SurfaceTexture updateTexImage to shared 2 EGLContexts - Problems on Android 4.4

Question

I am referring to this excellent example of how to encode the preview frames of the camera directly into an mp4 file: http://bigflake.com/mediacodec/CameraToMpegTest.java.txt

I have adopted the code in the way that I also would like to render the preview image on the screen. Therefore I got something like a GLTextureView with its own EGLContext. This Context is then used as shared EGLContext when I create the EGLContext for the encoder rendering:

mEGLContext = EGL14.eglCreateContext(mEGLDisplay, configs[0], sharedContext == null ? EGL14.EGL_NO_CONTEXT : sharedContext,
                attrib_list, 0);

In my render-loop I followed the tip of fadden... for every frame I do the following:

1. first I wait for the new image to arrive on the SurfaceTexture with awaitNewImage()
2. then I set the GLTextureView's context current and render the frame on it
3. after that I set the encoders context current and render the frame on it

This looks something like that:

mFrameWatcher.awaitNewImage();
mSurfaceTexture.updateTexImage();
_textureView.getEGLManager().makeCurrent();
_textureView.requestRender();
mInputSurface.makeCurrent();
mInputSurface.requestRender();

This worked well while I tested it only on my Nexus 4 with Android 4.3.

However, since I got the new Nexus 5 with Android 4.4 the encoder only gets 2 different frames per second from the SurfaceTexture... but these 2 frames are repeatedly drawn... so he encodes 15 times the same frame. ALTHOUGH the frames are rendered correct to my GLTextureView with 30 different frames per second. I first thought this might be a Nexus 5 problem - so I updated another Nexus 4 to Android 4.4... but it is the same on the Nexus 4 now.

I played around a bit - and finally I was able to solve the problem, by detaching and re-attaching the SurfaceTexture to the different context's when I switch them. This looks something like this:

mFrameWatcher.awaitNewImage();
mSurfaceTexture.updateTexImage();
_textureView.getEGLManager().makeCurrent();
_textureView.requestRender();
mSurfaceTexture.detachFromGLContext();
mInputSurface.makeCurrent();
mSurfaceTexture.attachToGLContext(_textureViewRenderer.getTextureId());
mInputSurface.requestRender();
mSurfaceTexture.detachFromGLContext();
_textureView.getEGLManager().makeCurrent();
mSurfaceTexture.attachToGLContext(_textureViewRenderer.getTextureId());

My question now is: Is this the correct way to do this? Honestly I thought the re-attaching of the SurfaceTexture should not be necessary when I use shared contexts. Also the re-attaching takes quite a long time... 3-6 ms for every frame with peeks on 12 ms, which could be better used for rendering. Am I doing/understanding somethind wrong here? Why did it work like a charm on the Nexus 4 with 4.3 without the need to re-attach the SurfaceTexture?

Evilminded

Sounds similar to #20387015 – Varicotomy

Can you look at the former case with systrace()? I'm curious if you're getting stuck in eglSwapBuffers() on 4.4. (There was a behavior change to TextureView in 4.4 that causes it to wait for previously-submitted buffers to be acquired by the consumer; in 4.3 if you submitted buffers too quickly it would just drop the old ones.) – Varicotomy

I will go deeper into this soon... But I'm not sure its the fault of the TextureView, since the preview rendered to the TextureView is displayed correctly with 30fps... however if I change the sequence and render to the encoder first and after that on the TextureView, I got a 30fps mp4 and a 2fps preview on the SurfaceTexture. My guess is it has to do something with the context siwtching... Our Nexus 7 2012 with Android 4.4 e.g. gets an ANR when we switch the contexts in the render loop... but that only occurs on the Nexus 7, the other devices with 4.4 get the fps drops... – Evilminded

FYI, full example is here: github.com/google/grafika/blob/master/src/com/android/grafika/… – Varicotomy

Answer 1

It appears this is in fact the same problem as this question. I put some details there; in short, you should be able to fix it by un-binding and re-binding the texture, which is essentially what you're doing with the awkward attach/detach sequence.

In my code, I was able to fix it by changing this:

GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);

to this:

GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);

in my texture renderer. I'll update the bigflake examples in a bit.

Varicotomy

thank's fadden - this worked for me and seems to be the way more elegant solution! Anyways I assume this still is a workaround for some odd 4.4 behaviour, am I right? As long as there is no real fix I'll mark your answer as solution. – Evilminded