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/*
* AVC helper functions for muxers
* Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
*
* 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 "avformat.h"
#include "avio.h"
const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end)
{
const uint8_t *a = p + 4 - ((long)p & 3);
for( end -= 3; p < a && p < end; p++ ) {
if( p[0] == 0 && p[1] == 0 && p[2] == 1 )
return p;
}
for( end -= 3; p < end; p += 4 ) {
uint32_t x = *(const uint32_t*)p;
// if( (x - 0x01000100) & (~x) & 0x80008000 ) // little endian
// if( (x - 0x00010001) & (~x) & 0x00800080 ) // big endian
if( (x - 0x01010101) & (~x) & 0x80808080 ) { // generic
if( p[1] == 0 ) {
if( p[0] == 0 && p[2] == 1 )
return p-1;
if( p[2] == 0 && p[3] == 1 )
return p;
}
if( p[3] == 0 ) {
if( p[2] == 0 && p[4] == 1 )
return p+1;
if( p[4] == 0 && p[5] == 1 )
return p+2;
}
}
}
for( end += 3; p < end; p++ ) {
if( p[0] == 0 && p[1] == 0 && p[2] == 1 )
return p;
}
return end + 3;
}
void ff_avc_parse_nal_units(ByteIOContext *pb, const uint8_t *buf_in, int size)
{
const uint8_t *p = buf_in;
const uint8_t *end = p + size;
const uint8_t *nal_start, *nal_end;
nal_start = ff_avc_find_startcode(p, end);
while (nal_start < end) {
while(!*(nal_start++));
nal_end = ff_avc_find_startcode(nal_start, end);
put_be32(pb, nal_end - nal_start);
put_buffer(pb, nal_start, nal_end - nal_start);
nal_start = nal_end;
}
}
static int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
{
ByteIOContext *pb;
int ret = url_open_dyn_buf(&pb);
if(ret < 0)
return ret;
ff_avc_parse_nal_units(pb, buf_in, *size);
av_freep(buf);
*size = url_close_dyn_buf(pb, buf);
return 0;
}
int ff_isom_write_avcc(ByteIOContext *pb, const uint8_t *data, int len)
{
if (len > 6) {
/* check for h264 start code */
if (AV_RB32(data) == 0x00000001) {
uint8_t *buf=NULL, *end, *start;
uint32_t sps_size=0, pps_size=0;
uint8_t *sps=0, *pps=0;
int ret = ff_avc_parse_nal_units_buf(data, &buf, &len);
if (ret < 0)
return ret;
start = buf;
end = buf + len;
/* look for sps and pps */
while (buf < end) {
unsigned int size;
uint8_t nal_type;
size = AV_RB32(buf);
nal_type = buf[4] & 0x1f;
if (nal_type == 7) { /* SPS */
sps = buf + 4;
sps_size = size;
} else if (nal_type == 8) { /* PPS */
pps = buf + 4;
pps_size = size;
}
buf += size + 4;
}
assert(sps);
assert(pps);
put_byte(pb, 1); /* version */
put_byte(pb, sps[1]); /* profile */
put_byte(pb, sps[2]); /* profile compat */
put_byte(pb, sps[3]); /* level */
put_byte(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
put_byte(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
put_be16(pb, sps_size);
put_buffer(pb, sps, sps_size);
put_byte(pb, 1); /* number of pps */
put_be16(pb, pps_size);
put_buffer(pb, pps, pps_size);
av_free(start);
} else {
put_buffer(pb, data, len);
}
}
return 0;
}
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