[MPlayer-users] [ASS subtitle rendering] confusing error message

[Tobias Jakobi]

Hi there,

I'm using mplayer-1.0_rc2_p20090731 on gentoo linux 32bit x86.

Lately I've been trying to optimize mplayer video output, since the
system it is running on is quite low-end. When playing back 720p H264
material with ASS subtitle rendering the CPU sometimes reaches 100%
utilization which results in skipping and AV-sync loses.

I did a few searches and ended up switching the video output module from
xv to gl, and then tweaking the settings. The GPU is a integrated Intel
i915 chip, but with recent mesa git master the use of GL output really
boosts the performance (going down from the mentioned 100% utilization
to around 60%).

However I noticed some strange error/warning message that appears when
using -ass and switching from xv to gl.

Here is a log when playing back a subtitled file with normal xv output
and -ass:
http://pastebin.com/m7928bf22

No abnormal messages concerning ASS rendering can be found.
Also this output can be found in the log:
[ass] Exporting mp_image_t, 1280x720x12bpp YUV planar, 1382400 bytes

(this seems to be the subtitle overlay)

Now, here is what happens when switching to gl output:
http://pastebin.com/m398faf87

Notice that the "Exporting mp_image_t" line from ass is gone. Also
notice these two new lines that seem to indicate a problem:
Couldn't open video filter 'ass'.
ASS: cannot add video filter

The funny thing is that even though these lines appear the subtitle
rendering works fine and according to the looks of the subs the ASS
engine is actually active.

Now, here is my question:
Why do these messages appear in the first place? Are they simply wrong
and the ass filter gets inserted into the playback chain anyway OR is
there really a problem that can't just be seen from looking at the video
output alone?

Greets,
Tobias