extracting SMPTE timecode embeded in an audio signal

Quote: litemover wrote on Thu, 01 June 2006 09:06
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> I'm trying to extract a SMPTE timecode signal from the right-side channel of an audio track. The audio track has music on one side in mono and SMPTE timecode on another. Ultimately, Iw ould like to be able to control a timeline from the SMPTE signal but I have no idea how to get it to work.

There are numerous hardware devices that can decode SMPTE timecode (even some soundcards). Are you looking for a msp only method?

Yes I need a solution that lets me insert the cd and extracts the SMPTE LTC audio track in MSP then allows me to put those values in a jit.column as well as control and mark the timeline using nothing but a Mac powerbook g4, tiger and MAX/MSP/Jitter

Thanks,
litemover

I do need the SMPTE signal from the audio track to sync other devices to. The SMPTE track is always an arbitrary track that the entire production uses to synch to so unfortunately, I can't just use the time from an sfplay~ object. I am using the sfplay~ object to play the track. I have tried opening the file in Jit and piping it to msp but I guess I need to actually exctract the bit information from the audio signal and unpack it into a digital signal.

Not sure how to do this.

Thanks for your replys though, keep'em coming.

litemover

You'll have to do some envelope-following (read: lowpass-filtering) to
extract the bits from the signal; they're encoded in the amplitude
envelope of the sound. Check out average~, slide~, or rampsmooth~ for
this.

What is it in Max that you need to sync to the SMPTE track?

Peter McCulloch

Thanks for the info,

I figured as much. It's going to take a long time for me to figure this one out.

I need to sync the timeline as well as Midi Show Control events from max to the audio SMPTE track. The events would then trigger external devices based on the audio SMPTE track post enveloped.

All of the events I work on where I need to sync to timecode are based on SMPTE LTC not MTC and the cds/DVDs/VHS... are striped with one channel of SMPTE LTC in audio format.

I'll play around and hopefully come up with a solution.

Thanks again,

litemover

litemover wrote:
> I'll play around and hopefully come up with a solution.

I would try to do it with mxj~ in Java... I am interested in that as
well, but other things have a higher priority at the moment....

Stefan

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I just began having a very bizarre problem trying to launch Max. I
get an error dialog box that says "Connection Error: The server may
not exist or is not operational at this time." as if I was trying
to connect to a server. I'm just trying to launch Max MSP. I've
never seen this before, and I've used Max recently. I did download a
Mac OS update. I had Tiger, but I upgraded o 10.4.7. Is there
something incompatible about this version of Tiger? How do i fix
this?

Anyone?

pz

Pamela Z
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shipping address (for packages too large for a standard mail slot):
Pamela Z 2440 Sixteenth Street PMB #171, San Francisco, CA 94103, USA

Pamela Z's CD "A Delay is Better" on the Starkland label is now
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And Max is trying to connect to a server.

You have an alias to a network volume in your search path. Max is
trying to resolve it at startup time.

When Max is open, go into File Preferences and hit the Print button.
You'll have a list of folders in the Max window. Go through that list
until you find the folder with the network alias, then remove it.

There is plenty of discussion of this on the list if you want more
details.

-- Peter

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