• added rate capping during rate control (must be at least 1.5x of target rate)
• extensive improvements and cleanups to rate control, especially single pass (improved efficiency by 1-2%)
• speedup of first pass, especially for preset faster (around 15% overall runtime), using spatio-temporal downsampling
• unified MCTF activation for low- and high-rate encoding
• various speedups, fixes, and cleanups