[CELT-dev] One question about comparison between HE-AAC v2 and CELT

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Thu Aug 5 11:00:07 PDT 2010

"Feilen, Michael" <michael.feilen at tum.de> a écrit :

> We're using CELT 0.7.1 in a real-time system at rates around 48  
> kBit/s and the audio quality is surprisingly good. I would say  
> comparable to a good VHF-FM stereo reception.

For mono, 48 kb/s should be OK. I just don't recommend doing 48 kb/s  
stereo though.


> Von: celt-dev-bounces at xiph.org [mailto:celt-dev-bounces at xiph.org] Im  
> Auftrag von wei
> Gesendet: Donnerstag, 5. August 2010 17:11
> An: Gregory Maxwell
> Cc: celt-dev at xiph.org
> Betreff: Re: [CELT-dev] One question about comparison between HE-AAC  
> v2 and CELT
> Thank you. If I want to implement an internet based Karaoke  
> software, and the bandwidth is around 50kbps, should I use Celt or  
> AAC LD? I want to ensure the stereo effect in the software :-)
> On Thu, Aug 5, 2010 at 11:06 PM, Gregory Maxwell  
> <gmaxwell at gmail.com<mailto:gmaxwell at gmail.com>> wrote:
> On Thu, Aug 5, 2010 at 11:01 AM, wei  
> <tsingmei at gmail.com<mailto:tsingmei at gmail.com>> wrote:
>> But Cisco adopts HE-AAC in it's telepresence product which is the dominant
>> HD video conference product. They use hardware to decrease the delay?
> The delay we're talking about is algorithmic delay. You can't reduce
> it with faster hardware. You can only reduce it via changing the
> format (or sometimes by increasing the sampling rate).
> I believe all AAC using Cisco telepresence equipment that I've seen  
> uses AAC-LD.
> For example:
> http://www.cisco.com/en/US/prod/collateral/ps7060/ps8329/ps8330/ps9573/data_sheet_c78-457905.html
> Also:
> http://www.thefreelibrary.com/Cisco+TelePresence+System+Uses+Fraunhofer+IIS+AAC-Low+Delay+Audio...-a0161912048
> Example configurations here show AAC-LD:
> https://supportforums.cisco.com/message/3140710

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