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/*
* G.729 bit format muxer and demuxer
* Copyright (c) 2007-2008 Vladimir Voroshilov
*
* 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 "avformat.h"
#include "internal.h"
#include "libavcodec/get_bits.h"
#include "libavcodec/put_bits.h"
#define MAX_FRAME_SIZE 10
#define SYNC_WORD 0x6b21
#define BIT_0 0x7f
#define BIT_1 0x81
#if CONFIG_BIT_DEMUXER
static int probe(const AVProbeData *p)
{
int i = 0, j, valid = 0;
while (2 * i + 3 < p->buf_size){
if (AV_RL16(&p->buf[2 * i++]) != SYNC_WORD)
return 0;
j = AV_RL16(&p->buf[2 * i++]);
if (j != 0 && j != 0x10 && j != 0x40 && j != 0x50 && j != 0x76)
return 0;
if (j)
valid++;
i += j;
}
if (valid > 10)
return AVPROBE_SCORE_MAX;
if (valid > 2)
return AVPROBE_SCORE_EXTENSION - 1;
return 0;
}
static int read_header(AVFormatContext *s)
{
AVStream* st;
st=avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id=AV_CODEC_ID_G729;
st->codecpar->sample_rate=8000;
st->codecpar->block_align = 16;
st->codecpar->ch_layout.nb_channels = 1;
avpriv_set_pts_info(st, 64, 1, 100);
return 0;
}
static int read_packet(AVFormatContext *s,
AVPacket *pkt)
{
AVIOContext *pb = s->pb;
PutBitContext pbo;
uint16_t buf[8 * MAX_FRAME_SIZE + 2];
int packet_size;
uint16_t* src=buf;
int i, j, ret;
int64_t pos= avio_tell(pb);
if(avio_feof(pb))
return AVERROR_EOF;
avio_rl16(pb); // sync word
packet_size = avio_rl16(pb) / 8;
if(packet_size > MAX_FRAME_SIZE)
return AVERROR_INVALIDDATA;
ret = avio_read(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t));
if(ret<0)
return ret;
if(ret != 8 * packet_size * sizeof(uint16_t))
return AVERROR(EIO);
if ((ret = av_new_packet(pkt, packet_size)) < 0)
return ret;
init_put_bits(&pbo, pkt->data, packet_size);
for(j=0; j < packet_size; j++)
for(i=0; i<8;i++)
put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0);
flush_put_bits(&pbo);
pkt->duration=1;
pkt->pos = pos;
return 0;
}
const AVInputFormat ff_bit_demuxer = {
.name = "bit",
.long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
.read_probe = probe,
.read_header = read_header,
.read_packet = read_packet,
.extensions = "bit",
};
#endif
#if CONFIG_BIT_MUXER
static int write_header(AVFormatContext *s)
{
AVCodecParameters *par = s->streams[0]->codecpar;
if ((par->codec_id != AV_CODEC_ID_G729) || par->ch_layout.nb_channels != 1) {
av_log(s, AV_LOG_ERROR,
"only codec g729 with 1 channel is supported by this format\n");
return AVERROR(EINVAL);
}
par->bits_per_coded_sample = 16;
par->block_align = (par->bits_per_coded_sample * par->ch_layout.nb_channels) >> 3;
return 0;
}
static int write_packet(AVFormatContext *s, AVPacket *pkt)
{
AVIOContext *pb = s->pb;
GetBitContext gb;
int i;
if (pkt->size != 10)
return AVERROR(EINVAL);
avio_wl16(pb, SYNC_WORD);
avio_wl16(pb, 8 * pkt->size);
init_get_bits(&gb, pkt->data, 8 * pkt->size);
for (i = 0; i < 8 * pkt->size; i++)
avio_wl16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
return 0;
}
const AVOutputFormat ff_bit_muxer = {
.name = "bit",
.long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
.mime_type = "audio/bit",
.extensions = "bit",
.audio_codec = AV_CODEC_ID_G729,
.video_codec = AV_CODEC_ID_NONE,
.write_header = write_header,
.write_packet = write_packet,
};
#endif
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