Horrible Strobing with Speed Change using V1 at DVinfo.net

Daniel Boswell · March 27th, 2007, 03:43 PM

I shot a piece using 30p and primarily 1/30 shudder and every instance where i changed speed (slower or faster than 100%) there is a horrible strobing effect on the DVD.

Everything played fine from timeline. Just the DVD showed this.

Is it a fields issue? Help!!!

Mark OConnell · March 27th, 2007, 03:49 PM

What were the compression settings for the DVD?

Chris Medico · March 27th, 2007, 06:53 PM

Quote:

Originally Posted by Daniel Boswell

I shot a piece using 30p and primarily 1/30 shudder and every instance where i changed speed (slower or faster than 100%) there is a horrible strobing effect on the DVD.

Everything played fine from timeline. Just the DVD showed this.

Is it a fields issue? Help!!!

What pulldown pattern did you have your software set up for? I'm assuming you are using FCP?

Daniel Boswell · March 27th, 2007, 10:17 PM

Quote:

Originally Posted by Mark OConnell

What were the compression settings for the DVD?

i just did "best quality DVD" 2 pass VBR in compressor. I just checked the m2v file and it play perfectly, so it is something within the burning that is causing it.

Daniel Boswell · March 27th, 2007, 10:18 PM

Quote:

Originally Posted by Chris Medico

What pulldown pattern did you have your software set up for? I'm assuming you are using FCP?

see my response above..its something with the DVD burning/playback that is causing it

Marcus Marchesseault · March 27th, 2007, 10:29 PM

I'll guess that the slowdown effect you are using doubles fields to slow down the action. It may be interpreting 30p as 60i with only one field, so you need to look into what Chris is asking about. I have no idea how your software handles progressive footage, but the answer probably lies in the fact that the V1 puts progressive footage in to a 60i stream. You might want to try a different method of slowing the footage until you get the issue sorted out.

Daniel Boswell · March 27th, 2007, 10:36 PM

Quote:

Originally Posted by Marcus Marchesseault

I'll guess that the slowdown effect you are using doubles fields to slow down the action. It may be interpreting 30p as 60i with only one field, so you need to look into what Chris is asking about. I have no idea how your software handles progressive footage, but the answer probably lies in the fact that the V1 puts progressive footage in to a 60i stream. You might want to try a different method of slowing the footage until you get the issue sorted out.

But why does my m2v file look fine if its something with my software? shouldnt it be something with my burning or the player i am using?

maybe i am confused?

Marcus Marchesseault · March 27th, 2007, 10:50 PM

Without seeing the footage, I can only guess, but:

"every instance where i changed speed (slower or faster than 100%) there is a horrible strobing effect"

The only thing that makes sense to me is that the software that is slowing down the footage is copying fields to make the slomo, but it doesn't recognize that 30p is really in both fields.

Your M2V may look fine because your computer is progressive scan. Your DVD player may interpret the footage as fields with no information so you get a blank field. I also think Chris' suggestion that it is a pulldown problem is really worth investigating.

Douglas Spotted Eagle · March 27th, 2007, 11:06 PM

without seeing the footage, I'd also go for the question of interlacing as well. If you shot 30p, pulldown shouldn't be coming into the discussion.
Haven't imported 30p from the shipping V1 into FCP, but a couple months ago, it was only seen as 60i.
Perhaps we can get Graeme Nattress in on the discussion. I'm reasonably good with FCP, but far from expert.

Chris Medico · March 28th, 2007, 11:09 AM

I suspect that software is expecting that each field in the V1 stream is normal interlaced and 1/60/sec apart in time when in reality they aren't.

I can picture a scenaro (my best guess) where the software would line double each field and then string them together with duplicates in between (or cutting in the case of faster than real time) to make the speed come out to what you have set.

Could you try using 200% (double speed) and 50% and see what the effects are (worse, better or the same)? Just wondering if those speeds are better than any odd number divisions.

Personally I use Avid Liquid so I don't have FCP right in front of me to help you more. If I can get over to my friends house in the next couple of days I'll see what I can dig up. He is currently covering the Duke Lacross stuff here in Durham and is pretty busy.

John Bosco Jr. · March 29th, 2007, 01:06 AM

Quote:

Originally Posted by Daniel Boswell

But why does my m2v file look fine if its something with my software? shouldnt it be something with my burning or the player i am using?

maybe i am confused?

I've had this problem with FCP in the past. Are you using FCP quicktime movie to encode before DVD studio pro? Unfortunately, I don't know what causes the problem because I get it very infrequently and I don't use progressive.

Anyway, I was able to get around the problem by re-making the movie. If you didn't make the Apple quicktime movie a self-contained one, you can try doing that, or you can use quicktime conversion before going to DVD studio pro. I used the quicktime conversion and my card's 8 bit uncompressed codec, but I think any codec would work.

The project took quite a bit longer to burn (approximately twice as long), but I didn't have the strobing or shudder problem. It's funny because I can burn many projects without a problem, and then every once in a while (a long while) this problem creeps up. That's why I'm unsure to what causes it because it doesn't occur consistently and all of my projects are standard definition (Beta or Beta SX) and interlace.

I want to add that I believe something might be going on with the computer at the time of creating the quicktime movie, but that's just pure speculation on my part. I guess I'm trying to justify the problem with some sort of a cause. Anyway, when this problem occurs, like you, there isn't any rhyme or reason why the so-called strobing effect or shudder to be there as the converted quicktime movie plays just fine. I'm baffled to the cause but, like I mentioned earlier, am able to get around the problem by re-creating a quicktime movie.

Todd Clark · March 30th, 2007, 07:17 AM

Your Shutter should have been 1/60. Rule of thumb is to double your frame rate when it comes to shutter. I.e. 24p should be shot with a 48 shutter and 30p should be 1/60.

March 27th, 2007, 03:43 PM	#1
Daniel Boswell Major Player Join Date: May 2003 Location: Temecula, CA Posts: 189	Horrible Strobing with Speed Change using V1 I shot a piece using 30p and primarily 1/30 shudder and every instance where i changed speed (slower or faster than 100%) there is a horrible strobing effect on the DVD. Everything played fine from timeline. Just the DVD showed this. Is it a fields issue? Help!!! __________________ DBoZ

March 27th, 2007, 11:06 PM	#9
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	without seeing the footage, I'd also go for the question of interlacing as well. If you shot 30p, pulldown shouldn't be coming into the discussion. Haven't imported 30p from the shipping V1 into FCP, but a couple months ago, it was only seen as 60i. Perhaps we can get Graeme Nattress in on the discussion. I'm reasonably good with FCP, but far from expert. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

March 28th, 2007, 11:09 AM	#10
Chris Medico Inner Circle Join Date: Aug 2006 Location: Efland NC, USA Posts: 2,322	I suspect that software is expecting that each field in the V1 stream is normal interlaced and 1/60/sec apart in time when in reality they aren't. I can picture a scenaro (my best guess) where the software would line double each field and then string them together with duplicates in between (or cutting in the case of faster than real time) to make the speed come out to what you have set. Could you try using 200% (double speed) and 50% and see what the effects are (worse, better or the same)? Just wondering if those speeds are better than any odd number divisions. Personally I use Avid Liquid so I don't have FCP right in front of me to help you more. If I can get over to my friends house in the next couple of days I'll see what I can dig up. He is currently covering the Duke Lacross stuff here in Durham and is pretty busy. __________________ http://www.LandYachtMedia.com

March 27th, 2007, 03:49 PM	#2
Mark OConnell Major Player Join Date: Feb 2007 Location: Seattle WA Posts: 420	What were the compression settings for the DVD?

March 27th, 2007, 10:29 PM	#6
Marcus Marchesseault Trustee Join Date: Nov 2005 Location: Honolulu, HI Posts: 1,961	I'll guess that the slowdown effect you are using doubles fields to slow down the action. It may be interpreting 30p as 60i with only one field, so you need to look into what Chris is asking about. I have no idea how your software handles progressive footage, but the answer probably lies in the fact that the V1 puts progressive footage in to a 60i stream. You might want to try a different method of slowing the footage until you get the issue sorted out.

March 27th, 2007, 10:50 PM	#8
Marcus Marchesseault Trustee Join Date: Nov 2005 Location: Honolulu, HI Posts: 1,961	Without seeing the footage, I can only guess, but: "every instance where i changed speed (slower or faster than 100%) there is a horrible strobing effect" The only thing that makes sense to me is that the software that is slowing down the footage is copying fields to make the slomo, but it doesn't recognize that 30p is really in both fields. Your M2V may look fine because your computer is progressive scan. Your DVD player may interpret the footage as fields with no information so you get a blank field. I also think Chris' suggestion that it is a pulldown problem is really worth investigating.

March 30th, 2007, 07:17 AM	#12
Todd Clark Regular Crew Join Date: Feb 2007 Location: Parma, Oh Posts: 172	Your Shutter should have been 1/60. Rule of thumb is to double your frame rate when it comes to shutter. I.e. 24p should be shot with a 48 shutter and 30p should be 1/60.