The Best Converter Software for TGA to JPG

Модератор: Николай Соколов

The Best Converter Software for TGA to JPG

Сообщение donaldrsimonn@gmail.com » 14 фев 2020, 05:59

Hi all,

I have always used JPEG for SL developments since the size is smaller and in a literal sense would reduce download time, but how about performance considerations?

Does PNG / TGA have any advantages over JPEG in SL applications apart from PNG being able to carry alpha configuration?
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Re: The Best Converter Software for TGA to JPG

Сообщение donaldrsimonn@gmail.com » 14 фев 2020, 06:00

As I understand it all uploads get turned into jpgs (jpeg2000 I think but I have no idea exactly what that is). MOST folks use png as far as I know as there is no point really in starting OUT "compressed" when the item will get MORE compress LOL. Do some tests on your own and decide.
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Re: The Best Converter Software for TGA to JPG

Сообщение donaldrsimonn@gmail.com » 14 фев 2020, 06:00

TGA and PNG have one huge advantage over JPG. They support an alpha channel, which JPG does not. Almost as important, they support layers, so you can build up an image from a composite of sub-images with different opacities, luminosities, etc. and can treat highlights, shadows, and whatnot as separate editable elements. JPG gives you none of that. I used TGA exclusively for years because I find it much easier to handle the alpha channel in that format, but I now use PNG almost as frequently. I never use JPG. Its only advantage is file size.
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Re: The Best Converter Software for TGA to JPG

Сообщение beatlefun » 14 фев 2020, 06:00

JPEG (but not JPEG 2000) has real trouble with sharp edges. Never store something with sharp edges, like a sign or a picture of text, in JPEG format. It will look terrible.

JPEG files are smaller, but there's no gain in sending them to Second LIfe, because they get decompressed, then recompressed as JPEG 2000 for storage on the asset servers.
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Re: The Best Converter Software for TGA to JPG

Сообщение bitterheated » 14 фев 2020, 06:00

I know there already are three good answers but to make it absolutely clear, Second Life only supports one image format, JPEG2000. Apart from the JPEG limitations Rolig and Animats mentioned, it should not matter which file format you choose to use locally. (I say should because there may be some minor differences in how efficiently the uploader handles the conversion from different formats.)

What viewer you use to upload may actually matter since they use different JPEG2000 libraries to convert the images. Firestorm uses Kakadu, a rather expensive commercial library. Other third party viewers (including self-compiled versions of Firestorm) use the open source OpenJPEG instead. Kakadu used to be regarded as the best option but things have changed and the official viewer switched from Kakadu to OpenJPEG recently. It may only be a matter of time before Firestorm does too.
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Re: The Best Converter Software for TGA to JPG

Сообщение donaldrsimonn@gmail.com » 14 фев 2020, 06:00

Incidentally, the only relation between the JPEG and JPEG2000 formats is that they were comissioned by and named after the same organisation. The Joint Photographic Experts Group launched JPEG in 1992 as a compact file format for photos. The format soon turned out to be a bit too limiting so it didn't take them long before they started from scratch and in 1997 they launched the everything-but-the-kitchen-sink JPEG2000.
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Re: The Best Converter Software for TGA to JPG

Сообщение jonsmaradona » 14 фев 2020, 12:19

JPG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPG typically achieves 10:1 compression with little perceptible loss in image quality. Click to find out more anyconv.com
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