Re: deprecating markerMode

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
>
>
>
>
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>
>  *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
>
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