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GH2 video fault. Help needed
  • bvarnalsbvarnals

    Hi, I have a GH2 have run a few different hacks on it and with most of them i seem to sometimes get some corruption to the clip (see screenshot link) It lasts a few seconds then goes away. I have a sandisk 32gb 95mb/s extreme pro card. Is there anything i can do to stop this happening? Different hack? Any suggestions?

    http://i42.tinypic.com/2le2zwj.png

  • 12 Replies sorted by
  • vicharrisvicharris

    What "hacks"?

  • bvarnalsbvarnals

    I'v had the '44mb/s vanilla', 'sanity 5.1' and also the 'no adverse effects' there have been others but can't remember which ones. Think I have this issue occasionally with all of them.

  • tetakpataktetakpatak

    Does this appear by playback in your camera? Or only with your editing software?

  • bvarnalsbvarnals

    I have trouble playing the files back on the camera it tends to say something about SD can't be read. This isn't just files with the problem above but files that seem fine when imported to the computer. I try turning the camera on and off but still can't playback some file.

    But no i haven't seen the above fault on the camera screen. Just on premiere pro or VLC player.

  • RobertoRoberto

    @bvarnals

    Your artefacts look like mine encountered while testing shutter speeds:

    image

    @Jodan suggested:

    From all I know this is caused by high compressing codecs: not all the information needed for a full frame is available for every frame - thus causing artefacts when displaying one of them (there's only data for the parts where there are changes within the frame while not changing parts of the frame still are there from previous frames).

    from http://www.personal-view.com/talks/discussion/2848/gh2-in-24p-noticeable-strobe-effect-with-any-motion-in-frame/p2

  • bvarnalsbvarnals

    Has anyone found a solution or better hack for dealing with this problem or should I try shooting at 1/40?

  • goannagoanna

    Nothing really to do with shutter speeds, although a blurrier image may be more forgiving to higher compression...

    Instead, try a lower compression hack.

  • bvarnalsbvarnals

    any suggestions of good ones?

  • goannagoanna

    I'll bump this thread and leave it to others to suggest better hacks for you.

    Then, if you're doing identical things to other users but getting different results, maybe it's time to start looking at your hardware, trouble-shooting to isolate the problem - as in trying same SD card in a different camera, different SD in your camera. (In the end, I never really understood what Panasonic's Venus Engine chips do, after all!)

    Note that Roberto's munged-up frame happened during a zip-pan; the codec couldn't cope with such fast-changing vision, whereas your own figurative shots should be placing far fewer demands on the codec (unless there's an awful lot of camera shake! ;-)

    If the truth be known, few of us go through our footage frame-by-frame like you have. Some people use players with a high degree of error-correction and so never see the artefact frames which might still be there. Others are used to glitches in original mts files but claim that it all gets cleaned up when doing a final render from their editing suite.

    Another thing: some hack files don't always play back in-camera. That's the price we pay :-)

  • bvarnalsbvarnals

    Cheers. It did cross my mind that this could be a hardware fault. Also i forgot to say that its not isolated to 1 frame but spans across a second or so of frames. It usually only occurs once in a clip and usually near the start. Thanks for your help

  • driftwooddriftwood

    That picture generally occurs when the encoder buffers is not assigned enough bitrate/ measured correctly.

  • goannagoanna

    @driftwood

    not assigned enough bitrate

    Isn't that another way of saying the compression is too high?

    image

    @bvarnals (Hope you don't mind me inserting your pic).

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