Some MPEG1 Files Do Not Play on MacOSX

Some non-standard MPEG1 files produced with Cleaner and Ligos do not play correctly in Mpeg Advance Xtra versions 1.0 and 1.01 on MacOSX. A white background is displayed instead of the movie. This issue is fixed in version 1.02 of the Xtra.

Technical background: MPEG1 files with dimensions larger than 352X288 pixels are legal according to the MPEG1 spec, but some decoders expect only standard NTSC or PAL streams. For greater compatibility with Windows 95 we still recommend compressing your movies at 320X240 or 352X240, even if newer versions of Windows and MacOS can handle MPEG1 files with larger frame sizes.

In the case of MacOSX there is a Quicktime API function called SetActiveSegment() that does not produce valid results and causes the white background effect when it is used with non-standard MPEG1 streams that have not been previously encapsulated in a Quicktime movie file. This function was used in versions 1.0 and 1.01 of the Xtra. Version 1.02 of Mpeg Advance Xtra does not use this function, so proper playback of non-standard MPEG1 files is possible.