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Poor performance for full screen Youtube videos on Mobility Radeon HD 4650

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  • Poor performance for full screen Youtube videos on Mobility Radeon HD 4650

    When I play youtube videos, they aren't really smooth. The low-res video playback in window is quite ok, but the same video on full-screen, or higher-res (720p) video (even worse) are not smooth (about 10 - 15 fps) and tearing occurs.

    When i connect TV (Full HD) via HDMI cable, results are even worse. Performance is poor (few fps for 720p video) and tearing is also more visible. Cpu is about 90 - 100% in use, both cores (Core2Duo, about 2GHz)

    I'm using Ubuntu 12.04 with gnome classic, compiz is disabled. AFAIR It also happend on 11.10 and 11.04. Once I tried fglrx, results were porobably better, but now I'm not interested in using fglrx anymore.

    I tried both Flash (newest Adobe plugin installed) and HTML5 youtube versions, results are similar.

    Tested in Chromium, newest from Ubuntu repo (I assume it's not browser related, so I didn't check in others).

    I know it's probably related to the lack of video acceleration in open source radeon driver, but is there anything I can try to get it working with some better results ? My gf's notebook with on-board Intel graphics is working much much better (smooth playback of same videos, no tearing).

  • #2
    After some more research I found out, that playback in totem works much better than inside chromium.

    Some full-hd video inside chromium on fullscreen (scaled down to 1366x768) takes about 60-100% of each cpu core (variable) with some fragments taking 100% - video rate drops. Also, as mentioned before, tearing occurs during whole video.

    In totem, same video on fullscreen takes about 30-60 % of each core, playback is constantly smooth and also there is no tearing.

    So the new question is: why chromium playback works much worse than in totem ?


    • #3
      Because video rendering (not decoding) is not accelerated with Flash and AMD this way and performance sucks even at 360p.

      The only solution is to use Google Chrome with the build-in Pepper Flash, go to about:flags, override the software driver blacklist to enable GPU acceleration in Chrome and restart it. Then you'll have accelerated video rendering.


      • #4
        Thanks for answer, but:
        - i'm not using flash, I use html 5 videos (effects on flash were quite similar)
        - on radeon open driver afaik videos are not accelerated anyway (lack of uvd documentation to write acceleration code)

        I'll try Pepper anyway, but I'd prefer to use html 5 video.