十分钟实现 Android Camera2 视频录制

柔光的暖阳◎ 2023-10-12 22:21 146阅读 0赞

### 1. 前言 ###

因为工作中要使用`Android Camera2 API`，但因为`Camera2`比较复杂，网上资料也比较乱，有一定入门门槛，所以花了几天时间系统研究了下，并在`CSDN`上记录了下，希望能帮助到更多的小伙伴。  
[上两篇文章][Link 1]使用`Camera2`实现了相机预览和拍照的功能，这篇文章我们接着上文，来实现`Camera2`视频录制的功能。

### 2. 前置操作 ###

#### 2.1 声明相机参数和成员变量 ####

首先还是声明相机参数和成员变量，比起前文增加了这些

private var mediaRecorder: MediaRecorder? = null
    private var isRecordingVideo: Boolean = false
    private val SENSOR_ORIENTATION_DEFAULT_DEGREES = 90
    private val SENSOR_ORIENTATION_INVERSE_DEGREES = 270
    private val DEFAULT_ORIENTATIONS = SparseIntArray().apply {
        
        append(Surface.ROTATION_0, 90)
        append(Surface.ROTATION_90, 0)
        append(Surface.ROTATION_180, 270)
        append(Surface.ROTATION_270, 180)
    }
    private val INVERSE_ORIENTATIONS = SparseIntArray().apply {
        
        append(Surface.ROTATION_0, 270)
        append(Surface.ROTATION_90, 180)
        append(Surface.ROTATION_180, 90)
        append(Surface.ROTATION_270, 0)
    }

完整的需要声明的相机参数和成员变量如下

//后摄 : 0 ，前摄 : 1
    private val cameraId = "0"
    private val TAG = CameraActivity3::class.java.simpleName
    private lateinit var cameraDevice: CameraDevice
    private val cameraThread = HandlerThread("CameraThread").apply {
         start() }
    private val cameraHandler = Handler(cameraThread.looper)
    private val cameraManager: CameraManager by lazy {
        
        getSystemService(Context.CAMERA_SERVICE) as CameraManager
    }
    private val characteristics: CameraCharacteristics by lazy {
        
        cameraManager.getCameraCharacteristics(cameraId)
    }
    private lateinit var session: CameraCaptureSession
    
    private lateinit var imageReader: ImageReader
    
    //JPEG格式，所有相机必须支持JPEG输出，因此不需要检查
    private val pixelFormat = ImageFormat.JPEG
    
    //imageReader最大的图片缓存数
    private val IMAGE_BUFFER_SIZE: Int = 3
    
    //线程池
    private val threadPool = Executors.newCachedThreadPool()
    private val imageReaderThread = HandlerThread("imageReaderThread").apply {
         start() }
    private val imageReaderHandler = Handler(imageReaderThread.looper)
    /** Live data listener for changes in the device orientation relative to the camera */
    private lateinit var relativeOrientation: OrientationLiveData
    
    private var mediaRecorder: MediaRecorder? = null
    private var isRecordingVideo: Boolean = false
    private val SENSOR_ORIENTATION_DEFAULT_DEGREES = 90
    private val SENSOR_ORIENTATION_INVERSE_DEGREES = 270
    private val DEFAULT_ORIENTATIONS = SparseIntArray().apply {
        
        append(Surface.ROTATION_0, 90)
        append(Surface.ROTATION_90, 0)
        append(Surface.ROTATION_180, 270)
        append(Surface.ROTATION_270, 180)
    }
    private val INVERSE_ORIENTATIONS = SparseIntArray().apply {
        
        append(Surface.ROTATION_0, 270)
        append(Surface.ROTATION_90, 180)
        append(Surface.ROTATION_180, 90)
        append(Surface.ROTATION_270, 0)
    }

#### 2.2 添加布局 ####

首先我们需要在`XML`中添加两个按钮，分别是录制按钮和停止录制按钮

#### 2.3 初始化MediaPlayer ####

我们需要在打开相机的时候，去初始化`mediaRecorder`

mediaRecorder = MediaRecorder()

完整代码如下

@SuppressLint("MissingPermission")
    private fun openCamera(cameraId: String) {
        
        cameraManager.openCamera(cameraId, object : CameraDevice.StateCallback() {
        
            override fun onOpened(camera: CameraDevice) {
        
                cameraDevice = camera
                mediaRecorder = MediaRecorder()
                startPreview()
            }
    
            override fun onDisconnected(camera: CameraDevice) {
        
                this@CameraActivity3.finish()
            }
    
            override fun onError(camera: CameraDevice, error: Int) {
        
                Toast.makeText(application, "openCamera Failed:$error", Toast.LENGTH_SHORT).show()
            }
        }, cameraHandler)
    }

### 3. 实现视频录制功能 ###

#### 3.1 关闭原本的Session ####

因为拍照和录制视频功能不好一起使用，所以需要先调用`closePreviewSession`，来关闭原来的`session`

private fun closePreviewSession() {
        
        session?.close()
    }

#### 3.2 给MediaRecorder设置参数 ####

接着，需要调用`setUpMediaRecorder()`来初始化`MediaRecorder`  
`setUpMediaRecorder`中，会给`mediaRecorder`设置很多预置参数

首先获取目标路径

val nextVideoAbsolutePath = getVideoFilePath(cameraActivity)
     
    fun getVideoFilePath(context: Context?): String {
        
        val filename = "VIDEO_${
          System.currentTimeMillis()}.mp4"
        val dir = context?.getExternalFilesDir("video")
    
        return if (dir == null) {
        
            filename
        } else {
        
            "${
          dir.absolutePath}/$filename"
        }
    }

然后设置`mediaRecorder`方向

val sensorOrientation = characteristics?.get(SENSOR_ORIENTATION)
    val rotation = cameraActivity.windowManager.defaultDisplay.rotation
    when (sensorOrientation) {
        
        SENSOR_ORIENTATION_DEFAULT_DEGREES ->
            mediaRecorder?.setOrientationHint(DEFAULT_ORIENTATIONS.get(rotation))
        SENSOR_ORIENTATION_INVERSE_DEGREES ->
            mediaRecorder?.setOrientationHint(INVERSE_ORIENTATIONS.get(rotation))
    }

最后给`meidaRecorder`设置若干参数项，这里我们默认给视频尺寸设置成了`1920*1080`，如果你的设备相机不支持这个分辨率，需要修改一下。

mediaRecorder?.apply {
        
        setAudioSource(MediaRecorder.AudioSource.MIC)
        setVideoSource(MediaRecorder.VideoSource.SURFACE)
        setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
        setOutputFile(nextVideoAbsolutePath)
        setVideoEncodingBitRate(10000000)
        setVideoFrameRate(30)
        setVideoSize(1920,1080)
        setVideoEncoder(MediaRecorder.VideoEncoder.H264)
        setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
        prepare()
    }

再来看下完整的代码

private fun setUpMediaRecorder() {
        
        val cameraActivity = this
    
        val nextVideoAbsolutePath = getVideoFilePath(cameraActivity)
    
        val sensorOrientation = characteristics?.get(SENSOR_ORIENTATION)
        val rotation = cameraActivity.windowManager.defaultDisplay.rotation
        when (sensorOrientation) {
        
            SENSOR_ORIENTATION_DEFAULT_DEGREES ->
                mediaRecorder?.setOrientationHint(DEFAULT_ORIENTATIONS.get(rotation))
            SENSOR_ORIENTATION_INVERSE_DEGREES ->
                mediaRecorder?.setOrientationHint(INVERSE_ORIENTATIONS.get(rotation))
        }
    
        mediaRecorder?.apply {
        
            setAudioSource(MediaRecorder.AudioSource.MIC)
            setVideoSource(MediaRecorder.VideoSource.SURFACE)
            setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
            setOutputFile(nextVideoAbsolutePath)
            setVideoEncodingBitRate(10000000)
            setVideoFrameRate(30)
            setVideoSize(1920,1080) //FIXME 如果你的设备相机不支持这个分辨率，需要修改一下
            setVideoEncoder(MediaRecorder.VideoEncoder.H264)
            setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
            prepare()
        }
    }
    
    fun getVideoFilePath(context: Context?): String {
        
        val filename = "VIDEO_${
          System.currentTimeMillis()}.mp4"
        val dir = context?.getExternalFilesDir("video")
    
        return if (dir == null) {
        
            filename
        } else {
        
            "${
          dir.absolutePath}/$filename"
        }
    }

#### 3.3 重新创建Session ####

接着就将`binding.surfaceView`和`recorderSurface`添加到`surfaces`

val recorderSurface = mediaRecorder!!.surface
    val surfaces = ArrayList<Surface>().apply {
        
        add(binding.surfaceView.holder.surface)
        add(recorderSurface)
    }

重新调用`cameraDevice?.createCaptureSession`，将`surfaces`传入

cameraDevice?.createCaptureSession(surfaces,
        object : CameraCaptureSession.StateCallback() {
        
    
            override fun onConfigured(cameraCaptureSession: CameraCaptureSession) {
        
                //待实现
            }
    
            override fun onConfigureFailed(cameraCaptureSession: CameraCaptureSession) {
        
                Toast.makeText(application, "onConfigureFailed", Toast.LENGTH_SHORT).show()
            }
        }, cameraHandler)

#### 3.4 开始录制 ####

当`onConfigured`调用后，我们执行下面这些代码，主要执行了这些操作

*  将`cameraCaptureSession`赋值给`session`
 *  `session?.setRepeatingRequest`，这将不断地实时发送视频流，直到会话断开或调用`session.stoprepeat()`
 *  调用`mediaRecorder?.start`录制视频

session = cameraCaptureSession
    
    val previewRequestBuilder = cameraDevice!!.createCaptureRequest(TEMPLATE_RECORD).apply {
        
        addTarget(binding.surfaceView.holder.surface)
        addTarget(recorderSurface)
    }
    session?.setRepeatingRequest(previewRequestBuilder!!.build(), null, cameraHandler)
    
    isRecordingVideo = true
    mediaRecorder?.start()

#### 3.5 录制视频完整代码 ####

binding.btnCaptureVideo.setOnClickListener {
        
        startRecordingVideo()
    }
    
    private fun startRecordingVideo() {
        
    closePreviewSession()
    setUpMediaRecorder()
    
    val recorderSurface = mediaRecorder!!.surface
    val surfaces = ArrayList<Surface>().apply {
        
        add(binding.surfaceView.holder.surface)
        add(recorderSurface)
    }
    
    cameraDevice?.createCaptureSession(
    	    surfaces,
    	    object : CameraCaptureSession.StateCallback() {
        
    	
    	        override fun onConfigured(cameraCaptureSession: CameraCaptureSession) {
        
    	            session = cameraCaptureSession
    	
    	            val previewRequestBuilder =
    	                cameraDevice!!.createCaptureRequest(TEMPLATE_RECORD).apply {
        
    	                    addTarget(binding.surfaceView.holder.surface)
    	                    addTarget(recorderSurface)
    	                }
    	            session?.setRepeatingRequest(
    	                previewRequestBuilder!!.build(),
    	                null,
    	                cameraHandler
    	            )
    	
    	            isRecordingVideo = true
    	            mediaRecorder?.start()
    	        }
    	
    	        override fun onConfigureFailed(cameraCaptureSession: CameraCaptureSession) {
        
    	            Toast.makeText(application, "onConfigureFailed", Toast.LENGTH_SHORT).show()
    	        }
    	    }, cameraHandler
    	)
    }
    
    private fun closePreviewSession() {
        
        session?.close()
    }
    
    private fun setUpMediaRecorder() {
        
        val cameraActivity = this
    
        val nextVideoAbsolutePath = getVideoFilePath(cameraActivity)
    
        val sensorOrientation = characteristics?.get(SENSOR_ORIENTATION)
        val rotation = cameraActivity.windowManager.defaultDisplay.rotation
        when (sensorOrientation) {
        
            SENSOR_ORIENTATION_DEFAULT_DEGREES ->
                mediaRecorder?.setOrientationHint(DEFAULT_ORIENTATIONS.get(rotation))
    
            SENSOR_ORIENTATION_INVERSE_DEGREES ->
                mediaRecorder?.setOrientationHint(INVERSE_ORIENTATIONS.get(rotation))
        }
    
        mediaRecorder?.apply {
        
            setAudioSource(MediaRecorder.AudioSource.MIC)
            setVideoSource(MediaRecorder.VideoSource.SURFACE)
            setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
            setOutputFile(nextVideoAbsolutePath)
            setVideoEncodingBitRate(10000000)
            setVideoFrameRate(30)
            setVideoSize(1920, 1080) //FIXME 如果你的设备相机不支持这个分辨率，需要修改一下
            setVideoEncoder(MediaRecorder.VideoEncoder.H264)
            setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
            prepare()
        }
    }

![在这里插入图片描述][fdf552c875734bfca809c2f512559e4c.jpeg]

我们运行程序，点击录制视频，过几秒点击停止录制，然后打开文件管理器，在`/sdcard/Android/data/包名/files/video`文件夹下，可以看到这个视频了

![在这里插入图片描述][1f12ca4a47704043aea14e327aa3836a.jpeg]

### 4. 停止录制视频 ###

停止录制视频比较简单，只需要释放`mediaRecorder`  
然后再调用`startPreview`重新开始预览就可以了

private fun stopRecordingVideo() {
        
        isRecordingVideo = false
        mediaRecorder?.apply {
        
            stop()
            reset()
        }
        //重新开始预览
        startPreview()
    }

### 5. 实现动态设置分辨率 ###

之前我们这是录制分辨率是写死的`1920*1080`，这样是不够动态灵活的，接下来我们来实现下动态设置分辨率

首先通过`characteristics`获取到可用的分辨率列表

val characteristics = manager.getCameraCharacteristics(cameraId)
    val map = characteristics.get(SCALER_STREAM_CONFIGURATION_MAP) ?:
            throw RuntimeException("Cannot get available preview/video sizes")

然后通过这个`map`来选择出最适合的分辨率，这里的选择规则是返回宽高比`3:4`的分辨率中最高的分辨率

videoSize = chooseVideoSize(map.getOutputSizes(MediaRecorder::class.java))
     
    fun chooseVideoSize(choices: Array<Size>) = choices.firstOrNull {
        
            it.width == it.height * 4 / 3 } ?: choices[choices.size - 1]

最后，将该分辨率设置到`mediaRecorder`中就行了

mediaRecorder?.apply {
        
        setAudioSource(MediaRecorder.AudioSource.MIC)
        setVideoSource(MediaRecorder.VideoSource.SURFACE)
        setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
        setOutputFile(nextVideoAbsolutePath)
        setVideoEncodingBitRate(10000000)
        setVideoFrameRate(30)
        //setVideoSize(1920, 1080)
        setVideoSize(videoSize.width,videoSize.height)
        setVideoEncoder(MediaRecorder.VideoEncoder.H264)
        setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
        prepare()
    }

### 6. 其他 ###

#### 6.1 本文源码下载 ####

下载地址 : [Android Camera2 Demo - 实现相机预览、拍照、录制视频功能][Android Camera2 Demo -]

#### 6.2 Android Camera2 系列 ####

更多Camera2相关文章，请看  
[十分钟实现 Android Camera2 相机预览\_氦客的博客-CSDN博客][Android Camera2 _-CSDN]  
[十分钟实现 Android Camera2 相机拍照\_氦客的博客-CSDN博客][Link 1]  
[十分钟实现 Android Camera2 视频录制\_氦客的博客-CSDN博客][Link 1]

#### 6.3 Android 相机相关文章 ####

[Android 使用CameraX实现预览/拍照/录制视频/图片分析/对焦/缩放/切换摄像头等操作\_氦客的博客-CSDN博客][Android _CameraX_-CSDN]  
[Android 从零开发一个简易的相机App\_android开发简易app\_氦客的博客-CSDN博客][Android _App_android_app_-CSDN]

[Link 1]: https://blog.csdn.net/EthanCo/article/details/131414981
[fdf552c875734bfca809c2f512559e4c.jpeg]: https://img-blog.csdnimg.cn/fdf552c875734bfca809c2f512559e4c.jpeg
[1f12ca4a47704043aea14e327aa3836a.jpeg]: https://img-blog.csdnimg.cn/1f12ca4a47704043aea14e327aa3836a.jpeg
[Android Camera2 Demo -]: https://download.csdn.net/download/EthanCo/87960340
[Android Camera2 _-CSDN]: https://blog.csdn.net/EthanCo/article/details/131371887
[Android _CameraX_-CSDN]: https://blog.csdn.net/EthanCo/article/details/125603671
[Android _App_android_app_-CSDN]: https://blog.csdn.net/EthanCo/article/details/126260794