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Workflow questions (audio issues, resolution mis-matches, etc)
To begin – thanks for contributing to this forum. I’ve learned a lot by looking at your posts here.
I’ve been experimenting with FCP and shooting live music this summer, running into all kinds of roadblocks along the way. Cameras available to me are a few Canon HV21, a few FlipHD and occasionally two Canon XL1S. I record audio with nice mics and the SoundDevices 722.
In my mind I envisioned a peaceful coexistence of all these technologies. In reality, I learned this was far from the truth. Getting any of these devices to sync with each other in FCP is a very time-consuming task and one that I have not successfully achieved.
I come from a strong audio background so let’s start there. I have mistakenly recorded the SoundDevices unit at 44.1kHz. No matter how I upsample to 48k it never lines up with the video for more than a few minutes. Changing the playback speed to 99.999% doesn’t help this problem, either. In my next video effort I will be sure to set the SoundDevices unit to 48k…will that even help? Is this drift coming from the cameras or the incorrect audio sampling rate?
Mixed resolution video seems to force the lowest common denominator. If I were to combine the 3 cameras listed above, the LCD would be the SD video from the Canon XL1S. I’d like to be able to upload HD vids to the web so should I not use the XL1S cameras?
I’ll stop with the questions up to this point. I’m having other online/offline issues but have posted that question to an existing thread. Thanks again for contributing to this forum – I’ve already learned a lot!
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2 Replies
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You are correct about the 48kHz sample rate. You can use Soundtrack Pro or Quicktime Pro to open the 44.1 audio and export as 48. But, I think this is not alone causing your sync issue. I believe the 722 has a frame rate setting that should be matched exactly to the frame rate the cameras are using. The problem is your cameras may be shooting at different rates. For instance, the Flip may be shooting exactly 30fps while your video cams may be shooting 29.97 or 59.94. I’m not familiar with your cameras. You need to be sure of the frame rates. Now, if the Flip is the only one shooting true 30fps you can use Compressor to change its clip’s frame rate to 29.97 or whatever it needs to be. Once everything is consistent, you should be good to go.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 3 (FCP 7.0.2, Motion 4.0.2, Comp 3.5.2, DVDSP 4.2.2, Color 1.5.2)Pro Tools HD w SYNC IO & 192 Digital I/O, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN
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While the SoundDevices 722 does not support frame rates you can set the Record Sample Rate to some rather odd choices to this audio guy:
- 32k
- 44.1k
- 47.952k
- 47.952kF – file stamped at 48 kHz
- 48k
- 48.048k
- 48.048kF – file stamped at 48 kHz
- 88.2k
- 96k
- 96.096k
- 96.096kF – file stamped at 96 kHz
- 176.4k
- 192k
I’m assuming that these odd sampling frequencies are to help offset the decimal-heavy frame rates that you are talking about (29.97, etc).
The clip info in FCP for my clips are as follows:
Canon HV21: (.mov)
1440 x 1080, 29.97 fps, Apple ProRes 422 (transcoded upon L&T)
48 KHz 16-bit Integer audioFlip Ultra HD: (.mp4)
1280 x 720, 29.97 fps, H.264 (raw file from camera)
44.1 KHz, 32-bit Floating Point(I haven’t used the XL1S yet)
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