MELP / MELPe encoding delay

[NOP]

I found somewhere that the MELP vocoder has 122 mS end-to-end delay.
Given that its lookahead is about 20 mS and its frame is 22.5 mS, I
wondered:
How was that 122 mS MELP delay computed?
How is the MELPe delay compared to MELP delay?

Thanks,
NOP

[twain]

> I found somewhere that the MELP vocoder has 122 mS end-to-end delay.

Yes, I've seen that too.

> Given that its lookahead is about 20 mS and its frame is 22.5 mS,
> I wondered:
> How was that 122 mS MELP delay computed?

Some of that is mentioned at Compandent's MELPe FAQ web site:
http://www.Compandent.com/melpe_faq.htm

It seems like the MELP encoding + decoding delay is only
(20 + 22.5) + 22.5 = 65ms !

All the rest are other delay factors that are specific to the network
it was computed for, such as packetizing, network delay, modem's serial
link delay, buffering, encryption / decryption, error coding / detection
/ correction, etc..

> How is the MELPe delay compared to MELP delay?

Again, see Compandent's MELPe FAQ web site:
http://www.Compandent.com/melpe_faq.htm

The 2400 bps MELPe has the same delay as the MELP. The lower rates
MELPe have longer delay (due to larger frame and lookahead).

Cheers,
Twain

[stra...@gmail.com]

There's lots of helpful information and data about the MELP vocoder and MELPe codec at:
Http://www.melpe.com
Incluing implementations, software, hardware and solutions