Trying to understand "uncompressed" video

Giganews Newsgroups
Subject: Trying to understand "uncompressed" video
Posted by:  Doc (docsavage…@yahoo.com)
Date: Tue, 18 Mar 2008

When the term "compressed" is used in relation to digital files, it's
my understanding that it's basically done one of two ways - "lossless"
where the data is all there but is assembled in such a way that
there's literally a savings of space, sort of like taking a sweater
and cramming it into a small container, where the fibers of the
sweater are jammed very closely together for the purpose saving space
and very rapidly "decoded" when viewing, and "lossy" where there's
actually data removed in such a way as to having minimal impact on
what you perceive when viewing/looking at the results - and adjustable
depending on decisions regarding tradeoff of size and quality. Would
you say this is correct?

However, reflecting on this - if you're compressing something, there
must be some starting point - i.e. some standard of data that's
considered the maximum amount of data possible - which is what I
understand "uncompressed" to be. (For purposes of ths question I'm
ignoring Hi Def, since I assume it's a new/different animal.) Looking
at for example Virtualdub, it gives an option to save as uncompressed
and the files are in fact much larger than the compressed version.

So is there just one kind of "uncompressed" - just one standard? How
would you define it?

When you take say a DV file off a Digital8 camcorder, then save the
file as "uncompressed", how is that file going to be different than
say an mjpeg file you capture via a capture card and then save as
"uncompressed"?

Is there such a thing as capturing uncompressed?  I've ever seen a
consumer camcorder that captured that way particularly given the
storage demands. None of my video software offers an option for
capturing uncompressed.

Thanks for all info.

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