FFmpeg UDP timeout, retrying with TCP callback

Question

I'm reading some RTSP stream in an iOS app using FFmpeg. If the firewall or other services stops the network from receiving via UDP, FFmpeg nicely falls back to reading via TCP. My question is: How can I be notified that the fallback to TCP happened? I need to know whether the app is reading the stream via UDP or TCP and still let FFmpeg do its nice fallback. Is there a callback for this? Is there a way to get the protocol that is using?

Thank you.

Answer 1

I found the solution: After the connection is made one can read the lower transport protocol from the AVFormatContext's private data (priv_data). Bellow is how I'm doing it:

-(BOOL)lowerTransportProtocolIsUDP
{
    RTSPState* rtsp_state = (RTSPState*) _avFmtCtx->priv_data;

    enum RTSPLowerTransport lowerTransportProtocol = rtsp_state->lower_transport;

    NSLog(@"lowerTransportProtocol = %d", lowerTransportProtocol);

    if (lowerTransportProtocol == RTSP_LOWER_TRANSPORT_UDP) {
        return YES;
    }

    return NO;
}

Where _avFmtCtx is a AVFormatContext instance.