Sony HDR-AS50R Read This First Manual page 74

Select a movie that you want to add in a highlight movie from the date or the
4
content list, then press the "Next" button.
The highlight movie creation starts.
You cannot select MP4 and XAVC S contents at the same time.
You can select up to 100 movies by date or file.
If you disconnect Wi-Fi connection of the camera and your smartphone while creating the
highlight movie, the camera continues to create movie.
Press the REC/ENTER button of the camera to finish creating the highlight movie.
Hint
Use the "Settings" menu in advance to change the movie length, BGM
* This setting is only available in some countries and regions.
*
and the audio mix.