avio brand should potentially talk about stss

[leo-barnes]

It might make sense to have some wording under the avio brand for sequences that this means that all samples should also be marked as sync samples.

[leo-barnes]

avio only applies to the primary item (or the inputs to the primary item). So it doesn't apply to sequences.

[leo-barnes]

Missed a section:

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.

Reopening.