Ursula Maplehurst authored Dec 01, 2017 and Sebastian Dröge committed Dec 06, 2017

1. Similar to 880f3d8a, don't consider not getting an output buffer as
   an error during flushing. I've seen the following sometimes when
   encoding:

   W GStreamer+amcvideoenc: java.lang.IllegalStateException
   W GStreamer+amcvideoenc:         at android.media.MediaCodec.getBuffer(Native Method)
   W GStreamer+amcvideoenc:         at android.media.MediaCodec.getOutputBuffer(MediaCodec.java:2886)

2. For amcvideodec/enc, call _find_nearest_frame (which grabs a fresh
   reference on a GstVideoCodecFrame) after we have an output buffer,
   so as to not leak the reference, in case getting an output buffer
   fails.

   Otherwise, if we get an error grabbing the output buffer, we leak
   the reference to the frame. This can cause issues with a
   v4l2bufferpool feeding the encoder not being able to clean itself
   up properly due to buffers still being marked as in-use.

https://bugzilla.gnome.org/show_bug.cgi?id=791258