MP4 to WebM Converter – 4 Best Methods to Convert MP4 to WebM
WebM to MP4 | Free Convert WebM to MP4 (Online and Desktop)
After successfully converting a 4k MP4 file to WebM, Windows explorer progress bar constantly loads, thumbnail refuses to generate, when libvpx-vp9 is used instead of libvpx (i.e. vp8). : r/ffmpeg