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Media Player 12: playback at higher speed is fragmented.

السؤال Media Player 12: playback at higher speed is fragmented.

  • Sunday, February 12, 2012 3:51 PM
     
     
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    1) Download a video tutorial in WMV format; (e.g. one of Peter Kuhn's videos at http://www.goodcat-trainings.net/) and start play back in WMP12.

    2) Increase the play back speed to factor 1.4 by pressing Ctrl-Shift-G.

    The audio playback speed increases as expected and remains continuous and undistorted.

    However the video playback sometimes stutters and becomes fragmented. It looks as if the "internal image pointer" would jump back and forth in steps of about 0.5 seconds a few times before the image becomes stable again. During this time, the images appear to be composed of parts of different images that do not belong togehter; just like mixing different puzzles.

    WMP apparently skips individual frames to remain in sync with the accelerated audio speed. However, since the WMV codec is akin to the MPEG codec, I assume that it also has some kind of I-frame as well as sorts of P- and B-frames. The effect I observed suggests that the play back function happens to drop I-frames every now and then. This would cause P- and B-frame difference data to be added to outdated I-frames.

    In accelerated playback, WMP should try to hit all "I-frames" and to drop only intermediate data if possible.

    Addendum:

    I submitted this issue using the form http://mymfe.microsoft.com/Windows%207/Feedback.aspx?formID=195, that I have been pointed to.

    • Edited by Frank Heimes Sunday, February 12, 2012 8:02 PM
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  • Monday, February 20, 2012 9:58 AM
     
     
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    Hi,

    Does the issue can be reproduced on other machine with different  display card?

    I would like to suggest update the the display card and firmware to the latest version to check if that can help.

    Thanks,

    Spencer Shi 

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  • Monday, February 20, 2012 11:00 AM
     
     
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    Thanks for your feedback and your suggestion.

    I observed this problem on a PC with a very outdated NVidia Card (MX 440, 2001).
    However, the VLC player (videolanclient) is able to play back the same video on the same hardware at various speeds without any artifacts. So at least regarding hardware support, WMP12 is behind its competitor.

    I also have access to a quad core PC with the latest graphics board and drivers. I'll check if the problem also arises on that PC, next week.

    However, IMHO, WMP12 may expose limited functionality if running on old hardware but it should not exhibit malfunctions.

    Frank.

     
  • Thursday, February 23, 2012 8:43 AM
     
     
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    Hi Frank,

    Our engineer was unable to reproduce this problem. They tried one of the videos suggested (specifically, http://www.goodcat-trainings.net/downloadtrainingpartvideo/8ceed1ca-1aed-4fd9-86ea-2cd90db34c1a), and did not see the video jumping around when fast-forward or fast-reverse were used.

    >>Download a video tutorial in WMV format; (e.g. one of Peter Kuhn's videos at http://www.goodcat-trainings.net/) and start play back in WMP12.

    Note that all of the videos at this site are mp4 (and not WMV).  Perhaps this is the reason they don’t see the problem?  This is on Windows 7 with WMP 12.

    Can you provide more explicit steps (including a link to an exact video to try)?

    Thanks,

    Spencer Shi

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  • Friday, February 24, 2012 9:53 PM
     
     
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    Hi Spencer,

    I tested some WMV videos from channel 9. As it turned out, the effect does not occur with videos in WMV format. So my initial post was inaccurate regarding the affected video file format.

    The goodcat training videos are in fact MP4 videos and the problem occurs when playing these videos. I also verified that the problem occurs when playing a Windows Phone 7 tutorial Video from channel 9 in MP4 format.

    The effect is more severe in other parts of the sequel and most apparent while Peter Kuhn is editing text. Try, for instance, part "15: About Page 2": http://www.goodcat-trainings.net/downloadtrainingpartvideo/aa35c388-7311-40e4-83ba-087babcbf2c5

    Regards,
    Frank


    • Edited by Frank Heimes Friday, February 24, 2012 9:54 PM
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  • Thursday, March 01, 2012 6:15 AM
     
     
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    Hi Frank,

    Sorry for the late response as I need to discuss the issue with other engineers.

    None of us are able to reproduce this here.  Perhaps it has to do with the GPU on the machine?  Can you  let us know the specifics of the video driver and card?

    Also to verify, this is WMP 12 on Windows 7 SP1?

    Finally, Ctrl-Shift-G does not affect playback speed in WMP 12.  We can speed it up using the FF/REW arrows though.  Can you provide more details on this key combination (does he have a plug-in, for example)?

    Thanks,

    Spencer Shi

    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

     
  • Friday, March 16, 2012 5:58 PM
     
     
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    Hi Spencer,

    the GPU is an NVidia Geforce4 MX 440 chip (from 2001) onboard a MSI 6513 mainboard.
    The driver version is 7.8.0.1  (nv4_mini.sys 6.14.10.7801 from 2005).
    The system has a Intel Pentium 4 single core CPU with 2 GHz clock and 2 GB RAM.

    The OS is Windows 7 Ultimate (32 bit, German), Service Pack 1. Windows 7 performs very well on that system - even better than Windows XP - besides the aero effects which are not supported by the GPU.

    The Windows Media Player that comes with Windows 7 (12.0.7601.17514, no third-party extensions) has the builtin hot keys Ctrl-Shift-S, Ctrl-Shift-N, and Ctrl-Shift-G for slow (0,5), normal (1.0), and fast (1,4) play back speed, resp.

    Regards,
    Frank.

    Edit:
    I verified, that the video corruption only occurs on that older hardware. No artifacts occur on a newer PC (Quad core, NVidia Radeon board). However, as I said, the VLC player (videolanclient) has no problems with the older hardware.