[linux-audio-dev] SMTPE/MTC Again

Paul Davis paul at linuxaudiosystems.com
Mon Apr 14 11:53:01 UTC 2003


>Paul Davis writes:
> > not for locating to a given position. i know you can interpolate
> > running SMPTE, but when you use SMPTE as a point in time to go to,
> > this option is not available. you therefore can't use SMPTE to specify
> > sample-accurate edit points, etc. 
>
>I really don't see the problem.
>
>IF every cycle is timestamped, then so is every sample.

SMPTE is two things (at least):

      * a protocol that encodes time information in an audio stream
      * a format for specifying time (HH:MM:SS:FF)

SMPTE cannot specify fractional frames because such things are not part
of the format (my understanding of this is based more on MTC, so
perhaps I need to say that MTC cannot encode fractional frames).

>Say you wand to drop-in at time t. Start playback,

wrong scenario. suppose i want to store the point in time where (say)
a zero crossing happens. SMPTE will not allow me to do that. i have to
store it as a sample position. if i use SMPTE, then i am not
guaranteed that the result actually refers to the desired sample.

--p






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