[TV] CPU Intensive teletext (1 Viewer)

velis

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  • July 16, 2009
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    MediaPortal Version: 1.1. beta
    MediaPortal Skin: Blue3 wide
    Windows Version: Win 7 Home Premium
    CPU Type: Athlon II 250 3GHz
    HDD: Seagate 120GB
    Memory: 2GB DDR3 1600
    Motherboard: Gigabyte Ga-MA790GPT-UD3H
    Video Card: Integrated Radeon HD 3300
    Video Card Driver: ATI Catalyst 9.11
    Sound Card: Onboard Realtek ALC889A
    Sound Card AC3: Optical SPDIF onboard
    Sound Card Driver: Win7 default
    1. TV Card: IPTV (no HW)
    1. TV Card Type: IPTV
    1. TV Card Driver: none
    2. TV Card:
    2. TV Card Type:
    2. TV Card Driver:
    3. TV Card:
    3. TV Card Type:
    3. TV Card Driver:
    4. TV Card:
    4. TV Card Type:
    4. TV Card Driver:
    MPEG2 Video Codec: ATI Avivo Decoder
    MPEG2 Audio Codec: ffdshow
    h.264 Video Codec: ATI Avivo decoder
    Satelite/CableTV Provider:
    HTPC Case: Thermaltake DH-102
    Cooling: a bunch of fans
    Power Supply: LC Power LC-5500
    Remote:
    TV: Samsung LE37B650
    TV - HTPC Connection: HDMI

    No SVN patches, just the downloaded MP 1.1. beta, no plugins, default skin.
    Activating teletext works fine, it also works as expected (page changes, etc.). However, every few seconds, the entire setup "freezes" for about one second. This results in video / audio playback stopping which tends to be a bit annoying. I'm guessing maybe at that time the teletext data refreshes the currently displayed page and MP goes to refresh it. But obviously that's done in the same thread as the playback thread and is quite CPU intensive - and that in the end causes the pause in the playback.

    Logs not attached because they don't show much of anything in regard to this problem and also because I'm at work right now and don't have them handy. But if relevant, I'll include them later.

    Two questions:
    1. Is this normal behavior in MP?
    2. Why is teletext display so CPU intensive?
     

    arion_p

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  • February 7, 2007
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    Teletext is not so CPU intensive to cause this delay. It is updated about 3 times/sec. It is however GPU memory and memory bandwidth intensive, because it creates the page bitmap in main memory and then the bitmap has to be transferred to GPU memory.
    Do you actually see CPU usage rise to near 100%?
    Do you have other plug-ins enabled? (try to disable all but the absolutely necessary plug-ins)
     

    velis

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  • July 16, 2009
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    I will do further testing tonight. ATM I don't know exactly how and what happens when this "pause" happens.
    Will report on CPU + GPU usage (if I can get GPU usage readings). Still, composing a page of teletext doesn't seem like a CPU intensive task - I would guess a few milliseconds should be more than enough.

    As for other plugins, I have none. I decided to make MP work this time first and only then start installing the plugins I want / need. So this installation is about as clean as it gets. The only garbage I have is from swapping a real GPU in place of integrated one + some codec uninstalls / reinstalls.
     

    velis

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    OK, did the additional testing.
    This is easiest to duplicate by changing TTX page, but it's not restricted only to page chages.
    At the time of page change, there's a short CPU usage spike (approx 200 - 250ms), which causes the MP to freeze.
    The attached logs show that at same times there are discontinuities in the TV stream.

    IMO something happens at page change that requires ~250 ms of my Athlon II and the teletext runs in the same thread as the TV playback. This in turn causes the client to stop parsing TV stream which also causes the sound pause.
    Oh, I run TTX opaque, not transparent, but that probably shows in the MP configuration log. I'm guessing this should be less CPU intensive (or maybe not).

    I also discovered that TTX won't display (well, the default MP page displays) for quite a while after changing the program (about 10 seconds?). My guess is that it wants to have all the pages in memory before it will display page 100.

    TTX also uses around 10% more of my CPU than video playback alone. Combined CPU usage is around 20%.
     

    velis

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  • July 16, 2009
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    Any news on this?
    Can you duplicate the problem?

    I have in the mean time raised TvServer priority so this should be much less of an issue, but I still find it interesting that MP TTX should spike the CPU so much only on my computer.
     

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