Apps Saving screencast to a file with mediaProjection API

[Fameempathy]

Hey I'm trying to develop an app which will save a screencast to a file. So far I've been able to produce a video files of correct length(when I recorded for 5 seconds it produced a 5 seconds video file), the problem is my videos are empty, when I try to run them in various video players it shows only black screen.
Logcat when I'm running my application:

08-29 14:47:57.722    1973-1991/com.example.stw.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented
08-29 14:47:57.722    1973-1991/com.example.stw.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xabdbee60, error=EGL_SUCCESS
08-29 14:47:58.870    1973-1991/com.example.stw.myapplication E/Surface﹕ getSlotFromBufferLocked: unknown buffer: 0xab659760
08-29 14:47:58.875    1973-1991/com.example.kamil.myapplication D/OpenGLRenderer﹕ endAllStagingAnimators on 0xab32c580 (ListPopupWindow$DropDownListView) with handle 0xa333d8d0
08-29 14:48:00.652    1973-1973/com.example.kamil.myapplication D/MPEG4Writer﹕ Video track stopping
08-29 14:48:00.652    1973-1973/com.example.kamil.myapplication D/MPEG4Writer﹕ Video track source stopping
08-29 14:48:00.652    1973-1973/com.example.kamil.myapplication D/MPEG4Writer﹕ Video track source stopped

My whole activity
My code

These code snippets might also be relevant:
I start with preparing video encoder

    private void prepareVideoEncoder() {
        mVideoBufferInfo = new MediaCodec.BufferInfo();
        MediaFormat format = MediaFormat.createVideoFormat(VIDEO_MIME_TYPE, VIDEO_WIDTH, VIDEO_HEIGHT);
      //some configuration
        try {
            mVideoEncoder = MediaCodec.createEncoderByType(VIDEO_MIME_TYPE);
            mVideoEncoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
            mInputSurface = mVideoEncoder.createInputSurface();
            mVideoEncoder.start();
        } catch (IOException e) {
            releaseEncoders();
        }
    }

Creating mediaProjection

mMediaProjection.createVirtualDisplay("Recording Display", screenWidth,
                screenHeight, screenDensity, DisplayManager.VIRTUAL_DISPLAY_FLAG_PRESENTATION, mInputSurface,
                null /* callback */, null /* handler */);

Then i drain video encoder and release video encoder at the end. I didn't want to post my whole app here becuase of the topic rules but you can have a look at the link I've provided earlier.

Cheers Kyle