In the past four months we've seen several new 1080p projectors released with a feature known generically as frame interpolation. The new Epson models have it, as does the Sanyo Z3000 and the Panasonic AE3000. Sanyo calls it Smooth Motion, and Panasonic calls it Frame Creation. But it is all the same concept: the projector evaluates the motion between individual frames of film or video, and creates interim frames to be displayed along with the real frames in the source. The objective is to reduce motion judder and provide a cleaner, more artifact-free viewing of film and video material.

Two complaints have been circulating about frame interpolation technology. One is that it can make a movie look more like digital video, something which people are calling, somewhat derisively, the Soap Opera effect. In essence, the complaint is that it makes a film, which has a slightly surreal and sensual quality, look like a CNN Situation Room HD broadcast, which by comparison is hard, cold, clear, and real (sometimes disturbingly real). When James Bond begins to look like Wolf Blitzer, you know you have a problem.

The second complaint is that, while frame interpolation can reduce or eliminate much of the film judder we see in movies, it introduces other artifacts which may be just as problematic. For example, instead of the judder, we may see some ghosting as subjects move across the screen, or some unnatural disintegration of the picture during momentary fast pans of the camera.

These complaints are well-founded. Some frame interpolation systems do indeed produce these undesirable side effects. But if it is done well, the picture can be virtually free of artifacts while it retains that mystical film quality. Ideally, what you see is an amazingly clean, stable, but still filmlike image that many will find irresistibly engaging.

Not All Frame Interpolation Systems are Created Equal

Don't make the mistake of seeing a frame interpolation demo on a particular video product and assume you've seen what it will look like on all video systems. Each vendor approaches it differently. They use different algorithms to generate the interim frames, and some generate more created frames than others. This causes the type and frequency of artifacts to vary from product to product. And beyond that, the Soap Opera effect tends to be more exaggerated on smaller screens than on larger ones. If you are projecting a 60" diagonal image, the effect will be more obvious than if you use that same projector to throw a 120" image. The Soap Opera effect can sometimes be more obvious and distracting on plasmas and LCD TVs than it tends to be on the projectors we've seen.

What you are watching makes a difference too. Among the 1080p projectors that have frame interpolation, the Epson models tend to produce a more obvious digital video effect than do either the Panasonic or Sanyo units. However, if you happen to be a fan of Pixar animations, this is irrelevant. The movie Cars has a reasonable amount of judder and flicker when played at 1080p/24. But if you engaged the frame interpolation system on the Epson 6500UB, it has nothing but a beneficial effect on the image. The picture is much more smooth and stable, and since the material is high contrast animation, there is no Soap Opera effect to be concerned about. The same is true of all animated films, from Toy Story to Finding Nemo to Ratatouille. With this type of material, the Epson system works beautifully.

If you don't watch movies, but rather watch a lot of sports in HD on channels broadcasting in 1080i, you may find frame interpolation particularly attractive. For whatever "soap opera" effects are present in the video system you have, they are irrelevant in sports-you want that maximum reality effect. Of course, Fox Sports, ESPN, and ABC all broadcast in 60p format, so frame interpolation is not needed. But with sports broadcasts in 1080i, it can help.

Similarly, music concerts on Blu-ray may be enhanced with frame interpolation. Again, if there is any soap opera effect, it is a good thing.

In the end, even if the frame interpolation system on your projector does have a particularly exaggerated digital video effect, this can work to your advantage in sports, music concerts, and animated films. You can always turn it off if you don't care for what it does to your traditional movies.

When it comes to traditional films, it is a different story. We find that the Epson units produce a noticeably greater degree of undesirable "reality" than do either the Panny AE3000 or the Sanyo Z3000. Furthermore, there are occasional ghosting artifacts and momentary flashes of something that should be there in a movie played on the Epson 6500 UB. We don't see these nearly as frequently on either the Sanyo or the Panasonic projectors. For this reason we consider the Epson implementation of frame interpolation, at least in its current iteration, to be the least successful of the three.

Conversely, the Panasonic AE3000 has the most robust and powerful version of frame creation that has appeared so far. When dealing with a 1080p/24 source, it generates three interim frames for every real frame, and plays them each at 96 Hz. (Panasonic is the only projector vendor that does this so far; both Epson and Sanyo generate one interim frame for each real frame.) That means on the AE3000, 75% of what you see on the screen is being created by the projector. Panasonic developed their own proprietary algorithms for Frame Creation in house. The result is an extremely smooth and artifact-free display of film. And in addition, the digital video effect is remarkably subtle in comparison to the Epson units. When the AE3000 is projected onto a 120" screen, the image looks like very clean film, not a CNN HD video broadcast.

Is Frame Interpolation Important for You?

Well, only you can decide that. For me personally, I am distracted by motion judder when I see it on the large screen. I was never bothered by it when watching a 42" plasma TV because the image was too small and the artifacts were less obvious. But at 120", the viewing experience is more immersive, and motion instability can be quite annoying. I'd rather have those artifacts gone if I have the option. So I am elated that vendors are now beginning to tackle this problem.

However, having said that, I must hasten to add that motion judder is not a problem in all films. For example, the new release of Thunderball in Blu-ray has very little judder. Yes, the script is bad and the acting is worse, but at least the cinematographer knew what he was doing. In this film there is very little camera panning, and when the camera does pan, it almost always moves slowly enough to avoid the introduction of judder. You can watch this film in its entirety in native 24p and see almost no judder at all, which is rather remarkable.

On the other hand, the new Casino Royale Blu-ray, while obviously a much better movie, is not nearly as successful in this particular regard. Moderate speed camera panning is rather frequent in this film, so you see more judder. We use this film to exercise the various frame interpolation systems on the projectors that have come out so far.

And by the way, contrary to what one might assume, motion judder is not a problem that is limited to action movies alone. The film Swimming Pool is an example of a very slow paced movie with no action whatsoever, and it is full of motion judder. It is not the amount of action in a film that produces motion artifacts, but rather the way the cinematographer handles the camera. So don't think that just because you are not watching stuff like 2 Fast 2 Furious that you won't be bothered by motion judder.

In the end, frame interpolation can be used with different types of film and video source material with great success. Sometimes it isn't necessary, and sometimes it helps enormously. And some frame interpolation systems are more comprehensive than others, so your results may vary as they say. We are extremely supportive of this new enhancement to video processing. Our hats are off to Panasonic in particular for showing how powerful the technology can be. We hope all vendors will give serious consideration to including it in their next generation video projectors.

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