[AG-TECH] RAT audio quality - Alternative codecs?

[Henry Hernando Caballero Corzo]

You're right Lloyd; using a headset highly increases the quality of 
sound in a conference. Indeed, we typically recommend this kind of setup 
to our users.

Sometimes though, they just don't have a headset at hand, or they just 
want to use their mere laptop so other people in their office can listen 
to the discussion and eventually take part of it.

This kind of setup (rather hostile for any conferencing solution) led us 
to think, could RAT itself overcome this kind of issues? thus 
originating the idea to eventually integrate higher-end codecs (which 
are known to successfully deal with these problems).

Regards,

Henry.

Lloyd Pearson wrote:
>
> Hello Henry,
>
> Have you tested with the academic using a headset microphone and 
> earphones?
>
> The use of a headset severely reduces (but doesn’t eliminate!) the 
> transference of sound from the incoming to the outgoing.
>
> Some laptops’ microphones can be very good at picking up fan noise, HD 
> noise, keystroke noise etc, so a headset can be preferable.
>
> Most echo cancellers can be significantly affected by the acoustic 
> environment, and any movement of the academic would change the 
> acoustic parameters of his environment. It is not uncommon for many 
> reputable echo cancellers to take several seconds to stabilise when a 
> hand or object is moved close to a microphone or the microphone 
> position is moved.
>
> Changing the volume of the laptop speakers or gain of the laptop 
> microphone can give big clues about the cause of an echo or other 
> noise. Another useful tip is to hold the mouse pointer over a 
> participant’s name in the RAT window and press the scroll wheel. This 
> will mute their audio coming in to you, and place a line through their 
> name. Press the scroll wheel again to unmute them. As a general rule, 
> if you hear echo, mute each participant in turn until the echo 
> disappears. You will usually only hear single echos if other nodes are 
> causing them. However sustained echo (when the same word echos several 
> times) may be caused by yourself!
>
> Good luck.
>
> Regards,
>
> Lloyd Pearson
>
> AVCC Operator
>
> University of Otago
>
> Ph +64 3 479 8997
>
> /lloyd.pearson at otago.ac.nz <mailto:lloyd.pearson at otago.ac.nz>/
>
> *From:* ag-tech-bounces at lists.mcs.anl.gov 
> [mailto:ag-tech-bounces at lists.mcs.anl.gov] *On Behalf Of *Henry 
> Hernando Caballero Corzo
> *Sent:* Tuesday, 22 September 2009 4:38 p.m.
> *To:* ag-tech at lists.mcs.anl.gov
> *Subject:* [AG-TECH] RAT audio quality - Alternative codecs?
>
> Hi everyone,
>
> Hope you can advise me in the following issue.
>
> Scenario:
>
> Say we're holding a videoconference which joins people from two 
> different types of nodes:
>
> -A conference room with an adequate AG node setup (audio equipment for 
> echo cancelling (ClearOne RAV 600), ambient microphone, high-end 
> speakers, etc.)
>
> -A "casual participant" (an academic who joins the conference from his 
> workplace and uses his personal AG-equipped laptop sporting integrated 
> microphone and speakers)
>
> Then a lot of -predictible- problems related to audio arise. Audio 
> quality can degrade so badly (enormous echo and noise) that ends up 
> ruining the meeting. We certainly know we're dealing with a 
> "non-recommendable" scenario, but the fact is, we need it to work.
>
> First question:
>
> 1. How do you guys deal with this kind of setups? (if there's some way)
>
> Going deeper in this issue, I -almost inevitably- turned my eyes on 
> RAT. Even though RAT works well under controlled setups, We certainly 
> expect it to perform much better when used in uncontrolled 
> environments like the described above. So, there're some more 
> questions to ask:
>
> 3. Is RAT lacking important features like: ultra-wideband sampling, 
> echo cancelling, noise suppression, active voice detection, 
> discontinuous transmission (among others) ?
>
> 4. Or it's all about tweaking with RAT options? (some of the above 
> features seem to be included, not sure if they work well though)
>
> 5. What about Speex[1] and/or SILK[2] codecs? Would it be feasible to 
> integrate these codecs to the Access Grid?
>
> * I'm aware of this development[3], which is part of a contribution 
> from NCHC. It involves the integration of Speex into RAT, but I'm 
> really not sure if these features are included in the current version 
> of RAT that ships with the latest AG release
>
> * SILK claims excellent voicecall quality and the truth is, Skype can 
> in fact deal with our "problematic setup" with absolutely no problem
>
> Thanks in advance!
>
> Henry Caballero
>
> ----------------
>
> AG node administrator - Universidad de los Andes 
> (http://ag-mox.uniandes.edu.co)
>
> [1] http://speex.org/
> [2] https://developer.skype.com/silk
>
> [3] http://www.nchc.org.tw/en/core_content/download.php?FILE_ID=152
>