From 93a4067c5561646fd7ddf21ea81ed371b1c4e063 Mon Sep 17 00:00:00 2001 From: Yannis Guyon Date: Tue, 17 Sep 2024 13:21:06 +0000 Subject: [PATCH] Add Sample Transform Derived Image Items (#224) SHA: 70d14e6f18427cffd134a0bc2a785778a4b21c78 Reason: push, by y-guyon Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> --- index.html | 753 ++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 665 insertions(+), 88 deletions(-) diff --git a/index.html b/index.html index bc53034..15baadf 100644 --- a/index.html +++ b/index.html @@ -1490,7 +1490,7 @@ - + +
@@ -2078,6 +2201,14 @@

Table of Contents

4.2 Derived Image Items
  1. 4.2.1 Tone Map Derived Image Item +
  2. + 4.2.2 Sample Transform Derived Image Item +
      +
    1. 4.2.2.1 Definition +
    2. 4.2.2.2 Syntax +
    3. 4.2.2.3 Semantics +
    4. 4.2.2.4 Constraints +
  • @@ -2154,7 +2285,7 @@

    NOTE: File writers may want to set the still_picture and reduced_still_picture_header flags to 1 when possible in the Sequence Header OBU part of the AV1 Image Item Data so that AV1 header overhead is minimized.

    2.2. Image Item Properties

    2.2.1. AV1 Item Configuration Property

    -
    Box Type:                 av1C
+
    Box Type:                 av1C
 Property type:            Descriptive item property
 Container:                ItemPropertyContainerBox
 Mandatory (per  item):    Yes, for an image item of type 'av01', no otherwise
@@ -2273,19 +2404,19 @@ 
    The track shall be a valid MIAF image sequence. 
     
  • The track handler for an AV1 Image Sequence shall be pict. 
-    
  • The track shall have only one sample description entry. 
+    
  • The track shall have only one AV1 Sample description entry. 
     
  • 
-     If multiple Sequence Header OBUs are present in the track payload, they shall be identical.
+     If multiple Sequence Header OBUs are present in the track payload, they shall be identical.
      
    
    
    
    4. Other Image Items and Sequences
    
    
    4.1. 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: 
    
    
    
    An AV1 Alpha Image Item (respectively an AV1 Alpha Image Sequence) is an AV1 Auxiliary Image Item (respectively an AV1 Auxiliary Image Sequence), and as defined in [MIAF], with the aux_type field of the AuxiliaryTypeProperty (respectively AuxiliaryTypeInfoBox) set to urn:mpeg:mpegB:cicp:systems:auxiliary:alpha. An AV1 Alpha Image Item (respectively an AV1 Alpha Image Sequence) shall be encoded with the same bit depth as the associated master AV1 Image Item (respectively AV1 Image Sequence).
    
@@ -2294,74 +2425,489 @@ 
    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.
    
    
    4.2. Derived Image Items
    
    
    4.2.1. 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 'altr' entity group as recommended in [HEIF].
    
+   
    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 'altr' entity group as recommended in [HEIF].
    
+   
    4.2.2. Sample Transform Derived Image Item
    
+   
    In these sections, a "sample" refers to the value of a pixel for a given channel.
    
+   
    4.2.2.1. Definition
    
+   
    When a derived image item is of type sato, it is called a Sample Transform Derived Image Item, and its reconstructed image is formed from a set of input image items, constants and operators.
    
+   
    The input images are specified in the SingleItemTypeReferenceBox or SingleItemTypeReferenceBoxLarge entries of type dimg for this Sample Transform Derived Image Item within the ItemReferenceBox. The input images are in the same order as specified in these entries. In the SingleItemTypeReferenceBox or SingleItemTypeReferenceBoxLarge of type dimg, the value of the from_item_ID field identifies the Sample Transform Derived Image Item, and the values of the to_item_ID field identify the input images. There are reference_count input image items as specified by the ItemReferenceBox.
    
+   
    The input image items and the Sample Transform Derived Image Item shall:
    
+   
      
+    
    • 
+     
      each have a pixi property and an ispe property;
      
+    
    • 
+     
      have the same number of channels and the same chroma subsampling (or lack thereof) as defined by the pixi and 'av1C' properties;
      
+    
    • 
+     
      have the same dimensions as defined by the ispe property;
      
+    
    • 
+     
      have the same color information as defined by the colr properties (or lack thereof).
      
+   
    
+   
    Each output sample of the Sample Transform Derived Image Item is obtained by evaluating an expression consisting of a series of integer operators and operands. An operand is a constant or a sample from an input image item located at the same channel index and at the same spatial coordinates as the output sample.
    
+   
    No color space conversion, matrix coefficients, or transfer characteristics function shall be applied to the input samples. They are already in the same color space as the output samples.
    
+   
    The output reconstructed image is made up of the output samples, whose values shall be each clamped to fit in the number of bits per sample as defined by the pixi property of the reconstructed image item. The full_range_flag field of the colr property of colour_type nclx also defines a range of values to clamp to, as defined in [CICP].
    
+   
    An 8-bit primary MIAF image item can be combined with another 8-bit hidden MIAF image item, both used as input image items to a Sample Transform Derived Image Item, with an expression corresponding to ReconstructedSample = 256 × PrimarySample + HiddenSample. The primary MIAF image item and the Sample Transform Derived Image Item are both part of the same altr group. This will be perceived as a backward-compatible regular 8-bit image to readers not supporting Sample Transform Derived Image Items, and can be decoded as a 16-bit image otherwise, making that pattern a bit-depth extension mechanism.
    
+   
    4.2.2.2. Syntax
    
+   
    An expression is a series of tokens. A token is an operand or an operator. An operand can be a literal constant value or a sample value. A stack is used to keep track of the results of the subexpressions. An operator takes either one or two input operands. Each unary operator pops one value from the stack. Each binary operator pops two values from the stack, the first being the right operand and the second being the left operand. Each token results in a value pushed to the stack. The single remaining value in the stack after evaluating the whole expression is the resulting output sample.
    
+
    aligned(8) class SampleTransform {
+    unsigned int(2) version = 0;
+    unsigned int(4) reserved;
+    unsigned int(2) bit_depth; // Signed 8, 16, 32 or 64-bit.
+    unsigned int(8) token_count;
+    for (i=0; i<token_count; i++) {
+        unsigned int(8) token;
+        if (token == 0) {
+            // Push the 'constant' value to the stack.
+            signed int(1<<(bit_depth+3)) constant;
+        } else if (token == 1) {
+            // Push the sample value from the 'input_image_item_index’th
+            // input image item to the stack. At most 'reference_count'.
+            unsigned int(8) input_image_item_index; // 1-based
+        } else {
+            if (token < 128) {
+                // Unary operator. Pop an operand from the stack.
+            } else {
+                // Binary operator. Pop the right operand
+                // and then the left operand from the stack.
+            }
+            // Apply operator 'token' and push the result to the stack.
+        }
+    }
+}
+
    
+   
    4.2.2.3. Semantics
    
+   
    version shall be equal to 0. Readers shall not process a SampleTransform with an unrecognized version number.
    
+   
    reserved shall be equal to 0 in files conforming to this version of this specification. The value of reserved shall be ignored by readers.
    
+   
    bit_depth determines the precision (from 8 to 64 bits, see Table 1) of the signed integer temporary variable supporting the intermediate results of the operations. It also determines the precision of the stack elements and the field size of the constant fields. This intermediate precision shall be high enough so that all input sample values fit into that signed bit depth.
    
+   
+    
+    
+     
+      
+     
+      
+      
+      
+      
     Table 1 - Mapping from bit_depth to the intermediate bit depth. 
    Value of bit_depth
+      Intermediate bit depth (sign bit inclusive) num_bits
+    
    0
+      8
+     
    1
+      16
+     
    2
+      32
+     
    3
+      64
+   
    
+   
    The result of any computation underflowing or overflowing the intermediate bit depth is replaced by -2num_bits-1 and 2num_bits-1-1, respectively. Encoder implementations should not create files leading to potential computation underflow or overflow. Decoder implementations shall check for computation underflow or overflow and clamp the results accordingly. Computations with operands of negative values use the two’s-complement representation.
    
+   
    token_count is the expected number of tokens to read.
    
+   
    token determines the type of the operand (constant or input image item sample) or the operator (how to transform one or two operands into the result). See Table 2. Values other than the ones in the table below are reserved.
    
+   
    Note: token values greater than 1 and less than 128 are unary operators, and token values greater than or equal to 128 are binary operators.
    
+   
+    
+    
+     
+      
+     
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
+      
     Table 2 - Meaning of the value of token. 
    Value of token
+      Name
+      Input count
+      Meaning before pushing to the stack
+      
+       Value pushed to the stack
    (
+       
+        L
+       
+        and 
+       
+        R
+       
+        refer to operands popped from the stack for operators)
+    
    0
+      constant operand
+      0
+      
+       
+        
+         2
+         
+          bit_depth
+          +
+          3
+         
+        
+       
+        bits from the stream read as a signed integer.
+      constant value
+     
    1
+      sample operand
+      0
+      Sample value from the input_image_item_indexth input image item.
+      input image item sample value
+     
    2
+      negation operator
+      1
+      Negation of the left operand.
+      
+       
+        -
+        L
+       
+     
    3
+      absolute value operator
+      1
+      Absolute value of the left operand.
+      
+       
+        |
+        L
+        |
+       
+     
    4
+      not operator
+      1
+      Bitwise complement of the operand.
+      
+       
+        ¬
+        L
+       
+     
    5
+      bsr operator
+      1
+      0-based index of the most significant set bit of the left operand if the left operand is strictly positive, zero otherwise.
+      
+       
+        {
+        
+         
+          
+           0
+          
+          
+           if
+           L
+           ≤
+           0
+          
+         
+         
+          
+           truncate
+           (
+           
+            log
+            2
+           
+           L
+           )
+          
+          otherwise
+         
+        
+       
+     
    128
+      sum operator
+      2
+      Left operand added to the right operand.
+      
+       
+        L
+        +
+        R
+       
+     
    129
+      difference operator
+      2
+      Right operand subtracted from the left operand.
+      
+       
+        L
+        -
+        R
+       
+     
    130
+      product operator
+      2
+      Left operand multiplied by the right operand.
+      
+       
+        L
+        ×
+        R
+       
+     
    131
+      quotient operator
+      2
+      Left operand divided by the right operand if the right operand is not zero, left operand otherwise. The result is truncated toward zero (integer division).
+      
+       
+        {
+        
+         
+          
+           L
+          
+          
+           if
+           R
+           =
+           0
+          
+         
+         
+          
+           truncate
+           (
+           
+            L
+            R
+           
+           )
+          
+          otherwise
+         
+        
+       
+     
    132
+      and operator
+      2
+      Bitwise conjunction of the operands.
+      
+       
+        L
+        ∧
+        R
+       
+     
    133
+      or operator
+      2
+      Bitwise inclusive disjunction of the operands.
+      
+       
+        L
+        ∨
+        R
+       
+     
    134
+      xor operator
+      2
+      Bitwise exclusive disjunction of the operands.
+      
+       
+        L
+        ⊕
+        R
+       
+     
    135
+      pow operator
+      2
+      Left operand raised to the power of the right operand if the left operand is not zero, zero otherwise.
+      
+       
+        {
+        
+         
+          
+           0
+          
+          
+           if
+           L
+           =
+           0
+          
+         
+         
+          
+           truncate
+           (
+           
+            L
+            R
+           
+           )
+          
+          otherwise
+         
+        
+       
+     
    136
+      min operator
+      2
+      Minimum value among the operands.
+      
+       
+        {
+        
+         
+          
+           L
+          
+          
+           if
+           L
+           ≤
+           R
+          
+         
+         
+          
+           R
+          
+          otherwise
+         
+        
+       
+     
    137
+      max operator
+      2
+      Maximum value among the operands.
+      
+       
+        {
+        
+         
+          
+           R
+          
+          
+           if
+           L
+           ≤
+           R
+          
+         
+         
+          
+           L
+          
+          otherwise
+         
+        
+       
+   
    
+   
    constant is a literal signed value extracted from the stream with a precision of intermediate bit depth, pushed to the stack.
    
+   
    input_image_item_index is the 1-based index of the input image item whose sample is pushed to the stack. Shall be at least 1 and at most reference_count.
    
+   
    4.2.2.4. Constraints
    
+   
    Sample Transform Derived Image Items use the postfix notation to evaluate the result of the whole expression for each reconstructed image item sample.
    
+   
      
+    
    • 
+     
      The tokens shall be evaluated in the order they are defined in the metadata (the SampleTransform structure) of the Sample Transform Derived Image Item.
      
+    
    • 
+     
      There shall be at least one token.
      
+    
    • 
+     
      The stack is empty before evaluating the first token.
      
+    
    • 
+     
      There shall be at least C elements in the stack before evaluating a token, where C is that token’s input count (defined by Table 2).
      
+    
    • 
+     
      There shall be exactly one remaining element in the stack after evaluating the last token. This element is the value of the reconstructed image item sample.
      
+   
    
+   
    Non-compliant expressions shall be rejected by parsers as invalid files.
    
+   
    
+    Note: Because each operator pops one or two elements and then pushes one element to the stack, there is at most one more operand than operators in the expression. There are at least 
+    
+     floor
+     (
+     
+      token_count
+      2
+     
+     )
+    
+     operators and at most 
+    
+     ceil
+     (
+     
+      token_count
+      2
+     
+     )
+    
+     operands. token_count is at most 255, meaning the maximum stack size for a valid expression is 128.
+   
    
    
    5. 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.
    
-   
    5.1. 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.
    
-   
    5.2. ster group
    
+   
    5.1. 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.
    
+   
    5.2. 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.
    
    
    6. Brands, Internet media types and file extensions
    
    
    6.1. Brands overview
    
-   
    As defined by [ISOBMFF], the presence of a brand in the compatible_brands list in the FileTypeBox can be interpreted as the permission for those AV1 Image File Format readers/parsers and AV1 Image File Format renderers that only implement the features required by the brand, to process the corresponding file and only the parts (e.g. items or sequences) that comply with the brand.
    
+   
    As defined by [ISOBMFF], the presence of a brand in the compatible_brands list in the FileTypeBox can be interpreted as the permission for those AV1 Image File Format readers/parsers and AV1 Image File Format renderers that only implement the features required by the brand, to process the corresponding file and only the parts (e.g. items or sequences) that comply with the brand.
    
    
    An AV1 Image File Format file may conform to multiple brands. Similarly, an AV1 Image File Format reader/parser or AV1 Image File Format renderer may be capable of processing the features associated with one or more brands.
    
-   
    If any of the brands defined in this document is specified in the major_brand field of the FileTypeBox, the file extension and Internet Media Type should respectively be ".avif" and "image/avif" as defined in § 10 AVIF Media Type Registration.
    
+   
    If any of the brands defined in this document is specified in the major_brand field of the FileTypeBox, the file extension and Internet Media Type should respectively be ".avif" and "image/avif" as defined in § 10 AVIF Media Type Registration.
    
    
    6.2. AVIF image and image collection brand
    
     The brand to identify AV1 image items is avif. 
-   
    Files that indicate this brand in the compatible_brands field of the FileTypeBox shall comply with the following:
    
+   
    Files that indicate this brand in the compatible_brands field of the FileTypeBox shall comply with the following:
    
    
-    Files that conform with these constraints should include the brand avif in the compatible_brands field of the FileTypeBox. 
-   
    Additionally, the brand avio is defined. If the file indicates the brand avio in the compatible_brands field of the FileTypeBox, then the primary item or all the items referenced by the primary item shall be AV1 image items made only of Intra Frames. Conversely, if the previous constraint applies, the brand avio should be used in the compatible_brands field of the FileTypeBox.
    
+    Files that conform with these constraints should include the brand avif in the compatible_brands field of the FileTypeBox. 
+   
    Additionally, the brand avio is defined. If the file indicates the brand avio in the compatible_brands field of the FileTypeBox, then the primary item or all the items referenced by the primary item shall be AV1 image items made only of Intra Frames. Conversely, if the previous constraint applies, the brand avio should be used in the compatible_brands field of the FileTypeBox.
    
    
    6.3. AVIF image sequence brands
    
     The brand to identify AVIF image sequences is avis. 
-   
    Files that indicate this brand in the compatible_brands field of the FileTypeBox shall comply with the following:
    
+   
    Files that indicate this brand in the compatible_brands field of the FileTypeBox shall comply with the following:
    
    
-    Files that conform with these constraints should include the brand avis in the compatible_brands field of the FileTypeBox. 
-   
    Additionally, if a file contains AV1 image sequences and the brand avio is used in the compatible_brands field of the FileTypeBox, the item constraints for this brand shall be met and at least one of the AV1 image sequences shall be made only of AV1 Samples marked as sync. Conversely, if such a track exists and the constraints of the brand avio on AV1 image items are met, the brand should be used.
    
+    Files that conform with these constraints should include the brand avis in the compatible_brands field of the FileTypeBox. 
+   
    Additionally, if a file contains AV1 image sequences and the brand avio is used in the compatible_brands field of the FileTypeBox, the item constraints for this brand shall be met and at least one of the AV1 image sequences shall be made only of AV1 Samples marked as sync. Conversely, if such a track exists and the constraints of the brand avio on AV1 image items are met, the brand should be used.
    
    
    NOTE: As defined in [MIAF], a file that is primarily an image sequence still has at least an image item. Hence, it can also declare brands for signaling the image item.
    
    
    7. General constraints
    
    
    The following constraints are common to files compliant with this specification:
    
    
    
    NOTE: This constraint further restricts files compared to [MIAF].
    
    
    8. Profiles
    
    
    8.1. Overview
    
    
    The profiles defined in this section are for enabling interoperability between AV1 Image File Format files and AV1 Image File Format readers/parsers. A profile imposes a set of specific restrictions and is signaled by brands defined in this specification.
    
-    The FileTypeBox should declare at least one profile that enables decoding of the primary image item. It is not an error for the encoder to include an auxiliary image that is not allowed by the specified profile(s). If 'avis' is declared in the FileTypeBox and a profile is declared in the FileTypeBox, the profile shall also enable decoding of at least one image sequence track. The profile should allow decoding of any associated auxiliary image sequence tracks, unless it is acceptable to decode the image sequence without its auxiliary image sequence tracks. 
+    The FileTypeBox should declare at least one profile that enables decoding of the primary image item. It is not an error for the encoder to include an auxiliary image that is not allowed by the specified profile(s). If 'avis' is declared in the FileTypeBox and a profile is declared in the FileTypeBox, the profile shall also enable decoding of at least one image sequence track. The profile should allow decoding of any associated auxiliary image sequence tracks, unless it is acceptable to decode the image sequence without its auxiliary image sequence tracks. 
    
    It is possible for a file compliant to this AV1 Image File Format to not be able to declare an AVIF profile, if the corresponding AV1 encoding characteristics do not match any of the defined profiles.
    
-   
    NOTE: [AV1] supports 3 bit depths: 8, 10 and 12 bits, and the maximum dimensions of a coded image is 65536x65536, when seq_level_idx is set to 31 (maximum parameters level).
    
+   
    NOTE: [AV1] supports 3 bit depths: 8, 10 and 12 bits, and the maximum dimensions of a coded image is 65536x65536, when seq_level_idx is set to 31 (maximum parameters level).
    
    
    If an image is encoded with dimensions (respectively a bit depth) that exceed the maximum dimensions (respectively bit depth) required by the AV1 profile and level of the AVIF profiles defined in this specification, the file will only signal general AVIF brands.
    
    
    8.2. AVIF Baseline Profile
    
    
    This section defines the MIAF AV1 Baseline profile of [HEIF], specifically for [AV1] bitstreams, based on the constraints specified in [MIAF] and identified by the brand MA1B.
    
-   
    If the brand MA1B is in the list of compatible_brands of the FileTypeBox, the common constraints in the section § 6 Brands, Internet media types and file extensions shall apply.
    
+   
    If the brand MA1B is in the list of compatible_brands of the FileTypeBox, the common constraints in the section § 6 Brands, Internet media types and file extensions shall apply.
    
    
    The following additional constraints apply to all AV1 Image Items and all AV1 Image Sequences:
    
    
      
     
    • The AV1 profile shall be the Main Profile and the level shall be 5.1 or lower. 
    
    
    
    NOTE: AV1 tiers are not constrained because timing is optional in image sequences and are not relevant in image items or collections.
    
    
    NOTE: Level 5.1 is chosen for the Baseline profile to ensure that no single coded image exceeds 4k resolution, as some decoder may not be able to handle larger images. More precisely, following [AV1] level definitions, coded image items compliant to the AVIF Baseline profile may not have a number of pixels greater than 8912896, a width greater than 8192 or a height greater than 4352. It is still possible to use the Baseline profile to create larger images using grid derivation.
    
-   
    
-     A file containing items compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox: 
+   
    
+     A file containing items compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox: 
     
    avif, mif1, miaf, MA1B
    
-    
    A file containing a pict track compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
+    
    A file containing a pict track compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
     
    avis, msf1, miaf, MA1B
    
-    
    A file containing a pict track compliant with this profile and made only of samples marked sync is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
+    
    A file containing a pict track compliant with this profile and made only of AV1 Samples marked sync is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
     
    avis, avio, msf1, miaf, MA1B
    
    
    
    
    8.3. AVIF Advanced Profile
    
    
    This section defines the MIAF AV1 Advanced profile of [HEIF], specifically for [AV1] bitstreams, based on the constraints specified in [MIAF] and identified by the brand MA1A.
    
-   
    If the brand MA1A is in the list of compatible_brands of the FileTypeBox, the common constraints in the section § 6 Brands, Internet media types and file extensions shall apply.
    
+   
    If the brand MA1A is in the list of compatible_brands of the FileTypeBox, the common constraints in the section § 6 Brands, Internet media types and file extensions shall apply.
    
    
    The following additional constraints apply to all AV1 Image Items:
    
    
      
     
    • The AV1 profile shall be the High Profile and the level shall be 6.0 or lower. 
@@ -2374,9 +2920,9 @@ 
      The AV1 level for High Profile shall be 5.1 or lower. 
    
    
    
    
-     A file containing items compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox: 
+     A file containing items compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox: 
     
    avif, mif1, miaf, MA1A
    
-    
    A file containing a pict track compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
+    
    A file containing a pict track compliant with this profile is expected to list the following brands, in any order, in the compatible_brands of the FileTypeBox:
    
     
    avis, msf1, miaf, MA1A
    
    
    
    
    9. Box requirements
    
@@ -2509,7 +3055,7 @@ 
    
       -
       ISOBMFF
-      The coded payload may be placed in idat rather than mdat, in which case mdat is not required.
+      The coded payload may be placed in idat rather than mdat, in which case mdat is not required.
    
    
    9.1.2. Requirements on additional image item related boxes
    
    
    The boxes indicated in the following table may be present in an AVIF file to provide additional signaling for image items. The boxes may be present inside the box indicated in the "Containing box" column. If present, they shall use the version indicated in the table and AVIF readers are expected to understand them. The order of the boxes is indicative in the table. Specifications may require specific order and shall be respected. Additionally, the free and skip boxes may be present at any level in the hierarchy. AVIF readers are expected to ignore them. Additional boxes in the meta hierarchy not listed in the following table may also be present and may be ignored by AVIF readers.
    
@@ -2720,6 +3266,8 @@ 
    Add information on tmap, grpl and altr
    
     
  • 
      
    Replace recommendations regarding still picture flags in image items by a note
    
+    
  • 
+     
    Add section 4.2.2 "Sample Transform Derived Image Item"
    
    
   
   
    
@@ -2891,13 +3439,22 @@ 
    avif, in § 6.2
    
  • avio, in § 6.2
    
  • avis, in § 6.3
+   
  • bit_depth, in § 4.2.2.3
+   
  • constant, in § 4.2.2.3
    
  • grpl, in § 5
+   
  • input_image_item_index, in § 4.2.2.3
    
  • layer_size, in § 2.3.2.3.4
    
  • MA1A, in § 8.3
    
  • MA1B, in § 8.2
    
  • OperatingPointSelectorProperty, in § 2.3.2.1.2
    
  • op_index, in § 2.3.2.1.4
+   
  • reserved, in § 4.2.2.3
+   
  • Sample Transform Derived Image Item, in § 4.2.2.1
+   
  • sato, in § 4.2.2.1
    
  • ster, in § 5.2
+   
  • token, in § 4.2.2.3
+   
  • token_count, in § 4.2.2.3
+   
  • version, in § 4.2.2.3
   
   
    Terms defined by reference
    
   
      
@@ -2941,6 +3498,8 @@ 
      cmex
      
    • cmin
      
    • colr
+     
    • derived image item
+     
    • dimg
      
    • image_height
      
    • image_width
      
    • imir
@@ -2963,10 +3522,16 @@ 
      altr
      
    • compatible_brands
      
    • filetypebox
+     
    • from_item_id
      
    • idat
+     
    • itemreferencebox
      
    • major_brand
      
    • mdat
+     
    • reference_count
+     
    • singleitemtypereferencebox
+     
    • singleitemtypereferenceboxlarge
      
    • sync
+     
    • to_item_id
     
    
    
  • 
     [MIAF] defines the following terms:
@@ -2985,6 +3550,8 @@ 
    N
    
    AV1 Bitstream & Decoding Process Specification. LS. URL: https://aomediacodec.github.io/av1-spec/av1-spec.pdf
    
    [AV1-ISOBMFF]
    
    AV1 Codec ISO Media File Format Binding. LS. URL: https://aomediacodec.github.io/av1-isobmff/
+   
    [CICP]
+   
    H.273 : Coding-independent code points for video signal type identification. International Standard. URL: https://www.itu.int/rec/T-REC-H.273
    
    [HEIF]
    
    Information technology — High efficiency coding and media delivery in heterogeneous environments — Part 12: Image File Format. International Standard. URL: https://www.iso.org/standard/66067.html
    
    [ISOBMFF]
@@ -3302,65 +3869,74 @@ 
    N