VIDEO "SLIDE" SHOWS

INTRODUCTION

A recent thread on MUG has been a discussion about doing "slide" shows on video. Having done numerous real slide shows for my church, and having done this three times with video: twice with MSP 5.02, and a more recent occasion with Premiere 5.1, I thought I'd share my experiences and thoughts on the subject.

SCANNING THE PICTURES

I used PhotoShop for scanning and manipulating the source pictures. There are lots of other paint programs out there that will work just as well as I don't really use any super-advanced PhotoShop features for this project (for the most part).

I generally scanned the pictures at 300dpi. For a 5x3 snapshot, this gives you 1500x900 pixels to work with. For some pictures that I was going to zoom up on closer, I scanned at 600dpi. I then adjust color balence and brightness before cropping the picture down to the final size.

The video capture card I use (AVMaster) does video at 640x480 with square pixels. Square pixels make life so much easier. The crop tool in PhotoShop can be set to use a "fixed" crop size. I set it to use 640x480. This confines the rubber band to a 5:4 aspect ratio and causes PhotoShop to resample the cropped region to be 640x480.

If your card uses non-square pixels, you have another step. Let's say your card uses 720x480 to generate a 5:4 aspect ration. If you just crop your image to 720x480 and display that, it will be displayed shrunk in the horizontal dimension on the video ouput. Before cropping, you want to stretch it horizontally to 720/640=112.5% of the original size. Then do your 720x480 cropping.

If a picture is one I want to do a pan and/or zoom on, I don't crop it, but instead let moving path or the pan filter to do it (more about this later).

FRAMING THE PICTURES

Remember that video is a low resolution media. In that photograph, all 20 people may be recognizable, but on video, they are going to be a tiny blur up on a big screen. Fill the frame with the objects of interest. If there is a lot of stuff you want people to see, consider panning across it, zooming in, etc. instead of cropping it to a static 640x480 picture. More on Pan and Zoom below.

Sometimes, you will want to include more of the picture than can be covered by a 5:4 rectangle.  In these cases, your cropping will not fill the frame.  I like it better if the "exposed" portitions of the frame are painted black.  I find other colors or patterns to be distracting from the picture.  More often then not, these means having two black bands on the left and right of the frame with the picture between them as the picture is usually too tall to fit instead of too wide.

SAVING THE PICTURES

Save the pictures in an uncompressed format. That way, you don't lose anything on the way to MJPEG and the video editor can render faster because it doesn't first have to decompress before recompressing. I just name my pictures sequentially: pic001, pic002, etc. Be sure to always use the same number of digits so your directory listing doesn't put pictures 10-19 and 100-199 between pictures 1 and 2. Note this means I work out the order of the pictures before scanning them.

PACING THE SLIDE SHOW

The next step is to put together the music track to determine the length of the show. Divide the time by the number of pictures and add 2 seconds to that for the overlap time (see below on transitions). Set the default length of imported pictures to that value before you import the still pictures. That way, you won't have to alter the length of each individual picture after you import it. It'll just be the right length. About 8 seconds are so is the "right" answer. That's 2 seconds for the transition in, 4 seconds to display the picture, and 2 seconds for the transition out.

Now in reality, the above computation is a little simplistic. The opening, closing, and pan and zooms alter the computation.

If the opening has titles, you may want them to display longer, so figure out out long you want the opening sequence to be and  explude those pictures and time from the above compution. Ditto for the closing credits. Depending on the music, you may want to do a slow fade to black as well.

Pictures you are doing a pan and zoom on will probably need to be displayed longer than the 4 or 5 seconds (not counting transitions)  that work well for static shots (less than 4 seconds and you really don't get a good look at the picture, more than 5 or maybe 6, and the show starts to drag and get boring unless the picture is "doing" something, like being panned across). A moving shot can hold interest much longer. So, for each such shot, figure out how long the pan and zoom is going to be (take it *slow*), add 4 seconds for the overlap at the beginning and end. Subtract this time and these pictures from the computation above.

TRANSITIONS

The key here is to keep it simple. I generally choose a single transition and use it between every picture. I'm partial to page turns, although cross fade is nice into and out of a PAN and ZOOM if you want to start panning and zooming before the transition in finishes or continue after the transition out starts.

For page turns, I either let the picture "show through" or use a dark brown (like an old faded B/W photograph) back. Using a different transition on every picture is distracting and ugly, in my opinion, but do what you like.  If you're doing something ambitious like syncing transitions to the beat of rock music (much like described in my youth group video tutorial), the use of varied transitions will be more appropriate.

PAN AND ZOOM

There are three ways to do pan and zoom. The first is moving path, which is the method of choice in MSP. Be sure to preserve aspect ratio. The problem with this choice in Premiere is that  Premiere first resamples an imagine down to the project's resolution (640x480 for AVMaster), then applys the magnification, resulting in real ugly output. This is fine if you are shrinking, but horrible if enlarging.

In Premiere, you should use the Pan filter instead. Be sure to preserve aspect ratio by holding down shift (I think it is) while resizing the rubber band.

The main problem with both these methods is that the preview window is so small that you can't really see what is going on and have no control over acceleration. My prefered method is to use Adobe After Effects since you can create smother path and use the ease handles to have the pan speed up, then slow down before you change direction, then speed up again, resulting in a much more natural panning effect. Plus, the preview window is full size.  The automatic setting of Ease handles in the keyframe assistants do a good job.  I usually just create a composition for a single picture, create the .avi for that, and import the .avi back into Premiere.

RENDERING

One would think that when rendering frame after frame of the same still picture, that MSP and Premiere would just compress the still picture one time, then copy it over and over again for the subsequent identical frames. They don't. They recompress the still picture over and over again. If that wasn't bad enough, the AVMaster codec is slightly non-deterministic: You don't get the same bit for bit results everytime, resulting in a little bit of flicker. It looks a little like interlace flicker, but not as steady. Premiere has a reduce interlace flicker setting under field settings on clips that resolves the problem, so maybe the unsteadyness is just my eyes playing tricks on me. Premiere also has an "optimize stills" option for rendering that actually puts only a single copy of the still in the avi, resulting in smaller files. They warn this may not work with all codecs. As far as I can tell, it works with AVMaster, although I haven't really verified audio stays in sync if you're doing stuff to the beat of music.  My projects like this to date have just changed pictures asyncronously to non-rock music.