Presentation Formats for Audio Digitization
Audio presentation formats include MP3, Real Audio, and Windows Media. These are used to deliver online audio and for distribution on CDs or DVDs. These formats use compression to remove frequencies inaudible to humans, greatly reducing the size of the file (approximately 1/10th the size of uncompressed formats). Windows Media Audio (.wma), which requires the Windows Media player, and Real Audio (.ra), which requires the Real Audio player, are streaming formats, which transfer the audio data continuously, allowing online users to listen without downloading the entire file. MP3 can be streamed, but is more commonly used for downloading. Each time an MP3 file is saved, the compression process is repeated, resulting in progressive loss of data and likely deterioration of sound quality. Therefore, when files need to be edited for presentation, it is always best to make a copy of the uncompressed master (see Archival Format), do the necessary editing, and then save in the compressed format. Compressed formats are generally unsuitable for detailed phonetic analysis.
See also Sound Directions: Best Practices for Audio Preservation.
How to Record Audio
Dena'ina Case Study