[vlc] Re: VLC XVideo Output under Linux

[galenz at zinkconsulting.com]

On Sep 10, 2006, at 10:29 AM, galenz at zinkconsulting.com wrote:

> Hello,
>
> I have a machine with the Intel GMA 900 graphics chipset. It works  
> beautifully under Linux... except I'm still struggling to get video  
> playback acceleration working with VLC.
>
> I have three sample clips, played in VLC 0.8.4a under Fedora Core  
> 5. One DVD-resolution and bitrate, and two HD bitrate clips, one  
> 720p and another 1080i. With X11 Video output, the sample clips  
> works perfectly, but playback is CPU intensive and/or choppy.
>
> I want to use XVideo output, because my chipset supports XVideo and  
> Xvideo motion compensation. I found the DVD resolution clip worked  
> fine out of the box. But the HD clips didn't - VLC would segfault.  
> As far as I can tell, VLC is fairly well coded, so things should  
> generally work.
>
> I turned to the video drivers, as I think they're likely to be the  
> problem. After I increased the the CacheLines to 1100 in xorg.conf,  
> the 720p worked superbly in VLC. But 1080i still segfaulted. I  
> increased the CacheLines again and again, eventually to 9500, with  
> no luck. I've also increased VideoRam to 131072 - in the off chance  
> there was some sort of memory shortage going on.
>
> But it still doesn't work... so... what do I do? The VLC segfault  
> information doesn't seem very useful.
>
> I have reviewed the data available here:
> http://intellinuxgraphics.org/man.html
>
> Thoughts anybody?
>
> -Galen

I have been continuing testing:

I enabled LinearAlloc to 32768 - higher than the minimum values most  
people on Google suggest for HD.

When I attempt to play the 1080i file using XVideo, continues to VLC  
segfault. From /var/log/messages:
vlc[2871]: segfault at 00002aaab99d5000 rip 00002aaab869d8e3 rsp  
000000045006fc8 error 6

Note that the exact numbers vary a little bit each time. But it's  
always error 6. (Except one time out of dozens which is error 7.... I  
can only guess that was a fluke.)

Other than that, the only VLC-related errors in that log are like this:
audit(1157882914.686:23): avc: granted {execmem} for pid=2930  
comm="vlc" scontext=user_u:system_r:unconfined_t:s0  
tcontext=user=user_u:system_r:unconfined_t:s0 tclass=process

Occasionally, a similar line will occur that is like that but reads  
{execstack} instead of {execmem}.

I've also tested MPlayer with their XVideo extension. The results are  
very similar: the DVD and 720p resolution clips works, but the 1080i  
one fails. MPlayer reports:
"FATAL: Could not initialize video filters (-vf) or video output (-vo)."

It tends to imply this isn't strictly a VLC issue, but perhaps the  
VLC list could shed some light on how to resolve the problem.

-Galen

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