[FFmpeg-devel] FFV1 specification: plane_count prior to version 4

[Jerome Martinez]

In FFV1 specification, I read:

 > plane_count prior to version 4: without transparency: 2 else 3.
 > version 4 and later: gray: 1, gray+alpha or color:2, color+alpha:3

but in both headers (FrameHeader01 or GlobalHeader), I see chroma_planes 
flag, it looks like all versions of FFV1 bitstream are supporting gray 
(and gray+alpha).
Does it make sense to consider this difference between "prior to version 
4" and "version 4 and later" as applicable to the FFmpeg 
encoder/decoder, not the FFV1 bistream specification itself?