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

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

Hi Sassan,

First, the reason to have the information (mode-set and channels) in the 
MIME type, and not only in the file header is so that a receiver prior 
to downloading the complete content can determine its formats. If you 
only have them in the magic numbers, then you will need get the first 
bytes of content. A strong argument in this reasoning is email systems. 
Many do allow you to fetch everything except attachments which then 
later can be fetched if desired. In such a system as I understand it, 
you will get the MIME type of the attachment together with the main 
body. That way one can refuse to download an attachment one can't handle.

As VMR-WB is going to be extended and there will be a new mode-set 
later. I would think it is very appropriate that one can actually 
perform the above operation before download content, as there is a clear 
risk that the content of the file may not be playable on the device that 
downloads it.


sassan.ahmadi at nokia.com wrote:
> Now, if there is no MIME parameter associated with the storage format,
> is there any change regarding the media types registration in the draft?

See above arguments why I think it is appropriate to have parameters 
also in file format case.

However independently of the above issue, you will need to assign 
different MIME names to the RTP payload format and the file format: For 
example you could name them:

audio/vmr-wb-pt  (RTP payload type)
audio/vmr-wb-ff  (File format)

> 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?

Although this is an ongoing discussion, I think we should align where 
this is reasonable and we do agree. On the issue of defining two MIME 
types, one for the file format and one for the RTP payload format, I do 
clearly see the motivation for that statement.

I would also like to point out that the MIME types are going to expert 
MIME review and need to pass this. So not aligning it with clearly 
expressed views is going to make it harder. I am not saying to through 
your own reasoning overboard, however you better start a discussion with 
them if your view do not align on how things should be.


Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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S-164 80 Stockholm, Sweden | mailto: magnus.westerlund at ericsson.com

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