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Jerky/Sticky footage with Blackmagic Pocket Cinema Camera

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Mike Laloe
Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 15, 2014 at 11:46:42 am

Hi,

I'm getting jerky, stuttery footage when filming on the Blackmagic Pocket Cinema Camera - even when on a tripod.

I'm using the recommended media card so I'm sure it isn't the speed of the card. At first I thought it was my playback in Premiere but it's there even when rendered out.

I've checked the original files and transcoded them in case it's a codec thing but no luck.

Does anyone know if:

1) There's any way of sorting this?
2) If there's a way of smoothing of sticky/jerky footage in post e.g. After Effects?

Many thanks in advance for any help!

Mike.


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John Fishback
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 17, 2014 at 9:29:48 pm

What codec are you using? What frame rate?


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Mike Laloe
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 18, 2014 at 10:01:38 am

Thanks for responding - it's Apple Pro Res HQ - frame rate 25.

Here's the properties blurb...

File Path: G:\Berkut\BERKUT Black Magic\Blackmagic Pocket Cinema Camera_1_2013-07-14_1812_C0000.mov
Type: QuickTime Movie
File Size: 63.5 MB
Image Size: 1920 x 1080
Frame Rate: 25.00
Source Audio Format: 48000 Hz - 24 bit - Stereo
Project Audio Format: 48000 Hz - 32 bit floating point - Stereo
Total Duration: 00:00:05:01
Pixel Aspect Ratio: 1.0

QuickTime Details:
Movie contains 1 video track(s), 1 audio track(s) and 1 timecode track(s).

Video:
There are 126 frames with a duration of 1/25th.

Video track 1:
Duration is 0:00:05:01
Average frame rate is 25.00 fps

Video track 1 contains 1 type(s) of video data:

Video data block #1:
Frame Size = 1920 x 1080
Compressor = Apple ProRes 422 (HQ)
Quality = Most (5.00)

Timecode:
Timecode track 1 contains 1 type(s) of data:

Timecode data block #1:
Start Time = 18:12:08:00
Reel name =


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John Fishback
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 18, 2014 at 7:25:45 pm

Is the camera moving or panning while you see the stutter? Does it appear most on vertical edges? If so, this may be normal. A fast pan will result in stutter. The American Cinematographer Manual has charts that show the max speed you can pan through a given angle without stutter. If the camera is stationary, then something odd is happening. What shutter angle are you using? I'm not sure, but that might have an effect if the camera's panning.


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Mike Laloe
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 18, 2014 at 8:20:13 pm

Thanks for your posting - no the camera was stationery and on a tripod but the subjects arms were moving. I'm not 100% sure about the shutter angle but I think it was 180. I'm starting to think it might be a problem with the memory card. It's the recommended one but maybe it's just playing up?


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John Fishback
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 18, 2014 at 8:52:43 pm

Do you see the effect just on the arms? if so, their speed might cause the stutter. It's about the relative movement between camera and subject. It's also possible the stutter might be an artifact caused by rolling shutter. Here's an article rolling shutter from wikipedia: http://en.wikipedia.org/wiki/Rolling_shutter.

John

MacPro 8-core 2.8GHz, 16 GB RAM, OS 10.9.4, QT10.1, Kona 3, Dual Cinema 23, ATI Radeon HD 5870, 24" TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCP-X 10.1.3, Motion 5.0.7, Compressor 4.0.7
FCS 3 (FCP 7.0.3, Motion 4.0.3, Comp 3.5.3, DVDSP 4.2.2, Color 1.5.3)

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Roger Poole
Re: Jerky/Sticky footage with Blackmagic Pocket Cinema Camera
on Nov 20, 2014 at 1:38:55 pm

Your shutter speed needs to be at least X2 your frame rate. 25fps - 1/50th or more. This will impact the exposure but the footage should be smooth.


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