SMPTE timecode stops

[Digi]

Attempting to send SMPTE out of a laptop into the mic jack on a tower. I listen to the mic input through the towers OS to make sure I'm hearing the signal come in.

Started Arena, and noticed when I hit play on the laptop the SMPTE time code in Resolume will match the SMPTE wave on the laptop for only 1 frame. Then I seem to get no action from Resolume.

I can start and stop the SMPTE wave and it will match for that one frame. The time code in Resolume should be matching the wave on the laptop live right?

[Zoltán]

- make sure you get the SMPTE to resolume without any distortion, especially if you go from a line out to a mic in, signal distortion can cause trouble,
- also the signal has to be strong enough,
- some timecode generators can output a still time - the same frame all over - so make sure you have a rolling signal.
- make sure the smpte setting in resolume match your signal's properties.

[Digi]

I've checked all of that. Signal is strong and loud. Signal seems un-distorted. The hardware and cable used is not bad.
Signal is un-interrupted. I have been listening to it through my headset at the same time monitoring Resolume so that's not it. Lastly the wav is off the manual page. 44khz, 25fps. My settings in the preferences are set for exactly what the file says it is in the manual. I also tried changing the buffer. 1024, 2048, 4096.

Curious because of the way you responded about line out to mic in. How else would you send sempte from a pc to another? Even the CDJ method is RCA out to mic in so I'm not really sure why that would be a concern.

[Zoltán]

Curious because of the way you responded about line out to mic in. How else would you send sempte from a pc to another? Even the CDJ method is RCA out to mic in so I'm not really sure why that would be a concern.

line inputs are also an option on motherboards, and an SMPTE signal from a line output would overdrive a microphone input which expects a -20dB signal.
SMPTE is pretty resistant to distortions, but you never know what harmonics an overdriven input produces, and they can interfere with the signal recognition.

[Digi]

Uh you mean the other 3.5mm line in jack. I tried it just like the mic jack attempts. Same results.
The signal coming through my headset connected to the tower receiving the signal from the laptop sounds just as clear as hooking my headset directly up to the laptop.

[Joris]

As Ravensc suggests, when you get a single correct frame and then gibberish, this usually means the signal is coming in either too low or too loud.

Monitoring the signal over a speaker is a great way to check if you are getting *any* signal. Because of that, it's often used by the SMPTE supplier on show to let me know that he's sending the signal correctly and that the problem is in Resolume.

The problem is that our ears can hear if there's signal or not, but we cannot possibly hear if the signal is undistorted. Since we're dealing with an analog signal, a little distortion can already mess up the correct interpretation. In 100% of the cases where I've dealt with TC not being picked up correctly, the problem has always, always been the level of the incoming signal.

[Digi]

I'll mess with the volume but I can say I've also considered this too. Maybe I didn't find the perfect volume but I didn't realize it was that particular. I can say without listening to it, just monitoring in windows system sound window I have it set to where all but one bar is lit green. So it shouldn't be too loud but it should be very strong.

After I'm done putting this other machine back together I'll try it on there since it has a different motherboard.

[Joris]

Yeah, the peculiarity and overall fragileness are part of the reasons why I've grown to dislike SMPTE as a system for syncing anything. It was great 20 years ago when there were no real alternatives.

That a knowledgable person such as yourself still has problems setting it up in 2016, shows that it's time for something new.

[Oaktown]

Hey Digi, I've got a few notes/questions to add to this on this thread:

• How long is the unbalanced cable between your laptop and your server?
  Have you tried with another SMPTE file?
  Have you tried with a live SMPTE signal?
  Are you on Macs or PCs or a combination of both?

Try creating a new timecode file with http://elteesee.pehrhovey.net/ and see if you get the same result.

Also to answer your question re. how else you can get the SMPTE signal from computer to computer besides an audio cable, depending on your setup, you can use USB, Firewire, or Thunderbolt using an I/O, HD-SDI or HDMI using a capture card.

[Zoltán]

just a thought.... if you are playing your SMPTE (LTC) timecode backwards, resolume may not follow it.