Photoshop title jump
by Bob Cole
on
May 15, 2007 at 6:40:09 pm
I tried to use Photoshop for title generation but noticed that at transitions, even after rendering, the graphic jumps a bit. When I double-click I get another timeline with the PSD layers; when I double-click the text layer in that timeline, I finally get to see the Photoshop layer in the Viewer, and the file is offset from the center a bit. I thought I had the correct pixel dimensions -- any insights?
Re: Photoshop title jump by JeremyG on May 15, 2007 at 7:00:57 pm
Photoshop works in square pixels and SD NTSC does not. You need to work in square pixels in photoshop (720x540) then at the very last step unconstrain proportions and change size to 720x486 (or 480 if working in dv).
The other thing is to make sure the the full option is checked under Sequence > Render all and sequence > render selection. Once you have put a check next to the full options, hit option-r to render all.
Re: Photoshop title jump by billlee on May 16, 2007 at 3:45:02 am
This was the old method of using Photoshop.
As of Photoshop CS onwards, you can select non-square pixels as the Preset for a new document. This means that you can work with 720 x 480 NTSC (DV) or 720 x 486 NTSC (D1) frame sizes with Pixel Aspect ratios of other than 1:1. They even have frame sizes for anamorphic 16:9 video.
This means that the process of round-tripping between FCP and Photoshop is vastly improved, since you leave the frame size constant and work with non-square pixels when drawing. You can toggle the display between non-square and square pixels in Photoshop with View>Pixel Aspect Ratio Correction.
Re: Photoshop title jump by JeremyG on May 16, 2007 at 4:46:28 am
[billlee]"This was the old method of using Photoshop."
i hear ya, but he didn't say what version of Photoshop, and in CS I thought it was just a display not a design issue. The display allows you to toggle, but it warns you it's for display purposes only. Am I wrong about that?
Re: Photoshop title jump by billlee on May 16, 2007 at 5:41:57 am
Jeremy "The display allows you to toggle, but it warns you it's for display purposes only."
The message that Photoshop CS 2 gives you is "Pixel aspect ratio correction is for preview purposes only. Turn it off for maximum image quality."
I think this is there just to warn you that you are not dealing with square pixels, and that there may be round off errors with some wierd aspect ratios in displaying an image or selecting pixels. The advantages IMHO greatly outweigh any possible disadvantages with not having to rescale images multiple times if you are round-tripping between Photoshop and FCP. The only area which I don't know whether it handles the non-square pixels correctly is in filters that use radii of effect, such as the Gaussian Blur: when applied to an anamorphic image, it should give an effect which is circular instead of oval-shaped. I don't know if it actually does or not.
For so many years of Photoshop, all pixels were square and now you can set them to an anamorphic ratio. When you have the pixel aspect ratio turned on, you can now get guaranteed circles using the Eliptical marquee tool in conjunction with the Shift key without later having to rescale. A pencil tools one pixel square looks rectangular onscreen, but is actually one pixel wide and high. In essence, that's why Adobe made these presets available: to be used to edit frames for video.
If you look in the help for Photoshop CS 2, it has the following information:
"To help you create images for video, Photoshop has a Pixel Aspect Ratio Correction viewing mode that displays your image at a specific aspect ratio. For more accurate previews, Photoshop also has a Video Preview command that lets you immediately preview your document on a display device, such as a video monitor. To use this feature, you must have the device connected to your computer via FireWire. See also 'To preview your document on a video monitor'."
Re: Photoshop title jump by Bob Cole on May 16, 2007 at 4:56:53 am
Plot thickens, or I'm feeling even denser.
1. 720x540 .psd, imported straight into FCP. No pixel shift. But FCP automatically repositioned (centered?) the graphic for me. In the all-important y-axis the repositioning (revealed in the Motion tab) was in full pixels. Result: the graphic stays put during the dissolve.
2. I resized the same graphic above to 720x486. On the dissolve out from the graphic, there is tearing -- repeated pixels at the bottom of the fonts. FCP had again automatically centered the positioning, but this time 14.5 pixels vertically. When I changed this to 14 pixels even, the tearing disappeared but there is still a little jump on the dissolve from graphic to live action.
I must be missing something here. Version 2 should've been better than 1. Why is FCP recentering the graphic? Why the inconsistent results with that persistent jump?
Re: Photoshop title jump by billlee on May 16, 2007 at 6:27:03 am
When you import still pictures into FCP, it looks at the sizes of the images you are importing and makes some decisions based on those sizes. On images that it thinks are standard video images, it will set the pixel aspect ratio to one of: Square, NTSC - CCIR 601, PAL - CCIR 601, HDV (960x720), HD (1280x1080). If you are just one pixel out, it will default to square pixels.
Example: Importing an image 720 x 487 will import that image with a square pixel aspect ratio, whereas an image 720 x 486 will be imported as NTSC - CCIR 601.
When you drag such an image into your timeline, the image will be scaled if it is larger than the frame size. An example of this is that an image 721 x 487 was scaled to 99.86% to make the largest dimension (x or y) fit into the frame. Images smaller than frame size will not be scaled to fit.
If your sequence is 720 x 480 DV, then your pictures should also be 720 x 480 instead of 720 x 486 D1. Otherwise, set the scale to 100% and let the three extra pixels hang off the top and bottom of your frame. Likewise, if your sequence is D1, your pictures should be D1 (720 x 486), otherwise you will get a three pixel black line top and bottom of the frame (immaterial for TV, bad for web delivery).
So as to your situation, did you scale the picture in Photoshop, or in FCP? I can't remember running up against it automatically offsetting an image before, since the default position of images and video is at (0,0) which is the centre of the frame.
If you change the pixel aspect ratio of some clip in the timeline, then you have to replace it with another copy of that (modified aspect ratio) clip from the browser, since it won't visibly change aspect ratio once it is in the timeline.
Re: Photoshop title jump by Bob Cole on May 16, 2007 at 2:32:55 pm
This has turned into more of a puzzle than I'd thought. Doing the wrong thing works, and vice versa. Surely I must be doing something very basically wrong here.
1. In PS CS, I created 720x540 graphic. White (235/230/230) text over black background. Imported to FCP 720x486 timeline, the red line immediately appeared. I dissolved from graphic to live action, and rendered. Result: no jumps.
2. In PS CS, I non-proportionally changed the pixel dimensions of that same graphic to 720x486. In FCP, no rendering line. But two problems: (a) long vertical smear (faint but definite) at the right side of the last letter and (b) from the very first frame of the dissolve out to live action, the text jumps slightly larger, particularly in the vertical dimension. Putting a darker color on the font makes the smear even fainter but the dissolve still makes the text jump.
re: my earlier centering question: I was thinking that may be due to how I made the graphic inside PS, but it's still inconsistent. For Graphic #1 (720x540) above: When I double-click the graphic to pop up its own timeline, and then double-click each layer, the black background layer is centered at 0, 0, while the text layer is centered at 4.5, -16. For Graphic #2 (720x486): 4.5, -14.5. That half-pixel makes the dissolve-jump especially troublesome, as it creates a doubling-up of the lower part of the font. When I change that to 4.5, -14, the moire effect disappears but the dissolve jump remains.
Thanks for wading through this tedious and annoying problem. Any insights would be most welcome. Or should I just wait for FCP Studio 2?
Re: Photoshop title jump by billlee on May 17, 2007 at 1:11:41 am
OK, I set up a multi-layer Photoshop file (.psd) 720 x 486 (D1) and imported this into a D1 8-Bit uncompressed sequence to do some tests. I think I may have discovered why you are getting the results you have been getting.
A multi-layer photoshop file is storing the layers as a set of the smallest bounding boxes for each layer. This is true for both raster layers and for text layers.
If you have a 10 x 10 pixel square on your 720 x 486 D1 frame, then it is stored as a 10x10 box with an offset from the origin of the D1 frame. You can see this when you import this multi-layer psd file into FCP, drop it in the timeline, then double click on it to see the layers. If you turn on 'Image and Wireframe' in the Canvas view, clicking on each layer will show the bounding box of each layer. Since each bounding box is not centred on the frame, each bounding box will likely have a different offset from the centre of the frame and thus show a different set of values for the centre point in the Motion tab. The same is true for text layers, the text being stored with the bounding box for the text and the centre point of that bounding box.
Text layers are somewhat special, since you have to be careful about font metrics and rasterisation when moving to other applications or machines. When you move a text layer to FCP, there may be some subtle differences in the way the text is rasterised for compositing into the frame. Photoshop gives you the ability to anti-alias text and these have an effect on the way the text is displayed. These anti-aliasing settings will have an effect on the size of the bounding box when it is imported into FCP, and this is why your text may be changing position.
Re: Photoshop title jump by Bob Cole on May 17, 2007 at 1:14:06 pm
First, thanks for the fantastically informative test. It's a real service, and I hope Apple sees it. Your suggestions for a work-around are excellent, but what a PITA! Looks like I need to use one of the other ways to handle text graphics for FCP that you suggested (Motion or Live Type).
[billlee]"A multi-layer photoshop file is storing the layers as a set of the smallest bounding boxes for each layer. This is true for both raster layers and for text layers."
That little vertical smear that I referred to, just grazing the right side of my text, is probably the edge of this bounding box.
I think it's very odd, still, that when I import a wrong-sized graphic (720x540), FCP handles it fine (except for needing to render).
Re: Photoshop title jump by billlee on May 18, 2007 at 2:45:11 am
I've been doing some more thinking on this, and in the Photoshop help for CS2 there is the following note:
By default, type is displayed with the fractional widths option on. This option allows the spacing between characters to vary using fractions of whole pixels. In most situations, fractional character widths provide the best spacing for type appearance and readability. However, for type in small sizes (smaller than 20 points) displayed online, fractional widths could cause type to run together or have too much extra space, making it difficult to read.
Turn off fractional widths when you want to fix type spacing in whole-pixel increments and prevent small type from running together. The fractional character width setting applies to all characters on a type layer
