[mythtv] Re: [mythtv-commits] mythtv commits

Jesper Sörensen jesper at datapartner.se
Mon Aug 23 06:38:51 EDT 2004

Doug Larrick wrote:

> mythtv at cvs.mythtv.org wrote:
>> ---------------------------------------------------------------------------- 
>> Changes committed by bjm on Mon Aug 23 01:44:30 2004
>> Modified Files:
>>    in mythtv/libs/libmythtv:
>>         vsync.h vsync.cpp Log Message:
>> Fix a couple regressions. Re-implement the delay clipping when A/V sync
>> is way off. This prevents the series of freezes that may happen if the
>> initial timecodes are not even close. Update the comment and correct the
>> code to workaround the 'straddle' problem now called KeepPhase.
> Thanks for the clarification you added to the comment in KeepPhase, 
> but I must take objection to your removing the correction in the other 
> direction.  The code you deleted is important for HDTV to function 
> properly.  If the display time drifts too far away from the actual 
> retrace, the video hardware just doesn't have time to display such a 
> large frame, and we get jerky motion.

I'm with Doug here. Also, if I understand Doug's intentions correctly 
the A/V sync logic should reside in NuppelVideoPlayer and vsync.cpp 
should only deal with the low level frame syncing?

BTW, while debugging the recent mess with the broken audio timestamps I 
had difficulties to follow the logic in the A/V sync code so I've been 
working on a cleanup of  the code in NVPlayer. I also have a simple 
workaround for the timestamp problem but it's by no means a final 
solution - basically it ignores the timestamps when the diff is too big 
so it won't even attempt so sync it. I'd like to test it a bit more here 
first but then I'd like to get some comments from you guys and perhaps 
even get it into CVS...


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