Timecode

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TIMECODE[1]

Timecode is a digital time-stamp added to each video frame upon recording. Since every frame has its own unique timecode number, or address, you can use it to quickly find images and sounds according to their timecode. Precise frame locatian is what makes non linear editing possible. Mas! digital video cameras and some audio recorders generate and record a timecode signal wheneverthey're recording. Because the timecode caunt advances with each frame, YOti can also easily determine the running time of a shot or of an entire film.
Timecode looks like an advancing digital dock that counts hours, minutes, seconds, and frames. For example, 03:25:45:10 would be three hours, twenty-five minutes, forty-five seconds, and ten frames. These numbers are normally invisible but canbe machine-read and displayed in various ways during recording or playback. In ad. dition, timecode can be burned in-superimposed or incorporated into a litrle window over the picture (see Fig. 1-17). This can be helpful when people using different playback devices must refer to the same clips.
The SMPTE/EBU timecode in use today was standardized in the 1970s. In the United States and other NTSCcountries, it is known as SMPTE (Society of Motion Picture and Television Engineers) timecode-pronounced "simpty." SMPTE timecode has a time base of 29. 97 fps and is used for all video with that frame rate, including HD. .
In Europe and those parts of the world where the PAL broadcast standard predomínates, the EBU (European Broadcasting Union) timecode is used, which has a timebase of 25 fps.A third variant of SMPTE/EBU timecode, used in 24p video recording and sometimes in film cameras, offers a time base of 24 fps.
Analog consumer formats like VHS don't accormmodate timecode in shooting. Some consumer digital formats use a simplified proprietary timecode that may be incompatible with other manufacturers' equipment. Material without timecode can still be edited, but certainoperations can become more difficult (depending on the editing system); in some cases footage can be post-striped with timecode for editing.

[pic]
Fig. 1-17

The idea of timecode is simple: to assign a number to every frame of picture or sound. Timecode is a running 24-hour "dock" that counts hours, minutes, seconds, and frames (see Fig, 1-17). Timecode enables many different aspects ofproduction and postproduction and is pretty much essential for serious video and audio work. Timecode comes in a few different flavors, which can sometimes be confusing.

Types of Timecode
In all video timecode the frame count depends on the frame rate you're working in.
For example, when shooting at 30 fps (either 30p or 60i), timecode can advanee
as high as 23:59:59:29 (twenty-three hours,fifry-nine minutes, fifry-nine seconds,
and twenty-nine frames), One frame later it returns to 00:00:00:00, Note that since there are thirty frames per second, the frame counter only goes up to :29. This rimecode system is called SMPTE nondrop timecode. Many people just refer to it as SMPTE (pronounced "simpty") or "nondrop" (often written "ND"). This is standard, basic timecode often used in NorthAmerica and places where NTSC has been standard.
In Europe and other parts of the world where PAL video has been standard, video is ofren shot at 25 fps (25p or 50i). Here, EBU timecode is used, which has a similar 24-hour dock, except the frame counter runs up to :24 instead of :29.

DROP FRAME TIMECODE.
One of the joys of video is that wiith several formats, the frame rate is just slightlyslower than what you might think it is (by 0.1 percent). For example, 30 fps NTSC video is actually 29.97 fps (which is to say, 60i is really 59.94i). When you shoot 24p video, that usually means 23.976p.
You can't see the 0.1 percent reduction in speed, but it affects the overall running time of the video. Say you watch a movie shot at 29.97 fps that has nondrop timecode, and click a stopwatch...
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