RecordFBOActivity swapBuffers problem

[herbaini]

In RecordFBOActivity, when I start recording, which will have "mWindowSurface.swapBuffers" and "mInputWindowSurface.swapBuffers" .
The fast speed is Choreographer time which diffent on diffent Devices!(58-62 maybe)
I want get a stable FPS(for example 60) because I will do opengl compose then display and record.

Now I do by this at fixed fps:

public void run() {
            prepareGl();
            while (mRunning) {
                llNowNs = System.nanoTime();
                if (llNowNs - llBeginNs < llFrameCount * mRefreshTimeNs) {
                    llDelayNs = llFrameCount * mRefreshTimeNs - llNowNs + llBeginNs;
                    try {
                        Thread.sleep(llDelayNs / 1000000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    continue;
                }

                render(llFrameCount * mRefreshTimeNs);
                llFrameCount++;
            }
            releaseGl();
        }

Every render() I swapbuffer to encode surface and swapbuffer to display like in RecordFBOActivity.

Now the problem is swapbuffer to encode surface cost long time. I think is BufferQueue is Fence by something! What it is???

And which is best arch to do this???

I do not want to download Image then push to the encode! Which is ulgy and slowly!!!!

Very thanks!