[FFmpeg-user] Question about macroblocks in soft telecined video

Mark Filipak markfilipak.windows+ffmpeg at gmail.com
Sun Sep 6 07:20:39 EEST 2020

I can't answer this for myself because I don't have the tools needed to probe into undecoded 
macroblocks (at least, I don't think I have the tools).

I would guess that, for an undecoded video that's soft telecined (i.e. @24/1.001 FPS), the interlace 
in the macroblocks is field-based (i.e. the same as if @30/1.001 FPS), not frame-based (i.e. the 
same as if @24 FPS). Specifically, for YCbCr420, blocks 5 (Cb) & 6 (Cr) are deinterlaced into top & 
bottom fields (in the top-half & bottom-half of the blocks) rather than being progressive.

Is my guess correct?

Thanks so much!
- Mark.
Racism is like roaches. When you switch on the light, they scurry.
But if you don't switch on the light, you don't know they're there.

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