This program is designed to fix the problem with playing movies recorded
with Canon digital cameras on some Windows versions.

Canon digital photo cameras from PowerShot series (it's possible that the
problem may occur with other models too) are able to record movies in AVI
format. However, on some Windows versions there is a problem with playing
these files - the file is playing at incorrect speed, either much faster
or much slower than it should, which results (among others) in sound
distortion - very high or very low pitch (this is independent from the
program used to play the file; the problem seems to be related to DirectX
layer itself and not to a particular player application).

This problem comes from the fact that the camera records the sound at sampling
rate 11024 Hz, which is nonstandard for Windows (the standard frequency for
Windows is 11025 Hz). In some situations, Windows seem to be unable to play
the sound correctly at that rate (in other systems - like Linux - this problem
does not occur).

Due to a very small difference between 11024 Hz and 11025 Hz we can simply
force the file to play at 11025 Hz rate, which removes the problem. Such a
change is virtually unnoticeable - with a 10-minute movie, the difference in
playing time is around 0.1 second. The included program does exactly this -
it checks whether an AVI file has an audio sampling rate of 11024 Hz in it's
header and changes this value to 11025 Hz if found.

To use the program, type:

fixavi filename.avi

on the DOS/Windows command line. "filename.avi" is of course the name of the
file you want to "fix". The file must have the audio track encoded at 11024 Hz;
if it doesn't, the program will not modify any data in the file.
As the program is written in Turbo Pascal for DOS, it doesn't understand
long Windows filenames. If you want to convert a file with a long name, you
must specify it's short name as "filename.avi" (you can see the short name in
the leftmost column of the output from a "dir" command). However, files from
photo cameras usually have names that fit in the 8+3 characters filename limit
(in particular, movie files from Canon cameras we are talking about have names
of the form MVI_nnnn.AVI where nnnn is a four-digit number).

Source code is also included (the main file fixavi.pas and the library module
support.pas). The program is distributed under the GPL licence.

Jaroslaw Rafa
raj@ap.krakow.pl