ffmpeg_vp9_2pass.sh

# ./ffmpeg_vp9_2pass.sh input.mp4 2M 96k 1920 60

set -x

input="$1"
bitrate="${2:-2M}"
audio_bitrate="${3:-96k}"
scale="'min(${4:-1920},iw)':'ih*$4/iw'"
fps="${5:-60}"

output="${input%.*}_vp9_2pass.webm"
threads=48

ffmpeg -i "$input" -c:v libvpx-vp9 -filter:v "scale=$scale" -pass 1 -b:v $bitrate -r $fps -threads "$threads" \
  -frame-parallel 0 -slices 8 -quality good -speed 1 -aq-mode 0 \
  -lag-in-frames 25 -auto-alt-ref 1 -sn -c:a libopus -b:a $audio_bitrate -ac 2 -y \
  -an -f webm /dev/null < /dev/null
ffmpeg -i "$input" -c:v libvpx-vp9 -filter:v "scale=$scale" -pass 2 -b:v $bitrate -r $fps -threads "$threads" \
  -frame-parallel 0 -slices 8 -quality good -speed 1 -aq-mode 0 \
  -lag-in-frames 25 -auto-alt-ref 1 -sn -c:a libopus -b:a $audio_bitrate -ac 2 -y \
  -f webm "$output" < /dev/null