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MPEGGroup / FileFormat

MPEG file format discussions
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content_encoding for mski item #75

Closed farindk closed 5 months ago

farindk commented 1 year ago

ISO/IEC 23008-12:2022 specifies an image item with item_type=mski for lossless storage of region masks. Section 6.10.2.1 says that the mski data may be compressed as specified in the infe box's content_encoding of this item.

However, it is not possible to specify any content_encoding as this is only included in the infe box if item_type=mime (infe box version 2, 3). Box versions 0,1 have content_encoding, but no item_type.

Is this a defect in the standard or am I missing something?

cconcolato commented 1 year ago

Looks like a defect indeed. Thank you for the report. We'll more on a fix asap. We should have been more careful and should have enforced requiring bitstreams before finalizing the standard.

cconcolato commented 5 months ago

Fixed in FDAM1 of 2nd Edition by removing the sentence saying "may be compressed".