[linux-audio-user] SMPTE timecode reader

plutek plutek at infinity.net
Tue Dec 19 09:57:47 EST 2006

On 12/19/2006 09:36:33 AM, Paul Davis wrote:
> On Mon, 2006-12-18 at 22:13 -0500, plutek wrote:
> > during shooting. we were going to feed the studio64-xtc LTC to both
> the
> > cameras and ardour, but had trouble locking cameras to that code --
> i
> > actually think this may have been a problem with the feed from my
> end,
> > but we didn't have time to debug it. we ended up feeding
> > camera-generated LTC into ardour in realtime while shooting.
> what do you think ardour is going to do with timecode during
> recording?
> i just want to make sure that you're not thinking you could slave to
> it.
> you should never record while slaved to a non-sample-accurate clock
> source, and LTC is absolutely not sample accurate. slaving to timecode
> is useful during playback, not during recording. this is true of not
> just ardour, but everything else. if you want video/audio sync during
> recording, you need to use blackburst or some equivalent to provide a
> single clock source to the video and audio gear. this is actually
> preferable during playback too, but most people don't have the
> equipment
> for this. as was noted earlier, with digital audio, there are
> alternatives to using timecode anyway.

we were not trying to lock everything together (although the cameras  
were jam-synced together); we simply wanted to end up with the same  
timecode striped on a track of all devices, audio and video, as a  
reference for post. yes, i take your point about blackburst, and we'll  
see if we run into problems during post -- in the end, it should not be  
a huge issue because the video edits will allow some "munging" along  
the timeline. still, once we get to post, the ability to directly parse  
and lock to incoming LTC might simplify things.

today i will be trying to lock with MTC via my opcode studio64-xtc, but  
it looks like ardour may be lacking the framerate i need for this  
project. the video producer used 29.97 non-drop. now, i must confess to  
some slight confusion about the real meaning of all the combinations of  
29.97, 30, drop, and non-drop, but ardour 0.99.3 doesn't show any 29.97  
options for MTC, so am i out of luck here?



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