VirtualDub documentation: deciphering errors

Useful error reporting is, unfortunately, one of the toughest programming tasks, especially when the errors must be meaningful to both the users and the programmer.  Please note that many of these errors are caused by third-party device drivers that are not under my control; the best I can do is to modify VirtualDub to try to diagnose the symptoms and elaborate on the errors.

"VCM cannot decompress to a format we can handle."

This means the video compression codec is not accepting 16-bit, 24-bit, or 32-bit RGB as usable decompression formats.  This is very unusual since Video For Windows-based players will have difficulty playing such a video (DirectShow-based players will have better luck).  The most common reason for getting this error is attempting to open a Motion JPEG file when Pegasus PICVideo is installed.  To fix the problem, go to Video/Compression, configure PICVideo MJPEG, and uncheck "force YUY2 output."

"VideoSourceAVI error: unspecified error (-100)"

This error actually means exactly what it says -- unspecified -- but the usual cause of the error is a corrupted frame in your AVI file that the decompression codec rejected.  Such errors are particularly apt to happen with MPEG-4 V3 (DivX) files, since those files tend to be transferred across multiple machines, each of which can introduce errors.  There is no fix for the problem except to reobtain a clean copy.

"Error 422: Cannot add wave buffers."

Capturing with MP3 audio is the usual cause for this capture error.  It doesn't appear on all systems, but on those that do, you may be able to circumvent the error by forcing the audio buffer size to 4096 in Capture Settings.  Capturing with MP3 audio compression in real-time is not recommended for stability and performance reasons.