PIX240 and Sony F3 audio sync offset? at DVinfo.net

Mark Kenfield · April 19th, 2012, 09:03 AM

Hi guys,

I've been reading the various issues people have been having with audio sync and the Sony F3 when the mic is plugged directly into the PIX recorder.

Has anyone figured out the specific 'Audio Input Delay' required to sync PIX audio with the F3's HD-SDI video output?

Cheers

Matt Mayer · April 20th, 2012, 04:16 PM

I haven't done anything scientific, but 2 frames offset would be a good starting point to try.

The amount of offset you need depends on on the framerate. 1 Frame at 29.97 = ~33 ms, 1 frame at 23.976 = ~42ms

Mark Kenfield · April 21st, 2012, 11:17 PM

Thanks Matt, I'll give that a try. 2 frames at 25fps would be 80ms, so I'll see how that goes.

Mark Kenfield · May 5th, 2012, 12:38 AM

Well, as an update for anyone who's interested. After a bunch of tests we settled on 53ms as the delay for the F3 at 25p. Seems to have worked a charm.

A. J. deLange · May 26th, 2012, 10:46 PM

Can't help with the Sony but I had the same problem with a AG-AF100. To find out what the delay actually is I took the left channel from a stereo microphone and connected it to one of the camera's XLRs and connected the right channel to a channel on the Pix. I pointed the mic at a broadband source (an artificial water fall) and recorded a few seconds. I use an analysis program called IGOR which has the ability to strip audio channels from Quicktime files. Once the two channels were in the analysis program it was a simple matter to run the cross correlation and find the peak. The camera lags the recorder by 97.25 mS. Setting the Pix to 97 mS aligns camera and Pix audio to within 12 samples.

April 19th, 2012, 09:03 AM	#1
Mark Kenfield Major Player Join Date: Apr 2007 Location: Melbourne, Australia Posts: 470	PIX240 and Sony F3 audio sync offset? Hi guys, I've been reading the various issues people have been having with audio sync and the Sony F3 when the mic is plugged directly into the PIX recorder. Has anyone figured out the specific 'Audio Input Delay' required to sync PIX audio with the F3's HD-SDI video output? Cheers

April 20th, 2012, 04:16 PM	#2
Matt Mayer New Boot Join Date: Sep 2009 Location: Chicago, IL Posts: 21	Re: PIX240 and Sony F3 audio sync offset? I haven't done anything scientific, but 2 frames offset would be a good starting point to try. The amount of offset you need depends on on the framerate. 1 Frame at 29.97 = ~33 ms, 1 frame at 23.976 = ~42ms __________________ Matt Mayer -- Sound Mixer/Applications Engineer Sound Devices, LLC

April 21st, 2012, 11:17 PM	#3
Mark Kenfield Major Player Join Date: Apr 2007 Location: Melbourne, Australia Posts: 470	Re: PIX240 and Sony F3 audio sync offset? Thanks Matt, I'll give that a try. 2 frames at 25fps would be 80ms, so I'll see how that goes.

May 5th, 2012, 12:38 AM	#4
Mark Kenfield Major Player Join Date: Apr 2007 Location: Melbourne, Australia Posts: 470	Re: PIX240 and Sony F3 audio sync offset? Well, as an update for anyone who's interested. After a bunch of tests we settled on 53ms as the delay for the F3 at 25p. Seems to have worked a charm.

May 26th, 2012, 10:46 PM	#5
A. J. deLange Major Player Join Date: Jun 2004 Location: McLean, VA United States Posts: 749	Re: PIX240 and Sony F3 audio sync offset? Can't help with the Sony but I had the same problem with a AG-AF100. To find out what the delay actually is I took the left channel from a stereo microphone and connected it to one of the camera's XLRs and connected the right channel to a channel on the Pix. I pointed the mic at a broadband source (an artificial water fall) and recorded a few seconds. I use an analysis program called IGOR which has the ability to strip audio channels from Quicktime files. Once the two channels were in the analysis program it was a simple matter to run the cross correlation and find the peak. The camera lags the recorder by 97.25 mS. Setting the Pix to 97 mS aligns camera and Pix audio to within 12 samples.