[asterisk-users] Silk for Free

[Steve Underwood]

Dean Collins wrote:
>
> http://www.pcworld.com/article/160653/skype_gives_away_highquality_audio_codec.html?tk=rss_news
>
> any thoughts?
>
They have said it will be royalty free, but they have said little else.

 From discussions with Skype people in the last few days they seem very 
reluctant to hand out source code, so it looks like they will provide 
binary blobs for whatever platforms they choose to support. They are 
clearly eager to get Skype broadly connected to corporate networks, but 
if they don't get this codec into a broad range of phones its a waste of 
time. Transcoding looses too much quality.. If they don't hand out the 
source, or at least provide a rigorous spec, I don't think this will 
fly. Even rigorous specs aren't really enough. Pretty much all modern 
codecs are defined by their reference implementation.

The bit rate is supposed to dynamically adapt to network conditions, 
when the code is used in conjunction with a suitable network performance 
monitor. Exactly what those bit rates are, however, still seems to be a 
mystery. They claim audio up to 12kHz, and specifically say they are 
suppressing the bass end below 70Hz "as it just sounds nasty". That's 
sad. 12kHz isn't really enough for high quality voice, and the extra bit 
rate needed to push the bandwidth to 15kHz is small. Also, a deep man's 
voice looses something when you cut off at 70Hz. You really want the 
bass to extend to 40Hz or 50Hz.

Regards,
Steve