FGLRX - terminology

[hirolau]

Could some happy fellow describe the following terms with one sentence each?

XV

Composite

AIGLX

Thanks in advacne!
Harald

[bridgman]

Xv - one of the APIs (Application Programming Interfaces) available for video playback in an X environment. The player calls Xv and passes it video frames which are typically "the wrong size and the wrong format", ie they are the size of the compressed video not the size of your screen window, and are typically in some kind of YUV format rather than the RGB format required by the display.

Xv usually passes the frames to a GPU driver, which performs colour space conversion (YUV to RGB) scaling (video size to window size), and sometimes de-interlacing and post-filtering. These are typically the most expensive operations to perform on a CPU so even Xv offloads a lot of CPU work.

Composite -- means different things at different times, unfortunately

EXA composite is the acceleration function which accelerates Render operations. The Composite extension allows windows to be redirected to an offscreen buffer so that a compositing desktop manager (Compiz, Kwin, Metacity etc..) can "composite" (assemble) them into a nice desktop image. To add to the confusion, sometimes a compositing desktop manager uses EXA composite, but mostly it uses OpenGL.

AIGLX - there are two ways for a 3D (OpenGL) app to draw to the screen - direct and indirect. Until fairly recently, indirect rendering (which goes through the X server) was always unaccelerated. Indirect rendering makes use of a protocol called GLX, or openGL over X. A couple of years ago, the X/DRI framework was modified to let indirect rendered graphics make use of the hardware acceleration drivers, so that GLX became Accelerated Indirect GLX, or AIGLX.

Everyone wanted AIGLX, mostly because it was supposed to "solve all their problems". Now that everyone *has* AIGLX, what everyone really wants instead is RDR (Redirected Direct Rendering).

[rbmorse]

Life would be good were it not for everyone, eh?

[RealNC]

Well, what everyone actually wants is drivers that don't suck, not RDR :P

[bridgman]

Life would be good were it not for everyone, eh?

Nah, life would be boring