File size difference between TGA & PNG, AFTER UPLOAD

Hi Everyone,

After a few discussions about the merits of these 2 different file types. I've come up with some questions that no-one has yet been able to answer. I hope some of you may be able to help. (or a linden if they're reading this!)

TGA & PNG are 2 different file types with differing compression algorithms. This means that before upload, the same image, in the 2 formats will be different file sizes.

Once uploaded both will get converted to the SL compression norm of JPEG2000.

Therefore:

1 - If those 2 differing sized images are then compressed via JPEG2000 into SL, will the PNG still be smaller in file size on the inventory servers?

2 - If a PNG is smaller, would there be a significant reduction in client side lag if people were to realise this and begin to use this smaller file size for texture uploading?

3 - How can anyone tell how much file space a texture uses?

Look forward to replies

((edited a little for clarity))

the image is compressed to jpeg2k by the client before it even leaves your computer, so there is no difference, and jpeg 2k its many times smaller than png or tga


see # 1

also depends on what kind of lag your talking about, 99.99% of the loading lag is becuase of the asset server looking for and fetching untold amounts of data at any given moment

your personal system lag, doesnt care what format the image is saved in, once it hits your video memory its pure raw RGB/A and no matter what the image was saved in its going to use the same space as any other image of that size


not that im aware of

i did an eyeball test a couple years ago, guessing that SL is compressing to ~30%, using normal jpg @ 24 bit would put a 512x512 image in the filesize range of 50kb

course this is all dependent on many factors, ie i can make a solid white 1024x1024 solid white image @ 100% quality in less than 10k, + jpeg 2k is better at compression, but then theres the question of 32 bit blah blah blah