* 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>
User often want to set encoder properties on encoding profiles,
this introduces a way to easily 'preset' properties when defining the
profile. This uses GstStructure to define those properties the same
way it is done in `splitmux` for example as it makes simple to handle.
This also defines a more complex structure type where we can map a set
of properties to set depending on the muxer/encoder factory that has
been picked by EncodeBin so it is quite flexible.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1002>
Instead of going through the list of known muxers go ahead and
instantiate the muxer specified as 'preset name' as this specifies
the exact element factory name to use.
