Question

我已经尝试了此博客中的以下教程（http://android-er.blogspot.kr/2013/05/get-current-frame-in-videoview-using.html），其中介绍了如何使用MediaMetadataRetriever从视频源捕获视频帧。但，仅当视频位于手机本地时才有效。

有什么方法可以在 VideoView通过IP流式传输视频时捕获视频帧吗？

Answer 1

我找到了解决这个问题的方法。由于使用SurfaceView时出现的低级硬件GPU原因，VideoView似乎不允许这样做。

解决方案是使用TextureView并使用MediaPlayer在其中播放视频。 Activity需要实现TextureView.SurfaceTextureListener。使用此解决方案截取屏幕截图时，视频会冻结一段时间。此外，TextureView不会显示播放进度条的默认UI（播放，暂停，FF / RW，播放时间等）。这是一个缺点。如果您有其他解决方案，请告诉我:)）

以下是解决方案：

public class TextureViewActivity extends Activity 
    implements TextureView.SurfaceTextureListener, 
                OnBufferingUpdateListener, 
                OnCompletionListener, 
                OnPreparedListener, 
                OnVideoSizeChangedListener 
{
    private MediaPlayer mp;
    private TextureView tv;
    public static String MY_VIDEO = "https://www.blahblahblah.com/myVideo.mp4";
    public static String TAG = "TextureViewActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_texture_view);

        tv = (TextureView) findViewById(R.id.textureView1);
        tv.setSurfaceTextureListener(this);
    }

    public void getBitmap(TextureView vv)
    {
        String mPath = Environment.getExternalStorageDirectory().toString() 
                + "/Pictures/" + Utilities.getDayTimeString() + ".png";   
        Toast.makeText(getApplicationContext(), "Capturing Screenshot: " + mPath, Toast.LENGTH_SHORT).show();

        Bitmap bm = vv.getBitmap();
        if(bm == null)
            Log.e(TAG,"bitmap is null");

        OutputStream fout = null;
        File imageFile = new File(mPath);

        try {
            fout = new FileOutputStream(imageFile);
            bm.compress(Bitmap.CompressFormat.PNG, 90, fout);
            fout.flush();
            fout.close();
        } catch (FileNotFoundException e) {
            Log.e(TAG, "FileNotFoundException");
            e.printStackTrace();
        } catch (IOException e) {
            Log.e(TAG, "IOException");
            e.printStackTrace();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.media_player_video, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) 
    {
        Surface s = new Surface(surface);

        try
        {
            mp = new MediaPlayer();
            mp.setDataSource(MY_VIDEO);
            mp.setSurface(s);
            mp.prepare();

            mp.setOnBufferingUpdateListener(this);
            mp.setOnCompletionListener(this);
            mp.setOnPreparedListener(this);
            mp.setOnVideoSizeChangedListener(this);

            mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mp.start();

            Button b = (Button) findViewById(R.id.textureViewButton);
            b.setOnClickListener(new OnClickListener(){

                @Override
                public void onClick(View v) 
                {
                    TextureViewActivity.this.getBitmap(tv);
                }
            });
        }
        catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  
    }

Answer 2

视频视图是SurfaceView的子类，因此Pixel Copy也可以拍摄视频视图的屏幕截图

将此方法放在某些Util类中

/**
 * Pixel copy to copy SurfaceView/VideoView into BitMap
 */
 fun usePixelCopy(videoView: SurfaceView,  callback: (Bitmap?) -> Unit) {
    val bitmap: Bitmap = Bitmap.createBitmap(
        videoView.width,
        videoView.height,
        Bitmap.Config.ARGB_8888
    );
    try {
    // Create a handler thread to offload the processing of the image.
    val handlerThread = HandlerThread("PixelCopier");
    handlerThread.start();
    PixelCopy.request(
        videoView, bitmap,
        PixelCopy.OnPixelCopyFinishedListener { copyResult ->
            if (copyResult == PixelCopy.SUCCESS) {
                callback(bitmap)
            }
            handlerThread.quitSafely();
        },
        Handler(handlerThread.looper)
    )
    } catch (e: IllegalArgumentException) {
        callback(null)
        // PixelCopy may throw IllegalArgumentException, make sure to handle it
        e.printStackTrace()
    }
}

用法：

usePixelCopy(videoView) { bitmap: Bitmap? ->
            processBitMp(bitmap)
        }

如何在Android中捕获VideoView的屏幕截图或视频帧

2 个答案: