[Speex-dev] size of speex packets when VAD/CNG is enabled

[Fabio Pietrosanti (naif)]

Yes but it seems to me that in the Speex RTP profile there's no such 
possibility of specifying which kind of sample are inside the RTP packet 
(having multiple sample inside).

If i have 4 sample:
voice sample 1
silence sample 2
voice sample 3
silence sample 4

How the aggregated payload will look like?

I would like to be able to specify somewhere, for example using 4 bit, 
if there's voice or not and putting inside the payload only:
voice sample 1
voice sample 3

I don't know which is the size of the "silence sample" in speex.

In AMR 4.75 it's 6byte for example and it can be reduced to 1 bit.

What about in speex?

Fabio

Ashhar Farhan wrote:
> you can use the marker bit on the RTP.
>
> - farhan
>
> On Tue, Aug 19, 2008 at 12:04 PM, Fabio Pietrosanti (naif)
> <lists at infosecurity.ch> wrote:
>   
>> Hi all,
>>
>> supposing to have speex working at 3.95, when VAD/CNG is employed, which
>> is the size of those "silence" samples respect to voice samples?
>>
>> I am wondering if it could be possible to lower even the transmission of
>> VAD/CNG samples by specifying "outbound" in the communication channel
>> only 1 bit instead of sending the whole VAD/CNG packet.
>>
>> I am doing the same for AMR where i strip-off the AMR SID describing
>> VAD/CNG and simply send "1 bit" in a custom appropriate header of the
>> transmission protocol. With AMR 4.75, sample of 13byte, additionally i
>> also cut-off the the 1byte AMR header by making AMR samples to be
>> transmitted of 12byte.
>>
>> Are those kind of "bandwidth" optimization feasible also for speex?
>>
>> a) size of VAD/CNG samples being replaced by "1 bit" instead of
>> transporting the whole sample
>> b) cutting-off the speex header to reduce the sample size (and
>> re-attaching it a standard-one on the other side before playing)
>>
>> I don't know if the first (a) or the second (b) would be feasible or
>> would cause problems.
>>
>> Fabio
>>
>> p.s. i am talking about a voip application
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>>