A .idx file normally has entries like:
timestamp: 00:00:26:760, filepos: 000000000
timestamp: 00:00:35:202, filepos: 000001000
timestamp: 00:00:41:074, filepos: 000002000
timestamp: 00:00:48:215, filepos: 000003000
There's no show duration, so we use a default and replace it if a new one comes along.
Do you have IDX files with something else in them? Could you provide a full sample?
Thanks.