Compound prediction mode for nonrd pickmode.
Allow for compound prediction mode in nonrd_pickmode for ZEROMV. For real-time encoding, 1 pass with non-zero lag-in-frames. Added speed feature to control the feature. Enabled for speed >=6 for now, under VBR mode. avgPSNR/SSIM metrics positive on ytlive set, for speed 6: some clips up by ~3-5%, some clips neutral gain, average gain across clips is ~1%. Small/negligible decrease in speed. Change-Id: I7a60c7596e69b9a928410c5ee2f9141eecd8613d
Showing with 85 additions and 16 deletions