Open baumanj opened 2 years ago
Thank you. The version of the spec is more recent than what's currently supported by the ComplianceWarden. Let's see how we can progress on an update, I have a TODO to list the request changes.
If that's urgent let me know, I could implement this before update the rest of the specs.
You do understand that ICC operates or XYZ or LAB or RGB or CMYK, while nclx operates before that on RGB --> R'G'B' --> YCbCr. Both should be present. Techincally primaries of nclx are incompatible with ICC profile, sure, but still.
Both are only required if the primaries or transfer characteristics aren't representable with CICP values (possible, but unlikely)and the matrix coefficients aren't BT.601 (again, quite unlikely). So while there are important use cases which require both, the vast majority should only need one. See https://github.com/AOMediaCodec/libavif/wiki/CICP for more.
Eventually the spec will be updated (see https://github.com/AOMediaCodec/av1-avif/issues/164 and https://github.com/MPEGGroup/FileFormat/issues/39), but right now the published text is clear.
Is https://github.com/AOMediaCodec/av1-avif/issues/164 or any of the discussion blocking the addition of this new test?
The additional checks would be:
@cconcolato It seems that https://github.com/MPEGGroup/FileFormat/issues/39 would allow to close https://github.com/AOMediaCodec/av1-avif/issues/164 and unlocks here. Correct?
@rbouqueau what's important is that:
Regarding the color restrictions, in terms of spec and publication status, we have
HEIF ISO/IEC 23008-12:2022 (published) (https://dms.mpeg.expert/doc_end_user/documents/140_Mainz/wg11/MDS22076_WG03_N00749.zip) says:
Quantity (per item): At most one for a given value of colour_type
HEIF ISO/IEC 23008-12:2022 AMD1 to be published at the end of the year (see https://github.com/AOMediaCodec/av1-avif/issues/164#issuecomment-1572516221) will say:
Quantity (per item): Either at most one, or two with restriction described below In addition, following definitions specific to the use of colour information in image items also applies: — When two ColourInformationBoxes are associated with an image item, one shall have a colour_type value of 'rICC' or 'prof' (providing either restricted or unrestricted ICC profiles respectively) and the other one shall have a colour_type value of 'nclx' with colour_primaries equal to 2 and transfer_characteristics equal to 2 (2 indicating "unspecified", since these data are supplied by the ICC profile instead).
To close this issue, I think we should implement only 1 (in the master branch) and 2 (in a branch that should be merged only after the AMD is officially approved/published).
Per HEIF (ISO/IEC 23008-12:2017) § 6.5.5.1:
This is in the process of being amended in DIS 23008-12 to be
but multiple associations of
colr
boxes of the samecolour_type
per item should be disallowed under either standard. However, these inputs generate no errors or warnings:invalid-avif-colr-multiple.zip