mp4 with no sound

Hmmmm. There must be something in the whole-movie version that iMovie does not like. Possibly it is a format issue, or something in the movie is copyrighted, or something about how it was rendered. iMovie can be more sensitive than other apps about formats and rendering issues.

If the sound plays in QuickTimePlayer try exporting it as audio only. Then drag the exported audio clip into iMovie and see if it plays there. If it does, then you can sync it up with the video in iMovie and see if it will export with sound.

-- Rich

To cover the bases, make sure that you sound settings are not set to mute.

If all O.K. there, note that not all Mp4 vids work in iMovie. It must be Mp4/AAC. AAC stands for Advanced Audio Coding.

Try importing your video to your desktop and converting your troublesome clips to H.264, Mp4/AAC with the free

download, Handbrake. Do that even if the codec already is indicated to be Mp4/AAC. Re-rendering often cures the issue.

You can get Handbrake here:

https://handbrake.fr/

A simple way to do it is to open Handbrake and do a File/Open Source. Navigate to your video and choose it as the source from the resulting screen. Then do File/Start Encoding. Wait a couple of minutes for the conversion to complete. Then save and import the converted clip into iMovie.

-- Rich

Is it possible that the clip is DRM protected, in which case it would not play in iMovie, although it would play in iTunes? You can go to your iTunes library and check whether it is protected. Control-click on the song title in the library and select Song Info from the dropdown menu. Then click on the File tab in the box that appears. Under the heading "Kind" it will show whether the song is protected.

-- Rich

No, you cannot make the assumption that an MPEG-4 video file is unprotected just because it is an MPEG-4. If it is a commercial video it will be copyright protected. If it is a home video file, you can upload it to You Tube or Facebook and see if a copyright flag appears.

-- Rich

Did you make the music yourself or use a song from someone else? If the latter it could still be copyrighted.

The purpose of copyright is to prevent someone from using the song in a project, or publishing it, without permission of the artist. It still might play in other apps or players. iMovie does not allow use of copyrighted songs unless they are licensed.

It could also be that the audio is in a format not supported by iMovie.

— Rich

Terrific! It was a bit of a shot in the dark, but glad that it worked.

-- Rich