mp4 - ffmpeg-converted video file won't play in Windows Media Player or Movies & TV - Video Production Stack Exchange
Converting WebM to MP4 Using FFmpeg
ffmpeg converting from mkv to mp4 without re-encoding - Stack Overflow
Quick Guide to Convert MP4 to H264 in/without ffmpeg
GitHub - dswinton/Batch-H.264-Converter: Point it at a folder full of movies and it will convert anything that's not MP4 + H.264 + AAC into that format