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Re: Definition for ma:compressions and ma:format

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Tue, 30 Nov 2010 06:25:29 +1100
Message-ID: <AANLkTi=ZbyY4iGS_CW=M_9ax1BBRb2RS2mitidwwj48_@mail.gmail.com>
To: "Evain, Jean-Pierre" <evain@ebu.ch>
Cc: Joakim Söderberg <joakim.soderberg@ericsson.com>, "public-media-annotation@w3.org" <public-media-annotation@w3.org>, Robin Berjon <robin@berjon.com>, Torbjörn Einarsson <torbjorn.einarsson@ericsson.com>, David Singer <singer@apple.com>
The codecs parameter of the MIME types has not been used extensively
other than by MPEG FAIK. Ogg recently added it to their MIME type
definition. WebM doesn't need it because it has restricted its codecs
to VP8 and Vorbis. However, it is relatively simple to add the codecs
parameter to the end of existing MIME types even if they are not

I would prefer using the codecs parameter on the MIME type in
ma:format (why not call it ma:mimetype?). I also agree that
ma:compression is obsolete then and should be removed.

Incidentally, HTML5 also uses MIME types with codecs parameter for this purpose.


2010/11/30 Evain, Jean-Pierre <evain@ebu.ch>:
> It's a long time since I went to see the list of registered MIME types. I wonder where this is going with e.g. several video or mp4 Mime types (generic and vendor specific).
> And I it looks like if it's just the beginning. Even some authors propose different types with the name under different vendors spaces ?!?!?!
> Any views?
> Jean-Pierre
> -----Original Message-----
> From: public-media-annotation-request@w3.org [mailto:public-media-annotation-request@w3.org] On Behalf Of Joakim Söderberg
> Sent: lundi, 29. novembre 2010 11:48
> To: public-media-annotation@w3.org
> Cc: Robin Berjon; Torbjörn Einarsson; David Singer
> Subject: Definition for ma:compressions and ma:format
> Regarding the definition for ma:compressions and ma:format.
> The response I got from my colleague, Torbjörn Einarsson, is that he agrees with LC comment (LC-2418, Robin Berjon), in that's unclear what to return for "ma:compression" as it is defined now.
> "- even something as simple as JPEG can be coded in different ways. The file format was called "jfif", but as we know "jpeg" became de facto."
> He suggest that the mime-type (which is well defined) should be in ma:format (as it is) but also include rfc4281 extensions (that describes what's in the file).
> Then consequently ma:compression becomes somewhat obsolete, but it could be used in for the case there are no codec parameters, and then perhaps rename it to "ma:codecs".
> /Joakim
> substantial: It's unclear what to return for Compression. Is JPEG a compression? Something more specific? Is it case sensitive? Partially controlled?
> substantial: Does ma:format include media type parameters?
Received on Monday, 29 November 2010 19:26:21 UTC

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