[MacDV] Re: Photoshop resolution for DV?

[Derek Roff]

> The first video I'm creating will consist of mostly still
> images created in Photoshop that I will pan across and zoom in and
> out of. I will be burning the video to DVD and it will be viewed on a
> 37" 9:16 LCD TV. How do I figure out what size and resolution to
> create my Photoshop documents?

Terminology can get confusing.  Image size, in terms of inches, dots per 
inch, or pixels per inch, does not apply to video.  Resolution (in pixels) 
of the displayed video image will be fixed, and at a fairly miserable 
level, by the output device, namely your 37" 9:16 LCD TV.  This pixel 
resolution is what you want to work with.  This is probably a "high 
definition" TV, but in this marketing-driven world, you can find very 
different specs and resolutions on TVs sold as HD.

I would start the search for the pixel count by looking in the manual for 
your TV.  Somewhere, it should tell you the maximum resolution/pixel count 
that the TV can handle, and the settings needed to display that resolution. 
We would hope that your TV would be able to handle 1080p, meaning a frame 
resolution of 1920 × 1080 or just over 2 megapixels.  That's about the 
best resolution/HD format available for current home or broadcast HDTV.

<http://en.wikipedia.org/wiki/1080p>

>From the display pixel count, you can begin to calculate the size (in 
pixels) of your images.  As another poster mentioned, you don't want to 
zoom in on a photo to a resolution where the software has to start creating 
or interpolating pixels.  Make sure that at the maximum zoomed moment of 
display, the zoomed/cropped part of the photo will have 1920x1080 pixels to 
work with for display on the screen.

Then work backwards through your panning and zooming intentions, to figure 
the total pixel resolution needed for each image that you plan to use.  For 
example, if you planned to zoom in on a portion of a photo that was half 
the length and half the height of the entire photo, then your starting 
resolution would need to have twice as many pixels in height and in length 
(four times the total pixel count).  1920 times 2 = 3840, 1080 times 2 = 
2160, so for this hypothetical zoom, start with an image of at least 3840 x 
2160.

If the planned panning and zooming for each different image vary a lot, you 
may need to start with different pixel counts for each image.  If they are 
mostly similar, you could prepare all your images for the worst 
case/maximum zoom.

Since you are comfortable in PhotoShop (I am not), I wonder if producing 
your titles within that program would be effective.  This would get around 
the rotated text problem for those elements that begin as photos or 
graphics.  It doesn't help with any titles that you need to place on the 
video shot as video.

Unless you have a true HD video camera, then the resolution of the video 
shot with your camcorder will be significantly less than the resolution of 
your still photos and graphics.  You will have to handle the difference in 
resolution between the video and the stills at some stage.  I've never 
tried mixing standard definition and high definition in the same iMovie. 
Perhaps you should convert all the video to HD first.  Perhaps you should 
do the graphics and stills in standard definition video resolution, and 
create your iMovie as a standard definition 16:9 movie.  Then display that 
image on your LCD TV, letting the TV up-convert the image as best it can. 
Others on this list might have suggestions for that part of the strategy.

Derek

Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek at unm.edu