Re: [codec] #15: Efficiently combine pre-encoded audio

stephen botzko <stephen.botzko@gmail.com> Wed, 12 May 2010 16:20 UTC

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Date: Wed, 12 May 2010 12:01:19 -0400
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From: stephen botzko <stephen.botzko@gmail.com>
To: Jean-Marc Valin <jean-marc.valin@octasic.com>
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Subject: Re: [codec] #15: Efficiently combine pre-encoded audio
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It might be valuable to be able to obtain the VAD without having to decrypt
the bitstream, since that also can become a problem as the number of streams
grows.

There is a security consideration (traffic analysis), however, it still
might be worth thinking about.

Stephen Botzko

On Wed, May 12, 2010 at 11:44 AM, Jean-Marc Valin <
jean-marc.valin@octasic.com> wrote:

> Benjamin M. Schwartz wrote:
>
>> The cheapest solution, of course, is transmit-side activity detection.
>> Maybe we need to specify a way for a receiver to request that the
>> transmitter employ (or not employ) VAD.
>>
>
> I think you can do better than an encoder VAD. All you need to do is make
> sure that the relevant information you need for a VAD can easily be decoded
> from the bit-stream without having to do a full decoding. For example, if
> you're able to easily extract the gain and spectral envelope, you can do a
> VAD based on that without even having to look at the other parameters in the
> bit-stream.
>
>        Jean-Marc
>
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