如何在 Android 中捕获 VideoView 的屏幕截图或视频帧

Posted 2023-02-25

【中文标题】如何在 Android 中捕获 VideoView 的屏幕截图或视频帧

【英文标题】：How to capture screenshot or video frame of VideoView in Android

【发布时间】：2014-12-11 23:05:07

【问题描述】：

我尝试了此博客 (http://android-er.blogspot.kr/2013/05/get-current-frame-in-videoview-using.html) 中的以下教程，该教程展示了如何使用 MediaMetadataRetriever 从视频源捕获视频帧。 但是，它仅在视频位于手机本地时才有效。

有没有办法在 VideoView 通过 IP 流式传输视频时捕获视频帧？

【参考方案1】：

Video View 是 SurfaceView 的子类，因此 Pixel Copy 也可以截取视频 View 的屏幕截图

把这个方法放在某个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)
        

【讨论】：

酷！非常感谢你。注意使用 PixelCopy 时的 @TargetApi(24)。

【参考方案2】：

我已经找到了解决这个问题的方法。在使用 SurfaceView 时，由于低级硬件 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 将需要实现 TextureView.SurfaceTextureListener。使用此解决方案截屏时，视频会冻结一小会儿。此外，TextureView 不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:)

解决办法如下：

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();
          
    

【讨论】：

这是否适用于来自 IP 摄像机的 .cgi 格式流图像？