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

[Jean-Marc Valin]

wei <tsingmei at gmail.com> a écrit :

> 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 :-)

I don't believe any existing codec can give you good stereo music  
quality at 50 kb/s *while* having a low delay. You should either  
switch to mono or increase the bit-rate.

    Jean-Marc

> On Thu, Aug 5, 2010 at 11:06 PM, Gregory Maxwell <gmaxwell at gmail.com> wrote:
>
>> On Thu, Aug 5, 2010 at 11:01 AM, wei <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
>>
>