W3C home > Mailing lists > Public > public-tt@w3.org > April 2014

Liaison response - template on MIME type parameter for TimedText

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Wed, 30 Apr 2014 18:48:05 +0000
To: "watanabe@itscj.ipsj.or.jp" <watanabe@itscj.ipsj.or.jp>
CC: Timed Text Working Group <public-tt@w3.org>
Message-ID: <CF8703C2.1CF50%nigel.megitt@bbc.co.uk>
Dear Mr. Watanabe,

Thank you for your liaison N14444 of April 2014.

We think that we can indeed find a solution together.  We are looking into creating a table of formal "short names" for the profiles of W3C TTML and
the profiles of formats derived from it (such as SMPTE-TT, EBU-TT, and so on).  If MPEG were to propose how to step from the four-character-code of
the sample entry (XMLSubtitleSampleEntry and XMLMetaDataSampleEntry) to something that identifies "a document compatible with one or more profiles of TTML", then we could propose a string composed of a set of one or more these short names as the next parameter.

For example, say W3C defines two profile short names "W3CTTML" and "EBUTTML", and MPEG defines the name "TTML" as referring to the overall
family, one might see

codecs=stpp.TTML.W3CTTML+EBUTTML,avc1

as a codecs string of a file carrying AVC (H.264) and TTML subtitles that
are additionally EBU-TT conformant.

We would check with those deriving from TTML (e.g. at SMPTE, EBU and DECE) if this approach and design are acceptable, before we formalise this.

Kind regards,

Nigel Megitt, David Singer (chairs, Timed Text Working Group, W3C)

--

Nigel Megitt
Lead Technologist, BBC Technology, Distribution & Archives
Telephone: +44 (0)3030807996
Internal (Lync): 0807996
BC4 A3 Broadcast Centre, Media Village, 201 Wood Lane, London W12 7TP




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Received on Wednesday, 30 April 2014 18:47:55 UTC

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