十分钟实现 Android Camera2 视频录制

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? = nullprivate var isRecordingVideo: Boolean = falseprivate val SENSOR_ORIENTATION_DEFAULT_DEGREES = 90private val SENSOR_ORIENTATION_INVERSE_DEGREES = 270private 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 : 1private val cameraId = "0"private val TAG = CameraActivity3::class.java.simpleNameprivate lateinit var cameraDevice: CameraDeviceprivate 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: CameraCaptureSessionprivate 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)private lateinit var relativeOrientation: OrientationLiveDataprivate var mediaRecorder: MediaRecorder? = nullprivate var isRecordingVideo: Boolean = falseprivate val SENSOR_ORIENTATION_DEFAULT_DEGREES = 90private val SENSOR_ORIENTATION_INVERSE_DEGREES = 270private 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

<Button    android:id="@+id/btn_capture_video"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="bottom|center"    android:layout_marginRight="16dp"    android:text="录屏"    android:visibility="visible"    app:layout_constraintBottom_toBottomOf="parent"    app:layout_constraintLeft_toLeftOf="parent"    app:layout_constraintRight_toRightOf="parent" /><Button    android:id="@+id/btn_stop_capture"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="bottom|left"    android:text="停止录屏"    android:visibility="visible"    app:layout_constraintBottom_toBottomOf="parent"    app:layout_constraintLeft_toLeftOf="parent"    app:layout_constraintRight_toRightOf="parent" />

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.rotationwhen (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!!.surfaceval 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 = cameraCaptureSessionval previewRequestBuilder = cameraDevice!!.createCaptureRequest(TEMPLATE_RECORD).apply {    addTarget(binding.surfaceView.holder.surface)    addTarget(recorderSurface)}session?.setRepeatingRequest(previewRequestBuilder!!.build(), null, cameraHandler)isRecordingVideo = truemediaRecorder?.start()

3.5 录制视频完整代码

binding.btnCaptureVideo.setOnClickListener {    startRecordingVideo()}private fun startRecordingVideo() {closePreviewSession()setUpMediaRecorder()val recorderSurface = mediaRecorder!!.surfaceval 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()    }}

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

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

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
十分钟实现 Android Camera2 相机拍照_氦客的博客-CSDN博客
十分钟实现 Android Camera2 视频录制_氦客的博客-CSDN博客

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 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

来源地址：https://blog.csdn.net/EthanCo/article/details/131418829