The BitVice Encoder uses a two pass compressing scheme to detect certain patterns of the temporal changes in the input material.

In the first pre-flight pass, statistics concerning coding complexity are gathered. Then this data is processed and fed into the second pass, which performs the Variable Bit Rate Encoding. This means that the available bits are appropriately distributed over the different video segments such that constant visual quality is obtained.

This could be done in one pass, but the effect would be suboptimal and not even near the quality necessary for demanding DVD productions. That's why the BitVice concept uses a two pass compressing scheme.

The structure of each GOP is adjusted according to different measures and statistics from the pre-flight pass. The BitVice does not encode an I-frame or even P-frames where not needed. This is one of the tactics, used in the BitVice concept, to minimize misplacement of valuable bits.

One of the most demanding tasks for an MPEG2 encoder is to compress still pictures. Why? Because the picture is - still. MPEG2 was designed for motion pictures, not stills. Many DVD productions of today may have several still picture segments in their "motion picture" sequences, enough to kill any ordinary MPEG2 Bit Rate Control.

That's why Innobits invented a special method for still pictures encoding into MPEG2 streams.

Different bit allocation schemes are used for each kind of scene complexity level. Many of these schemes are unique to the BitVice.
A substantial part of the research work at Innobits has been devoted to resolve the many suboptimal issues inherent in the standard, and common practice of, bit rate controlling algorithms. This is one of the most important strategies used, and incorporated in the BitVice concept, to optimize the allocation of valuable bits.

For historical reasons and for the lack of any much better and short enough name, we decided to keep the somewhat misleading name of this option. Therefore a technical explanation will follow. It should never need to be turned off. Most users who use DV codecs from Apple must leave it turned on, to maintain color and level transparency. However, a few of these users have come to like the darkening effect that such codecs produce when this option is unchecked. Therefore it is still left as a user option in the user interface. For those who use DV codecs from other vendors this option has no relevance, so they might as well leave it turned on. The actual MPEG-2 encoding process starts with an input of decompressed RGB pictures, which are expected to be gamma corrected for TV (2.2). When selected, this option forces BitVice to to explicitly tell the codec to leave the frames at gamma 2.2 after decompression. Most QT codecs compatible with international TV standards will do this by default, which renders this option without effect. DV codecs made by Apple though usually don't, instead they change the gamma from 2.2 (which is standard for the DV format) to 1.8 (which is rather unique standard for Apple monitors).

We guess that the Apple engineers probably designed it this way because they thought that the decompressed pictures were going to a Mac monitor, not to an MPEG-2 encoder

A BitVice droplet is a small (less than 1 MB) copy of the BitVice application, but with all settings already entered. All the controls are dimmed down and cannot be changed. So, just make a new droplet if you want one with other (or even the same) settings.

Once you have created a droplet in the folder where you want the resulting MPEG-2 files, you can drag and drop up to 200 QuickTime movies onto it. This will start a batch encoding, using the same settings for all of them. You can create as many droplets as you want and you can even run several of them concurrently. They can be started completely independent of each other.