QTW 37 - QuickTime for Windows 2.0.1 Can't Read My JPEG Picture

Technical Q&As


QTW 37 - QuickTime for Windows 2.0.1 Can't Read My JPEG Picture (1-July-95)


Q I have a 320x255 picture that opens properly with QuickTime 2.0 on the Macintosh but can't be opened under Windows 3.11 with QuickTime 2.0.1's Picture Viewer. Why can't I open this picture with QuickTime for Windows?

A There is a bug in the QuickTime for Windows JPEG marker scanning code. This bug causes any byte with a value of 255 (0xff) in the JPEG header to be interpreted as a JPEG marker, which in turn caused a redraw problem. Any height or width with a least-significant-byte value of 255 will cause a problem.

The scanner code will be fixed in the next release after 2.0.2. Until then, create JPEG's that don't have heights or widths with a least-significant-byte value of 255. In fact, both should be a multiple of 4 to achieve optimal performance from the JPEG codec.

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