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

Craig Tinson craig at 8010.co.uk
Fri Oct 14 09:59:18 EDT 2005

Jules Gosnell wrote:

> 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
this is just another stab in the dark that came to mind - do you have 
any differences in the "general playback" section of setup between the 
two machines? deinterlacing playback settings for example?

like I said just a stab in the dark - first thing that came to mind


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