See Bug #907644 for a similar issue with MKV files.

With MP4 and MP3 files, with just one such file on the playlist and looped (with repeat mode on), the file is played through twice with no problem, then it just stops at the end. Restarting the video by double-clicking on the playlist item works.

As in #907644, if you add another file (or another instance of the same file) to the playlist and let it loop between the two, there’s no problem. But with the single file repeating the bug is 100% reproducible. Not reproducible with VLC.

Steps to reproduce:
1. Load an MP3 or MP4 in Totem.
2. Set ’Repeat Mode’ on.
3. Let the file play through two rounds.

What happens:
At the end of second play, the playing stops and does not start again by itself.

What I expect to happen:
For the file to repeat ad infinitum.