Video Post-processing a VideoPlayer's render texture

I'm trying to apply a simple post-processing effect to the RenderTexture that my VideoPlayer renders to (specifically, I just want to alpha-blend a semi-transparent texture over it). But my Google-fu seems to be failing me on the best way to go about this.

It seems that one solution would be to put the RenderTexture in front of an additional camera, do the post-processing with that camera (either in OnRenderImage or by simply putting my overlay between the render texture and the camera) and having that camera render to yet another render texture. But that seems like overkill for what should be a really simple task.

Are there any simpler way s to alpha-blend a texture into the output of a VideoPlayer?