Soulstorm

I am just curious... Lets say that I want to make a console application that will manipulate images or sound (doesn't make any difference in my question). An example of image manipulation is to convert an image from CMYK to RGB color or stretch it. An example of sound manipulation is to make conversions between formats (aiff, mp3, aac), or de-noise the sound.

Either way, I imagine that there are graphics and sound libraries that handle these kinds of manipulations. I know there are 2 libraries that may do these things (OpenAL and OpenGL) but are those enough?

Could you point me into the right direction (if I'm not already there)? Also, could you provide me with links to such libraries (and tutorials)? (preferably cross-platform, as I am on OS X and I don't intend to go to the windows world for a while..)

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