ISSUE-305: Registry of TTML profiles and short names

Profile short names

Registry of TTML profiles and short names

State:
CLOSED
Product:
Raised by:
Nigel Megitt
Opened on:
2014-05-01
Description:
In response to the liaison from MPEG File Format group at [1] on Codecs we decided to create a registry of short names against profiles of TTML, recorded as ACTION-284 [2] and to respond to the liaison with this proposal, which we did at [3].

[1] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0005.html
[2] https://www.w3.org/AudioVideo/TT/tracker/actions/284
[3] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0025.html

This was further discussed in the meeting of 1st May 2014, minutes at [4].

[4] http://www.w3.org/2014/05/01-tt-minutes.html

The group did not consider that namespace and schemaLocation would provide useful information for the intended purpose. Rather, it was proposed to create a table including the columns:

Short name, [required]
Profile URI, [required]
Profile document URL, [optional]
Specification URL, [optional]
Electronic representation (e.g. a schema) URL [optional]

This should be coincident with the design already proposed for content and processor profile designators.

We also noted that the TTML namespace is mutable and that not all profiles or variants have schemas at a known location. Merely referencing a profile defined by another organisation would not constitute any form of endorsement by W3C.

This issue should be used to track further debate on this topic.
Related Actions Items:
Related emails:
  1. Re: {minutes} TTWG Meeting 20/11/2014 (from nigel.megitt@bbc.co.uk on 2014-11-21)
  2. {minutes} TTWG Meeting 20/11/2014 (from nigel.megitt@bbc.co.uk on 2014-11-20)
  3. {agenda} TTWG Meeting 20/11/2014 (from nigel.megitt@bbc.co.uk on 2014-11-19)
  4. {agenda} TTWG Meeting 6/11/2014 (from nigel.megitt@bbc.co.uk on 2014-11-05)
  5. RE: {agenda} TTWG Meeting 23/10/2014 (from mdolan@newtbt.com on 2014-10-22)
  6. {agenda} TTWG Meeting 23/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-22)
  7. {agenda} TTWG Meeting 16/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-15)
  8. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from singer@apple.com on 2014-10-13)
  9. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from glenn@skynav.com on 2014-10-13)
  10. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from cyril.concolato@telecom-paristech.fr on 2014-10-13)
  11. RE: MPEG codecs parameter - discussion summary ISSUE-305 (from mdolan@newtbt.com on 2014-10-11)
  12. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from glenn@skynav.com on 2014-10-10)
  13. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from singer@apple.com on 2014-10-10)
  14. RE: MPEG codecs parameter - discussion summary ISSUE-305 (from mdolan@newtbt.com on 2014-10-10)
  15. Re: MPEG codecs parameter - discussion summary ISSUE-305 (from singer@apple.com on 2014-10-10)
  16. RE: MPEG codecs parameter - discussion summary ISSUE-305 (from mdolan@newtbt.com on 2014-10-10)
  17. MPEG codecs parameter - discussion summary ISSUE-305 (from nigel.megitt@bbc.co.uk on 2014-10-10)
  18. Re: {minutes} TTWG Meeting 9/10/2014 (from silviapfeiffer1@gmail.com on 2014-10-10)
  19. {minutes} TTWG Meeting 9/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-09)
  20. {agenda} TTWG Meeting 9/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-08)
  21. {agenda} TTWG Meeting 2/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-01)
  22. {agenda} TTWG Meeting 25/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-24)
  23. {agenda} TTWG Meeting 21/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-20)
  24. {minutes} TTWG Meeting 14/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-14)
  25. {agenda} TTWG Meeting 14/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-13)
  26. Re: {agenda} TTWG Meeting 7/8/2014 (from pal@sandflow.com on 2014-08-06)
  27. {agenda} TTWG Meeting 7/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-06)
  28. {agenda} TTWG Meeting 31/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-30)
  29. {agenda} TTWG Meeting 24/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-23)
  30. {agenda} TTWG Meeting 17/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-16)
  31. {agenda} TTWG Meeting 10/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-09)
  32. RE: {agenda} TTWG Meeting 19/6/2014 (from mdolan@newtbt.com on 2014-06-18)
  33. {agenda} TTWG Meeting 19/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-18)
  34. RE: {agenda} TTWG Meeting 12/6/2014 (from mdolan@newtbt.com on 2014-06-12)
  35. Re: {agenda} TTWG Meeting 12/6/2014 (from pal@sandflow.com on 2014-06-11)
  36. Re: {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  37. Re: {agenda} TTWG Meeting 12/6/2014 (from pal@sandflow.com on 2014-06-11)
  38. Re: {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  39. {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  40. RE: {agenda} TTWG Meeting 5/6/2014 (from mdolan@newtbt.com on 2014-06-04)
  41. {agenda} TTWG Meeting 5/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-04)
  42. {agenda} TTWG Meeting 29/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-28)
  43. Update to ISSUE-305 (from nigel.megitt@bbc.co.uk on 2014-05-23)
  44. {minutes} TTWG Meeting 22/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-22)
  45. {agenda} TTWG Meeting 22/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-21)
  46. Re: Draft TTML Codecs Registry - Issue-305 (from cyril.concolato@telecom-paristech.fr on 2014-05-20)
  47. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  48. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-20)
  49. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  50. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-20)
  51. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-20)
  52. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  53. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-20)
  54. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-20)
  55. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  56. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  57. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-20)
  58. RE: Draft TTML Codecs Registry - Issue-305 (from mdolan@newtbt.com on 2014-05-19)
  59. Re: Draft TTML Codecs Registry - Issue-305 (from singer@mac.com on 2014-05-19)
  60. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-19)
  61. Re: Draft TTML Codecs Registry - Issue-305 (from singer@mac.com on 2014-05-19)
  62. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-19)
  63. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-19)
  64. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-19)
  65. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  66. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  67. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-19)
  68. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  69. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-19)
  70. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  71. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  72. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-19)
  73. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-19)
  74. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-19)
  75. RE: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-19)
  76. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-19)
  77. Re: Draft TTML Codecs Registry - Issue-305 (from John.Birch@screensystems.tv on 2014-05-18)
  78. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-17)
  79. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-16)
  80. Re: Draft TTML Codecs Registry - Issue-305 (from glenn@skynav.com on 2014-05-15)
  81. Re: Draft TTML Codecs Registry - Issue-305 (from nigel.megitt@bbc.co.uk on 2014-05-15)
  82. {agenda} TTWG Meeting 15/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-14)
  83. Re: Liaison response - template on MIME type parameter for TimedText - ISSUE-305 (from nigel.megitt@bbc.co.uk on 2014-05-08)
  84. Re: {agenda} TTWG Meeting 8/5/2014 (from tmichel@w3.org on 2014-05-08)
  85. RE: Liaison response - template on MIME type parameter for TimedText - ISSUE-305 (from mdolan@newtbt.com on 2014-05-07)
  86. {agenda} TTWG Meeting 8/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-07)
  87. Re: Liaison response - template on MIME type parameter for TimedText - ISSUE-305 (from nigel.megitt@bbc.co.uk on 2014-05-07)
  88. ISSUE-305 (Profile short names): Register of TTML profiles and short names (from sysbot+tracker@w3.org on 2014-05-01)

Related notes:

We are discussing detailed requirements for this request.

Topic areas covered (thanks to MD = Mike Dolan for some of this):

1. using {profile} vs {namespace, schemaLocation},
There seems to be consensus that namespace/schemaLocation is not our first choice.

2. processor behaviour vs declaration of document conformance, aka Semantics
MD>> Yes, we have to work through this. TTML is different than AVC and MP4 brands in that the decoder is expected to conform to the brand (e.g. AVC profile and level) 100%. Thus, the AVC signaling is the ES profile and level (i.e. the TTML document) not the decoder requirements. So, using the TTML decoder requirements profile would be different.

3. syntax of the string formed by combining short labels,
Needs to be figured our after we figure out the requirements and the semantic design.

4. [mis]use of the @codecs parameter when @profiles or simply additions to the mime type would be better
MD>> Yes, we need to discuss the merits of building off the media type versus creating a new namespace with the 4C. It's not clear to me why the media type is not the obvious choice.

5. registration process of short labels in W3C
MD>> Yes, but after we figure out the requirements and semantic design.

6. amendments needed in external documents e.g. RFC 6381, IANA application/ttml+xml registration
MD>> OK, but this is a general DASH problem, not a W3C problem.

7. what are we trying to signal in the first place?
MD>> A. everything MP4 can carry with stpp?
MD>> B. for TTML, is it:
MD>> i. W3C profiles (e.g. SDP-US & IMSC)?
MD>> ii. External, but not extension, profiles (e.g. EBU-TT-D & CFF-TT)?
MD>> iii. Profile Extensions (e.g. SMPTE-TT & CFF-TT-M)?

Mike Dolan proposes dealing with those in the order #7, #4 and #2.

Nigel Megitt, 22 May 2014, 13:59:11

This was briefly discussed in yesterday's TTWG meeting [1] and I took ACTION-291 to find which issue is related to feature definition and the relationships between features. This turns out to be ISSUE-263 however the wording on that issue doesn't quite make it clear that feature relationships are the solution.

[1] http://www.w3.org/2014/05/22-tt-minutes.html

Nigel Megitt, 23 May 2014, 10:37:00

Post draft at https://www.w3.org/wiki/TTML/CodecsRegistry.

Glenn Adams, 24 May 2014, 04:27:57

Here's where I think we're up to with a restated requirements list for this feature, as a straw man:

1. Provide information external to a document D to allow a system to decide 'can I process this document'.
1a. Signal permitted processor profiles.
1b. Provide rules for inferring processors from content profiles.
2. Allow the system to select/initialise an appropriate processor P for processing the document.
3. Map the information into the profile and feature definitions that can be expressed within a document.
4. The signalling to be as concise as possible. (i.e. if a simpler scheme allows for more concision it would be preferred since fine grained precise data is more verbose and is not needed).
5. Format must be permissible in both MIME type and @codecs parameter.
6. Allow non-W3C recommendation profiles of TTML to be signalled.
7. Registration process must be defined.

And in the 'not a requirement' list:
X. Facilitate generic XML processing, e.g. BiM coding.

Nigel Megitt, 29 May 2014, 07:40:23

>Here's where I think we're up to with a restated requirements list for this feature, as a straw man:
>
>1. Provide information external to a document D to allow a system to decide 'can I process this document'.

In general, this is not possible by simple examination of an externally signaled profile designation. The reason being that a document may semantically extend/restrict such external designation, or may specify processor profile requirements that do not correspond to such external designation.

In other words, a conforming processor must still process the internal profile specifications in order to determine if a document can be processed.

>1a. Signal permitted processor profiles.

Not sure what "permitted" means.


>1b. Provide rules for inferring processors from content profiles.

This is now specified for internal profile semantics processing.

>2. Allow the system to select/initialise an appropriate processor P for processing the document.

This seems the only legitimate role of an external designation.

>3. Map the information into the profile and feature definitions that can be expressed within a document.

Not a requirement. Handled by internal profile mechanism.

>4. The signalling to be as concise as possible. (i.e. if a simpler scheme allows for more concision it would be preferred since fine grained precise data is more verbose and is not needed).
>5. Format must be permissible in both MIME type and @codecs parameter.
>6. Allow non-W3C recommendation profiles of TTML to be signalled.
>7. Registration process must be defined.

>And in the 'not a requirement' list:
>X. Facilitate generic XML processing, e.g. BiM coding.

Glenn Adams, 16 Oct 2014, 13:45:43

Closed during TTWG meeting 2014-11-20 on the basis that the remaining changes are captured in Issue-351, Issue-352 and Issue-353, and that the communication thread with MPEG has now completed. When our registry is available we will no doubt wish to communicate that back to MPEG for their interest, but there's no further action to take on this issue.

Nigel Megitt, 21 Nov 2014, 10:10:55

Changelog:

Created issue 'Register of TTML profiles and short names' nickname Profile short names owned by Nigel Megitt on product , description 'In response to the liaison from MPEG File Format group at [1] on Codecs we decided to create a registry of short names against profiles of TTML, recorded as ACTION-284 [2] and to respond to the liaison with this proposal, which we did at [3].

[1] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0005.html
[2] https://www.w3.org/AudioVideo/TT/tracker/actions/284
[3] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0025.html

This was further discussed in the meeting of 1st May 2014, minutes at [4].

[4] http://www.w3.org/2014/05/01-tt-minutes.html

The group did not consider that namespace and schemaLocation would provide useful information for the intended purpose. Rather, it was proposed to create a table including the columns:

Short name, [required]
Profile URI, [required]
Profile document URL, [optional]
Specification URL, [optional]
Electronic representation (e.g. a schema) URL [optional]

This should be coincident with the design already proposed for content and profile designators.

We also noted that the TTML namespace is mutable and that not all profiles or variants have schemas at a known location. Merely referencing a profile defined by another organisation would not constitute any form of endorsement by W3C.

This issue should be used to track further debate on this topic.' non-public

Nigel Megitt, 1 May 2014, 15:49:56

Description changed to 'In response to the liaison from MPEG File Format group at [1] on Codecs we decided to create a registry of short names against profiles of TTML, recorded as ACTION-284 [2] and to respond to the liaison with this proposal, which we did at [3].

[1] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0005.html
[2] https://www.w3.org/AudioVideo/TT/tracker/actions/284
[3] http://lists.w3.org/Archives/Public/public-tt/2014Apr/0025.html

This was further discussed in the meeting of 1st May 2014, minutes at [4].

[4] http://www.w3.org/2014/05/01-tt-minutes.html

The group did not consider that namespace and schemaLocation would provide useful information for the intended purpose. Rather, it was proposed to create a table including the columns:

Short name, [required]
Profile URI, [required]
Profile document URL, [optional]
Specification URL, [optional]
Electronic representation (e.g. a schema) URL [optional]

This should be coincident with the design already proposed for content and processor profile designators.

We also noted that the TTML namespace is mutable and that not all profiles or variants have schemas at a known location. Merely referencing a profile defined by another organisation would not constitute any form of endorsement by W3C.

This issue should be used to track further debate on this topic.'

Nigel Megitt, 1 May 2014, 16:00:58

Issue dissociated from any product

Nigel Megitt, 1 May 2014, 16:00:58

Issue dissociated from any product

Nigel Megitt, 7 May 2014, 18:55:36

Status changed to 'open'

Nigel Megitt, 7 May 2014, 18:55:36

Issue dissociated from any product

Nigel Megitt, 22 May 2014, 13:59:11

Issue dissociated from any product

Nigel Megitt, 23 May 2014, 10:37:00

Issue dissociated from any product

Glenn Adams, 24 May 2014, 04:27:57

Status changed to 'pending review'

Glenn Adams, 24 May 2014, 04:27:57

Issue dissociated from any product

Nigel Megitt, 29 May 2014, 07:40:23

title changed to 'Registry of TTML profiles and short names'

Glenn Adams, 19 Jun 2014, 14:28:06

Issue dissociated from any product

Glenn Adams, 19 Jun 2014, 14:28:06

Issue dissociated from any product

Glenn Adams, 16 Oct 2014, 13:45:43

Status changed to 'closed'

20 Nov 2014, 15:57:34

Issue dissociated from any product

Nigel Megitt, 21 Nov 2014, 10:10:55


David Singer <singer@apple.com>, Nigel Megitt <nigel.megitt@bbc.co.uk>, Chairs, Thierry Michel <tmichel@w3.org>, Philippe Le H├ęgaret <plh@w3.org>, Atsushi Shimono <atsushi@w3.org>, Staff Contacts
Tracker: documentation, (configuration for this group), originally developed by Dean Jackson, is developed and maintained by the Systems Team <w3t-sys@w3.org>.
$Id: index.php,v 1.326 2018/10/13 17:29:51 vivien Exp $