opus - Aug 2009 - Differences between low complexity and full complexity version of CELT?

Hi,

I am trying to understand the differences between low complexity and full
complexity versions of CELT.
Looking at the PEAQ results at
http://www.celt-codec.org/testing/test.0.6.0.shtml
I could not see any differences between the 2 graphs. I am sure I am missing
something.

Can you please comment on

1. What kind of source material will show a noticeable difference between low
complexity and full complexity versions?

2. What are the main advantages with full complexity over low complexity
overall?

3. Does the full complexity stream perform better with packet loss?

Thank you very much,
-raja.

On Wed, Aug 26, 2009 at 3:49 PM, raja gobi<raja.gobi at yahoo.com>
wrote:
> I could not see any differences between the 2 graphs. I am sure I am
missing something.
PEAQ is not always perfectly predictive of human listening tests.
The difference between low and full complexity is primarily the long
term predictor. PEAQ gives lower marks to the LTP than human listeners
do.
> Can you please comment on
>
> 1. What kind of source material will show a noticeable difference between
low complexity and full complexity versions?
Speech and other highly tonal signals.
> 2. What are the main advantages with full complexity over low complexity
overall?
Improved speech quality at low-bitrates.
> 3. Does the full complexity stream perform better with packet loss?
No. It performs worse with loss.