Field rendering and motion blur

SpaceBoy64 · Post by **SpaceBoy64** » Wed Oct 07, 2009 2:46 am

One thing I noticed working with ASP is that there doesn't seem to be an option for field rendering. Am I wrong?

When the camera does a quick move, I really notice the stuttering effect. I tried the motion blur, but the results were really poor and took way to long to render. Field rendering would be a great help.

I would like to see good motion blur like I get in Adobe After Effects too.

Is this something in the works? Is there a clever workaround? I know one possibility might be doubling the length and then using Final Cut Pro or After Effects to double the speed, but is there an easy way to do this?

Thanks.

slowtiger · Post by **slowtiger** » Wed Oct 07, 2009 10:01 am

Nobody in the industry does "field rendering". All use "progressive" which means each and every frame is rendered in its entirety, pixel by pixel.

Any European TV station which broadcasts that material will send it "fielded" because that's the way PAL works.

The strobing you experience can only be healed by: slower movements, or backgrounds with less detail, or motion blurring. It could also be healed by higher framerates, like 60 or 120 fps, but this would be outside any broadcasting or distributing standards, so it's not an option.

Gnaws · Post by **Gnaws** » Thu Oct 08, 2009 11:53 pm

slowtiger wrote:Nobody in the industry does "field rendering".

That's an interesting proclamation. Try Googling "DV field rendering".

slowtiger · Post by **slowtiger** » Fri Oct 09, 2009 9:24 am

*sigh*
Again. You don't do field rendering for drawn animation. Period.

J. Baker · Post by **J. Baker** » Fri Oct 09, 2009 1:36 pm

I wrote an app a while back that interlaced png images that were exported from Anime Studio. I'll have to dig it up and recompile it. I'll post it in a day or two.

SpaceBoy64 · Post by **SpaceBoy64** » Wed Oct 14, 2009 3:38 pm

slowtiger wrote:*sigh*
Again. You don't do field rendering for drawn animation. Period.

That should be a choice, not a restriction.

Most other apps allow for field rendering, but you can choose not to use it. I think it would help a great deal and I would like to have the option. Strobbing on fast moving objects is very distracting.

The motion blur in AS is just not what it should be. It takes quite a bit more time to render, and doesn't look like true motion blur. It's more like a motion trail.

SpaceBoy64 · Post by **SpaceBoy64** » Wed Oct 14, 2009 3:41 pm

J. Baker wrote:I wrote an app a while back that interlaced png images that were exported from Anime Studio. I'll have to dig it up and recompile it. I'll post it in a day or two.

Could you explain how I would set up my animation to render twice as many frames for this sort of thing? I know I could import into After Effects and double the speed of the clip to get interlacing.

slowtiger · Post by **slowtiger** » Wed Oct 14, 2009 3:50 pm

The motion blur in AS is just not what it should be. It takes quite a bit more time to render, and doesn't look like true motion blur.

Motion blur is done the same way in all applications, 2D as well as 3D: the moving object is placed in several positions between the two frames, then rendered with an opacity which corresponds to the number of positions. Let's say there are 10 positions between frame 1 and 2, so each pass would be rendered as 1/10 of 100% opacity, = 10% opacity.

More complex motion blur algorithms weight the opacity so positions near the starting frame (or the end frame) get more percentage. In any case, all the positions between frames still have to be rendered, which of course adds to the overall rendering time.

"True" motion blur is a complex special effect which also involves separate passes for highlights which would multiply over everything else.

In any case, I don't think that a handdrawn or graphic animation style blends well with an attempt of photorealistic motion blur. There's other ways to indicate speed, and other ways to prevent strobing.

SpaceBoy64 · Post by **SpaceBoy64** » Wed Oct 14, 2009 4:45 pm

slowtiger wrote: Motion blur is done the same way in all applications, 2D as well as 3D

Well, this is one way it's done, but not the only way, and not a very effective or realistic way either IMHO. Again, this comes down to aesthetic choice. Software shouldn't make aesthetic choices for you because of technical restrictions.

If you've ever used After Effects, you'd see what I mean. Things with motion blur actually look blurred in the direction of motion. I think this is done by using the motion vectors to apply a blur. Anime Studio doesn't do this, it also layers the final frame on top of the previously rendered positions and it's not blurred at all.

I did find this plug-in, but I think this should be a built in feature:
http://www.revisionfx.com/products/rsmb/gallery/

J. Baker · Post by **J. Baker** » Thu Oct 15, 2009 3:34 am

SpaceBoy64 wrote:
J. Baker wrote:I wrote an app a while back that interlaced png images that were exported from Anime Studio. I'll have to dig it up and recompile it. I'll post it in a day or two.
Could you explain how I would set up my animation to render twice as many frames for this sort of thing? I know I could import into After Effects and double the speed of the clip to get interlacing.

The way I was testing it was to render at 60 fps. Then I was interlacing every other frame to 60 fields (30 fps). I'll try to find my code tomorrow.

But I don't think it will give the motion blur effect you're looking for. I've actually thought about writing something that would only blur moving parts of a sequence of frames. Just haven't got around to it.

SpaceBoy64 · Post by **SpaceBoy64** » Thu Oct 15, 2009 6:55 am

J. Baker wrote: The way I was testing it was to render at 60 fps. Then I was interlacing every other frame to 60 fields (30 fps).

So, it's as simple as changing the FPS setting? I will try it.
Thanks.

J. Baker · Post by **J. Baker** » Thu Oct 15, 2009 7:39 am

SpaceBoy64 wrote:
J. Baker wrote: The way I was testing it was to render at 60 fps. Then I was interlacing every other frame to 60 fields (30 fps).
So, it's as simple as changing the FPS setting? I will try it.
Thanks.

Well, if you already started your animation, let's say at 24 fps, then change it to 60 fps... you'll have some issues. So it would be best to start new projects at 60 fps.

SpaceBoy64 · Post by **SpaceBoy64** » Thu Oct 15, 2009 8:47 pm

J. Baker wrote: Well, if you already started your animation, let's say at 24 fps, then change it to 60 fps... you'll have some issues. So it would be best to start new projects at 60 fps.

How could that work right? the sound would not sync correctly when I speed it up.

Usually, I work at 29.976 fps, for NTSC television, which is 59.95 fields per second. So, shouldn't I do my animation as I normally do it, and then change the frames per second to 59.95 before rendering?

My playback speed will still be 29.976 in the end.

I still have to experiment with this.

J. Baker · Post by **J. Baker** » Thu Oct 15, 2009 9:02 pm

SpaceBoy64 wrote:
J. Baker wrote: Well, if you already started your animation, let's say at 24 fps, then change it to 60 fps... you'll have some issues. So it would be best to start new projects at 60 fps.
How could that work right? the sound would not sync correctly when I speed it up.

Usually, I work at 29.976 fps, for NTSC television, which is 59.95 fields per second. So, shouldn't I do my animation as I normally do it, and then change the frames per second to 59.95 before rendering?

My playback speed will still be 29.976 in the end.

I still have to experiment with this.

Yes, your sound would be off if you already started your project at a fps other then 60 fps. It best to start a new project at 60 fps.

When you render at 60 fps, you then blend the upper lines of frame one with the lower lines of frame two and so forth. Giving you 60 fields per second and 30 frames per second.

I'm looking for the source now.

SpaceBoy64 · Post by **SpaceBoy64** » Thu Oct 15, 2009 9:23 pm

J. Baker wrote: Yes, your sound would be off if you already started your project at a fps other then 60 fps. It best to start a new project at 60 fps.

When you render at 60 fps, you then blend the upper lines of frame one with the lower lines of frame two and so forth. Giving you 60 fields per second and 30 frames per second.

If I animate 60 fps and play back at 60 fps, it would be in sync, but if I change it to 30 fps, it would no longer be in sync, would it?

I am trying this out right now on a previous project. I changed the fps from 29.976 to 59.95. I did notice that the animation is now half the length of the sound file. Now, maybe I see what you're talking about. If my animation is 120 frames long, it will remain 120 frames long no matter what I set the FPS at. Is there a way to scale the entire animation length?

Now I'm wondering if I should be using whole numbers, 30 and 60 fps, when I'm animating and let Final Cut Pro convert to the proper NTSC frames per second in edit.