[mythtv-users] Video Playback Issues

[Michael T. Dean]

On 02/23/2012 10:47 AM, Bill Meek wrote:
> On 02/23/2012 03:47 AM, Michael T. Dean wrote:
>> Note that if you have set vdpaubuffersize, you will need to unset it
>> when you upgrade to 0.25, after it's released.  Having vdpaubuffersize
>> set in unstable/development (and, eventually, 0.25), will almost
>> definitely cause problems with playback.
> Mike;
>
> I know I've read this warning before and removed mine.
>
> But there's no explicit mention of this in the release notes
> (http://www.mythtv.org/wiki?title=Release_Notes_-_0.25.) For
> example under the: Special Notices&  Instructions section.
> Which I'd be happy to add, if appropriate.

That sounds like a good idea to me.

> The release notes do have this line about 1/4 of the way down:
>
>     VDPAU: Dynamically optimise video buffer size [5e04d57]
>
> which gets to:
>
>     https://github.com/MythTV/mythtv/commit/5e04d57
>
> which says the setting was retained (and its meaning changed.)

Yeah.  That's the reason why you probably need it unset for next version.

> Looking at the code, the default value is set to 12 and the accepted
> range if the filter is set is 6-50. It adds this to some hard coded
> values.
>
> I'm pretty sure I can write a patch that would change the accepted
> range check to print a critical warning and guarantee that the
> default value was always used. If you'd like I'll submit a ticket with
> a  patch. I suspect that would be a better solution than relying on
> folks reading the release notes.
>
> Or I'm missing the point entirely?
>

The most information I can give is:

http://irc.mythtv.org/ircLog/channel/4/2011-05-23:13:21:38
and
http://irc.mythtv.org/ircLog/channel/4/2011-10-15:22:11:18

The 2nd being a nice clear description of the change in meaning of the 
option--it no longer uses the number specified, but uses what it thinks 
it needs plus the number specified.  Users who upgraded to 
unstable/development with it set tended to see terrible performance 
and/or memory issues that caused playback issues.

But, since the code actually does a good job, now, of dynamically 
resizing the buffer size as required, nearly everyone is better off not 
setting it.  (And if you do have problems without it set in 
unstable/development, the right fix is to adjust the dynamic-resizing 
code to be smarter so that we can fix MythTV playback for everyone.  :)

Mike