[Live-devel] FramedFilter Performance & Questions

[Julian Lamberty]

> No.  Assuming that your "afterGettingFrame()" function was passed as 
> a parameter to "getNextFrame()", then it will be called by 
> "FramedSource::afterGetting()" (which your "doGetNextFrame()" 
> implementation should have called once it completed delivery of 
> incoming data).
>   
So is my code correct? If the frame is not completely decodable, I call 
getNextFrame() again (on MPEG1or2VideoRTPSource). As I said, sometimes 
(irregular) there are ~10 to 20ms delay between consecutive calls of 
afterGettingFrame(). Sometimes the afterGettingFrame() function is 
called twice even if the first one has not come to an end. How can that 
be? Could you please have a look at the code? Thank you very much!

void Transcoder::doGetNextFrame()
{
    fInputSource->getNextFrame(inbuf, INBUF_SIZE, afterGettingFrame, 
this, handleClosure, this);
}

void Transcoder::afterGettingFrame(void* clientData, unsigned 
numBytesRead, unsigned numTruncatedBytes, struct timeval 
presentationTime, unsigned durationInMicroseconds)
{
    Transcoder* transcoder = (Transcoder*)clientData;
    transcoder->afterGettingFrame1(numBytesRead, numTruncatedBytes, 
presentationTime, durationInMicroseconds);
}

void Transcoder::afterGettingFrame1(unsigned numBytesRead, unsigned 
numTruncatedBytes, struct timeval presentationTime, unsigned 
durationInMicroseconds)
{   
        //Decoding
    dec_bytes = avcodec_decode_video(dec_codec_ctx, dec_frame, 
&got_frame, inbuf, size); //decoding inbuf (data chunks) to dec_frame

    if(got_frame) //decoded one complete frame
    {
        //Encoding
        gettimeofday(&begin_encoding_frame, NULL);
        enc_bytes = avcodec_encode_video(enc_codec_ctx, outbuf, 
fMaxSize, dec_frame); //encoding dec_frame to outbuf

        if(enc_bytes > fMaxSize) //more bytes encoded than framer can handle
        {
            fFrameSize = fMaxSize;
            fNumTruncatedBytes = enc_bytes - fMaxSize;
        }
        else
        {
            fFrameSize = enc_bytes;
            fNumTruncatedBytes = 0;
        }
                                 
        //Delivering
        memcpy(fTo, outbuf, fFrameSize); //copy outbuf to fTo for framer
        fPresentationTime = begin_encoding_frame;
        fDurationInMicroseconds = durationInMicroseconds; //just pass 
through durationInMicroseconds
        frame_ready = true; //frame ready for delivery
    }

    if(!frame_ready) //get more data
    {
        fInputSource->getNextFrame(inbuf, INBUF_SIZE, afterGettingFrame, 
this, handleClosure, this); //*problems*
    }
    else //deliver data and return
    {
        frame_ready = false;
        afterGetting(this);
    }
}

After that I have the MPEG4VideoStreamDiscreteFramer (without that, 
Transcoder::doGetNextFrame() isn't even called... why is that btw?) and 
an MPEG4ESVideoRTPSink. The streaming actually works, but I temporarily 
exceed 40ms to transcode one frame.
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