Determining reel number by reading DTS timecode on 35mm film
June 8th, 2007
In case you ever find yourself the lucky recipient of a used 35mm print with leaders that may or may not be on the correct reels and with no ID frames to verify which reel is which you would be well served to know how to read the DTS timecode. 99.99% of mainstream film has DTS timecode on it. Some smaller art/other films have it too.
The last four bits of the 20 bits between mark positions indicate the reel number. Look for a series of frames that the first bit toggles between 0 and 1 and use one of those frames. If you find a frame that has more than one bit difference it’s the title serial number.
A one is indicated by a transition (a small white dot before or after a slightly longer black spot) while a 0 is indicated by no transition (a long white OR black spot). A sync mark is indicated by the combination of a really long white and black spot.
Entry Filed under: Entertainment Industry, Technology
2 Comments Add your own
1. John Rudd | August 5th, 2007 at 9:26 pm
And, for anyone who’s curious about the rest of what’s shown up there,
a) The two fuzzy lines above the DTS signal are the analog stereo sound track for the film clip, and
b) The grainy white&black squares between the holes that are used to feed the film, and that look like old style “white snow” on a blank tv channel, are the digital audio track for the film.
2. dos | August 6th, 2007 at 7:13 am
Don’t forget the half of the SDDS digital track shown — the cyan strips on the outboard edges of the film.
The “white snow” is the Dolby Digital track… if you look closely you’ll see the Dolby ‘Double D’ trademark in the centre of each data block.
For those really interested… the analog track is a high magenta track complete with silver application. The vast majority of mainstream (or any really) releases went to cyan dye tracks two years ago.
If you’re really really interested, the “sound” in the two frames shown isn’t for the picture (not shown) beside it… it’s for the picture 21 frames behind it, plus or minus a few frames depending on the particular sound format. The DTS timecode is for the picture frame beside it though.
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