What happens during "deinterlace source video" while using QuickTime conversion?

Discussion in 'Digital Video' started by NRose8989, Oct 7, 2008.

  1. NRose8989 macrumors 6502a

    Feb 6, 2008
    So i shot some footage of my brother playing tennis using 60i on my HF10. After editing i exported the video using quicktime conversion, and i checked the box under settings to "deinterlace source video".

    Now what exactly happens when i check this box? does it just convert my video to 30p?

    if so am i just wasting time by shooting in 60i then de-interlacing, when i could just shoot in 30p from the camcorder?
  2. Exman macrumors member

    Oct 6, 2008
    What did you convert it to? .mov, mpeg2 (dvd)?

    When you are deinterlacing a video, you're converting it into a progressive scan video. You normally lose picture quality, in this case you definitely lose picture quality because Quicktime's deinterlacing filter quite ordinary.

    I suggest you keep the target video interlaced (same as the source in all cases), CRT TVs are interlaced so the picture should be pretty right. LCDs and plasma have no trouble handling interlaced video either.

    The Beijing Olympics was broadcast primarily interlaced ;) Bet you didn't have problems watching it :)
  3. NRose8989 thread starter macrumors 6502a

    Feb 6, 2008
    My output video is usually h.264, for viewing on the web.
  4. Courtaj macrumors 6502a


    Jul 3, 2008
    Edinburgh, U.K.
    Deinterlace it. Even if Quicktime is your only option, deinterlace it. Interlaced video looks like poo on LCD monitors.

    Did I mention that you should deinterlace it?

    Rock on.
  5. Courtaj macrumors 6502a


    Jul 3, 2008
    Edinburgh, U.K.
    No. If you keep the original clip then you still have the interlaced video for viewing on TVs even if you deinterlace for web viewing. If you shoot progressive, then you're stuck with progressive - which is no bad thing in itself, but shooting interlaced gives you both options. You can "do progressive" in post.

    Keep on truckin'.
  6. NRose8989 thread starter macrumors 6502a

    Feb 6, 2008
    OK thanks for the info.

    one more question...

    is it better to de-interlace using quicktime conversion (the check box) or to use a de-interlace filter in final cut (specifically FCE 4)?

    FCE 4 gives me the option to use either "upper" or "lower", what are these different options used for?
  7. huntercr macrumors 65816

    Jun 6, 2006
    It is much better to use deinterlacing filters in FCE rather than quicktime.

    Proper De-interlacing is not always simple. The "upper" and "lower" choice you see are required for the proper field order. for DV this is lower and HDV this is upper.

    I have no idea what's going to work for you, since I just read up on the HF10 and it also supports 30P written in 60i and I don't believe FCE supports 2:2 pulldown or "weave" field order a feature on the camera which I've never heard of. I'd refer to your manual and see if there's any way to force a particular field order.

    Anyway... deinterlacing can be done with the built in FCE filter, but the free Stibs de-interlacer plugin is better, and for complex motion the TMTS ( Too Much Too Soon ) Smart de-interlace filter is the best ( though it is not realtime ) both of them are free and can be easily found if you google for them.

    Exman is right though that you shouldn't deinterlace if your output medium is going to be TV.

    Good luck!
  8. Exman macrumors member

    Oct 6, 2008
    Again, if the source video is BFF (Bottom Field First/Lower), your target should also be BFF and vice versa. Some cameras record BFF, others TFF, you'll have to check the source.

    Whatever you do, don't get the fields mixed up, your video will turn out flickery and aweful (especially on a TV), i.e if source video = BFF, you encode the video TFF (Top Field First/Upper), the picture will be bad.

    Just remember:
    Source = BFF, Target = BFF
    Source = TFF, Target = TFF

    If you deinterlace a video (becomes progressive scan), chose "None" or "N/A" in the "Fields" setting.

    Another rule is, DO NOT encode an interlaced video into progressive scan unless you deinterlace it. The picture will also turn out bad.

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