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audio compression formats
mp2, mp3 |
compression using the MPEG video compression format. Compression doesn't alter sampling rate or bit depth. Allows the most options while encoding, and will compress from 2:1 to 120:1. Best for music. |
ra (real audio) |
compression using Real Audio proprietary streaming compression. Much compression is done by downsampling, bit rate conversion, and dithering. Will compress up to 60:1. Best for voice. |
µlaw |
the only non-lossy compression in this group; it encodes 16 bit digital audio data into a non-linear 8 bit stream, achieving 2:1 compression. |
ADPCM |
old method of compressing 8 bit data, acheiving 3:1 compression. |
MACE |
Now-defunct Macintosh proprietary audio compression, which acheived 3:1 to 4:1 compression on 8 bit data. |
Notes about compression formats:
- The only current contenders in the Internet streaming audio market are .mp3 and Real Audio. They are the only formats which allow high enough compression rates while being decodable on the fly by consumer computers.
- It has emerged that .mp3 is clearly superior for music, since the 128kbps setting, coupled with Joint Stereo encoding and Psy Modeling produces a result which sounds to most people to be "as good as CD audio," and has 12:1 compression.
- However, Real Audio acheives far greater compression for voice, and as such is the preferred format for streaming talk radio, newscasts, interviews, etc. Also, Real Networks offers video streaming which is compressed much more than any other format.
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