| SMPTE stands for the Society of Motion Picture and Television Engineers. This Society influences and often sets or establishes technical standards which are of importance to the entertainment industry. One of these standards, promulgated in 1969 primarily with video editing in mind, defined the method and means for encoding video tape in such a way that each video picture 'frame' on a given video tape is assigned and referable, visually and electronically, by a unique address in sequence with the frame addresses which precede and which follow. |
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SMPTE Time Code ("SMPTE" for short here in Hollywood) involves two
components: (a) so called 'visual' time code and (b) an electronically coded time
code. The former is sometimes called a 'burn window' - visible as an foreground overlay on
a video screen (see Marx Brothers illustration, above), it is usually a black square
containing white numbers in the form....
hours:minutes:seconds:frames
where, in the U.S., the 'seconds' counter increments one digit when the 'frame' counter moves from 29 back to 0 (i.e., 30 frames to each upward tick of the seconds counter... but !). The electronic form [either longitudinal audio time code or VITC (vertical interval time code)] is a parallel 'invisible' equivalent of the visual time code... but while the visible is read by humans on the screen, the latter is read by other machines to facilitate the synchronization or coordinated movement of two or more mechanical or digital devices (video deck with an audio deck with a computer, for example).
In feature film music the 'hours' segment (digits) is almost always used not
for hours but to signify the number of the picture 'reel' from which the video images have
been duped.
Because it provides a medium for the 'lock step' control and referencing of various mechanical devices such as VTRs, audio tape machines and computers, SMPTE Time Code has become an important, nearly a standard ingredient on film scoring stages. Remembering, though, that music for film is 'synchronized' with the picture by the act of composition, SMPTE's importance to the film composer while writing is more a matter of personal work habits and felt convenience as opposed to a newly arrived technological necessity for the art form. In short, indexing is just indexing... any reliable method will do. Some composer's, Bruce Broughton (Academy Award nominated for Silverado), for example, simply writes to real time references. Alan Silvestri (Academy Award nominated for Forrest Gump) writes to film footage references. While others, such as James Newton Howard, Marc Shaiman or Hans Zimmer employ both the indexing and mechanical sync features of SMPTE in their approaches to film composition. All are doing just fine as of this writing!.
"U.S. video moves at thirty (30) frames per second."
No way. Absolutely not. Or, well, it used to be 30fps... way back when video was only black and white! But when video tape machines began to handle full color images years ago, the techs felt they needed to slow the tape transit rate down to 29.97 frames per second. And that's where it remains today (in Europe its 25fps - EBU time code). When they did this, they screwed up the visual time code or 'burn window" - The SMPTE Society had originally designed that window to reflect not only a frame address, but an easily readable 'real time' or digital clock readout. So when the techs slowed things down for color. the digital 'time' you were seeing on the screen at any one point was not the time you were actually consuming to get to that point - for every minute of running time, you were accumulating a real time error of approximately two frames. So SMPTE adopted the DROP/NON-DROP format 'amendment' to their time code standard. Now, if in DROP format, the system is supposed to add two frames to the visual counter at every minute boundary except the decade boundaries (very much like the 'leap year' kludge). This comes to an adjustment of 108 frames an hour and so corrects for the discrepancy. BUT THE TAPE SPEED ALWAYS HAS, AND ALWAYS WILL BE THE SAME regardless of format - 29.97 frames per second. Many sequencer programmers don't get this and so the time code-to-real time conversions in their programs, if they have any at all, are not correct.
"My music will sync with the movie if I use SMPTE with the right black box."
No. Your audio deck or sequencer will synchronize (move along 'in step') with your video deck... that's true. But this has nothing to do with whether your music will match the picture until you realize that you must compose (creatively structure music... chose tempos, note values, meters, etc., whether on paper or ad libidum 'at the keyboard') in a fashion that allows your piece to ebb and flow together with the visual events and emotional moments appearing on the screen. Think of the difference between the medium (tapes and things) and the message (music and visuals). Having a typewriter doesn't ipso facto make one a writer!
