MediaRecorder：启动失败：-19

Question

我正在尝试了解如何使用相机录制视频。但它总是在开始录制时崩溃。而且我不知道为什么会这样。我现在不需要使用任何预览，只需记录到文件中。这是代码

    public static final String TAG = "tag";
    Button recBut;
    private MediaRecorder rec;
    private Camera camera;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        releaseCamera();
        recBut = (Button) findViewById(R.id.rec);

        camera = Camera.open(0);
        prepareCamera(camera);
        recBut.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (recBut.getText().toString().equalsIgnoreCase("start")) {
                    rec.start(); //logcat say that problem here
                    recBut.setText("RECING...");
                } else {
                    rec.stop();
                    rec.reset();
                    rec.release();
                    rec = null;
                    recBut.setText("START");
                    releaseCamera();
                }
            }
        });
    }

    private void prepareCamera(Camera camera) {
        List<Camera.Size> list = camera.getParameters().getSupportedVideoSizes();
        Log.i(TAG, "GENERAL SIZE - " + list.size());
        for (int i = 0; i < list.size(); i++) {
            Log.i(TAG, "SIZE| width - " + list.get(i).width + " hight - " + list.get(i).height);
        }
        rec = new MediaRecorder();
        camera.getParameters().setRecordingHint(true);
        rec.setCamera(camera);
        rec.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
        rec.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
        rec.setOutputFormat(MediaRecorder.OutputFormat.WEBM);
        rec.setVideoSize(720, 1280);
        rec.setVideoFrameRate(24);
        rec.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
        rec.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
        //        rec.setProfile(CamcorderProfile.get(0, CamcorderProfile.QUALITY_HIGH));
        rec.setOutputFile(
                Environment.getExternalStorageDirectory() + "/" + Environment.DIRECTORY_MOVIES + "/test.mp4");
        rec.setPreviewDisplay(null);
        try {
            rec.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void releaseCamera() {
        if (camera != null) {
            camera.release();
            camera = null;
        }
    }
}

清单，以防万一：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lexz.basiccamera">

    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest> 

Logcat：

E/MediaRecorder: start failed: -19
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.lexz.basiccamera, PID: 28879
java.lang.RuntimeException: start failed.
at android.media.MediaRecorder.start(Native Method)
at com.lexz.basiccamera.MainActivity$1.onClick(MainActivity.java:35)
at android.view.View.performClick(View.java:4802)
at android.view.View$PerformClick.run(View.java:20101)
at android.os.Handler.handleCallback(Handler.java:810)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:189)
at android.app.ActivityThread.main(ActivityThread.java:5529)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:956)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:751)

解决方案

看起来正确的工作相机类需要有 SurfaceView、SurfaceHolder 并实现 SurfaceHolder.Callback 并且不要忘记将此表面视图设置为相机。作为工作示例check this。

Answer 1

对我来说，问题是我没有解锁相机。设置相机前先解锁：

private void prepareCamera(Camera camera) {
    ...
    camera.unlock();        // Unlock the camera  
    rec.setCamera(camera);
    ...

Answer 2

rec.setOutputFormat(MediaRecorder.OutputFormat.WEBM);

它是 WEBM 容器中的数据。尝试替换为

 rec.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);