Automatically derive the minimum profile and level to be used for
encoding, based on the activated coding tools. The encoder will
be trying to generate a bitstream that has the best chances to be
decoded on most platforms by default.
Also change the default profile to "constrained-baseline" so that
to ensure maximum compatibility when the stream is decoded.
https://bugzilla.gnome.org/show_bug.cgi?id=719691
The libgstvaapi core encoders are meant to support raw bitstreams only.
Henceforth, we are always producing a stream in "byte-stream" format.
However, the "codec-data" buffer which holds SPS and PPS headers is
always available. The "lengthSizeMinusOne" field is always set to 3
so that in-place "byte-stream" format to "avc" format conversion could
be performed.
Various clean-ups to improve consistency and readability: rename some
variables, drop unused macro definitions, drop initialization of vars
that are zero-initialized from the base class, drop un-necessary casts.
Add gst_vaapi_encoder_set_keyframe_period() interface to allow the
user control the maximum distance between two keyframes. This new
property can only be set prior to gst_vaapi_encoder_set_codec_state().
A value of zero for "keyframe-period" gets it re-evaluated to the
actual framerate during encoder reconfiguration.
Add interface to communicate configurable properties to the encoder.
This covers both the common ones (rate-control, bitrate), and the
codec specific properties.
https://bugzilla.gnome.org/show_bug.cgi?id=719529
