Argh! My Loopable Soundtrack Does Not Loop Seamlessly.
Occasionally, when I provide my clients with a loopable score for their game, film, or other project, a certain concern regarding “loopability” may be raised after they review their deliverable files. The files typically include their audio loop in a number of formats, which may include .wav, .aiff, .caf, .aac, .ogg, or .mp3. I assure them that the track I have provided is seamlessly loopable, yet I’m often met with responses like, “There is a skip at the end of the loop”, or “The music loop is not seamless.” Does this sound like an issue you’re having? Well, let me shed some light on this common issue.
It’s not always the case, but the problem may not lie within the music itself, or within the composition, but rather with the format in which the loop has been compressed. I supply my clients with a lossless .wav file as well as a compressed .mp3 file. Lossless formats, such as the .wav file, contain the highest level of audio, with no degradation of the original music as it was recorded.
Compressed formats, such as the .mp3, contain a loss in audio quality. An .mp3 file may also have certain frequencies omitted, such as those below 20 hz and above 18k hz. The benefit is that most people would not notice the loss of these frequencies, and the resulting .mp3 file consumes far less memory. Whereas a .wav file may consume fifty, or more, megabytes (MBs), the .mp3 file may only consume one tenth of that size, or roughly five MBs, depending on the quality settings.
The main issue here is that a slight period of silence is introduced when an audio file is compressed with the .mp3 format. This gap cannot be removed from the file if it’s to remain an mp3. Trust me, I’ve tried. Your file will need to be compressed with a different format. If you’re working with video games, especially written in HTML5, a good alternative to the mp3 is the .ogg format.
When you reformat your file, you should begin with a lossless format such as .wav, .aiff, .flac, .caf, etc. If you begin with the mp3, your resulting file will contain the existing compression and losses. Worst of all, it will still have the “gap”. If you work with me, I’ll always make sure that you have a lossless format to work with. However, if you’ve received your audio from another source and a lossless format is not available to you, do your best to edit the audio — maybe adding a slight fade to the intro and outro, and then export in the new format. Otherwise, I would contact the original supplier and demand a lossless format.
You can use the free program Audacity to reformat your audio file.
For more information on ‘gapless playback’ see: http://en.wikipedia.org/wiki/Gapless_playback
Audacity download: http://audacity.sourceforge.net/