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

Re: deprecating markerMode

From: Glenn Adams <glenn@skynav.com>
Date: Mon, 14 Jul 2014 12:49:23 -0600
Message-ID: <CACQ=j+c_ukkgZ=fJEuArjEU7EYVmR+XaFwgAAB_ahWocvY5F8w@mail.gmail.com>
To: John Birch <John.Birch@screensystems.tv>
Cc: Nigel Megitt <nigel.megitt@bbc.co.uk>, TTWG <public-tt@w3.org>
On Mon, Jul 14, 2014 at 2:19 AM, John Birch <John.Birch@screensystems.tv>
wrote:

>  Hi Nigel,
>
>
>
> I don’t recall any debate on the mailing lists.
>
>
>
>
>
> When using SMPTE timecode **in the context of subtitling**, external
> context would dictate whether it is possible to calculate intervals between
> SMPTE timecode values.
>
> i.e. regardless of any attribute in the TTML file, only the external
> context *truly* knows if the ‘matching’ AV asset has continuous timecode.
>
>
>
> Even if a file is attributed as discontinuous markerMode, a processor
> might determine that the external AV asset is continuous (by examination of
> all frames for example) and thus determine intervals.
>
>
>
> In general for me, the actual markerMode is a moot point, since I would
> generally expect a processor to act ‘intelligently’… that is, treat the
> timecodes as markers (for in an out cues)… and perhaps only use timecode
> arithmetic if it was in possession of a ‘bigger picture’ of the timeline of
> the associated AV material.
>
>
>
> But, this is only my perspective from a subtitling point of view…
>
>
>
> If markerMode is deprecated, I would strongly suggest that all SMPTE
> timecodes are markers. I.e. the effective markerMode is then always
> ‘discontinuous’.
>

That is the intent of deprecation: to always force 'discontinuous'
interpretation.


>
>
> Best regards,
>
> John
>
>
>
>
> *John Birch | Strategic Partnerships Manager | Screen *Main Line : +44
> 1473 831700 | Ext : 2208 | Direct Dial : +44 1473 834532
> Mobile : +44 7919 558380 | Fax : +44 1473 830078
> John.Birch@screensystems.tv | www.screensystems.tv |
> https://twitter.com/screensystems
>
>
> *Visit us at IBC, RAI Amsterdam, 12-16 Sept, stand 1.C49*
>
> *P** Before printing, think about the environment*
>
>  *From:* Nigel Megitt [mailto:nigel.megitt@bbc.co.uk]
> *Sent:* 11 July 2014 15:03
> *To:* TTWG
> *Subject:* deprecating markerMode
>
>
>
> All,
>
>
>
> we noted in TTML1SE that ttp:markerMode may be deprecated, removing the
> possibility of using the value continuous (NB this is relevant only when
> timeBase = smpte). Can anyone remind me where the debate is on this? We
> don't seem to have an issue open for it and I don't recall discussing it.
>
>
>
> Kind regards,
>
>
>
> Nigel
>
>
>
> *--*
>
>
>
> *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
>
>
>
>  This message may contain confidential and/or privileged information. If
> you are not the intended recipient you must not use, copy, disclose or take
> any action based on this message or any information herein. If you have
> received this message in error, please advise the sender immediately by
> reply e-mail and delete this message. Thank you for your cooperation.
> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
> Registered Office: The Old Rectory, Claydon Church Lane, Claydon, Ipswich,
> Suffolk, IP6 0EQ
>    ­­
>
Received on Monday, 14 July 2014 18:50:12 UTC

This archive was generated by hypermail 2.3.1 : Thursday, 5 October 2017 18:24:16 UTC