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Old 08-27-09, 06:00 PM   #28
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Join Date: Jun 2009
Posts: 25
Default Re: Pure video = VDPAU ?

Originally Posted by mooninite View Post
It's not Linux that's at fault. Your card will not do H.264 decoding in the GPU. If you won't believe me then go see it for yourself. Go download a 1080p trailer and run it on Windows. Watch your CPU usage hit 100% and the video stutter. I'm sure you'll blow that off as to not having the drivers installed correctly or some other unrelated nonsense just to prove your point.
Well I tried your suggestion. I couldn't quite make a fair comparison, as i don't have a dual boot setup. Anyway here's what I did, with the results:

I tried a little experiment to compare video playback performance between Jaunty 9.04 and Windows XP.

The comparison wasn't totally fair, but I was surprised how badly Jaunty did. A fair comparison should be done with a dual boot machine. What I had to hand, however, were two Dell machines, one a little old, the other older. Here are their specs:

Oldest PC, running Ubuntu 9.04:
- Intel P4 1.5GHz
- 512MB RAM
- GeForce 6200 PCI, 180.44 nVidia driver
- 1440x900 LCD monitor

Somewhat newer PC, running Windows XP SP3:
- AMD Sempron 3400+ 1.8GHz
- 512MB RAM
- GeForce 6150LE, HyperTransport, integrated
- 1024x768 LCD monitor

The machines are not wildly different in their specs. The Windows graphics card may have the edge on bus bandwith, but its fill rate is less than the 6200 on Jaunty:

fill rates:
GeForce 6150LE 425 MP/s
GeForce 6200 600 MP/s

Also the 6200 has better 3D performance according to the specs, but we are only comparing 2D performance in this 'test'.

I used two video files:
MP4(H.264) 25 fps 1280x720
WMV(v9 advanced) 24 fps 1920x816

On the Windows machine I used Windows media player to play the WMV file, and the latest quicktime player to play the MP4 file.

On the Jaunty machine I used the latest mplayer build (from svn). Compiz was switched off. No filters were used. mttr was set correctly.

On Jaunty, the MP4 file played smoothly, but its smoothness was simply because it was playing the video back in slow motion! However, the audio was racing ahead, so the sound and video were totally out of sync. The same happened when playing in a window and in full screen mode.

On Windows, quicktime played the video flawlessly, no matter how I set the view, e.g. in full screen, fit to window, zoom of 1 (when it would not fit into the monitor screen).

Next I tried the wmv. I fully expected the Windows machine to choke, but no - it played back almost flawlessly! There was a slight, very occasional stutter now and then, nevertheless the video was most certainly watchable and enjoyable.

On Jaunty, the wmv was again in slow motion, but this time the video was also stuttering. The sound sputtered and eventually gave up. I tried using OSS for the sound driver instead of pulse - slight improvement in sound for the first few seconds, then stuttering badly. Basically, it was unwatchable.

Just to rub salt in the wounds, the Windows machine could play normal resolution youtube videos in full screen with no problem at all. In Jaunty, full screen flash became a slide show, which was troublesome to stop (hit escape key and wait, wait ...)

My experiment was really (to some extent) testing the differences between the OS's and the graphics drivers (no firefox and flash in the loop). It seems to indicate that there is a problem with the nVidia / xorg drivers on Jaunty or Linux in general.

As I said, it is not a totally fair comparison, but I was amazed all the same. Perhaps someone can do the same tests using a dual boot system?
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