Lossy & Compression

[Newbie]

What is the lossy differance between High quality video
(NTSC) and Video for local playback (2.1 Mbps NTSC)?

Which of the above two formats is higher quality (less
lossy)?

Does DV-AVI (NTSC) have any lossy?

Are DV-AVI files in a compressed file format?

 

[PapaJohn \(MVP\)]

The High quality video (NTSC) is Variable Bitrate with a Quality setting of
75 - with a total bitrate of 2334 kbps

The Video for local playback (2.1 Mbps NTSC) is Constant Bitrate - with a
total bitrate of 2060 kpbs

So the High quality video is better in quality than the video for local
playback.... and the file size is slightly higher also.

DV-AVI files are the same as that laid on the tape in the camcorder.... no
compression from there.

--
PapaJohn

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

..

 

[Guest]

So zipping DV-AVI files for archiving clips after finished
with a project should save massive amount of storage
space, correct, or not?

 

[Bob [MVP]]

No - not correct. DV-AVI is already a compressed video format. You
will not be able to compress it much (if any) more by zipping it. Don't
waste your time trying.

The only way to further compress DV-AVI would be to re-encode it to
another format, such as WMV.

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

 

[Guest]

Bob, I have just compressed a DV-AVI file using WinZip....the file was 118,906,368 bytes and is now 83,138,444 bytes a compression of around a third. This is a compression of about 30%. If you use the new version of winzip it would be even more compressed

----- Bob [MVP] wrote: ----

No - not correct. DV-AVI is already a compressed video format. Yo
will not be able to compress it much (if any) more by zipping it. Don'
waste your time trying

The only way to further compress DV-AVI would be to re-encode it t
another format, such as WMV

-Bo
___________________________
Microsoft MV
Windows XP Media Center Editio
www.microsoft.com/ehom

 

[PapaJohn \(MVP\)]

I'd never zipped one.... just tried a 3 minute one that is 648K in size and
the zipped file is 548K, a compression gain of a bit over 15%... maybe
that's not a lot for compression..... certainly not the 65 to 93% reductions
in size that I see by making high quality WMV from the DV-AVI files....

But it gains something for sure.
--
PapaJohn

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

..

Bob, I have just compressed a DV-AVI file using WinZip....the file was

118,906,368 bytes and is now 83,138,444 bytes a compression of around a
third. This is a compression of about 30%. If you use the new version of
winzip it would be even more compressed.

 

[Guest]

My message was to Bob, who said that you cannot zip a DV-AVI file. I was telling him that you can by up to 30% and still have access to the uncompressed format of DV-AVI. It was not meant in any way to be a comparison over what the uncompressed video quality of a DV-AVI would be like when compared to the highly compressed and lossy format of WMV

 

[Bob [MVP]]

I didn't say you could not do it. I just said you wouldn't be able to
compress it much more. And the reason I suggested that you not waste
your time, is that I assumed you were going to try to compress much
larger files, like several GB.

But the main point I was trying to make was that DV-AVI video _IS_ a
compressed format. Many people incorrectly believe it is uncompressed.

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

My message was to Bob, who said that you cannot zip a DV-AVI file. I

was telling him that you can by up to 30% and still have access to the
uncompressed format of DV-AVI. It was not meant in any way to be a
comparison over what the uncompressed video quality of a DV-AVI would be
like when compared to the highly compressed and lossy format of WMV

 

[Guest]

Hi Bob, yes thats right, you did not say you could not compress it....you said You will not be able to compress it much (if any) more by zipping it and all I was trying to show was that even with a fairly small DV-AVI you can get up to 30% compression. as the size of the file to be compressed increases then usually so does the chance of even higher compression

you should try compressing a small file you can sometimes end up with a file that is bigger than the original and thats because of the gain compressing the small file is less than the overhead in tagging all the code

I did not realise that DV-AVI was compressed I always thought it was a differential stream of data and sometimes called RAW. I suppose you could call that a compression of a kind

you might also be interested to know that the new version of winzip has an even higher compression capability. I did not use that higher ability in my examples because it is only available to users of version 9

----- Bob [MVP] wrote: ----

I didn't say you could not do it. I just said you wouldn't be able t
compress it much more. And the reason I suggested that you not wast
your time, is that I assumed you were going to try to compress muc
larger files, like several GB

But the main point I was trying to make was that DV-AVI video _IS_
compressed format. Many people incorrectly believe it is uncompressed

-Bo
___________________________
Microsoft MV
Windows XP Media Center Editio
www.microsoft.com/ehom

My message was to Bob, who said that you cannot zip a DV-AVI file.

was telling him that you can by up to 30% and still have access to th
uncompressed format of DV-AVI. It was not meant in any way to be
comparison over what the uncompressed video quality of a DV-AVI would b
like when compared to the highly compressed and lossy format of WM

 

[PapaJohn \(MVP\)]

When I think about compression, like taking a BMP image and making a zipped
file from it, I expect about 85% compression.... and I don't expect much
gain when compressing a JPG....

I think Bob's point is valid in that the gain by a zipping isn't substantial
because of the already compressed nature of the format... but sometimes a
30% gain is all you need to make a short DV-AVI clip fit on a CD without
having to get into multiple discs.
--
PapaJohn

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

..

Hi Bob, yes thats right, you did not say you could not compress it....you

said You will not be able to compress it much (if any) more by zipping it
and all I was trying to show was that even with a fairly small DV-AVI you
can get up to 30% compression. as the size of the file to be compressed
increases then usually so does the chance of even higher compression.

you should try compressing a small file you can sometimes end up with a

file that is bigger than the original and thats because of the gain
compressing the small file is less than the overhead in tagging all the
code.

I did not realise that DV-AVI was compressed I always thought it was a

differential stream of data and sometimes called RAW. I suppose you could
call that a compression of a kind.

you might also be interested to know that the new version of winzip has an

even higher compression capability. I did not use that higher ability in my
examples because it is only available to users of version 9.

 

[Guest]

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 mor

----- PapaJohn (MVP) wrote: ----

When I think about compression, like taking a BMP image and making a zippe
file from it, I expect about 85% compression.... and I don't expect muc
gain when compressing a JPG...

I think Bob's point is valid in that the gain by a zipping isn't substantia
because of the already compressed nature of the format... but sometimes
30% gain is all you need to make a short DV-AVI clip fit on a CD withou
having to get into multiple discs

 

[Bob [MVP]]

So zipping DV-AVI files for archiving clips after finished

with a project should save massive amount of storage
space, correct, or not?

This is the message I had originally replied to. So I guess you and I
just have a difference of opinion as to the definition of MASSIVE.
Anyway, glad to hear you're satisfied with the results you're getting
with WinZip. Zip away!....

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

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

----- PapaJohn (MVP) wrote: -----

When I think about compression, like taking a BMP image and making a zipped
file from it, I expect about 85% compression.... and I don't expect much
gain when compressing a JPG....

I think Bob's point is valid in that the gain by a zipping isn't substantial
because of the already compressed nature of the format... but sometimes a
30% gain is all you need to make a short DV-AVI clip fit on a CD without
having to get into multiple discs.
--
PapaJohn

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

..

Hi Bob, yes thats right, you did not say you could not compress

it....you
said You will not be able to compress it much (if any) more by zipping it
and all I was trying to show was that even with a fairly small DV-AVI you
can get up to 30% compression. as the size of the file to be compressed
increases then usually so does the chance of even higher compression. up with a
file that is bigger than the original and thats because of the gain
compressing the small file is less than the overhead in tagging all the
code. it was a
differential stream of data and sometimes called RAW. I suppose you could
call that a compression of a kind. winzip has an
even higher compression capability. I did not use that higher ability in my
examples because it is only available to users of version 9. wouldn't be able
to

compress it much more. And the reason I suggested that you not waste
your time, is that I assumed you were going to try to compress much
larger files, like several GB. video _IS_ a
compressed format. Many people incorrectly believe it is uncompressed.
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome message

file.

I
was telling him that you can by up to 30% and still have

access to
the

uncompressed format of DV-AVI. It was not meant in any way to be a
comparison over what the uncompressed video quality of a

DV-AVI would
be

like when compared to the highly compressed and lossy format of WMV

 

[Guest]

hello bob I am not the person who wrote about massive amount of storage space. 30% is at least a significant saving I think anyway lets leave it at tha

----- Bob [MVP] wrote: ----

So zipping DV-AVI files for archiving clips after finishe
with a project should save massive amount of storag
space, correct, or not

This is the message I had originally replied to. So I guess you and
just have a difference of opinion as to the definition of MASSIVE
Anyway, glad to hear you're satisfied with the results you're gettin
with WinZip. Zip away!...

-Bo
___________________________
Microsoft MV
Windows XP Media Center Editio
www.microsoft.com/ehom

I seem to have missed several messages on this topic. I had no

realised that a comparison between what you can get with a bmp against
jpeg still image was in question or that putting the resultan
compressed file onto a cd. I just wanted to say that here I can compres
a DV-AVI file so that it ends up being 2/3 its original size, I have no
tried it with the three files I have the results were 30% for a 114m
file, 34% for a 1.8gb file and 28% for a 1.5gb file. I would say tha
that result is a long haul from what bob said. maybe i am wrong but let
not labour it any mor

----- PapaJohn (MVP) wrote: ----
When I think about compression, like taking a BMP image an

making a zippe
file from it, I expect about 85% compression.... and I don' expect muc
gain when compressing a JPG...

I think Bob's point is valid in that the gain by a zipping isn'

substantia
because of the already compressed nature of the format... bu sometimes
30% gain is all you need to make a short DV-AVI clip fit on a C withou
having to get into multiple discs
-
PapaJoh

Movie Maker 2 - www.papajohn.or

Photo Story 2 - www.photostory.papajohn.or

.

Hi Bob, yes thats right, you did not say you could not compres

it....yo
said You will not be able to compress it much (if any) more b zipping i
and all I was trying to show was that even with a fairly smal DV-AVI yo
can get up to 30% compression. as the size of the file to b compresse
increases then usually so does the chance of even highe compression up with
file that is bigger than the original and thats because of th gai
compressing the small file is less than the overhead in taggin all th
code it was
differential stream of data and sometimes called RAW. I suppos you coul
call that a compression of a kind winzip has a
even higher compression capability. I did not use that highe ability in m
examples because it is only available to users of version 9 wouldn't be abl
t

compress it much more. And the reason I suggested tha you not wast
your time, is that I assumed you were going to try t compress muc
larger files, like several GB video _IS_
compressed format. Many people incorrectly believe it i uncompressed.
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome message

file.

I
was telling him that you can by up to 30% and still have

access to
the

uncompressed format of DV-AVI. It was not meant in any way to be a
comparison over what the uncompressed video quality of a

DV-AVI would
be

like when compared to the highly compressed and lossy format of WMV

 

[QuietDavid]

I am wondering how othr people store their movies - I found that 60 minutes of shooting results in a 13 gig file when I save it to my HD. Although I have
just fitted a 120 gig HD for my movie work, it will not take long to fill that up.

Leaving the shots on miniDV tape is too expensive for me, and to save them on DVD means using 3 to 4 DVDs for each hour of shooting. That too is will get
pretty expensive after a while.

Naturally it is no good storing them in one of the compression formats that result in losses, so what do others do?

When I make them into a movie they go on DVD OK, but that is no good for the clips that I might want to use for another movie later on.

Ideas much appreciated

David

 

[Digger]

My own opinion is that any archive format should, even though compressed, be
at least as good as DVD in terms of quality. I have personally settled upon
MPEG-2 (Constant bitrate, 8000 kbps, 720x480, 29.970, I-Frame only) and LPCM
Audio (lowest common denominator). The DVD standard is maxed out at 9000
kbps and so, in terms of bitrate, I really haven't lost much.

Irregardless, at 8000 kbps one can easily fit 60 minutes of high quality
video data per/ DVD+R and, using MPEG-2, the files are already in a format
suitable for subsequent editing, additional compression to other formats,
and/ or burning directly to DVD. The idea here is to archive the source
files as I-Frame only; effectively assigns a GOP = 1; DV format is
essentially an I-Frame only format; virtually lossless mpg compression.

 

[Bob [MVP]]

Digger, it's nice that you found an archive format that works for you,
but to claim to get "virtually lossless" MPEG-2 compression???? C'mon
now...

With I-frame-only encoding, you won't be performing any temporal
compression. But since your total bit rate is fixed at 8Mbps, you will
get more spatial compression.

If your video has lots of motion, but not very complex images, the
I-frame-only encoding can produce good results. But if you have video
with complex images, and not a lot of motion, the I-frame-only encoding
will produce worse results.

You can't have your cake and eat it too, and you can't get the same
quality with 8Mbps MPEG-2 as you can get with 25Mbps DV.

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

 

[Digger]

Bob, someone asked for an opinion and I gave one. I was speaking in broadly
defined terms and used "virtually lossless" only in a reference to the
difference between I-Frame and let's say GOP = 18. Reading carefully, you
will no doubt note the semicolon immediately preceding the phrase, and yes,
it was indeed a reflection back to the original subject..."I-Frame only."
If that was misleading, my apologies to you and all others mislead. I never
intended for anyone to think that the process of mpeg encoding is lossless.

As for losses incurred during transcode to lower bitrates, yes, losses are
inevitable and I would think most good folks understand the concept.
Perhaps I am wrong, but I do not think it is always necessary to state the
obvious. Considering the DVD standard is currently about as good as it
gets, motion compensation is literally a fact of life at burn-time anyway
and thus, for purposes of archival, it is simply an either - or - situation.
I choose to save the space up front. I do not however, encourage anyone
else to use my system to the exclusion of all other alternatives, but yes,
it works for me.

As I understand newsgroups, you are certainly free to offer your own
thoughts regarding a less compromising system for permanent archival. Your
reply seems to suggest a fairly good understanding of means and methods and,
as such, I would highly encourage you to contribute something more
beneficial to everyone here, including myself. I look forward to seeing
your own suggested solution with great interest.

 

[PapaJohn]

This is an open newsgroup and I encourage everyone to post whatever they
want to.... I will never disagree with someone's opinion.

But I, like you, have the right to post whatever I want. If I feel that
additional info might help the poster, I'll provide it.... and yes, if the
item is covered on one of websites, I'll point people to it.

You'll never see me going on the offensive with any poster or topic, as you
have done with your post... enough said on my part.
---
PapaJohn

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

Hello Digger. You have to be careful in this newsgroup. You are not

allowed to have an opinion that Papajohn or Bob (both MVP's) do not agree
with. You only have to read all of the messages in this thread to see that.
They are happy to point you to a website where you have to search for a
solution, assuming you understand whats written there. They are not happy to
discuss anything always going on the offensive as soon as anyone tries too.
Its a most strange newsgroup...Microsoft would do better by posting just one
message...forget the questions just got to...........and look in......... A
very strange room. The best thing is just ignore them both and have your
discussion...

 

[Bob [MVP]]

Digger,

I didn't mean to offend you. I'm sorry if I came across that way. It
was obvious by your post that you are knowledgeable in this subject
area.

My reply was really targeting those less experienced readers in the
newsgroup that could have misinterpreted your "lossless" comments.

In hindsight, I should have replaced the first paragraph of my reply
with a simple "FYI:", instead of addressing my comments to you directly.

Thanks for the feedback.

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

 

[Digger]

No problem Bob, and no offense taken. If I am wrong, then I am wrong and
should be corrected. If I write in a style that is easily misunderstood,
then it is probably my fault as well.

Bob, I don't often venture into the public arena very much anymore because,
if one is not always 100% politically correct, someone will be quick to
point it out...if one misspells a term, someone is sure to waste bandwidth
extolling the virtues of a dictionary...if one makes broadly defined
statements, someone will respond with "what is your source, and where is
your proof? I am simply too old to play those kinds of childish games
anymore, so I don't. As a result, I seldom contribute much more than a few
quick sentences in order to address narrowly limited issues.

"Once, I too was a child, but when I became an adult, I put away childish
things, including VH1."<g>

PappaJohn has done a phenomenal job, here, attempting to help people with
his website and pro-active participation. I realized very early on that he
is basically a one-man band and was surprised that he wasn't given more
support by other MVP's, right from the onset. He voluntarily shouldered an
impossible task and has poured a great deal of time into freely developing a
resource, which, although may not solve everyone's problem, is certainly
helpful to many. Upon occasion, I have offered limited input, but it is
PappaJohn who has always been there, and he has been there for "everyone."

Thus, I am actually very happy to see other MVP's participating here, and
sincerely welcome your input and assistance to the group as a whole.
Personalities aside, every little bit helps the main and ultimately, all
will benefit.

Cheers,

--
Digger

Digger,

I didn't mean to offend you. I'm sorry if I came across that way. It
was obvious by your post that you are knowledgeable in this subject
area.

My reply was really targeting those less experienced readers in the
newsgroup that could have misinterpreted your "lossless" comments.

In hindsight, I should have replaced the first paragraph of my reply
with a simple "FYI:", instead of addressing my comments to you directly.

Thanks for the feedback.

-Bob
____________________________
Microsoft MVP
Windows XP Media Center Edition
www.microsoft.com/ehome

<snipped>