How to Convert Frame Sequential Video to Half SBS?

[bstonearch]

Hey all, I ripped my 3D Blu-Ray disc using BD3D format (AVC+MVC). I then converted it to Frame Sequential using BD3D2MK3D. Following that, I upscaled each frame to 4k using Topaz AI. The resulting video is a frame sequential (left eye first) 3840x2160 video at 47.592fps.

I'm looking to take this video and convert it to Half SBS. Essentially, what needs to happen is;

- Extract even frames → Left eye
- Extract odd frames → Right eye
- Scale each eye to 1920×2160
- Stack them horizontally to create 3840x2160 frames
- Output at half the frame rate. Naturally, if the process is taking one left and one right frame and stacking them horizontally, the resulting frame rate should be ~23.796 fps since its using 2 input frames to create 1 output frame.

I've tried many different variations using FFMPEG and the result is never quite right. I figured I'd post here to see if anyone has any experience converting frame sequential to Half SBS. Any help would be awesome! Thanks

[jagabo]

Decoders usually weave the fields back together into interlaced frames. So in AviSynth:

SeparateFields()
# scale as  necessary
StackHorizontal(SelectEven(), SelectOdd()

[r0lZ]

IMO, it is much simpler to upscale the video to UHD during the conversion of the original BD to Full-SBS (not frame-sequential!) with BD3D2MK3D. You should just add the resize command in the avisynth script __ENCODE_3D_MOVIE.avs generated by BD3D2MK3D before launching the conversion.

For example, replace this line:
left = SelectEven(interleaved)
with:
left = SelectEven(interleaved).LanczosResize(3840, 2160)
And, of course, do the same modification for the right view.

It's easier, much simpler, quicker and you will not lose quality due to the two encodings.