G.711 Vs G.729

Hello

If quality is the most important thing, which one is better? What is the best codec for the best quality?

Thanks

Hi

Strange question but simple answer, G711, Now you have to ask which is better G711A or G711U.

Ian

I know that it should be G. 711 since it uses the most bandwidth and its not compressed, but I have heard that G 729 uses a speech technology that can actually make talking more clear. Is that true?

Hi

AFAIK No its not true. and from experiance also its not.

Ian

Quote:

I know that it should be G. 711 since it uses the most bandwidth and its not compressed....

Actually G.711 is compressed. There's about 13 bits of sample resolution squeezed into 8 bits. Each byte has an exponent and value, like the way floating point numbers are represented in a computer. It's not that good, but the algorithm is very simple and requires practically no CPU, so it will live on forever.

As for whether G.729 is clearer: you can find research that says perceived quality is better (measured in the form of Mean Opinion Score, MOS). It is designed to represent/model speech specifically rather than "general audio". Like a lot of modern codecs (e.g. AMR, GSM Enhanced Full Rate, Speex) it uses CELP (or ACELP) which is a way to encode packets of data according to a parameter table that is meant to describe speech. To make things complicated there is a family of algorithms in G.729 including wideband (7kHz), Annex A which is a low CPU power version, and there are also add ons for silence suppression and comfort noise generation. You could probably make an argument in favour of G.711 or G.729.

The great thing about G.711 is that it's supported by just about everything, so this makes interop very simple. Many fancy codecs (incl. G.729) need to be licensed, as they are someone's intellectual property, which means that not all devices will implement G.729. The flipside is that 'free' low bitrate coders (like Speex and iLBC) are too new to be implemented in everything.

There's a lot to be said for simplicity if you have the bandwidth to spare...

Hi its really good info guys

Additionally, I fell that the best way to judge various speech codecs like G.711 or G.729 is to understand their pros and cons and its specific application area

may be you can refer to this blog Understanding speech codecs: Pros & Cons

Interesting table of codec info here ...

http://www.ozvoip.com/codecs.php

and a bandwidth calculator here ...

http://www.bandcalc.com/

my experience judging strictly from experience and not looking at the technical aspects: in most cases with a broadband connection I feel the voice quality is much better with G711; for whatever reason this tends to increase even more so when connecting to a VSP for PSTN interconnect as opposed to a peer2peer situation. on the other hand on some lower bandwidth connections i have been able to use G729 for very clear conversation when G711 was totally unintelligible.