Description of the issue

(container format) (container element for independent frame (IF)) indicates this frame is an independent frame (IF) but USAC AudioPreRoll is present


ISO IEC 14496-12 (MPEG-4 ISO base media file format):
group_description_index: "gives the index of the sample group entry which describes the samples in this group"

ISO IEC 23003-3 (USAC):
AudioPreRoll: "If independently decodable frames (IF) [...] are to be signalled, they shall be signalled by means of the AudioPreRollEntry"

Possible solution/action

ISO IEC 14496-12:
Fix the muxer in order to correctly fill sbgp with this frame number, then remux the content.