* Add support for H265
* Don't overwrite original codec_data / streamheader in the output
caps, but instead allow them to change and send them to the
combiner at the right moment: encoder caps, reencoded GOP,
original caps, original GOP(s), and potentially encoder caps
and rencoded last GOP.
* For H264 / H265, force usage of a format with inband SPS / PPS
(avc3 / hev1), this is cleaner than misadvertising avc1, hvc1 and
some muxers like mp4mux will actually advertise both differently.
Unfortunately, while mp4 supports updating the codec_data and using
avc1 with no in-band SPS / PPS updates, it turns out some decoders
(eg chrome / firefox) don't handle this particularly well and stop
decoding after the reencoded GOP. We could expose a switch to
force usage of avc1 / hvc1 nevertheless, but for now stick to
requiring that the parser output SPS / PPS in-band with
config-interval=-1 (that has not changed)
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1249>
It was not working properly and the implementation of the smartencoder
element was weird. This introduce a number of changes (which are all
in one single commit because they basically all work together and lead
to basically reimplementing the element):
* Make smartencoder a bin so that the reencoding chain of elements are
inside of it instead of not having any parent. Those elements were not
be visible when dumping the pipeline which was very confusing.
* Make encodebin create the right encoder with a capsfilter (and parser)
to properly enforce the format specified by the user, and so that the
encoder properties specified in the encoding profile are respected.
* Use `decodebin` to do the decoding instead of selecting a decoder
ourself and not plug any parser etc...
* Ensure that negotiated format in the sinkpad of smart encoder is fixed
through time when the user requested a non dynamic output
* Add a parser at the beginning of the smart encoder
* Handle errors when reencoding
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/751>
Note that we didn't do it for encodebin, as it has a class struct. We
_could_ techincally use `G_DECLARE_DERIVABLE_TYPE()` for that one, but
that would mean also using a private struct, which is even more work for
no gain.
