Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMediaTypes)
Jose, On 7 Sep 2004, at 12:56, Jose Rey wrote:
-----Original Message----- From: Colin Perkins [mailto:csp@csperkins.org] Sent: Tuesday, September 07, 2004 12:03 PM To: Jose Rey Cc: IETF AVT WG; Dave Singer; Magnus Westerlund; IETF-Types Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMediaTypes)
On 17 Aug 2004, at 14:42, Jose Rey wrote:
Dave and I have been discussing this offline and come to the following conclusions:
1.- it is not envisioned that the 3GPP Timed Text payload format will be used for applications such as instant messaging or text conversation, which do not precise of text decoration for working properly, since there are other more appropriate media types covering these usages, like text/t140. Hence, video/ is enough.
I agree that this is not likely to be used for instant messaging or text conversation, although I don't understand why that would be relevant?
below..
Is this fundamentally text or a video codec? If it's a video codec, it should be under "video/", otherwise under "text/".
I think it is a video codec, since without the video capabilities (modifiers) it would just provide the same services as , e.g., conversational text=just plain timed text, for which it is not thought to be used.
There are other text formats that include formatting modifiers, for example "text/html". I don't understand why their presence would make this a video format.
2.- we are not clear on what exactly means to "relax rules for media registration under text/". I.e. is text/t140 an example of these "relaxed" rules or does it comply with the traditional rules as per rfc 2046? Does the relaxed rules just mean that besides text also payload headers of that media type are udnerstood?
My understanding is that the new rules are intended to allow formats such as 3GPP timed text to be registered under the text top-level media type, if appropriate, provided their domain of applicability is clearly specified (e.g. the domain of applicability might be that the type is defined for transfer via RTP only).
The MIME subtype /3gpp-tt cannot be used for HTML download since for that purpose a 3gp file and therefore the video/3gp MIME type is used. So I think this is indeed restricted to RTP. However, what is the gain of doing that?
My point was that, since this is restricted to transport via RTP, it can be registered under the "text" top-level media type.
Given the answer to the first question I think registering under text/ would not be of any use?
Why not? It would seem to be the natural home for a timed text format. Colin
-----Original Message----- From: Colin Perkins [mailto:csp@csperkins.org] Sent: Tuesday, September 07, 2004 2:26 PM To: Jose Rey Cc: Magnus Westerlund; IETF-Types; IETF AVT WG; Dave Singer Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMediaTypes)
Jose,
On 7 Sep 2004, at 12:56, Jose Rey wrote:
-----Original Message----- From: Colin Perkins [mailto:csp@csperkins.org] Sent: Tuesday, September 07, 2004 12:03 PM To: Jose Rey Cc: IETF AVT WG; Dave Singer; Magnus Westerlund; IETF-Types Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMediaTypes)
On 17 Aug 2004, at 14:42, Jose Rey wrote:
Dave and I have been discussing this offline and come to the following conclusions:
1.- it is not envisioned that the 3GPP Timed Text payload format will be used for applications such as instant messaging or text conversation, which do not precise of text decoration for working properly, since there are other more appropriate media types covering these usages, like text/t140. Hence, video/ is enough.
I agree that this is not likely to be used for instant messaging or text conversation, although I don't understand why that would be relevant?
below..
Is this fundamentally text or a video codec? If it's a video codec, it should be under "video/", otherwise under "text/".
I think it is a video codec, since without the video capabilities (modifiers) it would just provide the same services as , e.g., conversational text=just plain timed text, for which it is not thought to be used.
There are other text formats that include formatting modifiers, for example "text/html". I don't understand why their presence would make this a video format.
Ok, I was guiding myself more by the what I understood as type of apps. However, just for my clarity: if we wouldn't use the "relaxed rules" could I still use text/? Is text/t140 conformat to the 'traditional rules'?
2.- we are not clear on what exactly means to "relax rules for media registration under text/". I.e. is text/t140 an example of these "relaxed" rules or does it comply with the traditional rules as per rfc 2046? Does the relaxed rules just mean that besides text also payload headers of that media type are udnerstood?
My understanding is that the new rules are intended to allow formats such as 3GPP timed text to be registered under the text top-level media type, if appropriate, provided their domain of applicability is clearly specified (e.g. the domain of applicability might be that the type is defined for transfer via RTP only).
The MIME subtype /3gpp-tt cannot be used for HTML download since for that purpose a 3gp file and therefore the video/3gp MIME type is used. So I think this is indeed restricted to RTP. However, what is the gain of doing that?
My point was that, since this is restricted to transport via RTP, it can be registered under the "text" top-level media type.
What I mean is what would be the use of having two, not one or the other. I think that as Magnus says there may be more motivation to go for text/ because of the selectability. That and the above are good reasons for me. Summarising, it seems that we agree to choose text/. Great! I can change the registration to text/ if this settles it and submit the new revision and let the MIME people review it. Cheers, Jose
Given the answer to the first question I think registering under text/ would not be of any use?
Why not? It would seem to be the natural home for a timed text format.
Colin
At 1:25 PM +0100 9/7/04, Colin Perkins wrote:
Jose,
On 7 Sep 2004, at 12:56, Jose Rey wrote:
-----Original Message----- From: Colin Perkins [mailto:csp@csperkins.org] Sent: Tuesday, September 07, 2004 12:03 PM To: Jose Rey Cc: IETF AVT WG; Dave Singer; Magnus Westerlund; IETF-Types Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMediaTypes)
On 17 Aug 2004, at 14:42, Jose Rey wrote:
Dave and I have been discussing this offline and come to the following conclusions:
1.- it is not envisioned that the 3GPP Timed Text payload format will be used for applications such as instant messaging or text conversation, which do not precise of text decoration for working properly, since there are other more appropriate media types covering these usages, like text/t140. Hence, video/ is enough.
I agree that this is not likely to be used for instant messaging or text conversation, although I don't understand why that would be relevant?
below..
Is this fundamentally text or a video codec? If it's a video codec, it should be under "video/", otherwise under "text/".
I think it is a video codec, since without the video capabilities (modifiers) it would just provide the same services as , e.g., conversational text=just plain timed text, for which it is not thought to be used.
There are other text formats that include formatting modifiers, for example "text/html". I don't understand why their presence would make this a video format.
But text/html is not only rendering text, it is expressed in text. 3GPP renders text, but it is expressed in binary.
2.- we are not clear on what exactly means to "relax rules for media registration under text/". I.e. is text/t140 an example of these "relaxed" rules or does it comply with the traditional rules as per rfc 2046? Does the relaxed rules just mean that besides text also payload headers of that media type are udnerstood?
My understanding is that the new rules are intended to allow formats such as 3GPP timed text to be registered under the text top-level media type, if appropriate, provided their domain of applicability is clearly specified (e.g. the domain of applicability might be that the type is defined for transfer via RTP only).
The MIME subtype /3gpp-tt cannot be used for HTML download since for that purpose a 3gp file and therefore the video/3gp MIME type is used. So I think this is indeed restricted to RTP. However, what is the gain of doing that?
My point was that, since this is restricted to transport via RTP, it can be registered under the "text" top-level media type.
Given the answer to the first question I think registering under text/ would not be of any use?
Why not? It would seem to be the natural home for a timed text format.
Colin
-- David Singer Apple Computer/QuickTime
participants (3)
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Colin Perkins -
Dave Singer -
Jose Rey