RTMP_Write function use

Question

I'm trying to use the librtmp library and it worked pretty well to pull a stream. But now I am trying to publish a stream and for that I believe I have to use the RTMP_Write function.

What I am trying to accomplish here is a simple c++ program that will read from a file and try to push the stream to a crtmp server. The connection and stream creation is ok, but I'm quite puzzled by the use of RTMP_Write.

Here is what I did:

int Upload(RTMP * rtmp, FILE * file){
        int nRead = 0;
        unsigned int nWrite = 0;
        int diff = 0;
        int bufferSize = 64 * 1024;
        int byteSum = 0;
        int count  = 0;
        char * buffer;
        buffer = (char *) malloc(bufferSize);
        do{
                nRead = fread(buffer+diff,1,bufferSize-diff,file);
                if(nRead != bufferSize){
                        if(feof(file)){
                                RTMP_LogPrintf("End of file reached!\n");
                                break;
                        }else if(ferror(file)){
                                RTMP_LogPrintf("Error reading from file stream detected\n");
                                break;
                        }
                }
                count += 1;
                byteSum += nRead;
                RTMP_LogPrintf("Read %d from file, Sum: %d, Count: %d\n",nRead,byteSum,count);
                nWrite = RTMP_Write(rtmp,buffer,nRead);
                if(nWrite != nRead){
                        diff  = nRead - nWrite;
                        memcpy(buffer,(const void*)(buffer+bufferSize-diff),diff);
                }
        }while(!RTMP_ctrlC && RTMP_IsConnected(rtmp) && !RTMP_IsTimedout(rtmp));
        free(buffer);
        return RD_SUCCESS;
}

In this Upload function I am receiving the already initiallized RTMP structure and a pointer to an open file.

This actually works and I can see some video being displayed, but it soon gets lost and stops sending packages. I managed to understand that it happens whenever the buffer that I setup (and which I randomly required to be 64k, no special reason for that) happens to split the flv tag (http://osflash.org/flv#flv_format) of a new package.

For that I modified the RTMP_Write function and told it to verify if it will be able to decode the whole flv tag (packet type, body size, timestamp, etc..) and if it will not, then it should just return the amount of useful bytes left in the buffer.

  if(s2 - 11 <= 0){
      rest = size - s2;
      return rest;
  }

The code above takes notice of this, and if the value returned by RTMP_Write is not the amount of bytes it was supposed to send, then it knows that value is the amount of useful bytes left in the buffer. I then copy these bytes to the beginning of the buffer and read more from the file.

But I keep getting problems with it, so I was wondering: what is the correct use of this function anyway? is there a specific buffer value that I should be using? (don't think so) or is it buggy by itself?

Seymore