I've been reviewing the NUT spec for clarity and bugs and found one small issue with the way chapters are specified for info: chapter_id (s) The ID of the chapter this packet applies to. If zero, the packet applies to the whole file. Positive chapter_id values represent real chapters and MUST NOT overlap. chapter_start (t) timestamp of start of chapter chapter_len (v) Length of chapter in the same timebase as chapter_start. It's likely impossible to partition a file into chapters that cover the whole file without overlapping due to the requirement that chapter_len use the same timebase as chapter_start. Surely you could just cut the chapter lengths short and in most places it would only make a difference of a few frames, but it one wants to use chapters for cutting a file and later being able to rejoin the parts to get the original file, things would break badly. Using chapter_end in its own timebase or having positive chapter_ids implicitly ended by the start of the next chapter would both work, but would break the frozen syntax. Is this an issue anyone cares about? Is there a nice fix? I'll post any more issues I see as I continue to review. Rich