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Error in image handling |
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Registered: March 13, 2007 | Posts: 1,380 |
| Posted: | | | | This might have been posted before, but theres a bug in the image handling process. I add images to DVDP the image size reduces to 3 times smaller (known issue), contribute the images, and the come back bigger It just doesn't make sense. below is a screenshot of the sizes: |
| Registered: March 14, 2007 | Reputation: | Posts: 6,744 |
| Posted: | | | | This has nothing to do with DVDP but with how the JPEG file format works.
I don't know exactly why (i.e. technical "why") the image gets bigger, but I can tell you how it happens.
You take an existing JPEG, you resize it to a smaller image. But when you save it, you set the image compression to 100%.
The saved file will most likely be larger than the original file. | | | Karsten DVD Collectors Online
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| Registered: March 13, 2007 | Reputation: | Posts: 3,197 |
| Posted: | | | | Yeah, this is not a bug. Like Karsten said, DVD Profiler will try to upload the resized images at the maximum allowed file size, which is about 195k per cover. | | | First registered: February 15, 2002 |
| Registered: March 13, 2007 | Posts: 1,380 |
| Posted: | | | | DVDP downsizes a file, DVDP online upsizes the same file. If that is how its supposed to work, whats the logic behind it?
I know that lowering the compression rate, makes the file bigger. But why didn't DVDP do just that in the first place? Why first distort the image and THEN save it with better compression rate, when most of the damage have already been done? |
| Registered: March 13, 2007 | Reputation: | Posts: 3,197 |
| Posted: | | | | We are still talking about two different things. No one is denying that the first behaviour is a bug (or at least an undesired feature), but the second one isn't. | | | First registered: February 15, 2002 | | | Last edited: by Nexus the Sixth |
| | Blair | Resistance is Futile! |
Registered: October 30, 2008 | Posts: 1,249 |
| Posted: | | | | JPEG uses lossy compression. This means that every time an image is saved--even if not resized--some quality is lost. (The reasoning here is that you aren't typically going to resize and resave a photograph a large number of times. Those who edit images regularly keep the image file's RAW data or convert to another format that does not change the quality during each save, but the file size for these file is much greater. Then they convert back to JPEG in cases like this for the final release which reduces the file size for easier sharing.)
So, for us, since you are saving twice (first to your local db when you add the file through Profiler's Cover Scan's menu, and second when the file is resized to no larger than 700x500 and saved in the online database) quality is lost twice. To counter the amount of lost quality, the file size has to be increased. In your case, the images just happened to be close enough in dimensions pre- and post-resize that the file size change was larger than the original. If the image in your local database and the file size were much larger, you wouldn't have received this puzzling result. when submitting to the online database.
While a bit of a hassle, if you want to retain full quality from your scan in your local database, you should place the file directly into the folder that stores the cover images. Assuming you use the defaults, it's
In XP: C :\Documents and Settings\[UserName]\My Documents\DVD Profiler\Databases\[DatabaseName]\Images\ In Windows 7: C :\Users\[UserName]\My Documents\DVD Profiler\Databases\[DatabaseName]\Images\
Rename the file to that of the UPC and place an 'f' or a 'b' at the end of the file name for the front and back covers respectively.
Because the file is then only being saved once (not going through the first processing by the software mentioned above but instead directly copied to the end folder) it can in some cases help slightly increase the quality of the final scan stored in the online database when submitted. | | | If at first you don't succeed, skydiving isn't for you.
He who MUST get the last word in on a pointless, endless argument doesn't win. It makes him the bigger jerk. | | | Last edited: by Blair |
| Registered: March 14, 2007 | Posts: 5,734 |
| Posted: | | | | Quoting Blair: Quote: While a bit of a hassle, if you want to retain full quality from your scan in your local database, you should place the file directly into the folder that stores the cover images. And never ever touch the Media Banner switch. | | | Don't confuse while the film is playing with when the film is played. [Ken Cole, DVD Profiler Architect] |
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