diff --git a/index.bs b/index.bs index 7eb5639..271f7c5 100755 --- a/index.bs +++ b/index.bs @@ -91,6 +91,8 @@ url: https://www.iso.org/standard/66067.html; spec: HEIF; type: property; text: layer_id text: image_width text: image_height + text: ster + text: tmap url: https://www.iso.org/standard/68960.html; spec: ISOBMFF; type: dfn; text: compatible_brands @@ -102,6 +104,7 @@ url: https://www.iso.org/standard/68960.html; spec: ISOBMFF; type: property; text: iloc text: mdat text: idat + text: altr url: https://www.iso.org/standard/74417.html; spec: MIAF; type: property; text: miaf @@ -327,7 +330,9 @@ NOTE: The size of the last layer can be determined by subtracting the sum of the - The track shall have only one sample description entry. - If multiple [=Sequence Header OBUs=] are present in the track payload, they shall be identical.

-

Auxiliary Image Items and Sequences

+

Other Image Items and Sequences

+ +

Auxiliary Image Items and Sequences

An AV1 Auxiliary Image Item (respectively an AV1 Auxiliary Image Sequence) is an [=AV1 Image Item=] (respectively [=AV1 Image Sequence=]) with the following additional constraints: - It shall be a compliant [=MIAF Auxiliary Image Item=] (respectively [=MIAF Auxiliary Image Sequence=]). @@ -342,6 +347,24 @@ NOTE: The size of the last layer can be determined by subtracting the sum of the NOTE: [[!AV1]] supports encoding either 3-component images (whose semantics are given by the matrix_coefficients element), or 1-component images (monochrome). When an image requires a different number of components, multiple auxiliary images may be used, each providing additional component(s), according to the semantics of their aux_type field. In such case, the maximum number of components is restricted by number of possible items in a file, coded on 16 or 32 bits. +

Derived Image Items

+ +

Tone Map Derived Image Item

+ +A tone map derived image item ('tmap') as defined in [[!HEIF]] may be used in an [=AVIF=] file. When present, the base image item and the 'tmap' image item should be grouped together by an '[=AVIF/altr=]' entity group as recommended in [[!HEIF]]. + +

Entity groups

+ +The GroupsListBox ('grpl') defined in [[!ISOBMFF]] may be used to group multiple image items in a file together. The type of the group describes how the image items are related. Decoders should ignore groups of unknown type. + +

'altr' group

+ +The 'altr' entity group as defined in [[!ISOBMFF]] may be used to mark multiple items as alternatives to each other. Only one item in the 'altr' group should be played or processed. This grouping is useful for defining a fallback for parsers when new types of items or essential item properties are introduced. + +

'ster' group

+ +The 'ster' entity group as defined in [[!HEIF]] may be used to indicate that two image items form a stereo pair suitable for stereoscopic viewing. +

Brands, Internet media types and file extensions

Brands overview

@@ -696,7 +719,7 @@ Other versions of the boxes shall not be used. "-" means that the box does not h Used to store derived image definitions - grpl + [=AVIF/grpl=]   - ISOBMFF @@ -705,12 +728,20 @@ Other versions of the boxes shall not be used. "-" means that the box does not h   - altr + [=AVIF/altr=] 0 ISOBMFF   Used when images in a group are alternative to each other - + + +   + [=AVIF/ster=] + 0 + HEIF +   + Used when images in a group form a stereo pair + pasp   @@ -825,3 +856,4 @@ Other versions of the boxes shall not be used. "-" means that the box does not h - Clarify relationship between av1C, metadata OBUs and item properties - EDITORIAL: Update list of other item properties - Further clarify relationship between av1C, metadata OBUs and item properties + - Add information on tmap, grpl and altr