android - 如何从android中的视频中捕获帧？

Question

您好，我制作了一个在 android 中播放的自定义视频。带有一些简单的“播放”、“暂停”、“再次播放”和“捕获”按钮。现在我已经完成了除“捕获”之外的所有这些功能。我已经搜索过了很多链接和谷歌搜索了很多，但我找不到如何从 android 中运行的视频中捕获帧？我的代码如下:请帮助我:

主.java

package org.apache.android.media;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.URLUtil;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;

    import android.widget.VideoView;
    public class VideoViewDemo extends Activity {
        private static final String TAG = "VideoViewDemo";
        private VideoView mVideoView;
        private EditText mPath;
        private ImageButton mPlay;
        private ImageButton mPause;
        private ImageButton mReset;
        private ImageButton mStop;
        private ImageButton mcaptur;
        private String current;
        @Override
        public void onCreate(Bundle icicle) {
            super.onCreate(icicle);
            setContentView(R.layout.main);
            mVideoView = (VideoView) findViewById(R.id.surface_view);
            mPath = (EditText) findViewById(R.id.path);
            mPath.setText("http://daily3gp.com/vids/747.3gp");
            mPlay = (ImageButton) findViewById(R.id.play);
            mPause = (ImageButton) findViewById(R.id.pause);
            mReset = (ImageButton) findViewById(R.id.reset);
            mStop = (ImageButton) findViewById(R.id.stop);
            mcaptur = (ImageButton) findViewById(R.id.Captur);
            mPlay.setOnClickListener(new OnClickListener() {
                public void onClick(View view) {
                    playVideo();
                }
            });
            mPause.setOnClickListener(new OnClickListener() {
                public void onClick(View view) {
                    if (mVideoView != null) {
                        mVideoView.pause();
                    }
                }
            });
            mReset.setOnClickListener(new OnClickListener() {
                public void onClick(View view) {
                    if (mVideoView != null) {
                        mVideoView.seekTo(0);
                    }
                }
            });
            mStop.setOnClickListener(new OnClickListener() {
                public void onClick(View view) {
                    if (mVideoView != null) {
                        current = null;
                        mVideoView.stopPlayback();
                    }
                }
            });
            runOnUiThread(new Runnable() {
                public void run() {
                    playVideo();
                }
            });
            mcaptur.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                }
            });
        }
        private void playVideo() {
            try {
                final String path = mPath.getText().toString();
                Log.v(TAG, "path: " + path);
                if (path == null || path.length() == 0) {
                    Toast.makeText(VideoViewDemo.this, "File URL/path is empty",
                            Toast.LENGTH_LONG).show();
                } else {
                    // If the path has not changed, just start the media player
                    if (path.equals(current) && mVideoView != null) {
                        mVideoView.start();
                        mVideoView.requestFocus();
                        return;
                    }
                    current = path;
                    mVideoView.setVideoPath(getDataSource(path));
                    mVideoView.start();
                    mVideoView.requestFocus();
                }
            } catch (Exception e) {
                Log.e(TAG, "error: " + e.getMessage(), e);
                if (mVideoView != null) {
                    mVideoView.stopPlayback();
                }
            }
        }
        private String getDataSource(String path) throws IOException {
            if (!URLUtil.isNetworkUrl(path)) {
                return path;
            } else {
                URL url = new URL(path);
                URLConnection cn = url.openConnection();
                cn.connect();
                InputStream stream = cn.getInputStream();
                if (stream == null)
                    throw new RuntimeException("stream is null");
                File temp = File.createTempFile("mediaplayertmp", "dat");
                temp.deleteOnExit();
                String tempPath = temp.getAbsolutePath();
                FileOutputStream out = new FileOutputStream(temp);
                byte buf[] = new byte[128];
                do {
                    int numread = stream.read(buf);
                    if (numread <= 0)
                        break;
                    out.write(buf, 0, numread);
                } while (true);
                try {
                    stream.close();
                } catch (IOException ex) {
                    Log.e(TAG, "error: " + ex.getMessage(), ex);
                }
                return tempPath;
            }
        }
    }

Answer 1

您可以使用 MediaMetadataRetriever 获取视频帧。基本用法如下。

MediaMetadataRetriever retriever = new MediaMetadataRetriever();

// Set data source to retriever.
// From your code, you might want to use your 'String path' here.
retriever.setDataSource(yourPath);

// Get a frame in Bitmap by specifying time.
// Be aware that the parameter must be in "microseconds", not milliseconds.
Bitmap bitmap = retriever.getFrameAtTime(timeInMicroSeconds);

// Do something with your bitmap.

您可能想使用 FFmpegMediaMetadataRetriever以获得更好的性能。