Typically Offline Editors cut the footage together roughly with a few FX and a rough sound mix.
****Ripple Effect as Ben goes back in time > fade to Black & White > Covert to Analog****
Back in the day when I started you would offline at a low resolution on Avid (say AVR 12) and then once the edit is signed off you would take the tapes to an online linear suite with an Edit Decision List or EDL on a Floppy Disk where the video would be reconstructed from source tape to master tape at full resolution.
Usually you would then take an OMF file with Audio Media on a Jazz Disk to the Dubbing Suite where the Sound dub would be done by an Engineer and then laid back to either the Master or a 1st Generation copy.
****Ripple Effect as Ben comes forward 10 Years > Colour restored > Full uncompressed digital loveliness****
The Offline process nowadays for all non-linear usually consists of Offline (usually using DV to save processing time & storage space) at full SD res and a much more finished edit often with graphics and effects - sometimes the Offline edit is so good that very little needs to be done.
The role of a good onliner is to assemble the final edit, polish and make broadcast ready the edit for mastering and to correct any mistakes or perform last minute edits.
More and more online editors are also graders and can also do final sound level checks. They should also be technically savvy and able to perform miracles!
Basically:
Offline = Rough Edit Version(s)
Online = Final Edit Master
You can be both but I often find lots of people can be good offline editors but lack the nit picking, techinal background and attention to detail that a good onliner will have.
Post Edited (01-02-06 20:05)
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