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Frame doubling to 1080/60p with InterFrame
  • InterFrame is an AviSynth script that does motion compensated frame interpolation, to give you double frame rate video that plays back more smoothly. I find that it does a much better job of this than Twixtor. (for normal speed playback, at least. Twixtor might be better for slow motion) The video looks good enough that my prefered workflow is to shoot in 1080/30p and exhibit frame-doubled 1080/60p.

    Here is a very poorly shot before-and-after video:

    http://www-personal.umich.edu/~balazer/files/interframe_tests/

    To play back the sample video, I recommend VLC. Most PCs and players should play back the MPEG-2 version, but you'll need a fast PC to play the 1080/60p h.264 file. If playback is not smooth, try changing the video output module to DirectX. For best results, set your monitor's refresh rate to a multiple of 60 Hz.

    Another playback option is MPC-HC with ffdshow-tryouts beta 7 rev. 3154: set the output renderer to Overlay, and the ffdshow h.264 codec to ffmpeg-mt.

    The software I use:

    My workflow:

    In Sony Vegas, set the project properties to 1080/30p, 8-bit, with an audio sample size of 16 bits and the audio sample rate you want. Render to the DebugMode FrameServer. Set the DebugMode template to 'project properties'. Set the signpost mode to RGB32 and enable 'write audio'.

    AviSynth reads the signpost AVI, and ffmpeg reads from AviSynth. Attached is the AviSynth script, and two .bat files for drag-and-drop encoding with ffmpeg.

    For Internet distribution, I suggest encoding to MPEG-2 at around 26 Mbps. Obviously this is a high bit rate for the Internet, but it is fairly easy to find a PC and decoder fast enough to play it back. Many PCs and players aren't fast enough to decode low complexity h.264 mp4 at even 13 Mbps.

    For the highest quality, encode to high bit rate MPEG-2. It's easier to play this video than h.264, but obviously the files are too big to be easily distributed via the Internet.

    interframe.avs.txt
    137B
    h.264 13 Mbps for 60p.bat.txt
    902B
    mpeg2 80 Mbps.bat.txt
    233B
  • 10 Replies sorted by
  • Please remove scripts from the post and attach them to post as files.

  • is this better as virtualdub and the bobdoubler filter?

    i have downloaded what you use in your workflow.
    But where do you put those files, go they all in avisynth plugin folder..
    And how do i Set the DebugMode template to 'project properties'.
    In what map go's libFAAC dll?

  • x264 uses an interesting GOP structure:

    IbBbPbBbPbBb...

    The large B-frames (my notation) use the nearest two I- or P-frames as references. The small b-frames use their immediate neighbors as references. I set some x264 options to ensure that the InterFrame-interpolated frames always fall on the small b-frames.

  • Is InterFrame better than a bob doubler? It depends on your source footage. I find that the GH2's 30p is much sharper and cleaner than its 1080/30i, so I prefer to use 30p and InterFrame. If you are interested in high quality motion compensated bob de-interlacing, check out QTGMC.

    The InterFrame dependency files go in your AviSynth plugins folder, except for one file that goes in your system folder. Read the dependencies readme.

    In Vegas, the Render As dialog box has a pull-down labeled "Template". Set it to "Project Settings".

    You can put libfaac.dll in any folder in your path.

  • balazer, I'm playing back your sample footage on a Sony Bravia 1920 x 1080 monitor calibrated for color correction. I hope that I'm having Internet playback issues and that the heavy jitters and bluer I see on these footage are not part of the limitations on the GH2 in fast motion while panning and tilting up/down. This would be an unacceptable side effect in any professional production. I'm doing a lot of test setting at the moment on this topic with no too positive results yet. I will comeback with the final results.

  • Playback of the posted sample should mostly look very smooth. I think you are having playback issues. I can post an MPEG-2 file that's easier to play back, if that helps.

  • Any way for this to work in OS X?

  • I have uploaded a 20-Mbps MPEG-2 version of the frame-doubled clip that should play back correctly on more PCs. The link is in the first post.

    @sebben, you could use InterFrame on a Mac only if you're able to get Avisynth running under something like Wine. I don't know anything about frameserving from an NLE in Wine.

  • You haven't added any comments on shutter speed/angle effects on the fooage?

  • That video was shot with a 1/60 s shutter. It's actually the first part of a longer test with 1/60, 1/50, 1/40, and 1/30. My conclusion is that after frame doubling, 1/60 looks the best, by far. Frame doubling anything longer than 1/60 exaggerates the motion blur and makes it look smeared and unnatural. (It makes the effective shutter angle wider than 360 degrees) I would use 1/40 s in extreme low light if I couldn't tolerate using a higher ISO setting with 1/60. I can post the longer test video, if there's interest.

    Using a shutter shorter than 1/60 of course is an option, but I don't care much for the way it looks. 1/60 is the standard for video cameras. On a professional video camera, 1/60 s corresponds to the shutter being set to "off", which is the default.