[mythtv-users] Playback performance [all platforms]

Kevin Kuphal kuphal at dls.net
Mon Jan 9 00:47:56 UTC 2006


David Abrahams wrote:

>I notice that the performance of playback seems to be suboptimal.  For
>example, I captured some HDTV video over firewire using MythTV.  When
>I try to play it back using the frontend, it is totally unwatchable.
>The action occurs at about half speed because of stuttering and
>includes frequent pauses of up to a second.  I tried tweaking all the
>obvious settings in the Playback section of the front end's setup
>screen, to no avail.
>
>However, when I use VLC to play the same file, it looks almost
>perfect, with only barely perceptible jerkiness due, presumably, to
>the fact that my Mac Mini can't quite keep up with playback.  I
>grepped the MythTV source for CONFIG_DARWIN to find the
>Darwin-specific playback code, but came up empty.  Perhaps we *need*
>some darwin-specific playback code?  And if Darwin-specific playback
>code turns out to help, doesn't it indicate that the playback code
>MythTV is using for all other platforms today could be a whole lot
>more efficient?
>  
>
I believe so.  Similar to Linux, software playback is the norm unless 
other things are used to get hardware acceleration working.  On Linux we 
can use XvMC on some cards to get things to render accelerated in 
hardware.  I would expect that similar features would have to be taken 
advantage of (which VLC probably already does) to enable the 
acceleration on the Mac side.

Kevin


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