Reduce memory use for textures in OpenGL ES 1.1

Question

My scene in OpenGL ES requires several large resolution textures, but they are grayscale, since I am using them just for masks. I need to reduce my memory use.

I have t

Answer 1

With Imagination Technologies-based (aka PowerVR) systems, you should be able to use PVRTC 4bpp and (depending on the texture and quality requirements) maybe even 2bpp PVRTC variant.

Also, though I'm not sure what is exposed in Android systems, the PVRTextool lists I8 (i.e. greyscale 8bpp) as target texture format, which would give you a lossless option.