[mythtv] Question on Xv output and NuppelVideoPlayer

Isaac Richards ijr at po.cwru.edu
Fri Jul 2 23:10:30 EDT 2004

On Friday 02 July 2004 10:29 pm, Clyde Stubbs wrote:
> On Fri, Jul 02, 2004 at 09:42:24PM -0400, Isaac Richards wrote:
> > That's not the assumption at all.  The existing code assumes that
> > XvPutImage initiates the display of the image,
> Good, at least we agree on that.
> So, here's the code from ExAVSync:
> Now I know there is code elsewhere in the function that attempts to fudge
> the nexttrigger time, and it may well be that it does a very good job
> of compensating for the above scenario, but if the basic approach can be
> improved that surely is a good thing.

The whole point of the 'code elsewhere in the function that attempts to fudge 
the nexttrigger time' is to compensate for situations like this.  You also 
seem to be assuming that everything (drawing the OSD, copying frames around, 
interference from other threads) takes 0 time and doesn't affect the timing 
of the video display.

> Now, please comment on this scenario - if I've got anything wrong, please
> say so, but an explanation of why would be much appreciated.

Well, I can spend time explaining things line by line, or I can go through my 
patch queue and get bugzilla fully functional.

If you've got a patch or alternate approach that produces noticeably smoother 
video (while keeping audio in sync, of course), I'll be more than happy to 
apply it.


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