java - MediaRecorder.GetSurface() 返回 null

Question

我在我的 Nexus 5 上使用此代码进行屏幕录制，该 Nexus 5 运行 6.0.1，带有 7 月安全更新。屏幕录制在运行 5.0.1、6.0、6.0.1 的其他设备上工作正常，但它在我的手机上不起作用。当我尝试开始屏幕录制时出现以下错误。

E/MediaRecorder: SurfaceMediaSource could not be initialized!
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1995, result=-1, data=Intent { (has extras) }} to activity {MainActivity}: java.lang.IllegalStateException: failed to get surface
at android.app.ActivityThread.deliverResults(ActivityThread.java:3699)
Caused by: java.lang.IllegalStateException: failed to get surface
at android.media.MediaRecorder.getSurface(Native Method)

获取 Surface 进行屏幕录制失败。是什么原因造成的，我该如何解决？

源代码:

 public static MediaProjectionManager getmMediaProjectionManager(final MainActivity context) {
        DisplayMetrics metrics = new DisplayMetrics();
        context.getWindowManager().getDefaultDisplay().getMetrics(metrics);
        mScreenDensity = metrics.densityDpi;
        DISPLAY_HEIGHT = metrics.heightPixels;
        DISPLAY_WIDTH = metrics.widthPixels;
        mMediaRecorder = new MediaRecorder();

        mMediaProjectionManager = (MediaProjectionManager) context.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
        return mMediaProjectionManager;
    }

    @TargetApi(21)
    public static void startScreenRecording(Intent data) {
        mMediaProjectionCallback = new MediaProjectionCallback();
        initRecorder(null);
        mMediaProjection = mMediaProjectionManager.getMediaProjection(RESULT_OK, data);
        mMediaProjection.registerCallback(mMediaProjectionCallback, null);
        mVirtualDisplay = createVirtualDisplay();
        mMediaRecorder.start();
    }

    @TargetApi(21)
    private static VirtualDisplay createVirtualDisplay() {
        return mMediaProjection.createVirtualDisplay("MainActivity",
                DISPLAY_WIDTH, DISPLAY_HEIGHT, mScreenDensity,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mMediaRecorder.getSurface(), null /*Callbacks*/, null
                /*Handler*/);
    }

    @TargetApi(21)
    private static void initRecorder(MainActivity context) {
        try {
            mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
            mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
            mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
            mMediaRecorder.setOutputFile(Environment
                    .getExternalStorageDirectory() + "/video"+ System.currentTimeMillis()+".mp4");
            mMediaRecorder.setVideoSize(DISPLAY_WIDTH, DISPLAY_HEIGHT);
            mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
            mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
            mMediaRecorder.setVideoEncodingBitRate(VIDEO_ENCODING_BITRATE);
            mMediaRecorder.setVideoFrameRate(VIDEO_FRAME_RATE);
            mMediaRecorder.prepare();
        } catch (Exception e) {
            Log.e("Util", e.getLocalizedMessage());
        }
    }

    @TargetApi(21)
    private static class MediaProjectionCallback extends MediaProjection.Callback {
        @Override
        public void onStop() {

        }
    }

    @TargetApi(21)
    public static void stopScreenSharing() {
        mMediaRecorder.stop();
        mMediaRecorder.reset();
        if (mVirtualDisplay == null) {
            return;
        }

        mVirtualDisplay.release();

        destroyMediaProjection();
    }

    @TargetApi(21)
    private static void destroyMediaProjection() {
        if (mMediaProjection != null) {
            Log.e(TAG, "destroying projection");
            mMediaProjection.unregisterCallback(mMediaProjectionCallback);
            mMediaProjection.stop();
            mMediaProjection = null;
        }
    }

最好的问候

Answer 1

这基本上与 this one 相同的问题.我也面临这个问题。奇怪的是，它只发生在 Marshmallow 上，在 Lollipop 上它确实有效。

文档说:

Surface getSurface ()

May only be called after prepare. Frames rendered to the Surface before start will be discarded.Throws:
IllegalStateException - if it is called before prepare, after stop, or is called when VideoSource is not set to SURFACE.

但在 Mediarecorder.java 中，它是:

@throws IllegalStateException if it is called after {@link #prepare} and before {@link #stop}.

但是无论我将它放在 之前 还是 之后 prepare() 都没有区别，两者都不起作用。它抛出一个 IllegalStateException 真的很奇怪，尽管上面的事情都不适用。

然而，this solution来自 Matt Snider 确实在 Marshmallow 上工作。但由于 IMO 比较困难(尤其是在尝试录制音频时)，最好让它也与 MediaRecorder 一起运行。

如果有人想重现问题，只需使用 this或 this编码并在 Marshmallow 机器上运行。