Aer Lingus
Topic Author
Posts: 1217
Joined: Sun May 14, 2000 4:06 am

A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 4:30 am

Woh, when I saw the large version of this shot I was completely taken aback at the loss in quality.


Click for large version
Click here for full size photo!

Photo © Martin O'Connell



The HUGE amount of compression visable in the sky and on the tail is unbelieveable. Honestly now if I viewed that shot in the large version and if it wasnt my own, I'd say to myself "how did that get in ?".
The strage thing is that when I uploaded it, it had NO compression whatsoeverand looked completely different.....

And no this aint some shameless plug......

Martin
 
jderden777
Posts: 1677
Joined: Fri Jan 21, 2000 9:56 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 4:34 am

Martin,
the shot looks absolutely fine to me....not compressed at all...it's perfect! i would definitely have added it to my database...i don't see any compression in the sky...and the tail...it looks good to me....

jonathan d.
"my soul is in the sky" - shakespeare
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 4:53 am

I had the same problem with one of my photos


Click for large version
Click here for full size photo!

Photo © Staffan Hardie



Here is the same photo before the compression.
Click here

Don't know what could be done about it though, if the photos were much larger it would increase the server loads too much.

Regards,

Staffan
 
cfalk
Posts: 10221
Joined: Mon Dec 04, 2000 6:38 pm

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 4:54 am

I agree with Jon - I see nothing wrong.

Nice lighting.

Charles
The only thing you should feel when shooting a terrorist: Recoil.
 
Aer Lingus
Topic Author
Posts: 1217
Joined: Sun May 14, 2000 4:06 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 5:04 am

Really ? ?

the way this is going people are going to think this IS a plugging session..........god........

 
LGW
Posts: 4281
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 5:06 am

Martin, is this that post you where saying you where going to create to boost your average?

LGW

 Big thumbs up  Big thumbs up Big thumbs up
 
McRingRing
Posts: 1028
Joined: Mon Dec 10, 2001 2:59 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 5:23 am

I can see some compression by the nose, the wing and the tail, but it doesn't look like that big of a deal. Of course when you upload something and it turns out looking different it's easy to get upset. Especially since the scripts are supposed to decrease the file size without any loss in quality.
B==============) ~~~~
 
H. Simpson
Posts: 933
Joined: Sat Mar 10, 2001 7:30 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 5:42 am

may be your eyes are compressed??? Big grin
 
Guest

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:18 am

When I see some photo's on my screen looking crap, check your monitor.
It can change from 32bit back down to 16 bit.. or fewer colours?

Some other programmes can change a PC's monitor settings.
(Like my son's Championship Manager!)

Gerry/EDI
 
Mudozvon
Posts: 87
Joined: Wed Nov 03, 1999 6:02 pm

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:42 am

Very nice shot. The shadow from the wing is Something!!!
Nothing wrong to my eye here.
Leonid
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:50 am

I nominate Gerry for the Nobel prize, changing the monitor to 32 bit actually helps...

Guess this thread can be archived or deleted now...

Staffan
 
EGGD
Posts: 11880
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:52 am

I see that compression, on both shots, maybe it is you guys who should get your monitors checked out! I typed out some crap before about why you see the compression so bad on these shots, but I guess its not really that important.

Regards

Dan  Acting devilish

 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:55 am

I also noticed a funny thing, if I open an a.net photo while in 16 bit, then switch the monitor to 32 bit and open the same photo in a new window, they don't look the same compared side by side...  Confused

Thanks alot, now I'll enjoy this alot more!!  Smile/happy/getting dizzy

 
EGGD
Posts: 11880
Joined: Sat Feb 24, 2001 12:01 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 7:03 am

cooooooool, now i've changed it to 32bit it looks twice as bad!!!
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 7:08 am

Reload and it won't!

 
Guest

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 8:00 am

I was just about to flame you Staffan!
.... Thanks for the apology!

 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 8:13 am

I'm confused...did I say something wrong? It wasn't aimed as a rude message.

Sorry if you missunderstood me.

Regards,

Staffan  Smile
 
Guest

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 8:18 am

You mean it really helped?
The English language is such an ambiguous communication device!

Glad to be of service!

And what about Martin... resolved?

Gerry/EDI
 
Staffan
Posts: 3879
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 8:21 am

Yeah, it looks perfect now! Thanks!

Staffan  Smile/happy/getting dizzy
 
TomH
Posts: 950
Joined: Thu May 27, 1999 4:13 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 8:40 am

Martin,
Well, you got me to open the thing up twice, so I suppose that helps the hit counter. I don't understand how you feel you can judge the amount of compression by looking at sky, rather than detail on the aircraft itself.

More importantly, what was the file size you uploaded compared to the large version on A.net? That ratio should tell you something significant about the actual amount of compression. I noticed also that your H was <1024. I thought we were trying to standardize on 1024 at Johan's suggestion about 6-8 months ago. Yes, I know, it's optional, but I'm curious to know why so many folks aren't following the recommendation.
 
ckw
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 10:25 am

Tom, for info, compression is more detectable in the sky (or any areas of similar tone) than the aircraft because .jpeg works by compressing areas of similarity by throwing away "unnecessary" pixels. This can become apparent as a "blocky" appearance on what should be smooth tones (because some of the transitional colours have been dumped).

In areas where there are significant contrast variations (eg. on the plane itself) the compression program assumes this means interesting detail, so throws away less.

Another thought on this - don't some dial-up "speed-up" programs apply compression on the fly? Is it possible some ISP's might do this?

Cheers,

Colin
Colin K. Work, Pixstel
 
da Fwog
Posts: 845
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 3:10 pm

Colin, how would this work?!!? You have to get the data before you can compress it, by which time it's already reached your PC. You could only compress OUTGOING data! As for ISPs doing it - the processing overhead to re-compress a jpg would be prohibitive. Any idea how many there are in the average web page?  Nuts

Agree with your comment about the sky though. And the reason this is more detectable if you don't have your graphics card set to enough colours is that the exact colour chosen by the compression algorithm may not be available, so your graphics card will choose the next nearest one. This just compounds the "blocky" effect of the compression and makes it look even worse!
 
ckw
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Joined: Fri Aug 27, 2010 12:26 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 6:05 pm

Chris - you're right of course - it was late, I'd just spent hours fixing my PC, I was so releived just to be able to get it online again that I wrote any old rubbish - I was thinking of on-the-fly compression on the server side.

Cheers,

Colin
Colin K. Work, Pixstel
 
TomH
Posts: 950
Joined: Thu May 27, 1999 4:13 am

RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 9:24 pm

Colin,
I understand what you are saying about the sky. I think GIF files work in a similar manner, compressing more the white background of a document and less the printed area. Still, when someone says they can see it in the sky, are they looking at the image 100% or (more likely) some greater magnification? I didn't notice anything in the sky at 100%, but I haven't taken a second look.

I have heard AOL.com compresses all images unless you contact them and request they desist. I would assume this is on xmit side of their server of course.
Tom
 
ckw
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RE: A.net Compression. Definitely Needs Reviewing

Tue Jan 15, 2002 10:09 pm

Tom - I can't see any compression either - I think it was a case of people viewing in with a 16 bit display setting - can look similar. Gif files work slightly differently in that they use a very limited palatte for images - which is why its a poor format for photos.

Cheers,

Colin
Colin K. Work, Pixstel
 
Aer Lingus
Topic Author
Posts: 1217
Joined: Sun May 14, 2000 4:06 am

RE: A.net Compression. Definitely Needs Reviewing

Wed Jan 16, 2002 3:31 am

Thank you all for the inputs and please please please understand that this was not any gimmic to get extra views.
It was something that I felt looked really bad on my PC and thought made my shot look terrible, it really did. Some may feel that this was a waste of forum space and I apologise for it if thats the way you feel

Tom. I never knew anything about a standardised 1024 sized pic and the shot was uploaded UNCOMPRESSED (550K+)

Martin
 
TomH
Posts: 950
Joined: Thu May 27, 1999 4:13 am

RE: A.net Compression. Definitely Needs Reviewing

Wed Jan 16, 2002 9:21 am

Martin,
It was a while back that the image deminsion size of 1024 was brought up. I increased my average width to agree with what I took to be a new standard. I know that many contributors continue to put up smaller images so I guess it's your choice. Actually, when I'm uploading one of my old marginal B&W images scanned from a print (for which I no longer posses the negative) I have been tempted to upload a smaller image because quite simply, smaller in the case of marginal images looks better whether on the screen or on the printed page.

No way could I upload a 550K image with my dialup connection at home. That would take about 12 minutes, I think. When I opened your Airbus image large, it was only 66K according to the properties information. There does seem to be image manipulation going on, because one shot I recently upload was 207K on my hard drive but appears to be 156K on A.net. Image W size remained at 1024 but H was decreased slightly, probably due to the black bar at the bottom.

A bit confusing. Oh well, lots to learn.

Tom
 
da Fwog
Posts: 845
Joined: Thu Aug 19, 1999 5:25 am

RE: A.net Compression. Definitely Needs Reviewing

Wed Jan 16, 2002 4:11 pm

A.N. DOES compress the jpgs you upload. This is pretty sensible when you think about it. Some people optimize their jpgs before uploading (to get maximum compression with minimal loss of quality), and some people upload uncompressed pics. If some sort of re-compression was not performed, visitors to the site would find an uneven performance: some of the photos would open really quickly while others would take an age. Remember that the vast majority of people still use a dial up connection! Apart from which, the amount of extra storage space and bandwidth required to serve up those uncompressed images would need to be multiplied by several times.

I don't think there's really a problem with compression. Of course, from a pure quality point of view I'd like to see slightly less compression of the images, but as they are now, they're not bothering me.
 
TomH
Posts: 950
Joined: Thu May 27, 1999 4:13 am

Fwoggie

Fri Jan 18, 2002 2:28 am

Is the compression automatic? Hard to imagine they would do it manually. They can't tell how much compression I have already applied, right? So how are they going to know (without looking at the image) if they are damaging my image through excessive compression?
 
ckw
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RE: Fwoggie

Fri Jan 18, 2002 2:33 am

Tom - I think that's why they recommend upload with 0 compression, as the subsequent compression has a cumulative effect.

Cheers,

Colin
Colin K. Work, Pixstel
 
TomH
Posts: 950
Joined: Thu May 27, 1999 4:13 am

Colin

Fri Jan 18, 2002 10:12 am

You are probably right on reason for the 0 compression request. To be truthful, I laughed when I first read that 0 compression advice way back. To me, it seemed to defeat the purpose of JPEG in the first place. I have never uploaded at 0 compression. Most of mine are between 10-20%. Most of my color images come from PhotoCD, so I have no choice but to crunch them myself, otherwise I would never have time for the upload!

I have been printing B&W 5X8s lately (first time I've been in the darkroom in several years), and even those scans on my flatbed get compressed a little. Maybe 5-8%. I do regret however, that after all my care in editing, getting the final unsharp/sharp where I want it, that my lossy JPEG gets opened and then recompressed. Still, viewing them on A.net they don't look too far removed in quality from the original "parent" JPEG files I have on my hard drive.

Oh well, this works for me, so I'll keep at it.

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