Re: [AV Media Matters] Compression discussion.

[Bumdrum@sunbeach.net]

Hello there,

I must say I really enjoyed this posting...I've been following this
discussion
for many months and my mind was beginning to wobble BUT I like this
perspective...especially since I am not all that technical a
person....simply
interested in safeguarding a Barbados and Caribbean heritage...
Junior

tony gardner wrote:

>> compression in the video domain has gotten so darn
>> confusing that it is hard to define exactly what you are saying no to.
>
>I agree, especially as the picture quality depends on the coder for a
given
>MPEG level, and so is a question of operational judgement, good design and
>the right ancillary equipment before coding.
>
>>
>> BUT
>>
>> From an archival perspective there are many other concerns that may not
>> exist in current broadcast operations.  The needs are different and
>> therefore the requirements are somewhat different as well.  For one
>> thing ... one of the goals is to "pass the flame" on in
>> an intact fashion.  Why?  Well because we cannot anticipate now what
>> technology may evolve in the near and not so near future - and so
>> keeping the original content in a fashion that is as close to the way it
>> was in origination becomes very important. ...
>> If you already have high bandwidth should you reduce it for
>> archival storage?  I think that the answer is clearly no.  Materials
>> that have been acquired in already reduced bandwidth is another issue -
>> if you have already lost it.... there is no going back.
>
>This is the core of the argument. I do not accept your 'clearly no'
>statement - only that what you do, how you compress takes into account
these
>points seriously, and that a reasoned intelligent judgement is made. As
far
>as possible short term conveniance and cost must not be allowed to
determine
>the issue. The archivist has indeed a responsibility to keep things
properly
>and the accountant must accept that!
>
>BUT
>Film is different and news footage is different, but ...
>For material originated in a TV studio in SDI, and post produced without
any
>(further) compression to the final master tape, what now for the archiving
>of that? I can keep the original tape, but, as I said in another posting,
>I'm not sure of the durability of availability of current uncompressed
>formats. If I chose digital betacam, say, then I can get a machine when I
>need one several or more years from now, (at least seing from europe). But
I
>have compressed but remain very close indeed to the original uncompressed
>pictures - very close indeed. And I would argue that I have a good quality
>headroom as well, ie I can go to any of the current lower bit rate
>compression schemes for editing, versioning and transmission without
>significant concatenation problems.
>At the other end I would never suggest a DVD video as a suitable long term
>archive of such a programme, nor any of the low bit rate streaming
formats,
>or AVIs or whatever.
>Where my doubts are is in the middle - what about the professional 50Mbps
>formats - and maybe even the 20/25Mbps? No one says there won't be some
>artefacts, here and there - the decision is what you can accept. This I
>would argue is largely material dependant and different say for a major TV
>film series and say a based political discussion programme. (The resale
>value in ten years is higher for the first than the second).
>'Pass the flame on intact' is not the same as not compressing, because the
>compressed version can be so near the original as not to matter, and still
>be robust enough to go survive more compression in transmission etc..
>
>I've a feeling this correspondnace could go on forever ...
>
>best wishes
>tony
>
>                                   Tony Gardner
>
>                Press and Communication Service
>                               Audiovisual Unit
>                                    TRE120 1/63
>                            European Commission
>                   Wetstraat 200  1049 Brussels
>
>           +32 2 299 9161   +32 2 299 9218(fax)
>                             +32 75 828051(gsm)
>
>                     anthony.gardner@cec.eu.int
>