poor video playback performace with radeon

Johannes Truschnigg johannes at truschnigg.info
Mon Aug 8 23:35:27 PDT 2011

Dear Taneli,

On 08/08/2011 11:50 PM, Taneli Vähäkangas wrote:
> Hello.
> Watching 1080p 25fps mpeg4 video content (from a blu-ray disc) is
> not possible, the display rate is less than 10fps. (The AACS
> decryption of the content has been done separately off-line, before
> watching.) I have tried vlc, mplayer and ffplay, which all exhibit
> the same problem.

Given the system specs below, I'm afraid this is nothing out of the
ordinary. H.264 in 1080p generally is quite demanding to decode, and
your somewhat dated CPU just might not be up to the task.

> I have this hardware (from lshw):
> product: Cedar PRO [Radeon HD 5450]
> product: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
> (more info available by request, I don't know what would be
> relevant)

You should try to get your hands onto a build of mplayer with the
multithreading decoding features of ffmpeg enabled. I'm not sure that
will yield real-time decoding of your video source, but it should
improve performance a bit nonetheless.

I distantly recall ATI/AMD implementing some GPU video decode
acceleration API in their proprietary BLOB drivers, but I'm not sure how
(or if, with your card) you can use that.

> I'm running ubuntu natty and have open source
> xserver-xorg-video-ati driver from xorg-edgers PPA, version:
> 1:6.14.99+git20110801.104b2d7c-0ubuntu0sarvatt~natty

The free drivers don't support video decoding with GPU hardware
assistance yet. The best you can do is choose Xv or OpenGL as the video
output method in your player software (`mplayer -vo vx` or `mplayer -vo
gl`) and have your CPU work at actually decoding and rendering the video
data to that accelerated overlay, but that's as far as it gets these days.

> [...]
> In general, the system is responsive and for example watching dvds,
> glxgears or xmoto fullscreen is very smooth. There are two monitors
> connected, and I'm using metacity as window manager.

That is to be expected.

> Please keep me cc:d in replies as I'm not on the list. If this is
> the wrong forum, could you kindly point me to a better one.
> [...]

I think we're doing just fine here :)

You should look into the ffmpeg-mt and possibly mplayer2 projects to
learn how and where to get an appropriate build of those programs for
your distribution. Using that second processor core of your CPU should
improve the situation quite a bit - if it's still not enough, you'll
have to get a beefier machine if you don't want to wait for shader-based
video decoding (or UVD) support in the free drivers.

with best regards:
- Johannes Truschnigg ( johannes at truschnigg.info )

www: http://johannes.truschnigg.info/
phone: +43 650 2 133337
xmpp: johannes at truschnigg.info

Please do not bother me with HTML-eMail or attachments. Thank you.

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