Hi Devin!
----------------------------------------
> Date: Wed, 9 Jul 2014 09:21:02 -0400
> Subject: Re: Troubleshooting problematic DVB-T reception
> From: dheitmuel...@kernellabs.com
> To: luky...@hotmail.com
> CC: linux-media@vger.kernel.org
>
>> 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
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