Hello on http://www.ittiam.com/ (http://www.ittiam.com/) I found that there are the speech encoders MPEG4 CELP and MPEG4 HVXC and GSM-AMR - and there also is Ogg Speex. Does anyone know of freely downloadable MPEG4 CELP or HVXC encoders so I could do a comparison for different bitrates? Which speech encoder would be expected to have the best quality in for example the 8-16 Kbit/s range? What encoder would have the best quality output below the 8 kbit/s range? Are there any other speech encoders that are "better"? If so why? I know it depends on many factors but What would be the best speech encoder to encode speech for low bandwidth internet distribution?
Would MPEG4 CELP encoded speech mono wave at around 16 Kbit/s have a better perceived quality then a MPEG4 AAC-HE encoded file?
The MPEG4 CELP encoder sources are freely available from the MPEG CVS. I have a compile of that lying around at my HDD, unfortunately I'm away from home now.
About quality: I'm planning a vocodec listening test, comparing Speex, MPEG4 CELP, Acelp.net, Quallcomm PureVoice, g729, GSM-FR, VoxWare...
According to my current schedules, it might start somewhere between september and october (if I'm not too fed up with listening tests until then)
HE AAC wouldn't be featured in that test, though, since it's not a vocodec.
GREAT news !!!
I'm not good at doing high-bitrate music blind tests, but I'm sure I will be able to help at this one
nevermind. its already covered