Telecine:
The Edifis Sting disk storage system has been specifically designed for
use in the Telecine, Film and Colour Corrector environments. The key
features fall into four distinct application areas:
1. Use as a Colour corrector cache store.
2. Integral Wipe generator for frame comparison.
3. Scratchbox image retouching for sparkle, scratch removal and
travelling matte applications.
4. Uncompressed 10 Bit disk recorder and conformer with discontinuous
timecode capability.
Cache Recorder:
The colour corrector typically uses one disk channel of the Sting for
grabbing still frames. These are used as reference frames to compare
grades for scene-scene continuity. Both Pogle and DaVinci systems
perform this grab function using a custom interface which involves no
pre-roll. The Pogle system can grab frames manually, automatically or
as info. Frames. Proxy images are kept on the Pogle system, the full
resolution images being on the Sting. They are recalled by 'clicking'
the proxy image. The images reside in a reserved area at the start of
the clip on channel 1 of the Sting. During all these operations, the
second channel is available for play out of previous jobs.
Integral Wipe Generator:
Comparison of frames from different scenes can be performed using the
wipe generator. Sources can be between either disk channels, disk to
external source or between two external sources. Although still frames
are typically required, the wipe can be performed between moving
sources as well.
A T-Bar control interface, is used to control the wipe. Several shapes are possible including squares and corner wipes.
A simple Chroma-Keyer is also included to allow removal of blue screens. A background can be inserted from disk or external video input so ease the colour correction process.
Recording, Conforming and Timecode Transparency:
In simple terms, the material recorded can be played out in any order whilst maintaining original timecode.
Clips (Video and Audio contiguous frames) have names, in/out points, cues etc. They also have two time codes - internal disk code and external code.
The external code is held in a timeline that runs for the length of the recording. At any point on the timeline, the external code can change to a new base point. Thus only the changes or discontinuities need be stored. A number of options exist as to when the external code is entered into the timeline. Typically this is done whenever the system records new video. The machine behaves in same way as a VTR. The key advantage of the non linear storage is that a given timecode can be found directly by system software - rather than having to wind the deck. This allows non monotonic (later clips at earlier timecode) and duplicate timecode to be handled.
The external code cue or reset points are shown graphically on the control panel. They can be used as locate points even modified manually. Manual modification effectively re-stripes 'the tape' immediately from that cue point up to the next point.
Typically in grading, the machine is used to record successive complete graded shots. These are recorded one after another down the 'tape'. Each shot has with it its own code. No pre-extension of the working clip or job need be done. Free space is allocated as the recording progresses. If the resulting clip is played back, then the video, audio and timecode (LTC) come back exactly as recorded.
Play out may, however, be required in a different order to the original grading. This is accomplished by breaking the original job up into separate clips - one per continuous timecode block. A special function performs this automatically - more manually if required. Once the shots exist as separate clips, they can be played out in any order. The clips to be played are simply dragged into the correct sequence using the WEB browser interface. Alternatively an EDL can be used or a text based shot list.
A simple mechanism is employed to retrospectively re-stripe the last recording's timecode after the completion of the record pass. This alleviates the need to pre-stripe any code to 'edit into' from the colour-corrector.