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

[Jerome Martinez]

Le 02/05/2015 01:37, Michael Niedermayer a écrit :
> plane_count was 2 for gray prior to version 4 [...]

Got it.
Maybe I missed something else, but looks like decode_plane() is never 
called with plane_index = 1 if chroma_planes is 0.
Was it an implementation bug and actually plane_index = 1 is never used 
in the case of gray?

Additionally, I read this code:

 >         if (fs->transparency)
 >             decode_plane(fs, p->data[3] + ps*x + y*p->linesize[3], 
width, height, p->linesize[3], 2);

plane_index is 2 for the alpha plane if transparency is 1, in all cases.
but I understood that for version >= 4, plane_count is 2 if grey+alpha, 
so plane_index = 2 would not be possible.

shouldn't it be
         if (fs->transparency)
             decode_plane(fs, p->data[3] + ps*x + y*p->linesize[3], 
width, height, p->linesize[3], (f->version >= 4 && !f->chroma_planes) ? 
1 : 2);