[mythtv-users] .nuv format, mythtv, xine, mplayer, unichrome compatibility....

[Jules Gosnell]

I don't know much about video file formats so bear with me.

I am looking into why some of my recordings do not play well (with 
mythtv-0.18.1) on my frontend box (Epia Via Ezra 1gz with Unichrome 
enabled) but play fine on another machine (Opteron 64-bit 2gz) - pretty 
obvious you might think :-)

The recordings are made from a Hauppauge DVB Nova-T on the backend 
(mythtv 0.18.1) - and not transcoded, because the Nova-T kicks out 
MPEG2, which is what the Epia's h/w can assist with.

Recordings that I made some time ago, all seem to play fine with mythtv, 
xine and mplayer.

Some more recent recordings (perhaps since I upgraded to 18.1?) are a 
little odd - they exhibit sound 'stickiness' using MythTV on the Epia, 
but play fine on the Opteron. Initially I put this down to issues with 
the Unichrome driver, or the speed of the Epia, but have discounted both 
(xine produces a lot of video and audio artefacts when playing these 
recordings with AND without -Vxxmc - and, when with -V xxmc, cpu usage 
is usually below 10%).

Since it is possible to play the recordings without issue on the 
opteron, I know that the artefacts are not part of the original signal. 
So, I began thinking in terms of data format. I played various 
recordings using mythtv, xine and mplayer on both boxes.

Recordings that do not exhibit the sound issue running on mythtv/Epia 
seem to play fine in xine and mplayer no matter which box they are on.

Recordings that have the sound issue, do not. Using mythtv they play 
fine on the Opteron, but the sounds sticks on the Epia. Using xine, they 
exhibit artefacts and sound stickiness on both boxes. MPlayer sometimes 
picked the wrong audio channel (1 instead of 0) and also sometimes 
suffered from lipsyncing issues...

So, it looks like something has changed in my setup which is causing me 
to occasionally generate less portable recordings than I used to, and 
that these are causing problems on my Epia (probably because the 
unichrome h/w (which I cannot seem to prevent mythtv using) is tripping 
up on the format).

If xine (v0.99.4.), mplayer (1.0pre7try2-3.2.3) and, possibly, unichrome 
are having problems with mythtv-generated MPEG2 files that mythtv can 
play without issue, is this a bug in mythtv, the other three, or a grey 
area in the MPEG2 spec - or have I misread the symptoms ?

Any help with this wouldbe much appreciated. I can probably find 
somewhere to put files that exhibit the problem up for ftp.

Thanks for mythtv,


Jules


-- 
"Open Source is a self-assembling organism. You dangle a piece of
string into a super-saturated solution and a whole operating-system
crystallises out around it."

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 * Jules Gosnell
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