ISSUE-6: Temporal clips that require transcoding

temporal clipping and transcoding

Temporal clips that require transcoding

State:
CLOSED
Product:
Raised by:
Jack Jansen
Opened on:
2009-04-07
Description:
Not all temporal clippings are representable exactly without transcoding the original media. I think original media come in three flavors:

1. For some container formats (such as Ogg with Ogg Skeleton) there is no issue: the container allows encoding the finer-granularity clipping and synchronisation.

2. Other container formats are at the other end of the spectrum: there is no way we can address a certain point in time consistently for all tracks. These formats will always require transcoding (or we must say that MF cannot be used to clip these formats).

3. Some container formats are at the half-way point: they have the concept of Random Access Points, and these are the only points in time where you can seek (or clip) with the knowledge that you're at an I-frame and with audio/video in sync.

We need to come up with some general rules for what is allowed:
- can an implementation do transcoding?
- are there situations where transcoding is forbidden?
- are there situations where transcoding is required?

It may be good enough to define two parameters: MAX_OFFSET and MAX_SYNC_ERROR. MAX_OFFSET would define the maximum difference between the requested point in time and the actual point in time (with the actual always being before the requested for clipbegin, and after it for clipend).
MAX_SYNC_ERROR would define the maximum inter-stream synchronisation error introduced by the fragmenting.

With these two parameters we could then state that if a non-transcoded fragment is possible that fits the parameters transcoding is not allowed, and if such a fragment is not possible transcoding is required.

But: it may be that we want to treat things differently server-side (where the results could be cached by an intermediate caching server) and client-side (where the results will be directly user-visible).

Related Actions Items:
Related emails:
  1. Media Fragments Working Group: Agenda 09 June, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-06-08)
  2. Media Fragments Working Group: Agenda 02 June, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-05-31)
  3. Re: Media Fragments Working Group: Agenda 26 May, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2010-05-26)
  4. Media Fragments Working Group: Agenda 26 May, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-05-25)
  5. Re: Media Fragments Working Group: Agenda 19 May, Telecon 0900 UTC (from michael.hausenblas@deri.org on 2010-05-19)
  6. Re: Media Fragments Working Group: Agenda 12 May, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2010-05-19)
  7. RE: Media Fragments Working Group: Agenda 19 May, Telecon 0900 UTC (from erik.mannens@ugent.be on 2010-05-19)
  8. Media Fragments Working Group: Agenda 19 May, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-05-18)
  9. Re: Media Fragments Working Group: Agenda 12 May, Telecon 0900 UTC (from michael.hausenblas@deri.org on 2010-05-12)
  10. Re: Media Fragments Working Group: Agenda 12 May, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2010-05-12)
  11. Media Fragments Working Group: Agenda 12 May, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-05-11)
  12. Re: Media Fragments Working Group: Agenda 05 May, Telecon 0900 UTC (from michael.hausenblas@deri.org on 2010-05-05)
  13. RE: Media Fragments Working Group: Agenda 05 May, Telecon 0900 UTC (from davy.vandeursen@ugent.be on 2010-05-04)
  14. Media Fragments Working Group: Agenda 05 May, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-05-03)
  15. Media Fragments Working Group: Agenda 28 April, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-04-27)
  16. Media Fragments Working Group: Agenda 14 April, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-04-12)
  17. Re: Media Fragments Working Group: Agenda 07 April, Telecon 0900 UTC (from conrad@metadecks.org on 2010-04-07)
  18. RE: Media Fragments Working Group: Agenda 07 April, Telecon 0900 UTC (from davy.vandeursen@ugent.be on 2010-04-06)
  19. Re: Media Fragments Working Group: Agenda 07 April, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2010-04-06)
  20. Re: Media Fragments Working Group: Agenda 07 April, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2010-04-06)
  21. Media Fragments Working Group: Agenda 07 April, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-04-06)
  22. Re: Media Fragments Working Group: Agenda 31 March, Telecon 0900 UTC (from conrad@metadecks.org on 2010-03-31)
  23. Media Fragments Working Group: Agenda 31 March, Telecon 0900 UTC (from raphael.troncy@cwi.nl on 2010-03-31)
  24. Re: [ERRATA] Media Fragments Working Group: Agenda 17 March, Telecon *0900 UTC* (from silviapfeiffer1@gmail.com on 2010-03-17)
  25. RE: Media Fragments Working Group: Agenda 17 March, Telecon 1000 UTC (from davy.vandeursen@ugent.be on 2010-03-16)
  26. RE: Media Fragments Working Group: Agenda 17 March, Telecon 1000 UTC (from erik.mannens@ugent.be on 2010-03-16)
  27. Re: [ERRATA] Media Fragments Working Group: Agenda 17 March, Telecon *0900 UTC* (from ylafon@w3.org on 2010-03-16)
  28. Re: Media Fragments Working Group: Agenda 17 March, Telecon 1000 UTC (from philipj@opera.com on 2010-03-16)
  29. Re: Media Fragments Working Group: Agenda 17 March, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2010-03-16)
  30. [ERRATA] Media Fragments Working Group: Agenda 17 March, Telecon *0900 UTC* (from raphael.troncy@cwi.nl on 2010-03-16)
  31. Media Fragments Working Group: Agenda 17 March, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-03-16)
  32. RE: Media Fragments Working Group: Agenda 03 March, Telecon 1000 UTC (from erik.mannens@ugent.be on 2010-03-03)
  33. Re: Media Fragments Working Group: Agenda 03 March, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2010-03-03)
  34. RE: Media Fragments Working Group: Agenda 03 March, Telecon 1000 UTC (from Franck.Denoual@crf.canon.fr on 2010-03-03)
  35. Media Fragments Working Group: Agenda 03 March, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-03-02)
  36. Re: Media Fragments Working Group: Agenda 24 February, Telecon 1000 UTC (from tmichel@w3.org on 2010-02-23)
  37. Media Fragments Working Group: Agenda 24 February, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-02-23)
  38. Media Fragments Working Group: Agenda 17 February, Telecon 1000 UTC (from Raphael.Troncy@cwi.nl on 2010-02-16)
  39. Media Fragments Working Group: Agenda 10 February, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-02-09)
  40. Re: Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2010-02-03)
  41. Re: Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2010-02-03)
  42. Re: Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2010-02-03)
  43. Re: Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2010-02-03)
  44. Re: Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2010-02-03)
  45. Media Fragments Working Group: Agenda 3 February, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-02-03)
  46. Re: Media Fragments Working Group: Agenda 27 January, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2010-01-27)
  47. Re: Media Fragments Working Group: Agenda 27 January, Telecon 1000 UTC (from conrad@metadecks.org on 2010-01-27)
  48. Media Fragments Working Group: Agenda 27 January, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-01-27)
  49. Re: Media Fragments Working Group: Agenda 20 January, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2010-01-21)
  50. Media Fragments Working Group: Agenda 20 January, Telecon 1000 UTC (from raphael.troncy@cwi.nl on 2010-01-20)
  51. Media Fragments Working Group: Agenda 13 January, Telecon 1000 UTC (from erik.mannens@ugent.be on 2010-01-13)
  52. Re: !Last phonecall before publication (be part of it)! - Media Fragments Working Group: Agenda 16 December, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2009-12-16)
  53. Re: !Last phonecall before publication (be part of it)! - Media Fragments Working Group: Agenda 16 December, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2009-12-15)
  54. !Last phonecall before publication (be part of it)! - Media Fragments Working Group: Agenda 16 December, Telecon 1000 UTC (from erik.mannens@ugent.be on 2009-12-14)
  55. Re: Media Fragments Working Group: Agenda 09 December, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2009-12-09)
  56. Media Fragments Working Group: Agenda 09 December, Telecon 1000 UTC (from Raphael.Troncy@cwi.nl on 2009-12-07)
  57. Re: Media Fragments Working Group: Agenda 02 December, Telecon 1000 UTC (from michael.hausenblas@deri.org on 2009-12-02)
  58. Re: Media Fragments Working Group: Agenda 02 December, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2009-12-02)
  59. Re: Media Fragments Working Group: Agenda 02 December, Telecon 1000 UTC (from philipj@opera.com on 2009-12-02)
  60. Media Fragments Working Group: Agenda 02 December, Telecon 1000 UTC (from Raphael.Troncy@cwi.nl on 2009-12-02)
  61. Re: Media Fragments Working Group: Agenda 25 November, Telecon 1000 UTC (from silviapfeiffer1@gmail.com on 2009-11-25)
  62. RE: Media Fragments Working Group: Agenda 25 November, Telecon 1000 UTC (from davy.vandeursen@ugent.be on 2009-11-25)
  63. Media Fragments Working Group: Agenda 25 November, Telecon 1000 UTC (from Raphael.Troncy@cwi.nl on 2009-11-24)
  64. Media Fragments Working Group: Agenda 18 November, Telecon 1000 UTC (from Raphael.Troncy@cwi.nl on 2009-11-18)
  65. Re: Media Fragments Working Group: Agenda 07 October, Telecon 0900 UTC (from michael.hausenblas@deri.org on 2009-10-07)
  66. Re: Media Fragments Working Group: Agenda 07 October, Telecon 0900 UTC (from silviapfeiffer1@gmail.com on 2009-10-07)
  67. Media Fragments Working Group: Agenda 07 October, Telecon 0900 UTC (from Raphael.Troncy@cwi.nl on 2009-10-06)
  68. Re: Media Fragments Working Group: Agenda 30 September, Telecon 0900 UTC *NEW HOUR* (from silviapfeiffer1@gmail.com on 2009-09-30)
  69. Media Fragments Working Group: Agenda 30 September, Telecon 0900 UTC *NEW HOUR* (from Raphael.Troncy@cwi.nl on 2009-09-28)
  70. Re: minutes of 2009-09-17 F2F meeting, Day 1 (from silviapfeiffer1@gmail.com on 2009-09-25)
  71. Media Fragments Working Group: Agenda 23 September, Telecon 0900 UTC *NEW HOUR* (from Raphael.Troncy@cwi.nl on 2009-09-23)
  72. Re: Media Fragments Working Group: Agenda 9 September, Telecon 1200 UTC (from conrad@metadecks.org on 2009-09-09)
  73. RE: Media Fragments Working Group: Agenda 9 September, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-09-08)
  74. Media Fragments Working Group: Agenda 9 September, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-09-08)
  75. RE: Media Fragments Working Group: Agenda 2 September, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-09-02)
  76. Re: Media Fragments Working Group: Agenda 2 September, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-09-01)
  77. Media Fragments Working Group: Agenda 2 September, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-09-01)
  78. Re: Media Fragments Working Group: Agenda 26 August, Telecon 1200 UTC (from tmichel@w3.org on 2009-08-25)
  79. Re: Media Fragments Working Group: Agenda 26 August, Telecon 1200 UTC (from conrad@metadecks.org on 2009-08-25)
  80. Media Fragments Working Group: Agenda 26 August, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-08-24)
  81. RE: Media Fragments Working Group: Agenda 19 August, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-08-19)
  82. Re: Media Fragments Working Group: Agenda 19 August, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-08-18)
  83. Media Fragments Working Group: Agenda 19 August, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-08-18)
  84. Regrets: Media Fragments Working Group: Agenda 12 August, Telecon 1200 UTC (from golivrin@meraka.org.za on 2009-08-12)
  85. Media Fragments Working Group: Agenda 12 August, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-08-11)
  86. RE: Media Fragments Working Group: Agenda 5 August, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-08-04)
  87. Media Fragments Working Group: Agenda 5 August, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-08-04)
  88. Re: Media Fragments Working Group: Agenda 29 July, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-07-29)
  89. Re: Media Fragments Working Group: Agenda 29 July, Telecon 1200 UTC (from silviapfeiffer1@gmail.com on 2009-07-29)
  90. Re: Media Fragments Working Group: Agenda 29 July, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-07-28)
  91. RE: Media Fragments Working Group: Agenda 29 July, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-07-28)
  92. Media Fragments Working Group: Agenda 29 July, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-07-28)
  93. Re: Media Fragments Working Group: Agenda 22 July, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-07-22)
  94. Media Fragments Working Group: Agenda 22 July, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-07-22)
  95. Re: Media Fragments Working Group: Agenda 15 July, Telecon 1200 UTC (from conrad@metadecks.org on 2009-07-15)
  96. Re: Media Fragments Working Group: Agenda 15 July, Telecon 1200 UTC (from silviapfeiffer1@gmail.com on 2009-07-15)
  97. Media Fragments Working Group: Agenda 15 July, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-07-15)
  98. Re: Media Fragments Working Group: Agenda 24 June, Telecon 1200 UTC (from tmichel@w3.org on 2009-06-24)
  99. Media Fragments Working Group: Agenda 24 June, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-06-24)
  100. Re: Media Fragments Working Group: Agenda 17 June, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-06-17)
  101. Media Fragments Working Group: Agenda 17 June, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-06-17)
  102. Re: Media Fragments Working Group: Agenda 10 June, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-06-10)
  103. RE: Media Fragments Working Group: Agenda 10 June, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-06-10)
  104. Re: Media Fragments Working Group: Agenda 10 June, Telecon 1200 UTC (from ylafon@w3.org on 2009-06-09)
  105. Media Fragments Working Group: Agenda 10 June, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-06-09)
  106. RE: Media Fragments Working Group: Agenda 20 May, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-05-19)
  107. Media Fragments Working Group: Agenda 20 May, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-05-19)
  108. RE: Media Fragments Working Group: Agenda 13 May, Telecon 1200 UTC (from erik.mannens@ugent.be on 2009-05-13)
  109. Re: Media Fragments Working Group: Agenda 13 May, Telecon 1200 UTC (from michael.hausenblas@deri.org on 2009-05-13)
  110. RE: Media Fragments Working Group: Agenda 13 May, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-05-13)
  111. Media Fragments Working Group: Agenda 13 May, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-05-12)
  112. Re: Media Fragments Working Group: Agenda 29 April, Telecon 1200 UTC (from conrad@metadecks.org on 2009-04-29)
  113. RE: Media Fragments Working Group: Agenda 29 April, Telecon 1200 UTC (from davy.vandeursen@ugent.be on 2009-04-29)
  114. Media Fragments Working Group: Agenda 29 April, Telecon 1200 UTC (from Raphael.Troncy@cwi.nl on 2009-04-29)
  115. ISSUE-6: Temporal clips that require transcoding (from sysbot+tracker@w3.org on 2009-04-07)

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