[linux-audio-user] SMPTE timecode reader

Robin Gareus robin at gareus.org
Sat Dec 23 11:11:59 EST 2006

Hash: SHA1

> what do you think ardour is going to do with timecode during
> recording?

use it as offset.

I was interested in having a tool that reads the first [LTC]SMPTE from a
[analog] recording and use it as offset for the audio file that is
recorded along with. At the end I would only be interested in the
drift+jitter information (no varispeed).

In my experience that this is good enough for A/V sync (even to
sync snare hits on a music video!)

> i just want to make sure that you're not thinking you could slave to
> it.


> if you want video/audio sync during recording, you need to use
> blackburst [..] or some equivalent to provide a but most people
> don't have the equipment for this.

I would not recommend to use LTC, but It seems to be good enough for
most [low budget] video productions!

I've started to write a simple parser (counting the zero crossing from
the signal and decode the Manchester). It seems that Maarten's code
(level Threshold) works better and even more so if combined with some
band pass filter..

I've got a jack app that reads LTC and am working on libltcsmpte to both
read and write LTC time code; but it's going to take until 2007.

merry X-mas,
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