Editing pgm for 3D 4K video?

Try looking at VEGAS Pro: Video & audio for professionals (vegascreativesoftware.com)

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I have done this in the past. Of course, you load the video into the editor above and below each eye and line it up according to the audio (clap, etc.). Your 3D videos have to be created in 1080p or 720p however for 3D players/TVs/Projectors to recognize them.

My favorite program is EDIUS, but more expensive. I think you can only align video in Vegas and Edius. Powerdirector just does auto alignment--not sure, been awhile.

Some have had success creating Over/Under 4K 3D and showing on 3D equipped 4K TVs.

There is a whole process to doing this that will take several weeks/months to figure out, but well worth it. For example, I create full-frame left/right eye 3D video out of Edius, and load that into Powerdirector to create a frame-packed bluray video in 1080p 24fps or 720p 60fps (the two accepted bluray formats). The 720p loses some resolution, but having the 60fps makes the video much smoother. Example, you can take 4K video in 30 or 60 fps and create blurays that will be super smooth. I have over 8 years experience making 3D videos, and it's not something that can be taught quickly; it must be experienced over many hours of trying and trying and trying different workflows to make it work.  Your experience may differ, so don't get discouraged.

If you don't go bluray, you can make side-by-side and over/under 3D at 30fps that will work.

Many don't realize that there was never a spec for 4K 3D video, so it doesn't exist as a valid 3D format.