It can be used to discard closed captions from the input pad if the
matching video buffer already held closed captions.
It is useful in a scenario where captions are generated for an AV
stream, but the incoming stream already has embedded captions for
some intervals, and those original captions should be preferred.
It can also be used to make sure input CC meta is always dropped,
the default behavior remains to append aggregated CC to whatever
CC meta was already present on the input video buffer
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6072>
Cea608 (valid) padding removal is available on the input side of ccconverter
or configurable on cccombiner. cccombiner can now configure whether
valid or invalid cea608 padding is used and for valid padding, how long
after valid non-padding to keep sending valid padding.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6300>