Varicam sync issue

I've got a client who is shooting and editing in Varicam for the first time, having trouble during pre shoot testing with a 1 frame sync issue. I am by no means a varicam expert - in fact I'm a varicam baby - but they need help and I'm it.

The set up, AFAIK, is shooting 720p 24 (23.98), capturing via a AJHD 1400 and a blackmagic Decklink HD to a G5 with terrabytes of storage attached.

They are - wisely - trying to get the workflow right before they start shooting, but have apparently been on this for some time, and have managed to reduce the sync issue from 2 frames to 1, but can't get past this.

What possible problems should I look for? I figure on testing the imported quicktimes from the drive to see if they are in sync, but I haven't been onsite yet. They have the two extra downloads installed, and say that the camera is set up correctly to be 23.98. Eventually they want to go out to D5 for easy international HD/SD distrubution.

Is there a Blackmagic offset, or a FCP offset? Where can I find out what this should be?

cheers
Jude

When I was researching the Varicam workflow, before starting a short film last year, I seem to remember coming across a statement somewhere that Varicam sound was 3 frames off. We had recorded sound mixing directly to the camera and then downconverted to DVCam tapes (29.97fps, obviously), then captured at 29.97fps NDF and then reverse-telecined to 23.98fps for editing. When we made the OMF and delivered to a super-high-end sound facility, our contact at the facility told us the same thing, that the whole film was off by several frames (2-3), but he also told us the sync offset was pretty consistent and they fixed it easily.

I haven't worked with Varicam long enough to know whether we missed something, but is it possible that this is just a Varicam issue?


www.derekmok.com

>>is it possible that this is just a Varicam issue?<<

The more I read the more I'm starting to think that.

As an aside, I'm reading Andrew Balis' article on the varicam workflow and he says

". . . we brought in the footage into Final Cut at full recorded quality, working with the format in its native resolution. The media files were somewhat small and had low data rates, around 5.5Mb/sec for 24p, so there was easily enough room . . ."

So - he's saying that he can get in, via firewire, at a rate of 5.5Mb/sec footage that is exactly the same as the 100Mb/sec uncomrpessed stuff?

I don't get it. How can it be the same? I really want to get it though! Is it really as good as uncompressed via decklink HD, for eg? Could it go out to D5 looking just as good? Where did the other 94.5Mb/sec of data go?

First off, it is true. Every bit of footage I captured from the Varicam tapes, whether it be from the 1200 or the 1400...is 2 frames off sync. Audio is ahead of video by two frames. I slip the audio after I drop it into the timeline. Yes, it is a pain, but, it has to be done. I once captured 3 tapes with my laptop and all three tapes were 8 frames off. That was even more painful.

So - he's saying that he can get in, via firewire, at a rate of 5.5Mb/sec footage that is exactly the same as the 100Mb/sec uncomrpessed stuff?

YOu are getting 100megaBITS per second and 5.5 megaBYTES per second mixed up. I don't know the math, but DVCPRO HD is a 100Mb/s format (MegaBITS) which translates to about 6MB/s (MegaBYTES) for 720p24 at 23.98. Which makes this format very attractive. I get 6MB/s. DV is 3.5MB/s. DVCPRO HD 720p60 is 20MB/s.


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Thanks guys, and I'm going to add my vote to the 'that just happens with varicam' sync issue. Two frames in front of the audio.

On another note - even though I had all the settings matching, I could not for the life of me get FCP to capture at 23.98. It still says 59.98 in the video column and needs rendering when it hits the timeline. I thought maybe the internally generated bars were fooling FCP into thinking the whole clip was 60, but even when I started a capture way into the 24p test clip, it stayed 60. Any ideas?

There is an issue with the camera - it has been sent away for repairs because it is causing a hum, but I have no idea is this is related, or if I'm just missing something simple.

BTW - we are now capturing via firewire and it's all good. Lovely codec. So thanks for the maths lesson, Shane

Just to add to Jude and Shane's comments- I agree with Shane. The confusion over MBytes/sec vs Mbit/sec does seem to snag a lot of people. A bit is 8 bytes. So if you have a format at 25 MBit/sec like DV, then the rate is around 3 MBytes/sec. With DVCPRO HD, we have to remember that 100 Mbit is what is possible with that format, but not the bit rate for every DVCPRO HD format. 720p24 will have a lower bit rate than 1080p24 or 1080i60.

Also, when capturing through a capture card, then the video is brought in uncompressed, which is way beyond the bit rate of the format. These rates can run around anywher from around 60 MBytes/sec up to 150 MBytes/sec. What's the advantage- its not like the footage will look better- but it does make manipulation of the footage easier in post (like chroma-keying). As well as it allows for direct output to a higher-end deck than DVCPRO HD.

BTW- I wrote out Mbps as Mbit/sec and MBps as MByte/sec to try and lessen the confusion of what's being discussed.

Hope this adds a little something postive to the discussion.

Andrew Balis
Lead Final Cut Pro Instructor
www.moviola.com

Is the footage ultra smooth? Because the camera sets the flags in the footage. If the camera shot 24p, then the footage was flagged as such and pulldown will be removed. 60p, then 59.94. What does the footage look like?


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I said 1 bit = 8 bytes.

I meant to say 8 bits = 1 byte

>>Is the footage ultra smooth? Because the camera sets the flags in the footage. If the camera shot 24p, then the footage was flagged as such and pulldown will be removed. 60p, then 59.94. What does the footage look like?<<

The footage does look smooth, but, in comparison to what? I'm not sure how it should look, so I can't tell if it's overly clean. My test footage was only bars, a clapper and a short location interview. No fast moving camera or images. Unless you count the clapper, I guess.. I could look at that..

In the browser, in the video rate column, it says 59.94 against all my test captures. The sequence reads 23.98. Any test footage dropped into the sequence requires rendering. Is it normal for the video rate to show as 59.94, and the frames are removed fromthat, or should the video rate column show 23.98?

It feels like the extra frames are not being removed, although I have the checkbox for removing them set to do so. Am I on the right track, do you reckon?

>>As well as it allows for direct output to a higher-end deck than DVCPRO HD.<<

So does that mean that if I capture via firewire we can't go out to a D5 in the end? Not that we have a D5 onsite, it will have to be transported to another facility somehow, but am I restricting the output by choosing firewire in?

Thanks for the support, guys.

> The footage does look smooth, but, in comparison
> to what? I'm not sure how it should look, so I
> can't tell if it's overly clean.

Does it look like interlaced video...like the news or old soap operas...or does it have a film like cadence? Gah...I should post examples of both so you can see. But I can't today.

>
> In the browser, in the video rate column, it says
> 59.94 against all my test captures. The sequence
> reads 23.98. Any test footage dropped into the
> sequence requires rendering.

Of course...because the footage is 59.94, not 23.98. Different frame rate, so it will require rendering. You of all people should know better. OH...here's a test. After you render does it look the same? or more "stuttery?" Because I mix footage shot 60p at 59.94 (intended for slo-motion) with 23.98 footage by just dropping it in and rendering. Then it looks less like video and more like film.

>Is it normal for the
> video rate to show as 59.94, and the frames are
> removed fromthat, or should the video rate column
> show 23.98?

If the pulldown was removed when captured then it would show up as 23.98. The compressor is still 720p60. Sounds like the camera wasn't set to 720p24.

>
> It feels like the extra frames are not being
> removed, although I have the checkbox for removing
> them set to do so. Am I on the right track, do you
> reckon?

Just because you checked the box to remove them, if the footage hasn't been flagged as 720p24 by the camera, the frames will not be removed. The frame rate is dictated by the camera. If it is set to 720p60, then it will capture at 59.94. If 720p30, then 29.97...720p24, then 23.98. The camera sets "flags" on the tape to dictate how FCP will capture it. So even if you have your settings set to 720p24 DVCPRO HD, if the footage is 720p60, it will capture this as 59.94. No flags, FCP will not remove nothin'!
>
> >>As well as it allows for direct output to a
> higher-end deck than DVCPRO HD.<<

What was this question? If you have a capture card, you can output to HD tape. Depending on the card, you can output a variety of ways. The Kona 3 will cross convert 720p24 to 1080p 23.98, or even make 720p 59.94 to 1080p 23.98. Or output 720p23.98 to 720p 59.94. But the Kona LH does that too. It will also downconvert...and convert to any broadcast frame rate.
>
> So does that mean that if I capture via firewire
> we can't go out to a D5 in the end? Not that we
> have a D5 onsite, it will have to be transported
> to another facility somehow, but am I restricting
> the output by choosing firewire in?

Noooo. I capture via firewire and output to D5. The capture card converts the frame rate.
>
> Thanks for the support, guys.

No prob gal.


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Thank you for three things here Shane

1. I think this is a camera issue. As far as I can see, everything in post is set up correctly. The camera has been sent back to Panasonic, who are are hunting for a 'demo' to lend us while the insurance company begins crying, since a tech confirmed the brand new camera is faulty.

So your confirmation that the camera is possibly not flagging correctly, or not set to flag correctly, helps a lot. The slate says 24p, but that's not how it operates when I get it.

2. Confirmation that we can go out to D5 with the workflow, since everyone here has only just come around to 24p via firewire as a good thing, and I would hate to have to take it all back, and freak people out.

3. The tip on LF in HD about opening a new project for using the DVCPRO HD framerate convertor. One of the things that got said in passing yesterday was, 'and the framerate convertor doesn't work for some reason..' So this is going to make everyone very happy to hear.

I'm poring over Little Frog today, and since I now know the meaning of that, you might be pleased to hear that it's an almost entirely indigenous production that you're helping me with.

Glad to help you Jude.

Yeah, I capture Varicam via firewire, and we output to D5 via the Kona 3 at the DR Group here in town. After I add the sound tracks that are AIFF files exported from ProTools by the mixer. Rather slick workflow I have going.

And that DVCPRO HD frame rate converter tip is useful. Gladd the guy who told me about it figured it out.


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By the way, thanks for your excellent workflow tutorial, Andrew. I'll link it here for future readers

Panasonic HD and FCP HD

The screenshots especially got me through some dark points.

Just curious, jumping in on the end of the discussion, but: why shoot on Varicam in the first place if all the footage is at the same frame rate?? Much easier and no synch problems to shoot HDCam, and import it via HD/SDI to whatever you want to work in (i.e. DVCProHD) on the fly. A $600 capture card will do the trick with multiple tracks of audio.

I'm a big Varicam fan, but only when off-speed shots are required. Otherwise, HDCam is a whole lot more straightforward.

Just a thought for you.

Clay

ClayC Wrote:
-------------------------------------------------------
> Just curious, jumping in on the end of the
> discussion, but: why shoot on Varicam in the first
> place if all the footage is at the same frame
> rate?? Much easier and no synch problems to shoot
> HDCam, and import it via HD/SDI to whatever you
> want to work in (i.e. DVCProHD) on the fly. A
> $600 capture card will do the trick with multiple
> tracks of audio.

Simple. Cost.
- A weekly rental of a Varicam package is less than that of an F900 or F950.
-Storage. DVCPRO HD takes up less space than Uncompressed HD, which is what you'd have to capture HDCAM as if you want to reap the benefit. If you capture at DVCPRO HD, what was the point of shooting HDCAM in the first place?
-Time. If you have to mess with the offline/online cut, then you are open to timecode slippage...and it just takes longer to do as you have to recapture, and again it costs more because it means renting the deck AGAIN at $1000 a day. With Varicam, there is no offline/online. You capture at full res...edit at full res, output to D5 or HDCAM at full res

>
> I'm a big Varicam fan, but only when off-speed
> shots are required. Otherwise, HDCam is a whole
> lot more straightforward.

I haven't worked with HDCAM footage yet, but I'll have to disagree. Unless you can capture at full res, then it isn't as straightforward as DVCPRO HD. Yes, you'll wind up with a superior image, there is no denying that. But the cost increase is too much for the shows I work on. We barely get by with Varicam as it stands. Because network specs have changed to require HD shows, but budgets have BARELY increased to cover the increased cost HD has.


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All that, and also off-speed shots are required.

Shane,

Understand what you're saying. However, in my neck of the woods, the camera rental price is only nominally different. On a weekly or longer basis, negotiable to the same.

If you capture from HDCam to DVCProHD, then you can use the small Sony JH series player (again, only slightly more than the small DVCProHD deck), connect via one BNC cable from the deck to the player to a basic HD capture card, hit capture now and go. Or use a 9 Pin remote cable if you need/want device control. The advantage to bringing it down to DVCProHD is lower data rates and far less storage required. Yes, the image quality takes a hit, but if the final output is only broadcast or DVD, then imho still very good.

At the end of the day, I play out to file, send it over to a post house on an external drive, and let them pull the broadcast master. Far less expensive than mastering myself on either the HDCam or DVCProHD decks.

Since off-speed shots are required, all a moot point though. In that case then it's VariCam. For best results (smoothest motion, best quality) I always use the FRC-27, which adds cost but is in my experience far more reliable and thus ultimately faster.

Clay