Is it possible read separated Alpha/RGB pixels for rendering?

Hi All,

I want to make a texture from memory separated Alpha/RGB for webm(vp8) video format.

I already made an aligned ARGB data by CPU for GPU input, but the resolution is too high so it is slow.

Can I read the Alpha/RGB separated memory by EGL_LINUX_DMA_BUF_EXT or another method(vendor specific)?

Is there a way to merge ARGB using gpgpu programming to one buffer? I am sorry that I am newbie.

Any ideas would be appreciated.