How do I handle both video and film-based material?

[CubDukat]

I recently ran into this problem last week, when I taped the encore of the "Fringe" pilot. The intro to the "Day the World Stood Still" is obviously video-originated, but the rest of the program is regular film-based 720p with what I guess is a standard cadence.

I wanted to avoid making three or four separate .avs files (one for the intro, one for the "Earth" trailer, another for the main show, and the last one for the "24: Redemption" teaser), so I reinstalled the decimation plug-in where you have to do a pass in VirtualDub to create a file that the second pass uses to delete duplicates (FDecimate?) and used it to do the whole show. Needless to say, the end result was somewhat less than optimal, so I ended up replacing it with TDecimate(mode=0,hybrid=1). The video segments were jittery, but at least the main program looked fairly good, so I left it at that.

What I'd like to do is configure whatever decimation tool that I use so that the parts that are video will look completely normal, while the film-based parts will still be decimated correctly. I'll post a copy of the script I used later.

[edDV]

Normal 720p video is 59.94 frames per second. You can't convert this to 23.976P without re-calculating all frames (frame rate interpolation) which is lossy. You can easily convert 720p/59.94 to 480p/59.94 through frame resize. The 480p/59.94 can be converted to 480i with odd/even fields taken from alternate frames.

Film based 720p has frames repeating in a 2:3 pattern. Frame decimation can be used to expose the 23.976p sequence. This can then be resized to 480p/23.976.

Converting 720p to 480i is more complicated. First you create 480p/23.976, then you apply telecine to 480i/29.97.

So if you want one standard for mixed formats, 480p/23.976 requires reinterpolating standard video frame rate to 23.976, where 480i/29.97 can be done as stated above.

[jagabo]

I'm assuming all the video is 720p, not a mix of 720p and 1080i.

Use Trim() to break the video into segments, then:

For film converted to 60 fps progressive use TDecimate(cycle=5, cycler=3), encode progressive with 3:2 pulldown flags.

For 30 fps progressive segments decimate by 2 with SelectEvery(2, 0). Encode interlaced 30 fps.

For 60 fps segments (where every frame is different) decimate by 2 and encode interlaced, or SeparateFields().SelectEvery(4,0,3).Weave() and encode interlaced.

Or, if you want to be lazy, just encode the whole video interlaced after SeparateFields().SelectEvery(4,0,3).Weave(). The film segements won't look as good and you'll need more bitrate to maintain quality.