xserver-xorg-driver-ati

Bug #555286
Comment #67

Comment 67 for bug 555286

Revision history for this message

In freedesktop.org Bugzilla #28106, JasonPorter (jasonporter) wrote on 2011-05-12:

#67

(In reply to comment #40)
> I never gave it much thought, but thinking about it, this seems suspicious to
> me as I am pretty sure that this device has only 64MB of VRAM.

I'm using an X1400 here, with 128MB of vram. I'm not sure if that is helpful or not.

Here's some extra info for the fire, and one that surprised me when I discovered it yesterday: there are a few apps that render fullscreen video that do not exhibit the stuttering at all. This is new behavior, previously ANY video would cause the stuttering when fullscreened. This change that I'm seeing may not be the same on your systems, but it's worth testing.

A good example is the Hulu Desktop for Linux application, which streams high quality video fullscreen without any stutter. This uses the video card, the wifi connection, and the sound card at the same time, which is exactly the situation that causes problems for most people. The app specifies that it requires Flash 10.0.32 or higher, which suggests that it uses Flash for the video transport in some fashion. The application can be downloaded from http://www.hulu.com/labs/hulu-desktop-linux

Also, on my system, switching into HTML5 video mode on Youtube (using Google Chrome) allows fullscreen 720p streaming without audio stutter. The same video played in standard Flash video mode (in Chrome or in Firefox) stutters heavily when maximized, in both 480p and 720p formats. In fact, any Flash-based web-embedded video stutters when maximized, on any site that I've tried (Vimeo, CBS, etc), including even Hulu's own web-based player.

I'm not sure what the story is on this, it's confusing. Maybe on my particular hardware the radeon driver is able to cope differently with the particular video rendering method used by Hulu Desktop and the browser HTML5 video implementations. If the Hulu Desktop application is using Flash, it's doing it differently than viewing the same video on Hulu.com in a browser, because the web-embedded player stutters and the Hulu Desktop application doesn't, and both are (theoretically) streaming from the same source.

I'm running very current versions of Mesa, Gallium and the radeon driver, so the particular combination of behaviors that I'm seeing may be a recent change. I also have a relatively fast system (Core 2 Duo with an SSD) and as always, system load seems to have a big impact on this issue appearing or not. So your results may not be the same as mine.

possibly relevant information from glxinfo:
  direct rendering: Yes
  OpenGL vendor string: X.Org R300 Project
  OpenGL renderer string: Gallium 0.4 on ATI RV515
  OpenGL version string: 2.1 Mesa 7.11-devel

(In reply to comment #40)
> I never gave it much thought, but thinking about it, this seems suspicious to
> me as I am pretty sure that this device has only 64MB of VRAM.

I'm using an X1400 here, with 128MB of vram. I'm not sure if that is helpful or not.

Here's some extra info for the fire, and one that surprised me when I discovered it yesterday: there are a few apps that render fullscreen video that do not exhibit the stuttering at all. This is new behavior, previously ANY video would cause the stuttering when fullscreened.  This change that I'm seeing may not be the same on your systems, but it's worth testing.

A good example is the Hulu Desktop for Linux application, which streams high quality video fullscreen without any stutter.  This uses the video card, the wifi connection, and the sound card at the same time, which is exactly the situation that causes problems for most people.  The app specifies that it requires Flash 10.0.32 or higher, which suggests that it uses Flash for the video transport in some fashion.  The application can be downloaded from http://www.hulu.com/labs/hulu-desktop-linux

Also, on my system, switching into HTML5 video mode on Youtube (using Google Chrome) allows fullscreen 720p streaming without audio stutter.  The same video played in standard Flash video mode (in Chrome or in Firefox) stutters heavily when maximized, in both 480p and 720p formats.  In fact, any Flash-based web-embedded video stutters when maximized, on any site that I've tried (Vimeo, CBS, etc), including even Hulu's own web-based player.