[mythtv] mythvideo needs bob deinterlace

Tim Phipps mythtv-dev at phipps-hutton.freeserve.co.uk
Fri Jan 5 20:44:32 UTC 2007


On Friday 05 January 2007 00:40, you wrote:
> Hi there,
>
> Just noticed your mythtv bug posting  and wanted to ask you how you know
> that mythvideo is playing back your interlaced frames out of order... I ask
> because I also receive 25fps interlaced material (australia) and get
> horrible judder and occasionally I can get rid of it by pausing/unpausing
> the playback... I myself was thinking that maybe myth was playing frames
> out of order.... do you have any ideas on how to confirm whether this is
> happening?? Viktor

Hi Viktor,
	I know it's doing something wrong because the problem goes away if you enable 
bob de-interlace. When it's happening it looks terrible, anything moving 
looks like it flickers back and forth in a kind of 
two-steps-forward-one-step-back way. Which is exactly what would happen if 
the TV display was showing the odd/even frames in the wrong time order. If 
you switch on bob de-interlace it's impossible for the TV to get the order 
wrong since the frame buffer is drawn with only the correct frame for the 
display per TV frame.

The MythTV TV display must be able to sync up the TV encoder with the display 
of the frame buffer somehow but I don't know if it's down to the video 
material. All the TV stuff I have is recorded by Myth, the MythVideo stuff is 
ripped using dvdrip so there may be something wrong with video material that 
stops the Internal video player syncing up.

Cheers,
Tim.



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