Re: [AVT] RE: <draft-ietf-avt-rtp-vmr-wb-03.txt>: sampling rate

[Magnus Westerlund <magnus.westerlund at ericsson.com>]

Hi Sassan,

see below:

sassan.ahmadi at nokia.com wrote:

> > To avoid the unnecessary function I would propose that VMR-WB only 
> > defines 16kHz as RTP timestamp rate. If there is desire to have 
> > knowledge about source sampling rate that will be used, then 
> > one should 
> > define a parameter that indicates that. But I am not certain 
> > it really 
> > is needed.

[snip]

> 1- Only one RTP timestamp clock rate of 16000 Hz is used throughout the I-D.

I think this is a good change that simplify things.

> 2- A new optional MIME parameter "sampling-frequency" is defined with the following description:
>
> sampling-frequency:    The input/output media sampling frequency. Permissible values are 8000 (narrowband) or 16000 (wideband, default). If 16000 or not present, indicates that the input/output media sampling frequency is 16000 Hz.

As I indicated above, I am not certain what the usage of knowing the 
sampling frequency of the source material. Can you please provide some 
use cases when this actually is useful information. If you can motivate 
why there is good reason to have this information I don't see a problem 
of doing as you suggest. However I like to avoid defining things that 
are not really useful.

Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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