Audio encoding for WAP,modems etc.

[twistee]

Hi,

I have an assignment where I have to encode samples of sounds for 4 different technologies. 1. Wap style mobile access 2. standard modems 3. Cable modems 4. LAN.

I presume for normal modems you could say ogg or mp3. For cable you might be able to say ac3...maybe...and for LAN...i have no idea (i also have no idea about WAP either :confused: ). I presume the file size would get bigger as well as the quality. But im not sure which formats and what encoders/decoders to use (except for mp3,ogg - i know those). Any ideas?

[DSPguru]

mp3pro supply reasonable quality @ 64kbps.
speex can encode speech @ about 40kbps and lower.
you can search the web for other vocoders (speech coders), like dvsinc's AMBE, which supply brilliant results @ 2.4kbps.

btw : about lan,
Speex is used in the openh323 project, which includes a full voice-over-ip stack (rtp/rtcp).

[RadicalEd]

RealAudio 8 hits a major sweet spot at the low-mid bitrate range. 32-64 kbps are still very listenable whereas at those rates most codecs sound like toilet water :/