What About Animation on DVD? Doesn’t It Compress Poorly?

Some people claim that animation, especially hand-drawn cell animation such as cartoons and anime, does not compress well with MPEG-2 or even ends up larger than the original. Other people claim that animation is simple so it compresses better.

Neither is true. Supposedly the “jitter” between frames caused by differences in the drawings or in their alignment causes problems. An animation expert at Disney pointed out that this doesn’t happen with modern animation techniques.

And even if it did, the motion estimation feature of MPEG-2 would compensate for it. Because of the way MPEG-2 breaks a picture into blocks and transforms them into frequency information, it can have a problem with the sharp edges common in animation.

This loss of high-frequency information can show up as “ringing” or blurry spots along edges (called the Gibbs effect). However, at the data rates commonly used for DVD, this problem does not usually occur.

Why Do Some Discs Require Side Flipping? Can’t DVDs Hold Four Hours per Side?

Even though DVD’s dual-layer technology enables over four hours of continuous playback from a single side, some movies are split over two sides of a disc, requiring that the disc be flipped partway through. Most “flipper” discs are made because producers are too lazy to optimize the compression or make a dual-layer disc.

Better picture quality is a cheap excuse for increasing the data rate; in many cases, the video will look better if carefully encoded at a lower bit rate. A lack of dual-layer production capability is also a lame excuse; in 1997, very few DVD plants could make dual-layer discs, but this is no longer the case.

Very few players can automatically switch sides, but it’s not needed because movies less than four hours long can easily fit on one dual-layer (RSDL) side. The Film Vault at DVD Review includes a list of flipper discs. Note that a flipper is not the same as a disc with a widescreen version on one side and a pan and scan version or supplements on the other.

 Why Is the Picture Squished, Making Things Look Too Skinny?

Answer: RTFM. You are watching an anamorphic picture intended for display only on a widescreen TV. You need to go into the player’s setup menu and tell it your TV is standard 4:3 TV, not widescreen 16:9. It will then automatically letterbox the picture so you can see the full width at the proper proportions.

In some cases, you can change the aspect ratio as the disc is playing (by pressing the “aspect” button on the remote control). On most players you have to stop the disc before you can change the aspect. Some discs are labeled with widescreen on one side and standard on the other. In order to watch the full-screen version, you must flip the disc over.

Apparently, most players that convert from NTSC to PAL or vice versa can’t simultaneously letterbox (or pan and scan) an anamorphic picture. The solutions would be to use a widescreen TV, a multistandard TV, or an external converter. Or get a better player.

Do All Videos Use Dolby Digital (AC-3)? Do They All Have 5.1 Channels?

Most DVD-Video discs contain Dolby Digital soundtracks, but some discs, especially those containing only audio, have PCM tracks. It’s also possible for a 625/50 (PAL) disc to contain only MPEG audio, which is not widely used. Discs with DTS audio are required to also include a Dolby Digital audio track (in a few rare cases they have a PCM track).

Don’t assume that the Dolby Digital label is a guarantee of 5.1 channels. A Dolby Digital soundtrack can be mono, dual mono, stereo, Dolby Surround stereo, and so on. For example, Blazing Saddles and Caddyshack have monophonic soundtracks, so the Dolby Digital soundtrack on these DVDs has only one channel.

Some DVD packaging has small lettering or icons under the Dolby Digital logo that indicates the channel configuration. In some cases, a soundtrack has more than one Dolby Digital version: a 5.1-channel track and a track specially remixed for stereo Dolby Surround. It’s perfectly normal for your DVD player to indicate the playback of a Dolby Digital audio track while your receiver indicates Dolby Surround. This means the disc contains a two-channel Dolby Surround signal encoded in Dolby Digital format.