[MPlayer-users] ass subtitles, vo gl and amd video

Nick Koretsky nick_koretsky at ukr.net
Tue Sep 24 01:50:26 CEST 2013

On Mon, 23 Sep 2013 23:30:03 +0200 
 Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:

> On Mon, Sep 23, 2013 at 11:56:22PM +0400, Vladimir Mosgalin wrote:
> > Hi Nick Koretsky!
> > 
> >  On 2013.09.23 at 17:37:16 +0300, Nick Koretsky wrote next:
> > 
> > > It can be avoided using -vf ass but than i get blurry subs like vo xv.
> > > I tried dsize,scale,ass trick but apparently a8 is not fast
> > > enough to decode highbitrate 10-bit encode and do software scaling at
> > > the same time - video jerks on complex scenes...
> > > 
> > > attached is an example of offending subs
> > 
> > It's not software scaling that makes it slow, it's -vf ass filter
> > itself:
> I don't think so. At least not directly.
> I think this is caused by libass (at least our old internal copy?)
> handling \clip commands based on vector drawing really badly.
> It should be figuring a bounding box and using that, but instead
> it draws far too large areas (note: I admit this might not be
> an as easy solution as it sounds in reality - though at least
> for pure line drawing commands it shouldn't be such a bit deal either).
> I used this sed command:
> s#\\clip(.*l 1280 \([0-9]*\) 1280 \([0-9]*\) [^)]*)#\\clip(0,\1,1280,\2)#
> to generate the attached file.
> It plays about 4x faster in -vo gl, I think for -vf ass the difference
> will be even larger.
> Assuming this reproducible with the latest libass version this probably
> should be a feature request.

Yeah, this one works almost normally - a couple of frames are dropped but
nothing close to 1-2 fps of original. Also, it doesn't kill vlc :) Still,
nvidia plays original subs without any problems on the same class cpu and
vastly outdated gpu so there is something seriously wrong with either amd
gpu, fglrx driver, or the way mplayer/libass passes data to driver...

  Nick Koretsky (nick.koretsky at gmail.com)

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