Do all HDtracks.com aif files have four bytes of trailing nulls at end

[simoncn]

The length value in the FORM chunk header is 8 less than the total length of the FORM chunk (same for all chunks), so it sounds like the encoding is correct.

MinimServer never reads anything after the end of the FORM chunk and no users have reported a problem with this, so you should be safe to ignore anything after the end of the FORM chunk.