Alphanumeric sorting on DPX sequences

[rtX]

I just wanted to share a discovery that might cause a problem when generating a DCP from a DPX sequence (discovered by me with help from Carl).

dcp-o-matic sorts the DPX sequence alpha numerically - not numerically. Software like DaVinci Resolve outputs a DPX sequence with an alphabetic first part of the file name and a numeric second part. This means that, for example, Resolve may output a DPX sequence in which the first frame is named say "Test900000.dpx". If the length of your material exceeds 99,999 frames, you will find that say the 140,000th frame is, therefore called "Test1040000.dpx". Be conscious that an alphanumeric sort (as performed by dcp-o-matic) will, put that latter frame ahead of all frames named from "Test900000.dpx through to Test999999.dpx and your finished DCP will have the last part of your film ahead of the first part.

The work around is to make sure that you know the number of frames in your film and make sure that the numbering system you use takes this into account. In a film with about 140,000 frames, you should start the numbering part of the file name somewhere between 100000 and 859000, or a number greater than 1000000. Either that or you must pad the name with leading zeroes.

HTH

[carl]

Thanks for mentioning that. It's on the list to fix:
http://carlh.net/mantis/view.php?id=469