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1080p doesn't look smooth.. help?

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Roberto Etcheverry
1080p doesn't look smooth.. help?
on Feb 10, 2010 at 9:42:04 pm

Greetings.

Not too long ago my boss bought a Canon EOS 5D camera to start shooting in 1080p, our previous hdv experience was limited to 1080i sony cameras. We did a couple of commercials with it, mainly with static shots with people talking to the camera.

Later he has done some aerial and free hand (is that how you say it in english?) shots with it, and we've noticed a little "choppyness" on it, specially in areas with lots of movement (like near the borders of the screen on a travelling shot).

The footage looks good on the monitors (camera, computer, etc), but it's very noticeable when we look it trough the plasma monitor hooked to the imac with final cut pro.

Some tech specs:

- Using Final Cut Pro 7 on an iMac Core2 Duo 2.8 with 2 gigs of RAM.
- Video output with a panasonic plasma screen trough DVI output, 848x480 resolution and using Digital Cinema Desktop - Full Screen on Final Cut Pro.
- Video shot with a Canon EOS 5d in 1080p, converted to proress 4:2:2 codec using compressor to work in final cut pro.

Any sugestions?... or maybe we're just too used to the extra fields we get with 1080i and that's how 1080p is supposed to look like?


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Micah McDowell
Re: 1080p doesn't look smooth.. help?
on Feb 10, 2010 at 10:37:39 pm

You may be noticing rolling shutter artifacts... http://en.wikipedia.org/wiki/Rolling_shutter

This is a problem with all the video DSLRs as far as I know. They can give great results when locked down on a tripod, but with fast uneven motion (like the aerial and hand-held shots you mentioned) it can make it add a wobbling or distorted effect that could appear "choppy". It's not to say that you can't get great results out of these cameras, but you have to be cautious and know the limitations.

Of course, you may have a different issue, but this is a possibility.


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Lance Bachelder
Re: 1080p doesn't look smooth.. help?
on Feb 10, 2010 at 10:43:01 pm

Why the lower rez output thru plasma? Did you try setting up as 1080p output? Also you may want to burn a DVD or Bluray and view that on separate system.

Lance Bachelder
Southern California



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Norman Pogson
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 1:43:39 am

How about hooking the camera directly to the plasma and viewing the file direct from the memory card with either the supplied rca lead or get a HDMI and see if it plays smooth.

2gigs of RAM seems small these days for large video files, I have 4gigs and that seems not enough, I notice the newer Macs have 8gb of Ram

My Canon 7D Blog


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Jonathan Ziegler
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 1:53:01 am

Sounds like rolling shutter. No sudden movements with the camera or you will get weird artifacts (may not be the right word). Can you post the offending footage?


Jonathan Ziegler
http://www.electrictiger.com/
520-360-8293


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Terry Tsangaris
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 4:43:14 am

Any Footage shot in HD,HDV,or FULL-HD video format there is a choice to record in either i,interlaced or p,progressive scan.
Interlaced is used in older T.V. sets including acquisition for home or production houses through to transmitting for T.V. stations in standard definition 4.3 - 16.9 aspect ratio (2 fields per frame x 30 per second = 60 fields).
Progressive scan is selected for HD acquisition to provide a film look and also get Higher resolution best result for any work.
You can choose Interlaced in HD but you will get slightly lower res.
Choose the correct acquisition to suit you or your clients needs.

I believe with today's top non linear systems you can choose to convert from one to the other.

Happy snapping with your DSLR

Terry


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Ryan Orr
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 2:01:17 pm

Hmmm...I have a sneaky suspicion that this "choppiness" you are experiencing is due to using a really high shutter speed with the progressive frame rate. What was your shutter speed at the time of the aerial shots? If you are shooting at 24p, your shutter should be as close to 1/48 shutter speed as possible. 25p would need 1/50, and 30p would need around 1/60 shutter speed. The whole 180degree rule of thumb for film would apply here.

Although it's entirely possible that it could be the global shutter (did the video have a "jello-ey" look to it?), I more-so suspect it's the choppiness that is inherent when shooting progressively. Your first few shots with the 5D was on a tripod and static. The aerial shots were hand held and in the air? This is kinda giving me a clue on the high shutter speed error some ppl experience.

But the other suggestions of hooking up the 5D right to a 1080p HD television via the HDMI cable or burning the footage straight to a blueray would help out by process of elimination.

Good Luck,
Ryan


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Roberto Etcheverry
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 4:16:58 pm

Thanks for all the answers.

Indeed the footage was shot at a rather high shutter speed (1000 or so). We did an earlier test with automatic settings and we got a distracting blur with the movement so we tried a faster speed this time around.

I'll tell my boss to bring the camera to do some more experiments.

Also, what can I do in post to help alleviate this problem on the images we already have?. I'm also using twixtor to slow down the video a bit. I'll ask if I'm allowed to post a little bit of a sample.


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Roberto Etcheverry
Re: 1080p doesn't look smooth.. help?
on Feb 11, 2010 at 4:25:30 pm

Few things I forgot to address in my previous post (can you edit your posts here?)

I have another issue (I'll probably post another thread about it) that may be rolling shutter artifact, sometimes a frame gets darker than the other ones, but the weird thing was that the camera was all manual.

On the resolution, using the DVI in the plasma only accepts 848x480 and 1024x768, but that last one doesn't have the correct aspect ratio (16:9) so it gets distorted. It's an oldish plasma screen, don't have access to a true 1080p (they're not common here in Venezuela yet). Mainly we're doing the shooting in 1080p since the delivery medium will be TV (downsampled to regular ntsc) and higher quality to use on movie theater screens.

I'll post later to see if I get any results by playing around with the camera a bit.


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Andy Bissonnette
Re: 1080p doesn't look smooth.. help?
on Feb 14, 2010 at 1:12:40 am

What lens were you using? Is it possible that you had the Image Stabilization (IS) on? This will make pans/tilts/etc. look jerky or stutter.


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Jiri Fiala
Re: 1080p doesn't look smooth.. help?
on Feb 17, 2010 at 7:53:58 am

I think fast shutter speed may be the culprit, but it's evenmore likely you're just very much used to that immediacy of interlace. 50i and 25p look VERY different - 25p WILL look choppy if used in the same way as interlaced camcorder, i.e. fast swish pans and such.


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