shutter speed vs frame rate vs dvd quality

[William Busby]

I use the XHA1. But I don’t use FCP, so I can’t help you there.

What’s your reason for using 1/30 shutter? Even if you were shooting 24F the default (and recommended) shutter would be 1/48. The rule of thumb is double the frame rate to get the 180 degree shutter angle. I would suggest NOT using a 1/30 shutter and use 1/60 if you’re shooting 30F.

The other thing, why are you deinterlacing? It’s already progressive if you’re shooting in either of Canon’s F modes.

[George Sloan]

Thanks William,

OK the rule is to shoot with a 1/60 shutter when frame rate is 30F but if you do not obey that rule and instead shoot with a 1/30 shutter. What happens?

Specifically…why would the footage look ok every step of the way until
it reaches final output as a DVD. It is only at that point that the blurring occurs.

George

George Sloan Productions
http://www.sloanmotion.com
“Music Mountain” Channel 4 Windstream Cable TV
Cannon Xh A1 1080i>FCP7>ProRes>SD DVD>Delivery on DVD to Broadcast and DVD distribution

[William Busby]

It’s a bit difficult to guess since I have no idea on how you’ve been viewing it. But any slower shutter speed than necessary will begin to stutter and show more motion blur and the slower it gets the more pronounced it will be obviously.

These things aren’t going to be as noticeable while editing and just looking at the monitors on FCP’s interface. Do you have a client monitor attached as well? What are you viewing the dvd on?

Also as I’ve said earlier de-interlacing progressive footage to begin with is unnecessary and could possibly be causing issues as well.

[George Sloan]

The deinterlace setting you are refering to is only a preference
should you require Compressor to deinterlace. Since I chose Progressive
in the setting called “Output Fields” compressor knows not to deinterlace. So in this example everything stays progressive as you suggest it should be.

So when i view the footage off the timeline on several different external monitors the footage is looking good. (It also looks good on computer displays after compression to .MOV or Mp2.) Once burned to dvd and played back on these same external monitors the blurring occurs.

So I’m guessing the slow speed of 1/30 doesn’t seem to show up much until
compressed to dvd.???

George

George Sloan Productions
http://www.sloanmotion.com
“Music Mountain” Channel 4 Windstream Cable TV
Cannon Xh A1 1080i>FCP7>ProRes>SD DVD>Delivery on DVD to Broadcast and DVD distribution

[Todd Terry]

I don’t know what your problem is… but I’m pretty sure what it isn’t, and that’s shutter speed.

I can’t imagine any logical reason whatsoever that your slower-than-normal shutter speed would be causing those problems, especially since the video looks great right up until DVD playback. The slow shutter speed might cause the “blurring” you mentioned, but if so you’d certainly see that just as evident at all the earlier steps in the game. And there’s no reason at all that a slow shutter would cause the “jaggy” look you mentioned.

True, your shutter speed is twice as long as what would be considered “normal” for your frame rate… but I’m pretty confident that you’re barking up the wrong tree with looking at that as the source of your artifacts that show up only on DVD. It sounds much more like a compression or transcoding issue that is happening at the DVD authoring stage.

I wish I could be of specific help… but while we also shoot Canon (XLH1), we edit with Premiere CS3 and CS4 and do DVD authoring with Encore. I can think of a half dozen issues that might cause the same problems in our systems, but sadly I know bupkus about FCP.

Again, though, I’d bet the farm that you can eliminate your shutter speed issue as the culprit and look for the gremlins elsewhere.

Curious though, do you not get these artifacts when you author DVDs from footage shot at a more “normal” shutter speed (1/60th for 30p or NTSC footage, or 1/48th for 24p footage)? If you haven’t tried that, it sure would be easy to test to rule out the shutter speed issues

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[George Sloan]

Thanks Todd,

I was just starting to doubt my hypothesis as well. Reason being that
I tested a burn with Toast against my usual Apple Studio Pro burn.

1.Toast had very little of the blurry and ziggy artifacts as did
Studio Pro.

2. Toast was set to reencode.

Now I am thinking the problem is in the authoring software. In this case Studio PRO with shutter speed being just a contributing factor.

George

George Sloan Productions
http://www.sloanmotion.com
“Music Mountain” Channel 4 Windstream Cable TV
Cannon Xh A1 1080i>FCP7>ProRes>SD DVD>Delivery on DVD to Broadcast and DVD distribution

[Richard Herd]

[george sloan] “Width: 1280
Height: 720”

Preface: I checked out the forum to look up some canon camera information, but ran across this post. If you haven’t already, the compression forum can probably help.

I don’t understand why you’re setting your DVD picture size to HD. Before brining your picture into DVD Studio Pro, you first need to compress your HD image to one of Compressor’s predefined DVD settings. This will create a file that DVD Pro will then turn into a VIDEO_TS.

Step one: Export out of FCP a QT video.
Step two: Use compressor to compress step-one’s video into the proper video, using a predefined DVD setting
Step three: import step-two’s video into DVD Pro.

[george sloan] “That with too low a shutter speed(or other camera adjustments) would cause my video to look good everywhere along the line until final output.. which is playback on DVD. “ No.

[George Sloan]

Richard,

I was attempting to use Compressor to crop the HD Picture to 4:3
using the geometry tab. Does that work? Why wouldn’t that work?
It seems it would give me more control if it did work.

My Blurry question was eventually
answered by myself. The main problem all along was that I wasn’t
setting Studio Pro’s Preferences PRIOR to importing assets.

George

George Sloan Productions
http://www.sloanmotion.com
“Music Mountain” Channel 4 Windstream Cable TV
Cannon Xh A1 1080i>FCP7>ProRes>SD DVD>Delivery on DVD to Broadcast and DVD distribution