locked
Unexpected pixelation in WMV with Windows 7 RRS feed

  • Question

  • I am creating WMV file using Windows Media Format SDK in a medical application.Basically, we get tif images from a digital camera that we turn into bitmaps that we then add to a sink writer.

    We support a wmv and an mp4 option.

    This is done similarly to the example at

    https://msdn.microsoft.com/en-us/library/windows/desktop/ff819477(v=vs.85).aspx

    On windows 7 we observe some unexpected pixilation effects. No problem with a similar video generated in exactly the same conditions but in Windows 10.

    Comparison of videos created on Windows 10 & 7

    Is it a known issue?

    Is it a codec problem?

    How to workaround?

    Monday, February 27, 2017 3:45 PM

All replies

  • The screenshot to the right does look like it has compression artifacts, somewhat similar to when a key frame is missing. This means the problem could indeed be related to codecs. One way to find out for sure is to try a different codec, such as those shipped with LEADTOOLS Multimedia library. (Disclaimer: I work for LEAD).

    I'm not sure if it's easy with DirectShow to use non-Microsoft codecs when creating WMV files, but the library does have its own capture and convert controls that can use both LEAD and non-LEAD codecs. There's a free evaluation edition of the library at www.leadtools.com.

    Friday, March 24, 2017 11:50 AM
  • Thanks Amin,

    I am not sure I can use a different WMV codec easily but it's clear that the same data do not show the same artifact with an MP4 coded.

    We are thinking to move away from the Microsoft technology, which seems not reliable enough.
    We'll think of LeadTool when time comes.

    Friday, March 24, 2017 1:46 PM
  • Yes, I tried this.
    The problem seems to be inside the WNV file itself.

    The pictures above are from VLC but Windows Media Player shows the same issues

    Monday, March 27, 2017 7:54 AM
  • Many things in your response...

    Please see my answers:

    ok, so generally we can say, that the WMV file runs perfect on Win10, but has issues during playback on Win7.
    -> NO, THE FILE IS NOT GENERATED AS EXPECTED. A FILE GENERATED WITH WIN10 WORKS 0N WIN10 & 7 (I WOULD SAY CORRECTLY, NOT PERFECTLY).
    A FILE GENERATED ON WIN7 DOES NOT WORK ON WIN7 NO WIN10.
    Which exact configuration of the WMV encoding do you use ?
    -> I AM NOT SPECIFYING A PROFILE, JUST USING THE DEFAULT

    Can you post the source code where you Setup the Output Mediatype ?
    -> VERY SIMILAR TO https://msdn.microsoft.com/en-us/library/windows/desktop/ff819477(v=vs.85).aspx
    IF I CREATE A SAMPLE APP SHOWING THE PROBLEM, I'LL OPEN A MSDN CASE WITH IT, NOT USE FORUMS.

    Especially MF_MT_SUBTYPE.  Is it MFVideoFormat_WMV3 ?
    ->  YES

    Which Version of Windows Media Player do you use for the test?
    -> VARIABLE, MACHINE DEPENDENT (WE HAVE THOUSANDS OF CUSTOMERS)

    Is update kb2803821 installed on your System?
    -> YES, AT LEAST ON MY TEST MACHINE.

    Has your Win7 the newest updates installed?
    -> NOT SINCE AUG 2015. WHEN I TRY TO RUN WINDOWS UPDATE, IT SAYS DOWNLOADING BUT STAY STUCK AT 0% WITH NO TRAFIC ON THE WIFI CONNECTION. ANOTHER MS PROBLEM...

    Tuesday, March 28, 2017 8:05 AM