The calculated position was off. I'm not sure of the exact cause;
possibly because we're in AU-aligned byte-stream mode, which means
`transform` is true.
Replacing the math that calculates the NALU positions with code more
similar to what is already in use for `idr_pos` seems to have fixed it.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7318>
- Fix skipsize on _update_backlog failure.
- Add robustness to AU completion detection by using AUD when present. If we've
received a AUD we overwrite the first VCL NAL detection when the result was
negative. VCL following AUD is the first VCL of next AU.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5862>
- AU boundary detection reviewed to follow more closely H.264 spec. and more
specifically clauses 7.4.1.2.3 and 7.4.1.2.4.
- The gist of the changes is a look-a-head in then next AU required identify the
last vcl-nal of current AU and firt vcl-nal of next AU (according to
7.4.1.2.4) followed by the identification of the first nal of next AU
(according to 7.4.1.2.3).
- A backlog of all nals of current AU and next AU up to the point where current
AU can identified completed is kept.
- In NAL alignement mode vcl-nal are sent immediatly but the history is kept to
allow AU boundary detection. Non-vcl-nal can be delayed up to the reception of
the next vcl-nal to allow a correct AUD insertion.
- Based on this improved AU boudary detection we can avoid erronous AUD
insertion, like the one highlighted by test
test_parse_sliced_with_prefix_and_sei_nal_au.
- Add support for MVC AU boundary detection. (H.7.4.1.2.4)
- Explicitly report SVC not supported. We don't have the SVC NAL parsing
required to identify boundary. (missing dependency_id and quality_id fields
from SVC, see G.7.4.1.2.4)
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5741>
