Audio File Formats
This is page 2 of the presentation about common file formats for audio.
Page 1 introduced some basic digital audio concepts.
Digital Sound
Digital sound recordings can be compressed or uncompressed, and the compression can be lossless or lossy.
Lossless compression reduces file space but returns the complete digital recording when uncompressed. Lossy compression discards inaudible or less important parts of the recording to further reduce file size. Although this means some loss of quality, it is often not easily noticed.
| Extn | Description | Prop | Compressed | Lossy | MB/min |
| wav | Windows PC sound format | proprietary | no | 10 | |
| wma | Windows media audio | proprietary | yes | either | |
| mp3 | MPEG layer 3 | proprietary | yes | lossy | 1 |
| ra | Real Audio | proprietary | yes | lossy | 1 |
| flac | Free lossless audio codec | free | yes | lossless | 5 |
| ogg | Ogg Vorbis | free | yes | lossy | 1 |
| m4a | MPEG-4 | proprietary | yes | lossy | 1 |
| aiff | Apple sound format | proprietary | no | 10 |
Some digital recordings now include measures (TPMs) to control their use. Although sometimes called "copy protection", these don't actually stop production of counterfeit copies. These TPMs may restrict lawful access to the recording, even after copyright has expired. Some TPMs involve deliberate corruption of the recording, and some include software than can damage or compromise computer security.
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