Sound File Format

A sound file format is a file format for storing audio on a computer. There are several different formats, each with its own benefits and drawbacks. The difference between formats generally has to do with storage space versus sound quality. The processor of a computer typically decodes compressed sounds into a format that can be played by the computer.

The way the audio is compressed and stored is call the codec which determines how small the file size is. Some file types always use a particular codec. For example, ".mp3" files always use the "MPEG Layer-3" codec. Other files like ".wav" and ".dct" files support selectable codecs. For example, a ".wav" file can be encoded with the "PCM", "GSM6.10", "MPEG3" and many other codecs. Be careful not to confuse the file type with the codec - it often surprises people to
know you can have a "MPEG Layer-3" encoded ".wav" file. Some file types just contain the audio. But other file types can
contain additional header information which can contain other information about the file (eg .dct files have information about the sender, priority, notes and other data in the file itself).

Below is a description of audio formats supported by Scratch:

MP3
The most popular audio format, a lossy format playable in almost any device and program. Some open-source programs cannot play it due to patent issues, however.

WAV
The default uncompressed audio format on Windows, also playable in most programs.