Maybe libva 1.3.0 exposes a bug in xserver/glx, see the comment #18  at  https://bugs.freedesktop.org/show_bug.cgi?id=76755. Could you try with xserver 1.15.1 or 1.15.99.902 (1.16.0 RC 2)  ?

Thanks! It seems like my debian system is a bit outdated and I can't get xorg to compile for some dependency reason. As soon as either debian provides an updated xorg on any branch, or I managed to compile it, I'll come back with results.

Tried with 1.15.1; Same behavior.

Do you upgrade the whole graphics stack ?  Does it work for you if downgrading libva from 1.3.0 to 1.2.1 ?

If by the whole graphics stack you mean xorg libraries, I didn't upgrade them at that time. I have done it now, but didn't have any change on (mis)behavior.

I'll see if I can get libva 1.2.1 to compile.

Meanwhile, I'm attaching a screenshot of xine so that you can see what happens to subtitles when I use -V vaapi.

I'm falling back to xv rendering on the meanwhile, xine cpu usage rises from avg 17% to 64% respectively when going from vaapi to xv.

Created attachment 97707 [details]
screenshot of a xine window with weird subtitles.

I retested with the latest libva/intel-driver on manster branch. No reproduce.
Env:
-------------
Libva:          (master)0d60132599318695dd1af8d51d2b160623ac4406
Libva_intel_driver:             (master)0d3462360f624750233d77771d55f48bc00039e5
Xserver:                (server-1.15-branch)xorg-server-1.15.1-1-g7b3aa3f0be8d1334dbf23bd04258a8856a4329c7

Besides, the test command line is: 
mplayer -vo vaapi -va vaapi *.mp4 -sub *.srt;
The srt file I use is downloaded from the web.

I reported this against xine, not mplayer. The mplayer compilations I have access to lacks support to libva.

We are trying to narrow down the root cause and check whether the issue can be reproduced with other media player. Which platform are you using ?

x86_64

On 4/28/14, bugzilla-daemon@freedesktop.org
<bugzilla-daemon@freedesktop.org> wrote:
> https://bugs.freedesktop.org/show_bug.cgi?id=77408
>
> --- Comment #10 from haihao <haihao.xiang@intel.com> ---
> We are trying to narrow down the root cause and check whether the issue can
> be
> reproduced with other media player. Which platform are you using ?
>
> --
> You are receiving this mail because:
> You reported the bug.
>

Could you attach your xorg.0.log and the ouput of vainfo ?

Created attachment 98269 [details]
vainfo

Created attachment 98270 [details]
Xorg.log

as requested, Xorg.log output

The commit f26114aef700d28730f6586a71d9f2526f5083f5 in the driver exposes a bug in xine-lib-vaapi. I will attach a patch for your reference.

Created attachment 98392 [details] [review]
a patch for your reference to how to fill the subpicture in xine-lib-vaapi

Tested, works for me. Forwared to xine team at https://bugs.xine-project.org/show_bug.cgi?id=514

Thanks!