Blackmagic Forum

Multiple attempts to render MP4 with 24-bit audio result in files with no sound. Rendering in a YouTube 2160 preset with 16-bit sound renders just fine.

My experience with H264 in resolve is that its fishy. Not best quality and not compatible with all players. I just don't use it. Render out a master file and then use Adobe Media encoder or something to make mp4s.

If you don't have AME, ffmpeg does a great job, try X264 too.