Increased max values of periodic key frame for h26x codecs.
This allow more fine tunning of encoder that in certian scenario
want higher periodic key frame.
For example: it doesn't want a key frame each 10 seconds but
each 120 seconds.
https://bugzilla.gnome.org/show_bug.cgi?id=786320
Implements gst_vaapi_utils_h26x_write_nal_unit(), which writes NAL
unit length and data to a bitwriter.
Note that this helper function applies EPB (Emulation Prevention
Bytes), since otherwise produced codec_data might be broken when
decoder/parser considering EPB, starts parsing.
See sections 7.3 and 7.4 of the H264 and H264 specifications, which
describes the emulation_prevention_three_byte.
https://bugzilla.gnome.org/show_bug.cgi?id=778750
Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>
Since there is duplicated code in h264/265 encoder, we could
refactor it to avoid duplicated code.
https://bugzilla.gnome.org/show_bug.cgi?id=778750
Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>
