Now for MPEG-4, Apple uses the .m4v extension as a container format, and in fact if you rename an .m4v file to .mp4 it is likely to play on players that only read .mp4 files, since the two format are essentially equivalent.
Some of these movies are .avi files and others are .mp4 files. I've selected the Films section of the iTunes Library and opened the "Home Movies" tab. I've tried several ways of add the files including:
For some reason this fails for all the files except one. The one that works is an .mp4, but strangely none of the other .mp4 files (or any of the .avi files) appear in iTunes after I try to add them to the library.
It turned out that the reason I couldn't import most of the .mp4 files into iTunes is because they were read-only. If you try to import a read-only .mp4 file into iTunes it fails, silently. Once I removed the read-only setting they imported successfully. 041b061a72