[AG-TECH] High packet loss audio

Colin Perkins csp at csperkins.org
Fri Oct 21 03:56:04 CDT 2005

On 20 Oct 2005, at 17:49, Derek Piper wrote:
>     What version of RAT are you using? I've had no problems  
> enabling redundant transmission on Linux or Windows. I've done so a  
> number of times to help with bad networks. I'm using the bundled  
> versions of RAT with AG 2.3, and now 2.4 under Windows.
>     For those that haven't tried it: In RAT's options, select the  
> 'Transmission' page, and click 'Redundancy' and 1 for packet  
> offset. Hit apply and your transmission rate will double.

Since packet loss is caused by network congestion, you could also  
change the codec to use a lower transmission rate to see if that  
reduces the loss.

For example, the DVI codec is half the rate of PCM, but only slightly  
lower voice quality. Using DVI+DVI instead of PCM gives you the same  
transmission rate but much more resilience to packet loss (and would  
be good to use as a default in future versions of AccessGrid). Using  
GSM+GSM will noticeably reduce the voice quality, but again is more  
resilient to loss and will transmit at one third the rate of PCM  
without redundancy.

Also, try adjusting the various repair options at the receiver, since  
those can make a different in how well packet loss is concealed.


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