Filter framepack
  Generate a frame packed stereoscopic video.
    Inputs:
       #0: left (video)
       #1: right (video)
    Outputs:
       #0: packed (video)
framepack AVOptions:
  -format            <int>        ...V..... Frame pack output format (from 0 to INT_MAX) (default sbs)
     sbs             1            ...V..... Views are packed next to each other
     tab             2            ...V..... Views are packed on top of each other
     frameseq        3            ...V..... Views are one after the other
     lines           6            ...V..... Views are interleaved by lines
     columns         7            ...V..... Views are interleaved by columns


