[Tig] 4K digital intermediates using video technology

Kevin Wheatley hxpro
Thu Jun 23 17:20:37 BST 2005

Bob Friesenhahn wrote:
> Clearly both "video" and "digital intermediate" both use data.

indeed, but then all systems are analogue and digital (wave vs

> frames.  This is similar to traditional film editing.  Digital
> Intermediate is normally based on a full-color RGB format with an
> objective to preserve quality regardless of cost.

I don't think anybody does 'regardless of cost' !

> Today's Video (in compressed data form) differs from Digital
> Intermediate in that it is a collective whole (a sequence) using
> compression so that each frame is partially based on preceding frames
> (to support compression).  With this scheme, replacing an existing
> frame requires decompressing a series of frames, replacing the desired
> frame, and then re-compressing any subsequent dependent frames.  It
> may even be necessary to re-write the entire sequence.  Video is also
> typically subsampled in CbYCr (e.g. 4:2:2 or worse) as a way of
> reducing (compressing) color information.
> The Digital Intermediate approach supports random-access
> updates/editing while video is optimized for "linear" editing.

the above does not apply to professional video at least for 10+ years
there have been multiple non-linear digital editing and effects
systems working on everything from pop-promos, advertising, TV and
cinema films, either as custom hardware based solutions or based upon
'standard' computers, they were available before this point but I know
for sure where I've worked linear digital suites were out of the
window (sometimes literally :-) by this point. 

The use of compression has generally been on a frame basis (if you
think about DigiBeta, D1, D5, HDCAM, etc as compression) but inside
the 'computers' this is often uncompressed though not always. Only
broadcast/finished product goes via a MPEG or similar compression.

Its a quality level expectation thing...


| Kevin Wheatley, Cinesite (Europe) Ltd | Nobody thinks this      |
| Senior Technology                     | My employer for certain |
| And Network Systems Architect         | Not even myself         |

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