[LAD] SMPTE and jackd

Egor Sanin egor.sanin at gmail.com
Tue May 8 13:58:59 UTC 2012

On 5/8/12, Paul Davis <paul at linuxaudiosystems.com> wrote:
> what do you mean by "drop SMPTE frames" ?
Yes, I apologize, looking back, the question wasn't very clear.
Picture the following scenario.

I read the current jack frame (at the beginning of the process cycle,
say 'c') and convert it to SMPTE time, the result is


where n is some frame 'n'.  The next time around the process cycle,
c+1, the current jack frame has advanced by a number equal to the
period size.  An SMPTE frame occupies at least 1/30 seconds.  If the
jack period size is equivalent to more than 1/30 seconds, then SMPTE
time at c+1 will have advanced to


where a > 1.
Thus, we have, effectively, skipped over the SMPTE frame n+1.

My question is whether the preceding is true.

More information about the Linux-audio-dev mailing list