Merging VCube, User Manual

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Applications : Non Compensated Telecine at 24 fps Page 165
Applications
Non Compensated Telecine at 24 fps
A non-compensated telecine can be used with VCube. A film frame corresponds to a video frame, VCube can play-
back a 25 fps video capture at 24 fps in order to respect the real duration of the film and to avoid typical pitch/time
audio processing.
After a regular PAL capture, the Composition must be set to 24 fps. The fps information embedded in the Media
File cannot be changed from 24 fps to 25 fps to give correct playback. However it is possible to change the play-
back speed of the Clip in the VCube Timeline:
To change the Composition frame rate:
Settings > Format & Sync : Composition Video Format : Composition Frame Rate
To change the Clip Playback Speed: Double-click on the corresponding Clip in the Timeline to display Clip Info
Clips : Speed , set to 24->25 (96%).
Note: 1. VCube can still be synchronized to a 25 fps house clock.
Note: 2. Both external (25fps) or internal (24fps) TimeCodes can be displayed.
24fps Composition Chasing other Timecodes
VCube is able to play a 24 frames per second Composition, chasing a 25, 29.97 or 30 frames per second TimeCode.
VCube doesn't interpolate frames. It only uses its own ultra precise internal clock to manage the Composition
playback. The external reference TimeCode is only used to synchronize the internal clock.
When the reference TimeCode is different from the Composition TimeCode, it produces artefacts when seeking a
particular frame in the Composition. In the above example, red lines indicate that two different 30 fps TimeCode
positions can recall the same frame in a 24 fps Composition. The blue line does the same for a 25 fps reference
TimeCode.
Note: In nominal playback, such artefacts will only appear if Clips with mismatched frame rates
are included in the Composition. The Playback speed can be edited in Clips Info, enabling correct
playback. This feature is very useful at 25 fps for uncompensated telecine (frame per frame cap-
ture on a PAL video).