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RE: [AV Media Matters] The FILE is the thing ! Was -Digitizing Audio and Video
Some good points are raised here. A shorter reply.
I am a firm supporter of MXF, and have backed off a little on AAF only
because it is still very much in transition - in fact we will be
supporting MXF in the beta release on the SAMMA product that we are
currently developing (more on that some day soon). Both MXF and AAF are
file CONTAINERS, and as such what becomes of critical importance is the
files that are contained within either MXF or AAF. Our company has
received a generous grant from the Dance Heritage Coalition and the
Mellon Foundation to explore precisely these issues for the dance
community, and we are far from done with our work.
It is clear (to me at least) that the main issue is compression. If you
take away a proprietary encoding scheme, then most of these issues
become non-issues. This is the current situation with Audio files. 10
years ago there was extensive discussion of compression of Audio for
storage on servers, now it is a non-issue. This is due almost soley to
the reduction in the cost of storage. The reduction in the cost of
storage is an industry trend that has existed for many years. Although
"Moore's Law" is often misquoted in this area (Moore's Law had nothing
to do with Storage), it is important to note that over the years there
has been a steady decrease in the cost per storage as well as the
reduction in the physical size that storage has occupied. I do not argue
that bandwidth is also an extremely important element here, but the
bandwidth required for regular NTSC/PAL is well known and relatively
modest (as compared to many other applications such as HDTV). While I
anticipate that compression will be used for many years for bandwidth
sensitive applicatons (such as broadcast or distribution), the use of
LOSSY compression as a tool for reducing storage size begins to lose its
benefits as the incremental cost of saving the information in a LossLESS
fashion decreases. IF asked most people would certainly prefer to store
materials in a lossLESS fashion (which is identical to uncompressed for
this discussion) - the issue is clearly one of money. So, ASSUMING that
storage costs will continue to plummet over time, is there any real long
term point in even considering LOSSY compression for AV assets? I think
that the answer is no.
If the file itself is not LOSSY compressed there is really no Morphing
issue whatsoever. The data is the same when uncompressed as the original
- if you want to use a different type of lossless compression then all
one has to do is simply inflate the file and recompress it - again in a
lossless fashion. There is NO loss whatsoever in this process, and this
is a very simple type of scripting process that can run in batch mode in
the middle of the night when nothing else is going on - similar to the
backup process.
We are now in an "in between" time period, and I do not think that there
is anything wrong with recognizing that. Now it still is just a bit too
expensive for some archives. I do not see this as being the case even 5
years from now. Short period of time in the scope of things. To me it is
clear that the direction to go in is LOSSLESS compression or no
compression of analog AV assets. If you do there is really NO issue.
jim
Richard Hess wrote:
>
> I love it when the Jims discuss things!
>
> Jim (Wheeler) I agree with your point that archives cannot afford
> things--but, from my experience, archives often can't afford the initial
>
> migration from the original format.
>
> Jim (Lindner), I agree with your points about migration being the only
> way
> to ensure that files remain readable. In your point (4), below, you
> discuss
> the application to read the file as one of the challenges. I see that
> point
> involving any media that you lock away for extended periods of time:
> disk,
> tape, disc, flash ram, whatever. However, the challenge of morphing
> files
> from one form to another is far more daunting than the challenge of
> migrating files from one medium to another.
>
> Let's (for the sake of this discussion) agree that "morphing" the file
> means changing it in a trivial or non-trivial way so a later application
>
> may read it. In this process, you may break the ability of the
> application
> that generated it to read it. Let's take, for example, a Microsoft Word
> document that was created in version 6.0, the Windows 3.1 version. When
> you
> open that document in Word 2002, and save it, Version 6.0 can no longer
> read it, unless you use the "save as old version" command from Word
> 2002.
> When you "save as old version" you lose features that you embedded in
> Word
> 2002.
>
> Note, however, that this morphing is done by the application which, over
> at
> least a short period of time can at least demonstrate read compatibility
>
> (to some degree) with older versions of the file.
>
> Another example from word processing. I have some files that are in Word
>
> Perfect 4.2, I believe. Microsoft Word 97 and 2002 do not recognize
> these
> files. If I open them in Word Perfect for DOS version 5.0 and then save
> them WP 5.0 has created files that MS Word 97 and 2002 CAN read and then
>
> save in their native formats. This is an example of a two-step MORPHING
> process, and one of the things that Jim (L) rightfully is afraid of with
>
> media files.
>
> In general, the concept of data MIGRATION, is copying the same file from
>
> medium one to medium two assuring that it is not corrupted in any way. I
> am
> not sure how much MORPHING of the file happens during this MIGRATION
> process, as the MIGRATION generally happens at the operating
> system/storage
> file system level rather than at the application level.
>
> Let's look at another simple example from the word processing world--the
>
> reason for this will become clear in a moment. If I have a document in
> Word, I can fully edit it and all of the component parts are accessible
> for
> modification. If I publish this as an Adobe Acrobat (PDF) document, I no
>
> longer have the document in as editable a form as when I had it in Word.
>
> That is the beauty of the system, that is the pitfall of the system. I
> suspect that Adobe (and if they're no longer around, someone else) will
> maintain long-term readability of PDF files on a variety of operating
> systems (including the Palm, by the way). However the PDF is not the
> same
> as the Word document for repurposing (editing) for future use. I can
> capture pieces of the PDF, but, for example, the graphics are
> down-rez'd
> and the entire document is often (and should be) password protected for
> extracting pieces.
>
> This is where MXF and AAF come in. These are universal formats. In some
> respects, one can think of AAF as the Word document with all of the
> instructions and all of the pieces for assembling the final video. The
> final video, in a flattened form, can be distributed as an MXF file--and
>
> that is, at least on a simple level, the moving image equivalent of the
> Adobe Acrobat file.
>
> AAF is certainly an emerging standard and it, in itself, is changing
> over time.
>
> So, I think we all agree that the file is the thing (thanks Jim (?) for
> a
> good subject line), but I'm not sure that we agree or understand how
> that
> file will be treated.
>
> If we assume that the file has to be MORPHED as it is MIGRATED that is a
>
> new responsibility to put on the IT professionals as I understand their
> job
> description. There are artistic judgments in assessing how to MORPH a
> file--at least to the extent of "what options do you still want to do on
>
> the file." Perhaps the options can remain completely open, but
> rich-content, editable files such as AAF pose huge challenges for
> maintaining compatibility over time.
>
> One of these challenges is that the transforms applied to media are to
> some
> extent proprietary and the transform in software application "A" may
> sound
> different from an equivalent function in software application "B." When
> we
> add in the option of dedicated hardware processing (yes, that is still
> done, especially in video, just ask the folks like Quantel) then the
> gamut
> of processing possibilities broadens. One of the features of AAF is the
> ability of proprietary processes to encode "dark metadata" known only to
>
> that proprietary process. You will need that proprietary process to
> render
> the file.
>
> Bottom line, we're best off -- in my opinion -- of storing individual
> elements as well as rendered copies in the way the producer wanted to
> see
> them. In essence the final PDF plus the individual text and graphic
> elements that went into the PDF. This is not so we can create the final
> PDF
> again--we already have that--but so we can repurpose pieces of that to
> satisfy different demands of different revenue streams by using the same
>
> underlying data in differing combinations to tell different stories.
>
> If we accept that limitation, then the MORPHING process becomes less
> challenging and might be able to be done as part of the MIGRATION
> process,
> but I still see the MORPHING as a separate step. I also see PDFs, JPGs,
> and
> MXFs as long-term readable formats that will be supported at least for
> input well into the future, unlike Word Perfect 4.2 for DOS.
>
> But now, back to Jim W.'s initial question, what do we do for archives
> who
> don't have the budget and their material is wasting away? We had a long
> discussion on AMIA-L and a bit on ARSCLIST about an audio archive that
> we
> suspect is wasting away due to too-high humidity in their storage
> environment.
>
> We took a poll and received mixed responses--no consensus--but the
> responses were predictable based on the prejudices and experiences of
> the
> respondents. The bottom line, however, is that it's probably less
> costly--at least for the near term--to fix the environmental problems
> than
> it is to transfer the complete collection--and then maybe do it again in
>
> 20-40 years. There is no funding for a file-based, IT-based central
> archive
> for this material. There should be, but there isn't.
>
> I[ve deleted the posts by the two Jims--if you want me to forward them
> to
> you, please let me know.
>
> Cheers,
>
> Richard
>
>
James Lindner
Moderator: AV Media Matters Listserve
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