[mythtv] DVB recording issues

[Jason W]

On 2005/03/16 22:24, Peter wrote:
> 1) Using PS mode, sometimes I loose sound in a recording. If I rewind
> a bit I still loose sound at the same point, leading me to believe
> there is no sound in the recording. It appears to affect recordings
> randomly, on either of my two DVB-T cards on (seemingly) any channel.
>>From reading this and the -user list, it sounds as though running in
> TS mode might help this issue, and TS mode is the way forward anyway.

I have this same problem in Brisbane, Australia. Definitely with ABC and 
at least one other station here (cannot recall which, maybe Ten). I 
haven't had the time to look into it yet. Has not occurred while 
watching live TV yet.

The video keeps going fine and the sound just cuts out. The problem is 
with the recorded file and not in the frontend.

Running the recording through ProjectX demux and then using mjpegtools 
mplex to remux will let me play it with VLC and QuickTime. (Don't know 
if the demux/remux is necessary, but I always do it with DVB recordings 
to make sure the PS is clean). Usually this will give an MPEG which 
plays perfectly but I have on more than one occasion ended up with an 
mp2 file after the demux containing empty packets (many nul bytes in the 
file). I have not traced if this is ProjectX filling in the stream with 
empty packets or if it was recorded like that. It occurs on both 
recordings with AC3 and without (i.e. MPEG-2 audio only). When remuxing 
I have only been including the MPEG-2 audio and discarding the AC3 where 
it exists. Next time it happens I'll try the AC3 as well. It is possible 
that the AC3 stream is screwed and the MP2 is OK. I don't recall if I've 
successfully played back a stream with only MP2.

On a related note, how does one select which audio streams to play on 
the frontend? There was talk of an option to turn on/off preference for 
AC3 but I cannot find it. I am using the frontend on my PowerBook.

Is there an open bug for this yet? If so I will resubmit the above 
there. I have been running CVS HEAD for many months and this problem has 
existed I think since the big DVB patch came in. Do not recall it 
existing before then. In any case I will do some detective work when I 
get the chance and keep the list (and/or bugzilla) informed of developments.

Regards,

Jason Weathered