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Re: Why use time as a unit of measurement? (was: Proposal 0.0)

From: Luke-Jr <Luke7Jr@yahoo.com>
Date: Wed, 12 Feb 2003 12:19:24 -0500
Message-ID: <3E4A821C.4060403@yahoo.com>
To: public-tt@w3.org
I haven't had much time to read/contribute to this ML yet, but I just
thought it would be important to point out that using a time standard
(such as English time) would be a mistake since there are more than one
time standard (I myself have been recently switching over to use the
hexadecimal time standard). Yet using frame numbers would also be a
problem as the TT script might be used with different video
files/streams which have different framerates. I'm not sure what
alternative is left over, but those are two important things to consider...

lists@wiltgen.net wrote:

>Johnb@screen.subtitling.com wrote...
>
>  
>
>>FileX is indexed against the timecode that is stored as VBI data on TapeX.
>>So unlike SMIL - the media are separate - subtitles in one - video and
>>audio on another.
>>    
>>
>
>You can forget about SMIL, although I think that understanding what it is
>a useful prerequisite for anyone who wants to contribute.
>
>Unless I'm missing something, Proposal 0.0 works just the way you would like
>-- subtitles in one file, video and audio in another.
>
>  
>
>>In practice, the broadcaster will want to show adverts. These can occur
>>at **any time** during the broadcast, and may differ from showing to
>>showing...
>>    
>>
>
>In my previous post I described how this would work.  (Please let me know
>if the explanation didn't make seise.)
>
>  
>
>>Subtitles are frame accurate for lip synching.
>>    
>>
>
>I've explained a few times why time (rather than frame-based timecode)
>must be used.  As two examples, the TT should still work when taking a
>24fps film source to NTSC, or to the web via a QuickTime movie with a
>default timebase of 600 units/second whose video content is encoded at
>12fps.
>
>  
>
>>I can conceive of other situations where the assumption of 1 sec per sec
>>is invalid.
>>    
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>
>I know you're not serious, but I don't get the joke.
>
>  
>
>>...timebases can always be converted into a single format.
>>    
>>
>
>Exactly, and that single format is time.
>
>-- Charles Wiltgen
>   <http://playbacktime.com/>
>
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>  
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Received on Wednesday, 12 February 2003 12:20:23 GMT

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