The premier video codec used in Apple's Quicktime, that was showcased by the Star Wars Episode 1 trailer. Rather scalable, giving good results at bitrates ranging from 28k modem to CD-ROM. Gives better compression than MPEG 1, but uses far more processing power. Due to its proprietry nature, it is rather unpopular with Linux blokes, since a messed up licencing scheme is holding up a possible Linux version. There is some debate as to whether it is Apple or Sorenson that is at fault.

If you're phenominally rich, or are a warez d00d, then you can get the variable bitrate version, which gives far higher quality than the one included with Quicktime Pro

Sorenson begins with a key frame, then stores the changes that take place as the video progresses, supplying a new keyframe typically every five hundred or so frames, and whenever a drastic change in scene occurs. The key frames are compressed using YUV-9, where for every 4 x 4 block of pixels, 16 pixels of luminance data are stored, but only four blocks of chrominance data. Vector quantization, where 16 x 16 blocks are stored as co-ordinates in a lookup table of such blocks is used to describe the differences between frames. This is combined with a proprietry motion compensation algorithm.

Compressing video using Sorenson usually takes far longer than the running time of the video. A typical figure is 20 times the playing time, on a G3/266.

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