[solved] Dropping frames when watching live TV

Stéphane Lenclud

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  • April 29, 2013
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    It looks like I'm dropping frames while watching live TV not matter the video codec.
    I tried LAV, Microsoft and CyberLink codecs.
    Same effect when playing TS files.
    Playing MKV works just fine.
    Logs attached.
     

    mm1352000

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    I can see the dropped frames in the EVR log, but there's no obvious cause.

    Does the same happen for recordings?
    What happens if you [temporarily] disable your DD Live encoding?
    Please attach a screenshot of the MP render stats (shift + 1) and task manager CPU usage.
     

    Stéphane Lenclud

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    mm1352000

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    The screenshot makes it clear. TV content is 50 fps where you are. Your display is running at 23.97 fps, so [50 - 23.97 = 26.03] fps will have to be dropped. To solve, I guess you just need to enable automatic refresh rate changing so that the display runs at 50 fps.

    [edit:
    proper content frame rate = 50 fps
    actual frame rate = 23.97 fps
    difference between actual and proper frame rates = 26.03 fps
    expected frame drop percentage = [difference between actual and proper frame rates] / [proper content frame rate] = 26.03 / 50 = 52.06%
    actual frames dropped = 1402 frames
    actual frames drawn = 1319 frames
    total frames = [actual frames dropped] + [actual frames drawn] = 2721 frames
    actual frame drop percentage = [actual frames dropped] / [total frames] = 1402 / 2721 = ~51.5%

    51.5 is pretty close to the expected/predicted 52.06. ;)]
     
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    Stéphane Lenclud

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    Awesome that fixed it. Not sure when my display was set to 23Hz. Then again I've been quite busy playing with those drivers settings lately.
    upload_2015-12-21_0-57-51.png
     

    Stéphane Lenclud

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    Never used that Dynamic Refresh Rate feature before. I suppose as long as the driver frequency is higher than the video I'm ok.
    Mine was set to 23Hz in the driver for some reason.
    upload_2015-12-21_1-12-21.png
     

    mm1352000

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    I suppose as long as the driver frequency is higher than the video I'm ok.
    Incorrect. To get smooth video, the display/monitor frame rate should exactly match (or be a multiple of) the content frame rate.

    If the display/monitor frame rate is lower than the content frame rate then frames are dropped as you saw.
    If the display/monitor frame rate is higher than (and/or not a multiple of) the content frame rate then frames are repeated. People describe the effects in various ways including micro stutters, jerky panning etc.
     

    mm1352000

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    I assume so. I can't use it because my monitor only supports 60 Hz.

    [edit: Actually, if I recall correctly, the frame rate goes back to 60 Hz when the video is stopped and the MP GUI becomes visible again.]
     
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