[CELT-dev] Just a question on how things are going

John Ridges jridges at masque.com
Fri Aug 6 12:33:18 PDT 2010

Fair enough. Perhaps I can include the IETF standard in a future 
revision (if I can keep the old CELT symbols from colliding with the 
IETF codec symbols when I link it).

John Ridges

On 8/6/2010 1:10 PM, Jean-Marc Valin wrote:
> John Ridges <jridges at masque.com> a écrit :
>> In my case, I'm afraid the IETF standard is much too far away for me 
>> to wait. So I guess what you're saying is that waiting for the frozen 
>> bitstream for someone (like me) who's only using CELT isn't that 
>> important because CELT probably won't be improved upon as a 
>> standalone codec after the bitstream is frozen anyway. It seems kind 
>> of a shame but I can understand your reasons for it.
> I don't see what you don't like in this. I'm currently working getting 
> a CELT 1.0 codec (with frozen bit-stream) as soon as possible. The 
> only difference is that this 1.0 version will actually be part of 
> something bigger/better. Once the bit-stream is frozen, then the only 
> thing you can improve is the encoder (and that will likely happen), 
> whether or not it's part of a bigger codec. In the end, I don't see 
> what disadvantage you could find in this.
>> I've got one quick question if you don't mind. Do you know offhand at 
>> what bitrate the pitch predictor ceased to be useful? In my 
>> application my minimum bitrate is 35 Kbits/sec. If the pitch 
>> predictor helped at that bitrate, I might want to settle on a version 
>> of CELT that still had it. Thanks,
> The pitch predictor was moderately useful up to around 50-55 kb/s. So 
> it definitely helped at 35 kb/s. That being said, I'm not sure CELT 
> should really be used below about 40 kb/s in the first place. I find 
> that it tends to have too much distortion below that point. OTOH, the 
> hybrid codec which we've been working on can produce nearly perfect 48 
> kHz speech at 32 kb/s.
> Cheers,
>     Jean-Marc

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