多媒体——视频——使用摄像机录制视频

悠悠 2024-04-03 12:50 90阅读 0赞

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通过系统自带的摄像机可以很方便地录制视频，只要指定摄像动作为MediaStore.ACTION\_VIDEO\_CAPTURE即可。

当然，需要事先设定下列的录像参数：

1、MediaStore.EXTRA\_VIDEO\_QUALITY：用于设定视频质量；2、MediaStore.EXTRA\_SIZE\_LIMIT：用于设定文件大小的上限；3、MediaStore.EXTRA\_DURATION\_LIMIT：用于设定视频时长的上限。

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// 获取视频文件中的某帧图片
    public static Bitmap getOneFrame(Context ctx, Uri uri) 
    {
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();
        
        retriever.setDataSource(ctx, uri);
        
        // 获得视频的播放时长，大于1秒的取第1秒的帧图，不足1秒的取第0秒的帧图
        String duration = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
        
        int pos = (Integer.parseInt(duration)/1000)>1 ? 1 : 0;
        
        // 获取并返回指定时间的帧图
        return retriever.getFrameAtTime(pos * 1000, MediaMetadataRetriever.OPTION_CLOSEST);
        
    }

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布局：

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MediaUtil

package com.example.myapplication.util;
    
    import android.annotation.SuppressLint;
    import android.content.Context;
    import android.graphics.Bitmap;
    import android.media.MediaMetadataRetriever;
    import android.net.Uri;
    import android.os.Environment;
    import android.util.Log;
    
    import java.io.File;
    
    @SuppressLint("DefaultLocale")
    public class MediaUtil {
        private final static String TAG = "MediaUtil";
    
        // 格式化播放时长(mm:ss)
        public static String formatDuration(int milliseconds) {
            int seconds = milliseconds / 1000;
            int hour = seconds / 3600;
            int minute = seconds / 60;
            int second = seconds % 60;
            String str;
            if (hour > 0) {
                str = String.format("%02d:%02d:%02d", hour, minute, second);
            } else {
                str = String.format("%02d:%02d", minute, second);
            }
            return str;
        }
    
        // 获得音视频文件的缓存路径
        public static String getRecordFilePath(Context context, String dir_name, String extend_name) {
            String path = "";
            File recordDir = new File(context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS).toString() + "/" + dir_name + "/");
            if (!recordDir.exists()) {
                recordDir.mkdirs();
            }
            try {
                File recordFile = File.createTempFile(DateUtil.getNowDateTime(), extend_name, recordDir);
                path = recordFile.getAbsolutePath();
                Log.d(TAG, "dir_name=" + dir_name + ", extend_name=" + extend_name + ", path=" + path);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return path;
        }
    
        // 获取视频文件中的某帧图片
        public static Bitmap getOneFrame(Context ctx, Uri uri) {
            MediaMetadataRetriever retriever = new MediaMetadataRetriever();
            retriever.setDataSource(ctx, uri);
            // 获得视频的播放时长，大于1秒的取第1秒处的帧图，不足1秒的取第0秒处的帧图
            String duration = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
            Log.d(TAG, "duration="+duration);
            int pos = (Integer.parseInt(duration)/1000)>1 ? 1 : 0;
            // 获取指定时间的帧图，注意getFrameAtTime方法的时间单位是微秒
            return retriever.getFrameAtTime(pos * 1000 * 1000);
        }
    }

主代码：

package com.example.myapplication;
    
    import android.content.Intent;
    import android.graphics.Bitmap;
    import android.net.Uri;
    import android.os.Bundle;
    import android.os.Environment;
    import android.provider.MediaStore;
    import android.view.View;
    import android.widget.ImageView;
    import android.widget.RelativeLayout;
    import android.widget.TextView;
    
    import androidx.appcompat.app.AppCompatActivity;
    
    import com.example.myapplication.util.MediaUtil;
    
    public class MainActivity extends AppCompatActivity implements View.OnClickListener
    {
    
        private final static String TAG = "VideoRecordActivity";
        private int RECORDER_CODE = 1; // 录制操作的请求码
        private TextView tv_video;
        private RelativeLayout rl_video;
        private ImageView iv_video;
        private Uri mVideoUri; // 视频文件的路径对象
    
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            tv_video = findViewById(R.id.tv_video);
            rl_video = findViewById(R.id.rl_video);
            iv_video = findViewById(R.id.iv_video);
    
            findViewById(R.id.btn_recorder).setOnClickListener(this);
            findViewById(R.id.rl_video).setOnClickListener(this);
        }
    
        @Override
        public void onClick(View v)
        {
            if (v.getId() == R.id.btn_recorder)
            {
                // 下面准备跳到系统的摄像机，并获得录制完的视频文件
                Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
                intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1); // 视频质量。0 低质量；1 高质量
                intent.putExtra(MediaStore.EXTRA_SIZE_LIMIT, 10485760L); // 大小限制，单位字节
                intent.putExtra(MediaStore.EXTRA_DURATION_LIMIT, 10); // 时长限制，单位秒
                startActivityForResult(intent, RECORDER_CODE); // 打开系统摄像机
            }
            else if (v.getId() == R.id.rl_video)
            {
                // 创建一个内容获取动作的意图(准备跳到系统播放器)
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setDataAndType(mVideoUri, "video/*"); // 类型为视频
                startActivity(intent); // 打开系统的视频播放器
            }
        }
    
        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent intent)
        {
            super.onActivityResult(requestCode, resultCode, intent);
    
            if (resultCode==RESULT_OK && requestCode==RECORDER_CODE)   // 从摄像机返回
            {
                mVideoUri = intent.getData(); // 获得已录制视频的路径对象
    
    //            // 生成临时视频的保存路径
    //            String filePath = String.format("%s/%s.mp4",
    //                    getExternalFilesDir(Environment.DIRECTORY_MOVIES), "video_"+ DateUtil.getNowDateTime());
    //            // 把录制完的视频保存到临时路径
    //            FileUtil.saveFileFromUri(this, mVideoUri, filePath);
    
                tv_video.setText("录制完成的视频地址为："+mVideoUri.toString());
                rl_video.setVisibility(View.VISIBLE);
    
                // 获取视频文件的某帧图片
                Bitmap bitmap = MediaUtil.getOneFrame(this, mVideoUri);
    
                iv_video.setImageBitmap(bitmap); // 设置图像视图的位图对象
            }
        }
    
    }

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