OpenH264 is a free software library developed by Cisco that allows for the real-time encoding and decoding of video in the H.264 (MPEG-4 AVC) format.
for f in *.mkv; do ffmpeg -i "$f" -c:v libopenh264 -b:v 3M -c:a aac "$f%.mkv_openh264.mp4" done outlander s01 openh264