This is a regression introduced by https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3882 The av1c codec configuration parsing would always fail due to an off-by-one error, the content of an atom starting at offset 8 (i.e. the 9th byte) and not 9 (the 10th byte). Also introduce a break in order to not get stray warnings Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4433>