wwp@yahoogroups.com:
Re: bad conversion for small window
Thomas 2012-Dec-19 02:22:00
Well, Markus, I made(900x900) and (2000x2000) cubic QTVRs with Pano2VR and uploaded them under the "QTVR" section of prep page. They do show in the preview without artefacts, however they are requiring QuickTime. If I ask for Flash I still get QT. I suppose this is OK but a little inconvenient since my browsers disable QT by default. Is there something I could do to get these files into KRPano?
The prep page is also complaining that the "required" jpeg file is not present (I deleted it).
-- Tom
--- In #removed#, Yahoo Account wrote:
Yes, your description is right. The one thing to keep in mind is a) krpano can read JPEG-compressed QTVRs (including preview etc.), and b) the size of one tile must not be bigger than 2048 x 2048 pixels.
p2vr uses JPEG, so that's covered. The size of one cube face is displayed in the QTVR export settings, and the "tiling" setting is part of that, beneath the quality slider.
-Markus
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From: Thomas
To: #removed#
Sent: Tuesday, December 11, 2012 5:14 AM
Subject: Re: bad conversion for small window
Thanks for the explanation, Markus.
I will try my own conversion to cubic. But I am not familiar with creating .mov files for KRPano, nor tiled .mov filse. Do I understand correctly that all I need to do is create a small and a large .mov with Pano2VR and upload those? What tile number and cube face size should I use for best displayed resolution?
-- Tom
--- In #removed#, Yahoo Account wrote:
Hi there,
the reason for the compression artifacts is that the images are processed to result in cube faces of 1800x1800 pixels, with a jpeg level of ~70 (Pano2VR scale). It's a setting that has worked reasonably well in the past with a range of images with lots of noise/detail resulting in large jpegs while not introducing too much banding in images with large uniform gradients (e.g. sky). Of course it's a trade-off between fidelity, storage space, transmission time and server load.
Technically, the conversion is a ?drop-file-on-pano2vr? script running on an offsite computer that does periodic checks to see what needs to be converted, then uses the original image as input and an 1800x1800 cube face output setting. The .mov file stemming from that is compatible with the krpano flash player we're using, and serving one file (essentially six jpegs in a .mov wrapper) is easier on the server than pointing it at six cube faces which would result in six data streams instead of just one.
For maximum control, you can prepare and upload two .mov files (one small, one big, jpeg compressed, cube faces can/should be tiled for the big version). If those files are present, the server will use those custom-made files and send them unaltered to the flash player. (keeping the jpeg too would be nice, for thumbnail creation reasons) No guarantee that it'll work on the first try, though. Depending on the visitor's flash version, anything beyond 2000 pixels per tile per cube face may cause the flash player to run out of buffer memory.
-Markus
Somewhat unrelated, I found that adding a little overall noise to JPEGs seems to reduce banding since the algorithm is forced to use more data instead of blocking together sky gradients.
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From: Bostjan Burger
To: "#removed#"
Sent: Monday, December 10, 2012 8:14 AM
Subject: Re: bad conversion for small window
o.k. ... let see what will Markus say. There is still plenty of time before publishing. We even didn't announce the official opening of preparation server ;) ... but I am glad to see first uploads.
Bostjan
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From: Thomas
To: #removed#
Sent: Sunday, December 9, 2012 8:09 PM
Subject: Re: bad conversion for small window
Thanks, Bostjan, but...
I have just looked again and the defects are still there. Now that I look close the full screen image is also bad, with details much less sharp than in the image I uploaded, and RGB stripes next to the mast of the nearby boat. The stripes are closer to the mast in the large image, as if perhaps the problem has a fixed scale in pixels.
It looks the same on Firefox and Chrome browsers.
I hope the problem can be solved, else I will have to delete this submission.
Regards, Tom
--- In #removed#, Bostjan Burger wrote:
Tom,
I have checked your upload for the Best of 2012 and I can see very nice display of your panorama in small and full screen window. Please consider that immediately check might display other quality than the final one.
Bostjan
________________________________
From: Thomas Sharpless
To: #removed#
Sent: Saturday, December 8, 2012 2:46 AM
Subject: bad conversion for small window
Â
Hi,
I just uploaded a jpeg for "best of 2012" that I really hoped would look
sharp -- it is a 660 Mpixel stitch, reduced to 40 Mpix for WWP. The
fullscreen version looks OK but there is something wrong with the
conversion for the small view: resolution is bad, and there are rainbow
stripes next to some high contrast vertical features. I tried 3 different
jpegs of somewhat different sizes and all have the same problem.
I hope this can be fixed before I have to hit "publish". If it is my fault
I will be happy to do whatever is needed.
Regards, Tom
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