, invalid = 0;
|
|
uint8_t *b = p->buf;
|
|
while (b < p->buf + p->buf_size - 32) {
|
|
if ((*b & 0xf0) == 0xd0) {
|
|
valid++;
|
|
} else {
|
|
invalid++;
|
|
}
|
|
b += 33;
|
|
}
|
|
if (valid >> 5 > invalid)
|
|
return AVPROBE_SCORE_EXTENSION + 1;
|
|
return 0;
|
|
}
|
|
|
|
static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
|
|
{
|
|
int ret, size;
|
|
|
|
size = GSM_BLOCK_SIZE;
|
|
|
|
pkt->pos = avio_tell(s->pb);
|
|
pkt->stream_index = 0;
|
|
|
|
ret = av_get_packet(s->pb, pkt, size);
|
|
if (ret < GSM_BLOCK_SIZE) {
|
|
av_packet_unref(pkt);
|
|
return ret < 0 ? ret : AVERROR(EIO);
|
|
}
|
|
pkt->duration = 1;
|
|
pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gsm_read_header(AVFormatContext *s)
|
|
{
|
|
GSMDemuxerContext *c = s->priv_data;
|
|
AVStream *st = avformat_new_stream(s, NULL);
|
|
if (!st)
|
|
return AVERROR(ENOMEM);
|
|
|
|
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
|
|
st->codecpar->codec_id = s->iformat->raw_codec_id;
|
|
st->codecpar->channels = 1;
|
|
st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
|
|
st->codecpar->sample_rate = c->sample_rate;
|
|
st->codecpar->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 const AVOption options[] = {
|
|
{ "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
|
|
AV_OPT_TYPE_INT, {.i64 = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
|
|
AV_OPT_FLAG_DECODING_PARAM },
|
|
{ NULL },
|
|
};
|
|
|
|
static const AVClass gsm_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_probe = gsm_probe,
|
|
.read_header = gsm_read_header,
|
|
.read_packet = gsm_read_packet,
|
|
.flags = AVFMT_GENERIC_INDEX,
|
|
.extensions = "gsm",
|
|
.raw_codec_id = AV_CODEC_ID_GSM,
|
|
.priv_class = &gsm_class,
|
|
};
|