libs: encoder: vp8,vp9: reset frame_counter when input frame's format changes
When input frame's formate changes, vp{8,9} encoders don't reset their frame counter, hence the newly created frame could become a P-frame, leading to some major troubles (sigabrt in libdrm in case of vp9). This patch adds some frame prediction-related reset logic to the `flush' methods of GstVaapiEncoderVP8 and GstVaapiEncoderVP9 implementations.
This should fix #169 (closed)
Edited by Eugen Klim