Re: 744 frame rate with canon 5d mark ii

My first quick sync test -

5D MkII running firmware v1.10
picture set to 1920x1080
788T recorder for sound @48 kHz
Ambient TC slate
audio and slate @ 30ND timecode
head and tail slate each take
longest take was 3 minutes

I'm no FCP/Avid Jedi, so if you see something in my tests below that sounds weird, please don't be shy. I'll take any guidance from those more knowledgeable. Here goes:

Its on-board audio is consistently one-frame behind picture. Better than most dedicated video cameras we have seen... I don't have any instrumented test of its own audio and these tests aren't looking at that.

It is running 30 FPS. A slate at the head and tail, plus the running numbers on the slate, shows it holds frame numbers properly at 30ND. If you build new sync picture/sound segments from dual-system elements first, from the original assets with sound files at 48 kHz, there shouldn't be any sync issues. If you then want to pull down the files or reverse telecine/conform, then picture and sound are both done simultaneously.

If you have a picture chain which is separate from sound and you don't want to edit and release at 30 frames, here is where pulling down audio and running an F mode on sound may be helpful.

Another test I did was to convert the H.264 picture files from the camera to Apple ProRes. I then pulled these 30 FPS down to 29.97, then I reverse-telecined them to 23.98. At this point, the picture is running slower than shot by 0.1%. Sound will now start pulling away from picture unless the sound is pulled down (via an F mode). This may start to be noticeable for longer shots. The camera's max video file length is 12 minutes.

I hope this helps.

Jon Tatooles
Sound Devices, LLC



Jon Tatooles wrote:
I'm bringing in a 5D II tomorrow, so we should have some more information on it soon. It's remarkable how many inquiries we are getting about audio with this camera, especially since its firmware 1.10 now allows for manual aperture and ISO.

Phil, in your scenario, are you transcoding the picture elements to 23.98? That seems to be what many productions are experimenting with, since the camera shoots at 30p and they want the 24p look. There are a few ways to get the picture elements to 23.98.

Jon Tatooles
Sound Devices, LLC


acmesound@xxxxxxxxx wrote:
On Jun 2, 8:34 am, philper <spami...@xxxxxxxxx> wrote:
On Jun 2, 1:45 am, acmeso...@xxxxxxxxx wrote:



Philip,
Can you explain further? It would appear that if the clip is brought
into a 30fps environment, being origionally 30fps, there would be no
speed change. Only in the output, if going to NTSC, would there be a
speed change. The output slowdown would also slowdown the audio
If however your project was set to 29.97ndf then the clip would be
slowed down and thus the 48.048 would make sense as audio would then
be slowed down to match the slowed down picture....
Eric
Why 48.048? Where is the pull down happening?
No point in being logical here, we tried every combo of SR and TC fps
possible and the
only one that worked with FCP 6 was 30/48.048. Why? Everyone has
their suspicions,
mine is that we are fooling FCP into doing what we want instead of
what it (erroneously)
thinks is the right thing to do. It seems to have to do with how FCP
interprets the metadata
on the audio file and what it then does with it. We have also had
success recording with
a non-TC file recorder @ 48k, then changing the SR metadata to 48.048
in Wave Agent. This
same file would not sync w/ the 5D footage with 48k metadata.

Philip Perkins

wierd!
.

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