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Old October 18th, 2011, 01:44 PM   #1
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Compact digital recorder that doesn't lose sync?

I have a Zoom H1 and an H2. As many people know, both of them lose sync over time. So what other recorders in that price range and quality are available that maintain perfect sync?
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Old October 18th, 2011, 02:22 PM   #2
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Re: Compact digital recorder that doesn't lose sync?

The only way they can maintain "perfect" sync is to have a sync or timecode input. That isn't going to happen in the Zoom H2 price range.
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Old October 18th, 2011, 02:54 PM   #3
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Re: Compact digital recorder that doesn't lose sync?

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Originally Posted by Sebastian Alvarez View Post
I have a Zoom H1 and an H2. As many people know, both of them lose sync over time. So what other recorders in that price range and quality are available that maintain perfect sync?
There aren't any devices that meet your specifications.

Drift is a fact of life. Perfect doesn't exist. And even if you could find a "perfect" audio recorder, you'd pair it with an imperfect video capture. This situation is exactly why time code was invented. With time code you have a single master to which all other devices must sync. Works like a charm, but isn't cheap.
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Old October 18th, 2011, 03:23 PM   #4
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Re: Compact digital recorder that doesn't lose sync?

Sound Devices 700 series with timecode - but not in your price range.

Cheaper - Fostex FR-2 with timecode board (NB: not the FR-2LE).
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Old October 18th, 2011, 04:14 PM   #5
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Re: Compact digital recorder that doesn't lose sync?

Cheaper still - Tascam HD-P2, with a video sync input that can take composite and lock clock to it. But that is, I think, the least expensive device with sync.
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Old October 18th, 2011, 04:58 PM   #6
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Re: Compact digital recorder that doesn't lose sync?

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With time code you have a single master to which all other devices must sync. Works like a charm, but isn't cheap.
So I guess that single master is a device that generates a timecode and the other devices, both camera and audio recorder, have to be capable of synchronizing with that master device, right? Can that be done wirelessly, or is it always with cables?
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Old October 18th, 2011, 05:25 PM   #7
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Re: Compact digital recorder that doesn't lose sync?

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So I guess that single master is a device that generates a timecode and the other devices, both camera and audio recorder, have to be capable of synchronizing with that master device, right? Can that be done wirelessly, or is it always with cables?
That is done with cables. Timecode in video and file-based audio does not provide a sync reference for speed so while it will provides a single reference point (just like a slate) so you can aligm the files it does nothing to prevent drift over the duration of longer shots To prevent drift you need to slave both the audio and video sample cocks to a common timebase. Your camera must have a sync output or a genlock input. You audio record must have a wordclock intput. The master clock provides the clocking signal to both. It provides a common time signal in two flavours - blackburst or tri-level sync to slave the video camera sample clock to and wordclock to slave the audio device sample clock. You can also get an audio recorder that accepts video from the camera and slaves its sample clock to it, but none of those are even close to the budget limit you expressed. Good examples are the Sound Devices 788t at about $6500 and I believe the NagraVI at about $9 grand. The Tascam HD=P2 is a lot less, $1000, and it does have video sync BUT I've heard that it only works if the recorder is also receving timecode - I haven't been able to verify that but until you check it out thoroughly take the claim of sync to video blackburst with a grain of salt.
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Old October 18th, 2011, 05:35 PM   #8
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Re: Compact digital recorder that doesn't lose sync?

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You can also get an audio recorder that accepts video from the camera and slaves its sample clock to it, but none of those are even close to the budget limit you expressed. Good examples are the Sound Devices 788t at about $6500 and I believe the NagraVI at about $9 grand.
Ouch. So I guess I'll keep on relying on my good human ear for the time being. I don't know if anyone knows this, but which NLE does a better job at shrinking or stretching audio between Vegas and Edius? I use Edius for everything, but I also have Vegas, so if necessary I can process the audio from the recorder there and then importing it into Edius.
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Old October 18th, 2011, 06:11 PM   #9
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Re: Compact digital recorder that doesn't lose sync?

Hi Sebastian,

I've got a Sony PCM-D50 that I use for long recordings of stage shows. I edit in Vegas Pro. The D50 is pretty reliable at drifting 3 frames per hour slower than my Sony EX3. In vegas it is simple to do a very minor stretch to make them sync back up.

-Garrett
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Old October 18th, 2011, 06:32 PM   #10
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Re: Compact digital recorder that doesn't lose sync?

Thanks, Garrett. I think it's also a matter of how the different NLEs read the wav files. I imported the files into Vegas 10 to do the stretching to match perfectly, but it doesn't sync in Edius 6. If I sync them at the beginning, after 20 minutes or so they are out of sync by a few frames. But in Vegas they stay sync'ed from start to finish.
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Old October 19th, 2011, 02:40 AM   #11
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Re: Compact digital recorder that doesn't lose sync?

Quote:
Originally Posted by Steve House View Post
That is done with cables. Timecode in video and file-based audio does not provide a sync reference for speed so while it will provides a single reference point (just like a slate) so you can aligm the files it does nothing to prevent drift over the duration of longer shots To prevent drift you need to slave both the audio and video sample cocks to a common timebase. Your camera must have a sync output or a genlock input. You audio record must have a wordclock intput. The master clock provides the clocking signal to both. It provides a common time signal in two flavours - blackburst or tri-level sync to slave the video camera sample clock to and wordclock to slave the audio device sample clock. You can also get an audio recorder that accepts video from the camera and slaves its sample clock to it, but none of those are even close to the budget limit you expressed. Good examples are the Sound Devices 788t at about $6500 and I believe the NagraVI at about $9 grand. The Tascam HD=P2 is a lot less, $1000, and it does have video sync BUT I've heard that it only works if the recorder is also receving timecode - I haven't been able to verify that but until you check it out thoroughly take the claim of sync to video blackburst with a grain of salt.
When I said Sound Devices 700 series I was thinking more of the 702T which is about £1,599 +VAT in the UK (Canford Audio).

(Though I use the Nagra VI myself).
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Old October 19th, 2011, 05:27 AM   #12
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Re: Compact digital recorder that doesn't lose sync?

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Originally Posted by John Willett View Post
When I said Sound Devices 700 series I was thinking more of the 702T which is about £1,599 +VAT in the UK (Canford Audio).

(Though I use the Nagra VI myself).
Was looking for those recorders that have a provision to slave the audio sample clock to incoming video, blackburst or tri-level signals. The 702t/744t series don't have a video sync input, while the 788t does and can accept video blackburst or genlock as an external sync source. The 702/744 do have external timecode input, of course, but according to an email I received from SD a few years ago, they don't slave their audio sample clock rate to the incoming timecode's embedded clock as it's not sufficiently accurate.

Is my memory correct in that the Nagra does sync up to composite video?
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Old October 19th, 2011, 11:15 AM   #13
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Re: Compact digital recorder that doesn't lose sync?

IME, "adjusting" (shrinking or stretching) the audio track(s) should be avoided. It is MUCH easier to "pull up" the video to match the audio. Anywhere you make a video transition is a completely seamless opportunity to do a slight correction at that point.

I lay in the audio track (after mixing/editing if that is your work-flow) and use that as the MASTER reference in the video editor timeline. Then I drop in the video clips and align them with the reference audio track. There are commercial products like "PluralEyes" which do this alignment automatically for you. Singular Software - PluralEyes
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Old October 19th, 2011, 11:45 AM   #14
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Re: Compact digital recorder that doesn't lose sync?

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Originally Posted by Richard Crowley View Post
IME, "adjusting" (shrinking or stretching) the audio track(s) should be avoided. It is MUCH easier to "pull up" the video to match the audio. Anywhere you make a video transition is a completely seamless opportunity to do a slight correction at that point.

I lay in the audio track (after mixing/editing if that is your work-flow) and use that as the MASTER reference in the video editor timeline. Then I drop in the video clips and align them with the reference audio track. There are commercial products like "PluralEyes" which do this alignment automatically for you. Singular Software - PluralEyes
Richard,

Not sure what you mean by "pull up" the video but I'm curious as to why you would rather play with your video playback rate rather than the audio. Whenever you adjust the frame rate of the video you can experience many more problems with artifacts. You also are forcing the video to rerender every frame. So if you do happen to shoot and capture in a codec that is for final delivery you are needlessly adding to the processing time.

I would agree that if you do have a cut in your video you could cut the audio and make a slight adjustment to the audio track placement. In fact that's one of the reasons why I set up my dance show videos to cut out the dead time between numbers. But for things like ballet performances and plays where you can't make those cuts you have to stretch or shrink either video or audio. In my experience it's better to adjust the audio as it isn't noticeable whereas I have seen some really strange artifacts pop up in the video when trying to adjust by only a few frames over an hour.

-Garrett
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Old October 19th, 2011, 11:50 AM   #15
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Re: Compact digital recorder that doesn't lose sync?

One other thing I forgot to mention. Video should only be adjusted by whole frames. In other words, don't adjust a 24 second video shot in 24p by 1.5 seconds. You have to adjust by 1 or 2 seconds or you will see some really unwanted results. You can however adjust the audio by any length without the same nasty effects.

-Garrett
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