This question may sound a little bit complex or ambiguous, but I\'ll try to make it as clear as I can. I have done lots of Googling and spent lots of time but didn\'t find anyth
You could use OpenGL to do the trick. Please note however that you will need to have to render steps, one rendering the first video in a FBO and then the second rendering the second video, using the FBO as TEXTURE0 and the second as EXTERNAL_TEXTURE.
Blending, and all the stuff you want would be done by OpengL.
You can check the source codes here: Using SurfaceTexture in Android and some important information here: Android OpenGL combination of SurfaceTexture (external image) and ordinary texture
The only thing I'm not sure is what happens when two instances of mediaplayer are running in Parallel. I guess it should not be a problem.