Time code synching for HVX and separate audio system. at DVinfo.net

Stephen Pruitt · September 2nd, 2007, 07:58 AM

Hi all. . .

I'm thinking of taking the plunge and freeing my HVX from cables altogether by running with a separate audio system employing Sound Devices 442 and 744T units.

The 744T four track recorder generates all sorts of time codes, but I'm not certain of how I would initially synch the time codes for the HVX and the 744T and then let them both free-run for the rest of the batteries' lives.

Is this just "push start" at the same time, or can I use some other sort of mechanism to get it just right?

If the HVX had a time code in input, that would make it too easy.

Thanks very much.

Stephen

Steve Rosen · September 2nd, 2007, 09:24 AM

Stephen: I don't have it any more (it died), but a techno-friend modified an old wirless mike for me so that it sent camera timecode to the recorder (a Tascam HD P2)...

I found it easier, to be honest, to record a scratch track in the camera with the nose mike and line up the wave form in the timeline (I use FCP)..

Another way, sort of a combination of the above two, is to have the recorder send a wireless audio signal to the camera. That way you have useable audio in the camera but don't lose audio when the camera stops... Since the HVX records good quality audio, you can often depend on that and only use the double system audio for material not synced... and you always have the recorder audio available, which you can sync as above...

None of this sounds too sophisticated, I admit - but I'm an old film guy and timecode isn't all that important to me...

Dan Brockett · September 2nd, 2007, 10:02 AM

Hi Stephen:

Because the HVX is a prosumer sort of camera, it has no inputs or outputs for TC, other than Firewire. To my knowledge, there are no audio devices that can read Firewire TC.

My advice would be use a simple clapper board or if you want to get fancy, a TC slate. You can read about my experience in syncing multiple HVXs with a DEVA HDD recorder for a TV pilot I worked on here http://www.kenstone.net/fcp_homepage..._brockett.html

All the best,

Dan

Stephen Pruitt · September 2nd, 2007, 11:46 AM

Boy, this is depressing. . .

The reason I wanted to TC the HVX with the recorder was to eliminate the tremendous difficulty in lining up the audio tracks with the video tracks. What a mess that will be. . .

Any suggestions how to match the two up easily?

Thanks.

Stephen

Steve Rosen · September 2nd, 2007, 05:59 PM

Stephen: yeah, I mentioned it above.. the wave form of the audio will have very distinctive peaks and valleys, almost like finger prints, and all you have to do is lay the double system audio on a track below the one from the camera's nose mike, or wireless scratch track from the camera (knowing of course which scene you're working with) and slide the audio-only till it matches... Then delete the camera track...

It really isn't that difficult to "sync dailies".. TC isn't the end-all, in fact it can have problems of it's own, and your really screwed if you depend on it and it fails..

For 30 years, shooting documentaries on super16 film and recording audio on a Nagra, then transferring the audio to 16mm mag track, I was able to sync without the benefit of TC - sometimes without even the benefit of a slate.. I would look for a hard sound, like a "but" where I could clearly see the lips... And I'm talking documentaries where there're many hours of footage with lots of takes...

Don't worry, you don't have to be that primitive, but there are many ways around time code...

Also, it didn't occur to me that the HVX doesn't have TC out (in the wirless example above I was using a Canon XL H1), so you really are going to have to do it some other way.. but don't be depressed - it's filmmaking...

Chris Hocking · September 2nd, 2007, 06:55 PM

I've personally never tried it but this may be the answer you're looking for:

1. Get a standard wireless transmitter and receiver
2. Send time-code out of the 744 to the transmitter
3. Hook up the receiver to the HVX so that you record audio to the Left Channel

As a backup:

1. Get another standard wireless transmitter and reciever
2. Send a mono sum out of the 744 to the transmitter
3. Hook up the receiver to the HVX so that you have all the channels recorded to the right channel in case you have to manually sync up

Then when it comes to post, use this tool:

http://www.videotoolshed.com/?page=products&pID=26

I've downloaded the demo and had a quick play - it seems to do what it says.

However, that said, as others have suggested a Smart Slate would be the easiest and simplest method. As the HVX always records the on-board microphone as well on channels 3 + 4, you can always sync up by the sound waves should the slate fail.

You can get Time-code to LANC converters, so if you were recording to a Sony camera for example, you could do this relatively easily - however, the HVX doesn't have any "Aux Outs" that have time-code ability.

I hope this is of some help!

Chris!

Dan Brockett · September 3rd, 2007, 11:28 AM

Quote:

Originally Posted by Stephen Pruitt

Boy, this is depressing. . .

The reason I wanted to TC the HVX with the recorder was to eliminate the tremendous difficulty in lining up the audio tracks with the video tracks. What a mess that will be. . .

Any suggestions how to match the two up easily?

Thanks.

Stephen

Hi:

I agree with Steven, it's not really as big of a deal as you think it will be. If I can do it with three cameras rolling for around 8 hours a day for a week, I am sure you can do it too without too much trouble.

The keys are not starting and stopping the camera unnecessarily (each time you do, it requires another manual syncing up) and keeping VERY detailed and organized sound reports and slating each take.

If you are organized, it will be a minor inconvenience.

If you are disorganized, it will quickly become a nightmare.

The choice is yours.

Dan

Ryan Gardner · September 7th, 2007, 12:29 AM

Also, it helps to keep both devices running in Time-of-Day Timecode. This way you can slate randomly, when convenient, throughout the day to adjust for drift. Otherwise, you will easily be able to associate audio with video (by rough timecode comparison) and sync easily (after discovering the offset from each nearest slate take).

I am about to begin a 7 week project on the road and this is more or less the system I am using.

TingSern Wong · September 15th, 2007, 03:18 AM

I use the same "primitive" method to sync HVX202 and Sound Devices 722 recorder. No need for timecodes at all. Just align the peaks and valleys of the two WAV files and ... presto. Just make sure they are both set to 48Khz sampling frequency. The bits does not matter here. Although recording at 24 bits on 722 versus 16 bits on HVX202 - the dynamic range must be heard to be believed. Also, 24 bits recording makes a world of difference getting out the soft parts.

Peter Moretti · September 21st, 2007, 11:56 PM

Quote:

Originally Posted by TingSern Wong

... Just make sure they are both set to 48Khz sampling frequency. The bits does not matter here. Although recording at 24 bits on 722 versus 16 bits on HVX202 - the dynamic range must be heard to be believed. Also, 24 bits recording makes a world of difference getting out the soft parts.

He could also record w/o any additional problems at 96Khz, correct?

I'm glad to hear that 24-bit sound is worth the extra effort. I've been fighting to go with a double system (SD 302 and 702T), but have been getting a lot of flak about it: "16bit HVX sound is more than good enough."

TingSern Wong · September 22nd, 2007, 05:12 AM

Capturing sounds at 96K sampling rate means there are sounds at 48Khz to record. Even if there are, nobody will be able to hear them. For me, whether it is 96K or 48K - there is very little difference in the recorded sounds.

But, 24 bits versus 16 bits is a world of difference - especially when the sound is to be manipulated by a sound editor. There is so much headroom for you to play with. After you apply the filters, there is still no digital artifacts in a 24 bits sound.

Also, most of the live recordings are done without having the hindsight of how high the peak will go. So, I record on the "low" side - rather than to risk clipping the peaks (greater than 0dB). Once you lower the recording level, the limitation of 16 bits starts to show its head. There isn't much "data" at the lower volumes. If you capture at 24 bits, the amount of data that is still there at the equivalent lower levels of sound is startling.

I supposed the folks who tells you "16 bits is good enough" aren't sound engineers / sound editors to begin with.

September 2nd, 2007, 07:58 AM	#1
Stephen Pruitt Major Player Join Date: Aug 2006 Location: Overland Park, KS Posts: 228	Time code synching for HVX and separate audio system. Hi all. . . I'm thinking of taking the plunge and freeing my HVX from cables altogether by running with a separate audio system employing Sound Devices 442 and 744T units. The 744T four track recorder generates all sorts of time codes, but I'm not certain of how I would initially synch the time codes for the HVX and the 744T and then let them both free-run for the rest of the batteries' lives. Is this just "push start" at the same time, or can I use some other sort of mechanism to get it just right? If the HVX had a time code in input, that would make it too easy. Thanks very much. Stephen

September 2nd, 2007, 10:02 AM	#3
Dan Brockett Inner Circle Join Date: Feb 2006 Location: Los Angeles, California Posts: 2,109	No way Hi Stephen: Because the HVX is a prosumer sort of camera, it has no inputs or outputs for TC, other than Firewire. To my knowledge, there are no audio devices that can read Firewire TC. My advice would be use a simple clapper board or if you want to get fancy, a TC slate. You can read about my experience in syncing multiple HVXs with a DEVA HDD recorder for a TV pilot I worked on here http://www.kenstone.net/fcp_homepage..._brockett.html All the best, Dan

September 2nd, 2007, 09:24 AM	#2
Steve Rosen Major Player Join Date: Dec 2005 Location: Monterey, California Posts: 895	Stephen: I don't have it any more (it died), but a techno-friend modified an old wirless mike for me so that it sent camera timecode to the recorder (a Tascam HD P2)... I found it easier, to be honest, to record a scratch track in the camera with the nose mike and line up the wave form in the timeline (I use FCP).. Another way, sort of a combination of the above two, is to have the recorder send a wireless audio signal to the camera. That way you have useable audio in the camera but don't lose audio when the camera stops... Since the HVX records good quality audio, you can often depend on that and only use the double system audio for material not synced... and you always have the recorder audio available, which you can sync as above... None of this sounds too sophisticated, I admit - but I'm an old film guy and timecode isn't all that important to me...

September 2nd, 2007, 11:46 AM	#4
Stephen Pruitt Major Player Join Date: Aug 2006 Location: Overland Park, KS Posts: 228	Boy, this is depressing. . . The reason I wanted to TC the HVX with the recorder was to eliminate the tremendous difficulty in lining up the audio tracks with the video tracks. What a mess that will be. . . Any suggestions how to match the two up easily? Thanks. Stephen

September 2nd, 2007, 05:59 PM	#5
Steve Rosen Major Player Join Date: Dec 2005 Location: Monterey, California Posts: 895	Stephen: yeah, I mentioned it above.. the wave form of the audio will have very distinctive peaks and valleys, almost like finger prints, and all you have to do is lay the double system audio on a track below the one from the camera's nose mike, or wireless scratch track from the camera (knowing of course which scene you're working with) and slide the audio-only till it matches... Then delete the camera track... It really isn't that difficult to "sync dailies".. TC isn't the end-all, in fact it can have problems of it's own, and your really screwed if you depend on it and it fails.. For 30 years, shooting documentaries on super16 film and recording audio on a Nagra, then transferring the audio to 16mm mag track, I was able to sync without the benefit of TC - sometimes without even the benefit of a slate.. I would look for a hard sound, like a "but" where I could clearly see the lips... And I'm talking documentaries where there're many hours of footage with lots of takes... Don't worry, you don't have to be that primitive, but there are many ways around time code... Also, it didn't occur to me that the HVX doesn't have TC out (in the wirless example above I was using a Canon XL H1), so you really are going to have to do it some other way.. but don't be depressed - it's filmmaking...

September 2nd, 2007, 06:55 PM	#6
Chris Hocking Major Player Join Date: Dec 2005 Location: Melbourne, Australia Posts: 595	I've personally never tried it but this may be the answer you're looking for: 1. Get a standard wireless transmitter and receiver 2. Send time-code out of the 744 to the transmitter 3. Hook up the receiver to the HVX so that you record audio to the Left Channel As a backup: 1. Get another standard wireless transmitter and reciever 2. Send a mono sum out of the 744 to the transmitter 3. Hook up the receiver to the HVX so that you have all the channels recorded to the right channel in case you have to manually sync up Then when it comes to post, use this tool: http://www.videotoolshed.com/?page=products&pID=26 I've downloaded the demo and had a quick play - it seems to do what it says. However, that said, as others have suggested a Smart Slate would be the easiest and simplest method. As the HVX always records the on-board microphone as well on channels 3 + 4, you can always sync up by the sound waves should the slate fail. You can get Time-code to LANC converters, so if you were recording to a Sony camera for example, you could do this relatively easily - however, the HVX doesn't have any "Aux Outs" that have time-code ability. I hope this is of some help! Chris!

September 7th, 2007, 12:29 AM	#8
Ryan Gardner New Boot Join Date: Jul 2007 Location: Tampa, FL Posts: 8	Also, it helps to keep both devices running in Time-of-Day Timecode. This way you can slate randomly, when convenient, throughout the day to adjust for drift. Otherwise, you will easily be able to associate audio with video (by rough timecode comparison) and sync easily (after discovering the offset from each nearest slate take). I am about to begin a 7 week project on the road and this is more or less the system I am using.

September 15th, 2007, 03:18 AM	#9
TingSern Wong Major Player Join Date: Jan 2004 Location: Singapore, Rep of SINGAPORE Posts: 749	I use the same "primitive" method to sync HVX202 and Sound Devices 722 recorder. No need for timecodes at all. Just align the peaks and valleys of the two WAV files and ... presto. Just make sure they are both set to 48Khz sampling frequency. The bits does not matter here. Although recording at 24 bits on 722 versus 16 bits on HVX202 - the dynamic range must be heard to be believed. Also, 24 bits recording makes a world of difference getting out the soft parts.

September 22nd, 2007, 05:12 AM	#11
TingSern Wong Major Player Join Date: Jan 2004 Location: Singapore, Rep of SINGAPORE Posts: 749	Capturing sounds at 96K sampling rate means there are sounds at 48Khz to record. Even if there are, nobody will be able to hear them. For me, whether it is 96K or 48K - there is very little difference in the recorded sounds. But, 24 bits versus 16 bits is a world of difference - especially when the sound is to be manipulated by a sound editor. There is so much headroom for you to play with. After you apply the filters, there is still no digital artifacts in a 24 bits sound. Also, most of the live recordings are done without having the hindsight of how high the peak will go. So, I record on the "low" side - rather than to risk clipping the peaks (greater than 0dB). Once you lower the recording level, the limitation of 16 bits starts to show its head. There isn't much "data" at the lower volumes. If you capture at 24 bits, the amount of data that is still there at the equivalent lower levels of sound is startling. I supposed the folks who tells you "16 bits is good enough" aren't sound engineers / sound editors to begin with.