Hi, I think the MP4 spec supports DTS, ffmpeg muxes (multiplexes) h264/AVC and DTS-audio streams into MP4s fine, and VLC/Windows plays these DTS in MP4s fine. However, VLC/iOS doesn't play DTS in MP4s, the video plays, the audio doesn't play at all (some crackles and pops here and there, is the DTS ...