• svt-av1: Support crf quarter steps. Default --crf-increment to 0.25 for this encoder.
  This requires svt-av1 >= v4.0.0,
  if using an older version you may want to use crf-search with --crf-increment 1.
• svt-av1: Widen default crf search range [10, 55] -> [5, 70].