Description of the issue

(container format) (container element for immediate play-out frame (IPF)) or (container format) (container element for independent frame (IF)) does not indicate this frame is independent but (content format) (content element) (content field) (value) indicates this frame is independent




ISO IEC 14496-12 (MPEG-4 ISO base media file format):
sample_number: "marking of the sync samples within the stream [...] If the sync sample box is not present, every sample is a sync sample"
group_description_index: "gives the index of the sample group entry which describes the samples in this group"

ISO IEC 23003-3 (USAC):
usacIndependencyFlag: "Meaning of usacIndependencyFlag"

Possible solution/action

ISO IEC 14496-12:
Fix the muxer in order to correctly fill stss with this frame number or sbgp with group_description_index value not 0 for this frame number, then remux the content.