Synchronisation

SMPTE Time Code

Developed by the Society of Motion Picture and Television Engineers; pronounced "Simpty"
Identifies an exact position on tape or hard disk by assigning an address to each specified length
Each time code address is displayed using 8 digits and relates to hours, minutes, seconds and frames (HH:MM:SS:FF)

SMPTE Frame Rate Standards

There are various frame rate standards (frames per second) around the world; they vary from 24 fps to 30 fps;

Black and white video: 30 fps
Colour (USA and Japan): 29.97 fps
• This was chosen by the National Television Standards Committee, and spoilt the 30 fps simplicity. In order for a 30 fps SMPTE reader to translate this rate properly it has to drop 108 frames over the course of an hour. This has become known as drop frame code. Just to confuse matters there is also a 29.97 fps non-drop time code, which is sometimes used.
European Broadcast Union (EBU): 25 fps
• Black-and-white and colour run at the same speed, so a drop-frame code isn't necessary
Film: 24 fps

It's important for the frame rates to match when working with a project that's using a specific rate, otherwise the different media won't sync.

If you're the only one working on the project or you're not working with video or film, the frame rate you use is up to you. 25 fps is the European standard which makes it a good choice, and each frame allows a maximum resolution of 1/25^th of a second. 30 fps allows for a finer frame resolution of 1/30^th of a second.

Working with Video and Timecode

If a client provides a normal video cassette, timecode will often be recorded on the audio track. This type of timecode is known as longitudinal timecode (LTC), another name for SMPTE time code. For both video cassette and digitised clips, the timecode is also commonly 'burnt' into each frame, and provides a visual representation of the SMPTE time in the usual hours:minutes:seconds:frames format.

When working from video tape, the key issue is getting the audio version of the timecode to control playback in your sequencer . The most efficient way to achieve this is via a timecode reader (offered by some MIDI interfaces, for example) that can take the audio timecode signal from your video playback device and convert it into MIDI Time Code (MTC). Once the appropriate synchronisation settings are set this allows your sequencer's playback to follow the video playback, with the VCR acting as the master device. This arrangement works reliably enough and does not put any significant additional strain on the computer running the sequencer.

However, this traditional approach does involve a lot of time spent waiting for the VCR to rewind — hence the growing popularity of working with digitised video. This method has the advantage that the video playback window is controlled by the sequencer's own transport controls and the user can move instantly to any position within the clip by repositioning the Now Time line within the sequence. Playback can also be looped.

In a commercial context (and in an ideal world!), working with digitised video clips may not require any additional hardware, as long as the client can provide the composer with AVI or MOV files, including burnt-in timecode, on CD-ROM. However, playback of the video clip will place an additional load on processor, graphics card and hard drive, so a well-specified computer is recommended.

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