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technical notes

The QTVR system uses various codecs (compressors/decompressors) for the QTVR movies. Using different codecs affects the file size and the quality of the QTVR movie. After extensive tests and many invaluable suggestions from our visitors, we have decided to change the default codec from Cinepak to Photo JPEG.

The Photo JPEG codec generates a much higher quality image than the older Cinepak codec does. Even a JPEG 0% quality setting results in a better looking image than Cinepak 75%, with the added benefit that the file size is much smaller. The drawback is that slower systems (i.e. computers with slower processors like Intel 486 or Motorola 68040) may result in "jittery" playback as the processing requirements of Photo JPEG are greater than Cinepak.

It is possible to choose a compression quality to compose the movie, from zero to 100%. Of course, the lower is the compression quality, the shorter will be the time to download and see the movie. With JPEG we have found that 0% gives the best download times/performance ratio for movies served on the Web.

If you would like better a higher quality movie and tolerate accordingly higher download times, please let us know your preferred compression quality:

Keep the JPEG 0%: the playback of QTVR movies is just fine

Change to JPEG 50%: a better image quality is well worth the extra waiting time online

Switch back to Cinepak 0: the playback of QTVR movies is "jittery"

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