是否有一些简单的方法可以转换为存储在Matroska文件中的h264设置：
+ CodecPrivate, length 36 (h.264 profile: Baseline @L2.0) hexdump
01 42 c0 14 ff e1 00 15 67 42 c0 14 da 05 07 e8
40 00 00 03 00 40 00 00 0c 03 c5 0a a8 01 00 04
68 ce 0f c8
和使用RTSP流式传输matroska文件时的相同设置？：
a=fmtp:96 packetization-mode=1;profile-level-id=42C014;sprop-parameter-sets=Z0LAFNoFB+hAAAADAEAAAAwDxQqo,aM4PyA==
Base-64字符串解码为：
00000000 67 42 c0 14 da 05 07 e8 40 00 00 03 00 40 00 00 |gB......@....@..|
00000010 0c 03 c5 0a a8
00000000 68 ce 0f c8 |h...|
与mkv的CodecPrivate中的数据部分匹配。
答案 0 :(得分：1)
从ffmpeg：
提取从raw到CodecPrivate的转换/*
* AVC helper functions for muxers
* Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
* Modified by _Vi: stand-alone version (without ffmpeg)
*
* This file is based on the code from 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 <string.h>
#include <stdio.h>
#define assert(x) if(!(x)) { fprintf(stderr, "Assertion failed...\n"); return -1; }
#ifndef AV_RB24
# define AV_RB24(x) \
((((const uint8_t*)(x))[0] << 16) | \
(((const uint8_t*)(x))[1] << 8) | \
((const uint8_t*)(x))[2])
#endif
#ifndef AV_RB32
# define AV_RB32(x) \
(((uint32_t)((const uint8_t*)(x))[0] << 24) | \
(((const uint8_t*)(x))[1] << 16) | \
(((const uint8_t*)(x))[2] << 8) | \
((const uint8_t*)(x))[3])
#endif
#define avio_w8(pb, x) *(*pb)++ = x;
#define avio_wb16(pb, x) *(*pb)++ = ((x)>>8); *(*pb)++ = x&0xFF;
#define avio_wb32(pb, x) *(*pb)++ = ((x)>>24); \
*(*pb)++ = ((x)>>16)&0xFF; \
*(*pb)++ = ((x)>>8)&0xFF; \
*(*pb)++ = ((x)>>0)&0xFF;
#define avio_write(pb, b, l) memcpy((*pb), b, l); (*pb)+=(l);
typedef unsigned char uint8_t;
typedef int intptr_t;
typedef unsigned long uint32_t;
static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
{
const uint8_t *a = p + 4 - ((intptr_t)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;
if (p[2] == 0 && p[3] == 1)
return p+1;
}
if (p[3] == 0) {
if (p[2] == 0 && p[4] == 1)
return p+2;
if (p[4] == 0 && p[5] == 1)
return p+3;
}
}
}
for (end += 3; p < end; p++) {
if (p[0] == 0 && p[1] == 0 && p[2] == 1)
return p;
}
return end + 3;
}
const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){
const uint8_t *out= ff_avc_find_startcode_internal(p, end);
if(p<out && out<end && !out[-1]) out--;
return out;
}
int ff_avc_parse_nal_units(unsigned char **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;
size = 0;
nal_start = ff_avc_find_startcode(p, end);
while (nal_start < end) {
while(!*(nal_start++));
nal_end = ff_avc_find_startcode(nal_start, end);
avio_wb32(pb, nal_end - nal_start);
avio_write(pb, nal_start, nal_end - nal_start);
size += 4 + nal_end - nal_start;
nal_start = nal_end;
}
return size;
}
int ff_avc_parse_nal_units_buf(const unsigned char *buf_in, unsigned char **buf, int *size)
{
unsigned char *pbptr = *buf;
ff_avc_parse_nal_units(&pbptr, buf_in, *size);
*size = pbptr - *buf;
return 0;
}
int my_isom_write_avcc(unsigned char **pb, const uint8_t *data, int len)
{
unsigned char tmpbuf[4000];
if (len > 6) {
/* check for h264 start code */
if (AV_RB32(data) == 0x00000001 ||
AV_RB24(data) == 0x000001) {
uint8_t *buf=tmpbuf, *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);
avio_w8(pb, 1); /* version */
avio_w8(pb, sps[1]); /* profile */
avio_w8(pb, sps[2]); /* profile compat */
avio_w8(pb, sps[3]); /* level */
avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
avio_w8(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
avio_wb16(pb, sps_size);
avio_write(pb, sps, sps_size);
avio_w8(pb, 1); /* number of pps */
avio_wb16(pb, pps_size);
avio_write(pb, pps, pps_size);
} else {
avio_write(pb, data, len);
}
}
return 0;
}
#define H264PRIVATE_MAIN
#ifdef H264PRIVATE_MAIN
int main() {
unsigned char data[1000];
int len = fread(data, 1, 1000, stdin);
unsigned char output[1000];
unsigned char *output_f = output;
my_isom_write_avcc(&output_f, data, len);
fwrite(output, 1, output_f - output, stdout);
return 0;
}
#endif
在每个base-64解码块之前插入“00 00 00 01”并将其输入该程序输出CodecPrivate：
$ printf '\x00\x00\x00\x01'\
'\x67\x42\xc0\x14\xda\x05\x07\xe8\x40\x00\x00\x03\x00\x40\x00\x00\x0c\x03\xc5\x0a\xa8'\
'\x00\x00\x00\x01'\
'\x68\xce\x0f\xc8' | ./avc_to_mkvcodecpriv | hd
00000000 01 42 c0 14 ff e1 00 15 67 42 c0 14 da 05 07 e8 |.B......gB......|
00000010 40 00 00 03 00 40 00 00 0c 03 c5 0a a8 01 00 04 |@....@..........|
00000020 68 ce 0f c8 |h...|
00000024