[FFmpeg-devel] [PATCH] FFV1 specification: Reduce redundancy in the description of xxPlane() and xxLine()

Jerome Martinez jerome at mediaarea.net
Sat May 2 01:56:50 CEST 2015


New patch because I misunderstood the definition of plane_count.
Now LyX Document is 1 + ( ( chroma_planes || version < 4 ) ? 1 : 0 ) + ( 
alpha_plane ? 1 : 0 )

Le 02/05/2015 01:33, Jerome Martinez a écrit :
> Some notes:
> - I discarded the "if version >= 4" stuff for grayscale because I 
> don't see such limitation in the bitstream and in the source code. I 
> am thinking to add a specific section about decoder limitations (e.g. 
> bits_per_raw_sample accepted range, gray/alpha support...)
> - I hesitated to define
>   * quant_table_index_count = 1 + ( chroma_planes ? 1 : 0 ) + ( 
> alpha_plane ? 1 : 0 )
>   * plane_count = 1 + ( chroma_planes ? 2 : 0 ) + ( alpha_plane ? 1 : 0 )
>   but they are nowhere else in the specification, so I direclty put 
> these formulas in the "if".
>   I think it is a bit verbose in the "if" but has the advantage not to 
> have to define extra parameters and we focus on the bitstream instead.
> - xxPlanes and xxLines were never defined, so I replace undefined 
> functions by other undefined functions. Planes and Lines functions 
> will be defined in future patches.



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