I need help with removing two weird image anomalies

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  • Freelancer
    Junior Member
    Junior Member
    • Jul 2003
    • 2

    I need help with removing two weird image anomalies

    Hello

    My source is 5mbit MPEG-2, 25fps interlaced PAL. I am attempting to convert the source to 2mbit XviD using VirtualDub. After deinterlacing via blending both fields, there are still two anomalies present.
    But what puzzles me the most is that both unwanted effects are not always present in the very same 20-minute video clip. Most of the time, the image seems to be OK:

    Sample: OK



    But sometimes, this weird (annoying!) vertical effect is present:

    Unknown effect sample 1
    Unknown effect sample 2
    Unknown effect sample 3
    Unknown effect sample 4


    And sometimes, certain areas of the image are displaced. This seems to be the most visible on faces.

    Displacement sample 1
    Displacement sample 2
    Displacement sample 3
    Displacement sample 4

    So first of all, can someone identify these effects? I don't even know what to look for. The vertical effect seems to be somehow connected to interlace...? I've tried several methods but it won't go away. The quick fix is 2:1 reduction, but that will ruin the image clarity . Smoothing seems to eliminate the displacement... but unfortunatelly, image details are gone as well .
    Any feedback is appreciated!

    Regards,
    Freelancer
  • scdlcgs
    Gold Member
    Gold Member
    • Apr 2003
    • 134

    #2
    ok, since after a lot of proves that xvid, being as effective as it is, it may present some problems in the video, problems like the one you have mentioned. This wont work out every time, but maybe you can give it a shot. Try to replace the codec, xvid, for a more stable one, like divx, using virtual dub. If it doesnt work, maybe the gulty of all this is the source you used... or the way you ripped it (i dont know if you download it or its a rip version), anyway if this doesnt solve your problem, we´ll keep trying to help you.
    Scdlcgs- Improving... Editing is my thing! Have patience...

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    • Freelancer
      Junior Member
      Junior Member
      • Jul 2003
      • 2

      #3
      Unfortunately the problem is within the source itself (see: samples below). The source was not ripped or downloaded I captured it via digital satellite. A lot of transponders use interlaced video, which is deinterlaced during viewing using MPEG-2 post-processing.
      Other video clips that I have also captured had no such artifacts (they were captured from different stations). There was only standard interlace which was removed using VirtualDub's deinterlace (blend) filter.
      However this particular TV show from this particular TV station has these unwanted effects Overall I'm happy with the quality, since the anomalies are not always visible, but I'd really like to get rid of them. I appreciate your help.

      Freelancer

      Source sample (MPEG-2 5mbit)
      DivX 5.05 2.5mbit
      XviD 2.5mbit
      These show the displacement effect. The vertical anomaly is also present in the source itself, but I don't have any screenshots at the moment. But I think you can take my word for it
      Last edited by Freelancer; 2 Jul 2003, 06:53 AM.

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