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Choppy video with DSLR

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Alberto Bedin
Choppy video with DSLR
on Aug 24, 2013 at 3:06:30 pm

My videos recorded using DSLR are choppy when I right/left move the camera on a tripod (also a Manfrotto fluid Video Head 500AH).

This is a sample:
https://www.dropbox.com/s/ck02kke66d5musf/video_pan.zip

The sample has been recorded using a Nikon D4. I have the same problem with a Nikon D7000.

It looks like the image is... I don't know... flickering, flashing on the screen.

It happens always, even on sunlight.

I am able to reduce the problem, recording at 720p 30fps.

At 1024p 24fps the result is awful. Same at 25fps. 1024p 30fps is still bad.

I am sure this is not a playback problem because I tried to watch the video both on my desktop PC (i7, GeForce 570, 6GB Ram, SSD) and on my notebook (MacBook Air 13').

So my questions are:

1) Should I pan slower?

2) Have you ever encountered similar problems?

3) Please could you try to upload a small unedited 24fps 1080 pan video recorded with your DSLR?


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Steve Crow
Re: Choppy video with DSLR
on Aug 24, 2013 at 7:11:50 pm

The first thing I would check out is your shutter speed - are you keep it at 2x your frames per second or about 1/50th (1/48th in most cases) per second? You mentioned daylight shooting which made me wonder if you are trying to use the high shutter speed to cut down the light.

Steve Crow
Crow Digital Media
http://www.CrowDigitalMedia.com


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Alberto Bedin
Re: Choppy video with DSLR
on Aug 25, 2013 at 1:33:58 pm

Thank you for you reply.

Of course shutter speed is 1/60 for 30fps and 1/50 for 24fps and 25fps, I never use different settings.

I also tried to use 1/30s to obtain smoother frames but nothing change.

Have you ever had the same problem?


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Rob Manning
Re: Choppy video with DSLR
on Aug 25, 2013 at 5:37:10 pm

Hi Alberto,

I played the video back with WMP then loaded it into GoPro Studio, it plays fine in these.

Loading it with VLC did have the choppiness you are concerned about.

Technique-wise, the camera movment could be shot more slowly simply as a matter of good practices (for jello) but it did play back OK as noted.

Nikon (I don't own Canon to verify) has a set shutter speed for frame capture which is only changed in the Movie Settings.

That means when one changes the shutter before shooting (D7K) or during (D4/D800/D7100 etc.) the exposure is adjusted, not the actual frame rate of the capture.

This is easy to find by changing the speed during or before record, then reading the file data (properties) of the clip in Premiere or another NLE.

This is your file:

File Size: 40.6 MB
Image Size: 1920 x 1080
Frame Rate: 29.97
Source Audio Format: 48000 Hz - 16 bit - Stereo
Project Audio Format: 48000 Hz - 32 bit floating point - Stereo
Total Duration: 00:00:14:24
Pixel Aspect Ratio: 1.0

Video playback (generally) would be best when playing (storing) the files from a secondary drive and not the 'C' drive even with the Nvidia and SSD although your clip is short and should not be at issue.

(Flickering) The D7000 should be shot in Manual with Device Control on in the HDMI settings otherwise contrast detection (used for focus in Video) will change if say someone walks through the shot with a dark shirt or light shirt. Footage will brighten or darken and can only be fixed in post frame by frame which is a nightmare.

This can be exacerbated when using a variable f/stop zoom lens.

The D4 is a stellar camera but best practice is shooting in manual on that as well.

I have the D800 (stills/video) and a D7000, plus the D3S for non flash venue shooting.

(note) I just moved the clip to a render/edit drive and it played fine with VLC then played from the C drive (desktop stored) and VLC is choppy.

TMI or HTHs,

Rob Manning


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Alberto Bedin
Re: Choppy video with DSLR
on Aug 26, 2013 at 10:02:27 am

Thank you for you reply. I always shot in Manual btw :)

Before posting it, I tried to play it back using VLC in Windows and and QuickTime on Mac. Both were choppy. The Mac has a SSD and from windows I tried from an SSD and from a 7200rpm disk.

Is it really smooth on Windows with WMP? I will try, it is quite unbelievable for me!

Any other playback feedback from different systems?


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Bill Bruner
Re: Choppy video with DSLR
on Aug 26, 2013 at 12:05:12 pm

Alberto, I can confirm Rob's findings. The pan is perfectly smooth in WMP and choppy in QT (I played it in both). Looks like it's your render that is the problem, not the camera.

What format and bit rate did you render to?

Cheers,

Bill
Hybrid Camera Revolution


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Alberto Bedin
Re: Choppy video with DSLR
on Aug 26, 2013 at 3:50:33 pm

The video was not rendered.

It was extracted in that format from the camera (D4).

I tried with WMP and it is less choppy than with VLC and QT, but it is still a bit choppy. I tried on both SSD and WD 10000rpm disk


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Rob Manning
Re: Choppy video with DSLR
on Aug 26, 2013 at 10:37:43 pm

Is 6GB of RAM enough? General question for the thread.


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Alberto Bedin
Re: Choppy video with DSLR
on Aug 27, 2013 at 11:04:41 am

I think that RAM amount does not affect playback


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Rob Manning
Re: Choppy video with DSLR
on Aug 28, 2013 at 12:24:59 am

I know, it is just a bit odd.

There was a time when the codec/wrapper for DSLR video, taxed the system when played as h.264 out of the camera.

There are varying opinions these days because the GPU and multi-core CPUs have changed that but, have you tried transcoding the footage using Premiere, or whichever NLE is the platform in your system?

I habitually transcode project (to be published) footage using CineForm (GoPro) which increases the file size, but is less taxing on my now three year old core-duo laptop during editing.

It would be interesting in your case to see if that makes a difference although the specs you have on the desktop should be fine without transcodeing.


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Alberto Bedin
Re: Choppy video with DSLR
on Aug 29, 2013 at 5:20:57 pm

Thank you for your suggest.

I have just tried to render it as .mov QT, as H264 and as uncompressed avi, using Premiere.

In all cases I had the same output result.

I am sure that this is not a playback/codec problem but a source file problem.

Have you got any pan captured with your reflex? I would expect the same result...


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