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#include "avformat.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
static int probe(AVProbeData *p)
{
int i;
i=AV_RL16(&p->buf[0]);
if(i != SYNC_WORD)
return 0;
switch(AV_RL16(&p->buf[2]))
{
case 0x40:
case 0x50:
return AVPROBE_SCORE_MAX/2;
default:
return 0;
}
}
static int read_header(AVFormatContext *s, AVFormatParameters *ap)
{
AVStream* st;
ByteIOContext *pb = s->pb;
st=av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
url_fskip(pb, 2);
switch(get_le16(pb))
{
case 0x40:
st->codec->bit_rate = 6400;
break;
case 0x50:
st->codec->bit_rate = 8000;
break;
}
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id=CODEC_ID_G729;
st->codec->sample_rate=8000;
st->codec->block_align = 16;
st->codec->channels=1;
av_set_pts_info(st, 64, 1, 100);
url_fseek(pb, 0, SEEK_SET);
return 0;
}
static int read_packet(AVFormatContext *s,
AVPacket *pkt)
{
ByteIOContext *pb = s->pb;
PutBitContext pbo;
uint16_t buf[8 * MAX_FRAME_SIZE + 2];
int packet_size;
int sync;
uint16_t* src=buf;
int i, j, ret;
if(url_feof(pb))
return AVERROR_EOF;
sync = get_le16(pb); // sync word
packet_size = get_le16(pb) / 8;
assert(packet_size < 8 * MAX_FRAME_SIZE);
ret = get_buffer(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);
av_new_packet(pkt, packet_size);
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;
return 0;
}
AVInputFormat ff_bit_demuxer = {
"bit",
"G.729 BIT file format",
0,
probe,
read_header,
read_packet,
.extensions = "bit"
};
#ifdef CONFIG_MUXERS
static int write_header(AVFormatContext *s)
{
AVCodecContext *enc = s->streams[0]->codec;
enc->codec_id = CODEC_ID_G729;
enc->channels = 1;
enc->bits_per_coded_sample = 16;
enc->block_align = (enc->bits_per_coded_sample * enc->channels) >> 3;
return 0;
}
static int write_packet(AVFormatContext *s, AVPacket *pkt)
{
ByteIOContext *pb = s->pb;
GetBitContext gb;
int i;
uint16_t b;
put_le16(pb, SYNC_WORD);
put_le16(pb, 8 * 10);
init_get_bits(&gb, pkt->data, 8*10);
for(i=0; i< 8 * 10; i++)
put_le16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
put_flush_packet(pb);
return 0;
}
AVOutputFormat ff_bit_muxer = {
"bit",
"G.729 BIT file format",
"audio/bit",
"bit",
0,
CODEC_ID_G729,
CODEC_ID_NONE,
write_header,
write_packet,
.extensions = "bit"
};
#endif
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