Preference to use textual user data item

[krasimirkolarov]

We prefer the use of a textual userdata item to the use of the name field of the HandlerBox for human-readable labeling of tracks. HandlerBox names have not been historically used for human-readable labels, and therefore long-established practice conflicts with the suggested usage here.

[technogeek00]

@krasimirkolarov Is there a box already standardized for this in CMAF? The text currently for the label attribute is just utilizing the original text from the base ISOBMFF profile. I could not find a better CMAF defined reference so I kept it as is, though I do understand the label is typically something like SoundHandler, not great.

An alternative that could be pursued is generation of the label from the other box data, but that might be over-complicating it a bit.

[krasimirkolarov]

"@krasimirkolarov Is there a box already standardized for this in CMAF? The text currently for the label attribute is just utilizing the original text from the base ISOBMFF profile. I could not find a better CMAF defined reference so I kept it as is, though I do understand the label is typically something like SoundHandler, not great."

The concern is that it will not meet the need for a human-readable label as it is produced by currently available tools, so rather than "not great" we'd rather say "too often unsuitable".

Defining a userdata type for the purpose or adopting an existing userdata type from another ISO BMFF-based specification, for use in track userdata to carry a human-readable label, may be feasible. 3GPP 'titl' may be a candidate.

"An alternative that could be pursued is generation of the label from the other box data, but that might be over-complicating it a bit."

Our implementation does something like that as a fallback, when no appropriate human-readable titling or labeling can be found. A label assembled from the media type, track language, and track ID (or some other uniqueifier, such as a track number) is not overly complicated.

[haudiobe]

AHG 2020/10/19:

• we can improve this here to have a constructive label. @technogeek00 will provide a proposal
• we also believe that the MPEG CMAF specification can be improved taking the comment above into account.

[technogeek00]

Basic proposal for text and audio, open to suggestions on video, its far less clear cut.

[haudiobe]

Implemented: https://1drv.ms/w/s!AiNJEPgowJnWgqsz3EFQvnMD7BhN0w?e=42BwJJ