On `tbas and sabt track reference` feature

[podborski]

Summary

There are some files that claim to have tbas and sabt track references by defining that metadata in user-defined features field, but no such track references can be found. Probably the ff-conformance.xls issue.

Steps to reproduce

No response

Affected specifications

No response

Affected files

• hevc_tiles_single_track_nalm_all_intra.mp4
• hevc_tiles_single_track_nalm_rle.mp4
• hevc_tiles_single_track_nalm.mp4
• hevc_tiles_single_track_trif_full_picture.mp4