HDV vs. DV

How does it all fit?

It might seem that with as much a 4 times the resolution of standard DV, there must be a catch to fitting it into the same space. There is a catch and it's called MPEG-2. It's the same compression method used for DVD's. Instead of storing every frame of video, HDV stores a full frame every 12 to 15 frames, and the frames in between are comprised of only the data that changed from the previous (or next) frame. The net effect for you is that it might make the editing a little less responsive because there's more going on in the background, but for all practical purposes, it works fine and will work even better in the future as computers achieve their inevitable higher performance.

720p vs.1080i

The two resolutions of HDV have one primary difference. The 1280 x 720 format captures entire frames at once, a method called progressive scan, hence the name 720p. The 1920 x 1080 format captures the image in two interlaced "fields" and then combines the fields into a single frame by showing the even numbered scan lines for half the time and the odd numbered lines for the other half. This system is referred to as 1080i. Interlaced scanning is what we have lived most of our lives with for broadcast TV.

The advantage of 720p is that it is better at capturing fast action (auto racing, motocross, etc) at the expense of overall frame size. For UW use which generally doesn't entail lots of high speed action, 1080i is the preferred format because of the greatly increased frame size. The image to the right illustrates the number of pixels you can throw on the screen with the two formats.

HDV vs. DV Quality

The example scene to the right shows a 1080i scene with an inset of the same scene in DV resolution. You can see that there is much more spatial resolution in the HDV, but that the DV looks about as sharp, just smaller. That's because both are displayed pixel for pixel. Probably not a fair comparison.
Click the image to the right.

A much more representative way to compare quality would be to scale the DV up to the same size as the HDV just as would happen if you showed it on a TV screen. The DV has to be enlarged about 330% to cover the same horizontal area as HDV. The sample footage on the left shows the much lower true resolution DV image, even in this greatly compressed example.
Click the image to the right.

Using Legacy Media

There will be times that you may be forced to use old DV footage in an HDV production. You could, for instance have historical footage, or something that is extremely rare. In this case, you can put it into a small window, as in the example above. You might even get away with scaling it up if it isn't a subject that will degrade from the enlargement ( like a sparkling water background).

You could also use still images as backgrounds. Even an inexpensive digital camera has more spatial resolution than a 1080i frame. You and also pan across a still image (known as the Ken Burns effect) to introduce some additional motion into the scene. These still digital backgrounds can be used to superimpose titles, or as backgrounds for small windows of DV footage.

You can also "animate" still images by "warping" or "morphing" with special software to simulate subject movement.

The short video clip to the right contains a series of examples of how you can "fake" HDV materials with stills, animations and legacy DV clips. While the original of this is native 1920 x 1080 (highly compressed here for the web), absolutely none of it was shot with an HDV camera.
Click the image to the right.