Subject: Re: [linux-audio-dev] MTC, SMPTE, etc.
From: Iain Sandoe (iain_AT_sandoe.co.uk)
Date: Sat Jul 22 2000 - 19:30:58 EEST
Sat, Jul 22, 2000, Jörn Nettingsmeier
> Paul Barton-Davis schrieb:
>> In message <3978AB66.F0E9B7C9_AT_yahoo.com>you write:
>> >Paul Barton-Davis wrote:
>> >> >I'd rather say the solution is to not only decode the SMPTE frame,
>> >> >but also keep track of it's exact position in the audio stream. Works
>> >> who says its part of the same audio stream ? i would tend to have
>> >> SMPTE streaming in through a cheap interface, and not taking up a
>> >> channel on a good multichannel card.
>> >Sorry if this is a dumb question, as I've never done anything
>> >with SMPTE... but wouldn't this have exactly the same problems as
>> >trying to sync audio data from different cards?
>> i'm not sure. SMPTE is not even close to frame-accurate (the finest
>> resolution is 1/30 second or thereabouts). there is therefore a lot of
>> room for sloppiness.
> i'm confused. isn't this 1/30 sec (or 1/29.xyz or 1/24 or
> whatever) supposed to be a "frame" (= one image of the
> film)? what kind of frames are you talking about ?
I'm doubly confused... I was under the impression that SMPTE resolved to
"bits" which are 1/80th of a frame (at whatever frame rate we are using)...
i.e. approx. 0.5 ms
With a PLL this seems reasonable...
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