Time Synchronize SX-84 with Firewire

[ToasterNewbi818]

A very warm HELLO to the Newtek users all over the world :-)

I am working more an more with my VT5 and i figured out a maybe harmless problem.

If i connect one camera on my SX Board and an other Camera via Firewire
and i want to switch, than one camera is a little bit behind the other. Meaning that the signal of one camera needs a bit more time to arrive at the VT than the other.

Does anybody has a hint how to handle this problem??

Thanks for any answer :-)

Frank

[SBowie]

Hi Frank. I have an answer, but I'm afraid it's not a great one. The fact is that - while you can add a camera connected by IEEE1394 as a Switcher source - such sources always suffer from substantial latency. There is really no workaround. You would do better to connect the DV camera to your SX-8/84 using an analog connection.

[ToasterNewbi818]

Hi Steve, thanks for your answer.
Uhhhh thats a real hard workaround because i was very happy to have a perfect picture with this firewire. Is there a chance to to put something similar like a waitstate between the analog signal and the software?
Best regards
Frank

[rbartlett]

If you didn't have an SX84 (for which Steve's suggestion seems the most suitable), I'd suggest that if you wanted more than one input on a non-SX equipped VT that you'd do something along the line of this...

You can bring in more than one camera via firewire. I can't recall the exact max number per card or if certain chipset-driver combinations restrict this further. Adding a cheapie OHCI-1394 card and bringing your analog camera in via an analog->DV bridge would likely sync both cameras quite closely. But removing latency is very often the attractive option.

Similarly, an analog processor (digital color corrector) or certain digital processing inputs on SVHS VCRs will have a similar delay to DV when you put such a unit in-line with the analog camera. (I'm just trying to work through the cheapest options that you might already have in your kit bag without buying anything).

If the pure digital output of the camera is superior to the analog output of the camera then I'd highly recommend you check your cable quality or the run it takes. Both composite and Y/C outputs from digital camcorders are usually top-notch and indiscernable from DV over firewire. Sure, analog encoded video is tough to decode when there is no such thing as a perfect decoder but I let the engineers worry about the differences after all these years of it being normal to carry on regardless. IMHO

[Quiet1onTheSet]

If you didn't have an SX84 (for which Steve's suggestion seems the most suitable), I'd suggest that if you wanted more than one input on a non-SX equipped VT that you'd do something along the line of this...

You can bring in more than one camera via firewire...

The need for checking also for possible audio sync issues aside -- it might be worth mentioning, that the Firewire connection method, technically, should result in the transfer of reduced chroma (color) information, although you may not readily discern that, with your naked eye. That said, I'd prefer to err on the side of using the K.I.S.S. (Keep It Simple, "Silly") principle, through use of all analogue connections -- most *especially* if those cameras have a component or even an S-Video output option.
Q1

[SBowie]

Peter is right that in some (not all) cases, Y/C or even Composite transfer to VT can produce a superior image to IEEE1394.

[aporter]

We tested using 2 firewire cameras (each on it's own firewire card) for live switching and ran into the audio sync problem. In the process I came across the Behringer SHARK DSP110 Signal Processor which could be helpful if you wanted to delay the audio so that it would be in sync with the delayed firewire video. I never actually tried the unit though since we ended up going with all analog inputs. Another option would be to bring your audio in via the camera mic jack so that it arrives via firewire with the video.

Andrew