[mythtv-users] Performance of the HD MPEG2 decoders

Todd Ignasiak ignasiak at gmail.com
Sat Nov 19 04:15:14 EST 2005


On 11/18/05, Todd Ignasiak <ignasiak at gmail.com> wrote:
> On 11/18/05, Cymen Vig <cymenvig at gmail.com> wrote:
> > On 11/18/05, Todd Ignasiak <ignasiak at gmail.com> wrote:
> > > On 11/17/05, Robert Tsai <rtsai1111 at comcast.net> wrote:
> > <snip>
> > > >         http://www.gossamer-threads.com/lists/mythtv/users/127168
> > > >
> > > > --Rob
> > >
> > > Thanks for the link.  I missed that thread in all my searches.  There
> > > is a lot of good AMD64 info there.
> > >
> > > I guess ffmpeg is optimized for 64 bit, libmpeg2 is not, so that
> > > explains the performance I'm seeing.
> > >
> > >
> > > Now, if I could find a solution for the stuttering related to XvMC +
> > > OSD, I would be all set.
> >
> > What version of mythtv are you running? The current stable release has
> > the known bug with XvMC and the OSD. If you use the SVN version
> > (search around -- I think 7738 or 7739 was the latest before Live TV
> > was disabled for development work *) you'll get a grayscale OSD but
> > the stutter is pretty much gone.
> >
> > Maybe the above is common knowledge but I was surprised to see the
> > option to enable XvMC but no warnings about the stutter issue. Perhaps
> > I missed a glaring warning and rationally, an 0.18.1 release is
> > supposed to have issues so I'm not *too* surprised.
> >
> > (*) I'm not certain about this -- maybe Live TV is fixed in current SVN.
> >
>
> I'm using SVN 7737, which was shortly before Live TV was disabled, but
> I don't think it was the last one before the change.       I'll check
> it out tonight & see if I'm getting the grayscale OSD  (gray OSD would
> be fine with me, if it enabled smooth playback all the time).
>

Apparently the stuttering is related to the format of video being played.

I tried a few more tests tonight,  and I found that with 1080i content
("My Name Is Earl", NBC, 1080i) the OSD doesn't impact the video in
XvMC mode.  The playback is very good, regardless of the OSD, the
playback is solid.

When I switch to a 720p program ("Lost", ABC, 720p), any time the OSD
comes up, I get the audio/video stuttering while the OSD is up and for
a couple seconds after it goes off.


Performance with XvMC:
1080i, XvMC ON, Deint OFF, OpenGL Sync Off: User: ~42%, sys: ~6%, idle: ~50%
1080i, XvMC ON, Deint(bob) ON, OpenGL Sync Off:  User ~44%, sys: ~6%, idle: ~50%
720p, XvMC ON, OpenGL Sync Off: User 25%, sys: 4%, idle: 71%

I'm not sure why the performance is the same on 1080i with
deinterlacing on and off.


More information about the mythtv-users mailing list