In many cases background videos used in projection are too fast for slower music and other videos are too slow for faster music.
It is possible to enable automatic synchronization in the program so that the playback speed of the background video in the lyric display matches the speed of the song.
In order for the sync to take place, the lyrics and background video must have a BPM value set.
The BPM value of the lyrics can be set in the lyric editing window, in the Extra
The BPM value of the video can be set in the background selection tab.
Whenever a lyric is displayed, the program's global BPM value will be updated with the BPM value defined in the lyric.
And if the background video used in the slideshow of that lyrics has a set BPM value, the video will play at relative speed.
For example, if the lyrics are set to BPM=90 and the video is set to BPM=120, then the video will play at 0.75 speed.
Or if the song is BPM=120 and the video is BPM=90, the video will play at 1.33 speed.
To activate sync:
Enable the display of the BPM item in the windows menu, menu bar
Then right-click on the item to open the context menu and activate the sync background
The current BPM value will be displayed in the upper right corner of the main window.
It is recommended to use videos with a high FPS rate, as the FPS rate is a relevant factor in the playback quality when synchronization slows down the playback speed.
For example, if the video used has "only" 30 FPS and the synchronization performed sets the video speed to 0.5, then the video will be played, in practice, with 15 FPS, which will compromise the quality of the video playback.