Hi Devin! ---------------------------------------- > Date: Wed, 9 Jul 2014 09:21:02 -0400 > Subject: Re: Troubleshooting problematic DVB-T reception > From: dheitmueller@xxxxxxxxxxxxxx > To: luky-37@xxxxxxxxxxx > CC: linux-media@xxxxxxxxxxxxxxx > >> 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. Thanks for your advice! I agree capturing the whole mux for further analysis is the best thing todo. Thanks, Lukas -- 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
