NOTE: This Technical Q&A has been retired. Please see the Technical Q&As page for current documentation.

Technical Q&A QTW64
Intermittent Pixellation with CinePak Compression

Q We are getting good results compressing with CinePak at around 230K/second. Based on the recommended data rates (180-200K/second), we started compressing to 150K/second for video (320x240x15fps). Occasionally, we see a strange sort of pixellation during certain scenes. While these artifacts soon disappear, they look very bad. We have seen this on various computers using MovieShop, Premiere, and ConvertToMovie. What could be causing this?

A The pixellation is probably due to image content. There are four possible solutions, which you can try (alone or in any combination):

1. Use a different compression codec, such as Indeo.

2. Lower the frame rate and raise the quality in those portions of the movie that exhibit the pixellation.

3. To touch-up frames that have noisy (high-frequency) backgrounds, use Photoshop.

4. If the problem occurs when dithering on 8-bit color systems, use DeBabelizer to create an optimized color lookup table (clut).

[Aug 01 1995]


Developer Documentation | Technical Notes | Development Kits | Sample Code