Lossy & Compression

[PapaJohn \(MVP\)]

Well said Digger, and thanks for the good words.

Sometimes people address me in their initial post in a new thread.... which
causes me to instinctively pull back a bit. I'm never sure if that's a good
reaction on my part or not. I just don't want anyone to have the perception
that the newsgroup is mine, or belongs to a couple or a few of us. We're all
equal here.

The complexities of digital video work are such that no-one knows all the
answers (or even most of them).... I get most of my info from the posts, and
doing some homework from pointers in them.... from people like you, Bob and
many others.

Thanks
--
PapaJohn

Movie Maker 2 - www.papajohn.org
Photo Story 2 - www.photostory.papajohn.org

..

 

[QuietDavid]

Thanks for your reply Digger, much appreciated, tho I confess I don't
understand what you mean by LPCM and GOPs etc.

If I adopt your idea, what do I need to turn the MPEG back into AVI when I need
to edit the clips? Also, I do understand that something is lost when AVI is
turned in MPEG, but what exactly is lost? (I know quality goes down, but what
is taken out of the movie to make it lower quality.

Do they make any good compression utilities for Windows? (I don't have the
right gear for movies on my Mac so use a Windows comp for that) For the Mac we
use a program to compress files called Stuffit. It reduces the size of files a
lot, but doesn't introduce any losses.

Sounds like there is a fortune to be made for someone who xfers this
application to Windows for stuffing movies, if there is no Windows app that
does this. (I saw a post re Zip not reducing files enough to be worthwhile)

Cheers

David

 

[Rich]

I tried to zip a few large AVI files a few days ago. There is a limit with
WinZip to a 3 or 4 gig file (don't remember exactly). Some of my AVI's were
only about 5% reduction, some were in the 15% range. I managed to
temporarily clear up the hard drive space I needed. As I was unzipping all
the AVI's again I recall thinking this sure is taking a long time.

Rich

I seem to have missed several messages on this topic. I had not realised

that a comparison between what you can get with a bmp against a jpeg still
image was in question or that putting the resultant compressed file onto a
cd. I just wanted to say that here I can compress a DV-AVI file so that it
ends up being 2/3 its original size, I have now tried it with the three
files I have the results were 30% for a 114mb file, 34% for a 1.8gb file and
28% for a 1.5gb file. I would say that that result is a long haul from what
bob said. maybe i am wrong but lets not labour it any more

 

[John Kelly]

Hi there,

I am now using the new WinZip 9 with the new higher level of compression.
The results are variable dependent on the content of the file. I tried a 5
minute blank DV-AVI and it compressed down to a very very small file. What
I would call normal video gives quite differing results dependant on the
content. The best I now get is 31% (on the big stuff this is) and the worst
is 5% which is hardly worth the effort. I now have just over 280GB of free
space on my system so its not a problem, but I still compress them if they
are going into my archive (DVD disk storage) DV-AVI being the only method
at hand of storing and preserving the quality.

Best Wishes.....John Kelly
www.the-kellys.org