View Full Version : Any chance of recording sync sound 25P off Varicam?


Peter Corbett
August 23rd, 2010, 07:06 PM
I've resigned to the fact that I will have to keep my tape Varicam. I can record the 720 25P stream from a 27H Tape varicam using the undercrank on the Nanoflash, but the audio is late/out-of-sync. (This is for 50Hz users) Surely this must be fixable in the nano firmware?

Please?

Steve Phillipps
August 24th, 2010, 02:50 AM
Didin't someone suggest taking an audio feed from the Varicam's audio Out to an audio input on the Nano?
Steve

Peter Corbett
August 24th, 2010, 02:58 AM
Dio you mean into the mic input Steve? Probably not ideal, but if it works....

Steve Phillipps
August 24th, 2010, 03:44 AM
Yes, plug into the Audio Out on the back of the Varicam and feed that into the Mic In on the nanoflash. Would this work, and if so what would the quality of the audio be like? Don't know anything about audio really.
Steve

Dan Keaton
August 24th, 2010, 06:49 AM
Dear Peter,

Audio, as far as I know, is not supportted during over or under-cranking.

But, we have a special mode for converting 720p60 to 720p30, and 720p50 to 720p25.

This is in the video menu, 720p 60/50>30/25.

If I understand your question correctly, this should do what you want, and give you good audio.

This mode removes the duplicate frames present when the camera is set to 720p25 but is sending out 720p50 via the HD-SDI, and preserves the audio.

If you are using this mode, and the audio is out of sync, then will will correct this in firmware.

But, from your post, it appears that you are using our Over and Under-Crank feature, a completely separate function.

Peter Corbett
August 25th, 2010, 12:59 AM
Thanks Dan,

The trouble with the Varicam is that it puts out a constant 60fps regardless of what the frame rate is. there is no 50Hz system setting and thus no 720p50 on a Varicam (as there is on the HDX900 DVCPROHD).

If I shoot at 25fps, the recording device (or capture card) has to pull the redundant frames out of the 60fps stream and discard them. The AJA Ki-Pro and Kona cards do this and the audio is synced with video. By using crank on the Nano set to 25fps, I get the correct "PAL 50Hz" signal recorded to the Nano, but the Nano audio is late (really late). I'm sure this is firmware fixable as Aja have nailed it. I'm not sure how difficult or time-consuming it would be.

Peter

Dan Keaton
August 25th, 2010, 06:14 AM
Dear Peter,

So, this is a very special case.

Your camera is set to 720p25, but putting out 720p60, and you need us to convert that to 720p25.

While we can currently convert and preserve the audio for:
720p60 to 720p30 and
720p50 to720p25,
we do not currently convert 720p60 to 720p25 and preserve the audio.

You are using our Over and Under-Cranking feature in order to convert the frame rate.

We may be able, in the future to preserve the audio in this specific case, but in general, attempting to preserve the audio for all frame rates during Over and Under-Cranking is a difficult task.

Could you please run at test using an audio cable from your camera to the nanoFlash analog audio input?

Steve Phillipps
September 4th, 2010, 02:18 AM
Any joy with this Peter?
Steve