> I am trying to troubleshoot a (non-linux related) DVB-T issue and I basically > want to create statistics about both DVB and MPEG framing, errors, corruption, > missing frames, etc. > > The reason is that I believe there is a problem on the transmitting radio > tower, RF is fine between the tower and me, but the actual payload (MPEG) is > somehow bogus, errored or sporadically misses frames (due to backhaul problems > or whatever). > > If I would be able to create some statistics confirming that I see all the DVB > frames without any errors, but that the actual DVB payload (MPEG) has some > problems, I could convince the tower guys to actually fix the issue, instead > of blaming my antennas. > > > So, can anyone suggest a tool or method to troubleshoot this issue further? > > > tzap output for example confirms not a single BER error and the tuner keeps > full LOCK on the channel while the actual stream is stuttering. I probably wouldn't rely on the BER stats from tzap. Their implementation varies in quality depending on which tuner you have, as well as how they are sampled. Almost all demods will set the TEI bit on the MPEG frame if it's determined that there was a decoding error - I would be much more inclined to look at that. Your best bet is to record the whole mux for a few minutes, then run it through some different tools to see what class of errors you are hitting. Tools such as tsreader or StreamEye will give you a better idea what's going on. Once you know what class of failure you have (e.g. TEI errors, MPEG discontinuities, etc), then you can better isolate where in the chain the failure is being introduced. Having the recording of the mux will also let you analyze in depth the actual nature of the problem, rather than trying to analyze an ever-changing stream in real-time, where signal conditions can change over time. Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
