Subject: Re: [AVT] I-D ACTION:draft-ietf-avt-rtp-atrac-family-04.txt

From: Colin Perkins <[email-masked]>
Date: Wed, 7 Sep 2005 12:22:33 +0100

On 8 Jul 2005, at 20:50, [email-masked] wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts  
> directories.
> This draft is a work item of the Audio/Video Transport Working  
> Group of the IETF.
>
>     Title        : RTP Payload Format for ATRAC Family
>     Author(s)    : M. Romaine, et al.
>     Filename    : draft-ietf-avt-rtp-atrac-family-04.txt
>     Pages        : 28
>     Date        : 2005-7-8
>
> This document describes an RTP payload format for efficient and
>    flexible transporting of audio data encoded with the Adaptive
>    TRansform Audio Codec (ATRAC) family of codecs.  Recent  
> enhancements
>    to the ATRAC family of codecs support high quality audio coding  
> with
>    multiple channels.  The RTP payload format as presented in this
>    document also includes support for data fragmentation, elementary
>    redundancy measures, and a variation on scalable streaming.
>
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-atrac- 
> family-04.txt

I have a few minor comments on this draft:

  - All figures must be labelled, with a figure number and caption.

  - As I commented on -03, it might make sense for FrgNo to start from 0
    for the first fragment, for consistency with NFrames, rather than
    starting from 1 (this also avoids confusion when wrapping the  
counter,
    since it becomes clear that it wraps to zero, rather than to one).

  - I notice that the "Intended usage" part of the MIME registration has
    changed from "LIMITED USE" to "COMMON", yet the draft still  
indicates
    that an ATRAC license is required. This would seem to imply "LIMITED
    USE" would be appropriate.

Otherwise, this looks good.

Colin

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: Magnus Westerlund <[email-masked]>
Date: Wed, 07 Sep 2005 17:39:18 +0200

Hi,

Colin Perkins wrote:

>    changed from "LIMITED USE" to "COMMON", yet the draft still  indicates
I tried to find the definition of these values, but couldn't find it. 
Anyone having a reference?

Despite I have another view on the modifiers provided in the Intended 
usage field. I think that any media type that is standardized is 
intended for common usage, despite the fact that you need to license the 
codec for it. I got the impression that "LIMITED USE" is really for 
experimental format etc. Which I don't see that we can classify ATRAC as.

Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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---

From: Colin Perkins <[email-masked]>
Date: Thu, 8 Sep 2005 10:00:41 +0100

Hi,

On 7 Sep 2005, at 16:39, Magnus Westerlund wrote:
> I tried to find the definition of these values, but couldn't find  
> it. Anyone having a reference?

As far as I can tell, RFC 2048.

> Despite I have another view on the modifiers provided in the  
> Intended usage field. I think that any media type that is  
> standardized is intended for common usage, despite the fact that  
> you need to license the codec for it. I got the impression that  
> "LIMITED USE" is really for experimental format etc. Which I don't  
> see that we can classify ATRAC as.

There are standards track formats marked as "LIMITED USE" (e.g. RFC  
3862), as well as informational formats (e.g. RFC 3823). The  
definitions aren't clear though, so this might be something to raise  
during the media-types review.

Colin