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

[Jules Gosnell]

to follow up on my own posting...

for it to be a format issue is a bit wierd - because I thought that 
mythbackend would just be taking the data, already encoded, straight 
from my Nova-T and filing it, without doing any form of transcoding ? 
But my Nova-T has not changed and my version of Myth and possibly 
kernel, has.....

I guess this is where my lack of knowledge of exactly what is going on 
under the covers stops me from doing any more digging.

Can anyone lend a hand ? Maybe I am seeing the interaction of several 
related issues ?


Jules


Jules Gosnell wrote:

> 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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