[CELT-dev] CELT 0.6.0 released, submitted as IETF draft

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Mon Jul 6 16:34:57 PDT 2009

Hi John,

The way VBR currently works is that you control the (approximate)
bit-rate target with CELT_SET_VBR_RATE and then the argument you pass to
the encoder is just the *maximum* bit-rate allowed. So if the maximum
isn't important, you just pass a large value there and control the rate



John Ridges a écrit :
> Congrats JM. I've been looking forward to 0.6.0 for a while now, and
> I've just integrated it into my app and it works great. I have just one
> question though. I realize that the VBR implementation is brand-new and
> isn't finished yet, but I would like to use it and was wondering if you
> could give us all some idea of how you envision the VBR eventually
> working (in other words, how the VBR parameter would affect the
> bit-rate). Right now it appears to give me about half the bit-rate I ask
> for when encoding silence, bit will sometimes increase up to around the
> full bit-rate on occasion depending on the audio.
> Thanks,
> John Ridges
> celt-dev-request at xiph.org wrote:
>> Message: 1
>> Date: Sun, 05 Jul 2009 20:37:40 -0400
>> From: Jean-Marc Valin <jean-marc.valin at usherbrooke.ca>
>> Subject: [CELT-dev] CELT 0.6.0 released, submitted as IETF draft
>> To: celt-dev <celt-dev at xiph.org>
>> Message-ID: <4A514754.4020101 at usherbrooke.ca>
>> Content-Type: text/plain; charset=ISO-8859-1
>> Hi everyone,
>> I'm pleased to announce version 0.6.0 of CELT, with many quality
>> improvements. This includes better stereo coupling, better handling of
>> transients, and better handling of highly tonal signals. In addition,
>> packet loss robustness has been improved through the optional use of
>> independent (intra) frames. CELT now supports a larger dynamic range,
>> suitable for encoding 24-bit audio (float version only). There is also a
>> very early VBR implementation.
>> Now, 0.6.0 is also the version that just got submitted as an "IPR-free
>> codec" Internet draft:
>> http://www.ietf.org/internet-drafts/draft-valin-celt-codec-00.txt
>> For those who aren't aware of it, there is an ongoing discussion about
>> creating an IETF working group for standardising unencumbered audio
>> codecs that everyone can use. There will be a BoF at the next IETF
>> meeting (26-31 July) in Stockholm to discuss that. I encourage those
>> interested in taking part in the mailing list discussion (
>> https://www.ietf.org/mailman/listinfo/codec ) and/or attending the BoF
>> in Stockholm. I will be co-chairing this BoF with Jason Fischl from
>> Skype.
>> Cheers,
>>     Jean-Marc

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