JPEG Compression in Maya

[archaeology]

I'm not exactly sure where to post this question, but here it goes. When saving images as JPEGs from Maya or converting textures from another format to JPEG using Maya, Maya seems to automatically compress the JPEG which make the image look like crap. Is there a setting in Maya to turn JPEG compression off?

Thanks,

Aaron

[joojaa]

Jpeg is allways compressed, and allways slightly lossy no matter what you do (jpeg 2000 is a nother issue totaly tough, but thenagain jpeg 2000 isnt widely used)! The thing is a graphics artist should be wise NOT to use jpeg except at the last stage of deployment. Even then its wise to carefully manualy compress to the ratio you need in some software that has compression previews.

but this from the manual with the magic keywords jpeg and compression yelded the following quote:

Compression is controlled by the environment variable AW_JPEG_Q_FACTOR. Setting it to 1 gives the lowest quality (most compression) and setting it to 100 gives the highest quality (least compression). The default value is 75.

use PNG it has more to offer...in terms of compression and loslessnes.

[archaeology]

Thanks for the info. I appreciate the quote from the manual as well.

Aaron

[drblacksnake]

JPEG is compressed lossy image format so if You are sane, then don't use it ever except special cases, where filesize is crucial (e.g. webdesign). This means You cannot turn compression off, even compression is at its 100% quality. Use tga/tiff and, if not photoshop, then at least some image viewer to convert images to JPEG. ACDSee is good, since You can set compression quality and convert a bunch of different images and sequences by few clicks.
For more pro-aproach use photoshop - there You can interactively find compromise between file quality and size.

You could browse a manual before ask:
Compression is controlled by the environment variable AW_JPEG_Q_FACTOR. Setting it to 1 gives the lowest quality (most compression) and setting it to 100 gives the highest quality (least compression). The default value is 75.

Nevertheless there was mentioned lossless JPEGs, I don't know a soft able to produce such ones since I doubt even photoshop 100% quality JPEGs aren't lossless. Perhaps it is worth to test.

[joojaa]

Also maya comes witha a utility for convertting (and batch convertting) images called imgcvt

it can convert all maya formats to any other maya format. Its usefull if you have a loy of iffs (the only reason to not render to iff in my personal experience is if you need a floating point image with mr).

[joojaa]

Interesting the exact same reply! With more or less same structure aswell.

[drblacksnake]

Yes, imgcvt is good, but sometimes make pain in ass when converting from non-maya-iff to non-maya-iff.
At least once I've got output sequences of total crap when -f TIFF -t TGA was used and it was noticed only later, after original TIFFs were deleted. Stupid me!
Also slower than some GUI things since one should think more - not only about right images to pick, but also figure out correct syntax, since sometimes input files have weird periods. Also writing a line for just one image is not consumed time worth.
ACDSee is quick at this, especcially in JPEG cese, unfortunately it (v5.0) doesn't support alphas for other cases.

[archaeology]

I appreciate the feedback. I should add that I wasn't asking for rendering purposes. When we render, we render to TIFF.

Instead, I'm asking because I've written an exporter for X3D, one of its features is the ability to convert the content authors textures upon export. As X3D only supports external textures in JPEG, GIF, and PNG formats, I'm attempting to figure out how to get the best quality when writing the converted files to these formats.

I've looked for the JPEG compression stuff in the manual in the past and hadn't found what I was looking for. However, I realize I'm not always the best at searching through manuals. I only asked now because Alias had a reporter interview me as part of an Alias customer story. I'm just trying to work out some of the bugs before the story hits the Alias web site.

So I really appreciate the feedback.

Thanks,

Aaron

[fakeproject]

While it's really unfortunate that some users seem to assume that no one reads the manual before asking a non-obvious question (or has need to use a JPEG), the benefit of that behavior is that the truly helpful users look that much better in comparison. Thanks so much to everyone for helping out- it is really appreciated.

I use the X3D exporter that archaeology is working on, and I export X3D content to be displayed on the web. It's a really great tool, and JPEGs are the best-supported image format in all browsers. Of course, the problem for me has been that the JPEG compression in Maya really screwed up my textures, and even though I could manually resize and compress them for the web, it's much easier to use the options available in RawKee (which is dependent on the internal JPEG settings in Maya).

So yeah, again, thanks. Having this working will really streamline my workflow.

[joojaa]

Hmm, but why use jpeg? PNG is much better in all respects than jpeg. Besides teh formats used by videocards will eevnattualy be losseless so even intermediary going trough somethings thats poetenttialy losseless is a bit... Umm wonky.

[archaeology]

Two reasons
1) Leave it up to the choice of the content developer
2) PNG support is still a bit iffy in some of the X3D browsers

[joojaa]

Well then shouldnt you leave the compression quality up to the content developper too?

And why is what maya renders the issue shouldnt your exporter take care of convertting the assets anyway.

Oh and incidenttaly maya uses the same code as imgcvt for its conversions as it internaly reders allways out the same stuff.

[archaeology]

Well, the idea was to allow the developer to set the value in the export settings.

As it looks, in order to maintain cross-platform consistancy, the developer can set the JPEG compression in the Maya.env file.

The exporter uses the Maya API and mel commands to do the texture conversions. I've done it this way so that the exporter will work on WinXP, OSX, Linux, and IRIX.

I'm interested in using imgcvt. I would just say, that I recognize that the way I'm currently doing this isn't necessarily the best way to perform the texture conversions. So I'm interested in hearing if there are better options.