GStreamer codecparsers-based decoders are the only supported decoders now.
Though, FFmpeg decoders are still available in gstreamer-vaapi 0.3.x series.
Rationale: playbin2 links all elements at run-time. Once vaapidecode
is created and a NEWSEGMENT event arrives, downstream element may not
be ready yet. So, delay this event until next element is chained in,
otherwise basesink could output "Received buffer without a new-segment.
Assuming timestamps start from 0".
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Otherwise, the decoder would always create its own X display instead
of probing it from the downstream element, which is not reliable.
e.g. DISPLAY is not :0 or when running on Wayland.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>