[x264-devel] chroma_format_idc parameter

[Loïc Le Loarer]

Le jeudi 11 octobre 2007 à 17:11:57 +0700, Viet Dung a écrit:
> Hi,
> I'm using the *Alex Izvorski's *project to generate the bitstream's header.
> In this bitstream i found that the parameter chroma_format_idc = 0, it means
> all the slices in this video sequence have chroma components equal to zero?

Yes, chroma_format_idc = 0 means monochrome format, so there is no
chroma. (1 is 4:2:0, 2 is 4:2:2, 3 is 4:4:4).

> But why the chroma coefficients(include DC and AC ones, all these have value
> <> 0) are encoded and transfered?

Maybe the information "chroma_format_idc = 0" is wrong,
chroma_format_idc is present in the stream only if High profile, in
other profile, it is absent and should be inferred to 1. Maybe the
inferrence is not correctly done by the program you are using.

Best regards.
-- 
Loïc

"heaven is not a place, it's a feeling"