librtmp接收flv流中提取h264码流:根据多个资料汇总

Love The Way You Lie 2022-06-13 12:11 155阅读 0赞

rtmpdump可以下载rtmp流并保存成flv文件。  
如果要对流中的音频或视频单独处理，需要根据flv协议分别提取。  
简单修改rtmpdump代码，增加相应功能。  
1 提取音频:  
rtmpdump程序在Download函数中循环下载:  
....  
 do  
 \{   
....  
nRead = RTMP\_Read(rtmp, buffer, bufferSize);  
....  
\}while(!RTMP\_ctrlC && nRead > -1 && RTMP\_IsConnected(rtmp) && !RTMP\_IsTimedout(rtmp));  
....  
  
原程序是收到后写文件，生成flv。  
现在，在写之前分别提取音视频，提取音频比较简单，直接分析buffer(参考RTMP\_Write函数里的方法).  
注意的是，rtmpdump里用的是 RTMP\_Read来接收，注意它的参数。为了方便，也可以直接用RTMP\_ReadPacket。后面的视频使用RTMP\_ReadPacket来接收并处理。  
  
int RTMP\_Write2(RTMP \*r, const char \*buf, int size)  
\{   
  RTMPPacket \*pkt = &r->m\_write;  
  char \*pend, \*enc;  
  int s2 = size, ret, num;  
  
  
 if (size < 11)  \{   
   /\* FLV pkt too small \*/  
   return 0;  
 \}  
  
  
  if (buf\[0\] == 'F' && buf\[1\] == 'L' && buf\[2\] == 'V')  
   \{   
     buf += 13;  
     s2 -= 13;  
   \}  
  
  
  pkt->m\_packetType = \*buf++;  
 pkt->m\_nBodySize = AMF\_DecodeInt24(buf);  
 buf += 3;  
 pkt->m\_nTimeStamp = AMF\_DecodeInt24(buf);  
 buf += 3;  
 pkt->m\_nTimeStamp |= \*buf++ << 24;  
 buf += 3;  
 s2 -= 11;  
  
  
 if (((pkt->m\_packetType == RTMP\_PACKET\_TYPE\_AUDIO  
                || pkt->m\_packetType == RTMP\_PACKET\_TYPE\_VIDEO) &&  
            !pkt->m\_nTimeStamp) || pkt->m\_packetType == RTMP\_PACKET\_TYPE\_INFO)  
   \{   
     pkt->m\_headerType = RTMP\_PACKET\_SIZE\_LARGE;  
     if (pkt->m\_packetType == RTMP\_PACKET\_TYPE\_INFO)  
      pkt->m\_nBodySize += 16;  
   \}  
 else  
   \{   
     pkt->m\_headerType = RTMP\_PACKET\_SIZE\_MEDIUM;  
   \}  
  
  
BYTE outbuf2\[640\];  
int nLen2 = 640;  
  
  
AVManager::GetInstance()->Decode((BYTE\*)(pkt->m\_body+1), pkt->m\_nBodySize-1, outbuf2, nLen2);  
//实际音频内容为pkt->m\_body+1，大小是pkt->m\_nBodySize-1。这里的声音是speex编码。  
为什么跳过第一字节，可以参考：http://bbs.rosoo.net/thread-16488-1-1.html  
  
evt\_OnReceivePacket((char\*)outbuf2, nLen2);//回调出来  
  
  
  
RTMPPacket\_Free(pkt);  
pkt->m\_nBytesRead = 0;  
  
2   
视频处理  
可以参考rtmpsrv.c  
把 nRead = RTMP\_Read(rtmp, buffer, bufferSize);改成：  
  
RTMPPacket pc = \{ 0 \}, ps = \{ 0 \};  
 bool bFirst = true;  
while (RTMP\_ReadPacket(rtmp, &pc))  
\{  
if (RTMPPacket\_IsReady(&pc))  
 \{  
      if (pc.m\_packetType == RTMP\_PACKET\_TYPE\_VIDEO && RTMP\_ClientPacket(rtmp, &pc))  
    \{   
        bool bIsKeyFrame = false;  
     if (result == 0x17)//I frame  
    \{   
        bIsKeyFrame = true;  
    \}  
    else if (result == 0x27)  
    \{   
        bIsKeyFrame = false;  
    \}  
static unsigned char const start\_code\[4\] = \{0x00, 0x00, 0x00, 0x01\};  
fwrite(start\_code, 1, 4, pf );  
//int ret = fwrite(pc.m\_body + 9, 1, pc.m\_nBodySize-9, pf);  
  
  
if( bFirst) \{   
  
  
//AVCsequence header  
  
  
//ioBuffer.put(foredata);  
  
  
//获取sps  
  
  
int spsnum = data\[10\]&0x1f;  
  
  
int number\_sps = 11;  
  
  
int count\_sps = 1;  
  
  
while (count\_sps<=spsnum)\{   
  
  
int spslen =(data\[number\_sps\]&0x000000FF)<<8 |(data\[number\_sps+1\]&0x000000FF);  
  
  
number\_sps += 2;  
  
  
fwrite(data+number\_sps, 1, spslen, pf );  
fwrite(start\_code, 1, 4, pf );  
  
  
//ioBuffer.put(data,number\_sps, spslen);  
//ioBuffer.put(foredata);  
  
  
number\_sps += spslen;  
  
  
count\_sps ++;  
  
  
\}  
  
  
//获取pps  
  
  
int ppsnum = data\[number\_sps\]&0x1f;  
  
  
int number\_pps = number\_sps+1;  
  
  
int count\_pps = 1;  
  
  
while (count\_pps<=ppsnum)\{   
  
  
int ppslen =(data\[number\_pps\]&0x000000FF)<<8|data\[number\_pps+1\]&0x000000FF;  
  
  
number\_pps += 2;  
  
  
//ioBuffer.put(data,number\_pps,ppslen);  
  
  
//ioBuffer.put(foredata);  
  
  
fwrite(data+number\_pps, 1, ppslen, pf );  
fwrite(start\_code, 1, 4, pf );  
  
  
number\_pps += ppslen;  
  
  
count\_pps ++;  
  
  
\}  
  
  
bFirst =false;  
  
  
\} else \{   
  
  
//AVCNALU  
  
  
int len =0;  
  
  
int num =5;  
  
  
//ioBuffer.put(foredata);  
  
  
while(num<pc.m\_nBodySize)   
\{   
  
  
len =(data\[num\]&0x000000FF)<<24|(data\[num+1\]&0x000000FF)<<16|(data\[num+2\]&0x000000FF)<<8|data\[num+3\]&0x000000FF;  
  
  
num = num+4;  
  
  
//ioBuffer.put(data,num,len);  
  
  
//ioBuffer.put(foredata);  
  
  
fwrite(data+num, 1, len, pf );  
fwrite(start\_code, 1, 4, pf );  
  
  
num = num + len;  
  
  
\}  
  
  
\}

\}  
\}

具体视频分析的见: http://blog.csdn.net/cssmhyl/article/details/8128478

http://blog.chinaunix.net/uid-15063109-id-4273162.html