[AVT] RE: <draft-ietf-avt-rtp-vmr-wb-03.txt>: Storage format

[sassan.ahmadi at nokia.com]

Hi Magnus,

> > As I mentioned in my previous reply, the storage format 
> does not have any MIME parameter associated with it. 
> 
> Actually I think you are not correct. It makes a lot of sense to have 
> the following parameters also for the file format.
> 
> mode-set: So that you can indicate what is used in the file. 
> For example 
> by using mode-set=3 you can indicate interoperable mode.

Since the VMR-WB decoder does not need any mode information, therefore, the use of mode-set parameter does not give you any advantage. If you generate a storage file with any mode, even switch between permissible modes, why do you need to signal it to the decoder where it does not need that information?

For the interoperable mode, we are using a different magic number and file extension, so again the decoder does not need any additional information.

 
> channels: Indicate the actual number of channels present in the file

This parameter is included in the multi-channel file header. So, why do you need to signal it again?

 
> dtx: To indicate that DTX is used in this file
> 
> What do you say?

The storage format in VMR-WB always uses DTX concept (i.e., for silence frames nothing but a NO_DATA frame type is stored and at some points during silence periods, SID_UPDATE frames are saved. The VMR-WB simulation does not allow the use of "-dtx" and "-mime" command line options together since "-mime" command line option uses the DTX concept.

Therefore, this is a redundant parameter for the file storage.
 
> > I am not following the discussion on media types registration.
> > Considering that we have only MIME parameters associated with RTP
> > payload, could you please tell me how does this discussion 
> affect VMR-WB
> > I-D?
> 
> My conclusions of the discussion is that you will need to define one 
> MIME type for the RTP payload format, and another for the 
> file format as 
> they have different formats.
> 

Now, if there is no MIME parameter associated with the storage format, is there any change regarding the media types registration in the draft?

By the way, the media types registration rules that you referred to is still an individual draft and still under review and discussion, we cannot really follow any of the guidelines in this draft until they are finalized. Can we?

Regards

-Sassan Ahmadi   

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