打開相機并獲取相機流，并將yuv數據轉換成nv21
1.導入依賴
在app下的build.gradle中加入
?def camerax_version ="1.0.1"
implementation"androidx.camera:camera-core:${camerax_version}"
implementation"androidx.camera:camera-camera2:${camerax_version}"
implementation"androidx.camera:camera-lifecycle:${camerax_version}"
implementation"androidx.camera:camera-view:1.0.0-alpha28"
2.相機布局文件
使用androidx 的布局
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
? ? xmlns:app="http://schemas.android.com/apk/res-auto"
? ? xmlns:tools="http://schemas.android.com/tools"
? ? android:layout_width="match_parent"
? ? android:layout_height="match_parent"
? ? tools:context=".MainActivity">
? ? <androidx.camera.view.PreviewView
? ? ? ? android:id="@+id/textureView"
? ? ? ? android:layout_width="match_parent"
? ? ? ? android:layout_height="match_parent"
? ? ? ? tools:layout_editor_absoluteX="0dp"
? ? ? ? tools:layout_editor_absoluteY="0dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
3.打開相機
private var textureView:PreviewView? =null
private val executor =Executors.newSingleThreadExecutor()
private val permissionsRequestCode =Random.nextInt(0,10000)
private var lensFacing:Int =CameraSelector.LENS_FACING_FRONT
//打開相機需要的權限
private val permissions =listOf(Manifest.permission.CAMERA,Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE)
override fun onCreate(savedInstanceState:Bundle?) {
????????super.onCreate(savedInstanceState)
????????setContentView(R.layout.activity_main)
? ? ? ? textureView = findViewById(R.id.textureView);
}
//先檢測權限如果有權限就打開相機
override fun onResume() {
????????super.onResume()
? ? if (!hasPermissions(this)) { //檢測權限
????????ActivityCompat.requestPermissions(
????????????????this,permissions.toTypedArray(),permissionsRequestCode
? ? ? ? )
????}else {
????????bindCameraUseCases()//打開相機
????}
}
/** 綁定預覽和獲取圖片數據*/
@SuppressLint("UnsafeExperimentalUsageError","UnsafeOptInUsageError")
private fun bindCameraUseCases() =textureView?.post{
? ? ?val cameraProviderFuture =ProcessCameraProvider.getInstance(this)
? ? ?cameraProviderFuture.addListener(Runnable {
? ? ? ? ? val cameraProvider =cameraProviderFuture.get()
? ? ? ? ? val preview =textureView?.display?.let {
? ? ? ? ? ? ? ?Preview.Builder()
? ? ? ? ? ? ? .setTargetAspectRatio(AspectRatio.RATIO_4_3)
? ? ? ? ? ? ? .setTargetRotation(it.rotation)
? ? ? ? ? ? ? .build()
? ? ?}
? ? ?val imageAnalysis =ImageAnalysis.Builder()
? ? ? ? ? ?.setTargetAspectRatio(AspectRatio.RATIO_4_3)
? ? ? ? ? ?.setTargetRotation(textureView!!.display.rotation)
? ? ? ? ? ? .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
? ? ? ? ? ? .build()
? ? ? var frameCounter =0
? ? ? var lastFpsTimestamp =System.currentTimeMillis()
? ? ? var yuvBits:ByteBuffer? =null
? ? ? ?imageAnalysis.setAnalyzer(executor,ImageAnalysis.Analyzer{ image->
? ? ? ? ? ? val yuvBuffer = image.image?.let { YuvByteBuffer(it,yuvBits)} //獲取相機流并轉換成nv21
? ? ? ? ? ? image.close()
? ? ? ? ? //檢測相機幀率
? ? ? ? ? ? val frameCount =10
? ? ? ? ? ? if (++frameCounter %frameCount ==0) {
? ? ? ? ? ? ? ? ?frameCounter =0
? ? ? ? ? ? ? ? val now =System.currentTimeMillis()
? ? ? ? ? ? ? ? val delta =now -lastFpsTimestamp
? ? ? ? ? ? ? ? val fps =1000 *frameCount.toFloat() /delta
? ? ? ? ? ? ? ? Log.d(TAG,"FPS: ${"%.02f".format(fps)}")
? ? ? ? ? ? ? ? ?lastFpsTimestamp =now
? ? ? ? ? ? }
? ? ? ?})
// Create a new camera selector each time, enforcing lens facing
? ?val cameraSelector =CameraSelector.Builder().requireLensFacing(lensFacing).build()
// Apply declared configs to CameraX using the same lifecycle owner
? ? cameraProvider.unbindAll()
? ? ? ? ?val camera =cameraProvider.bindToLifecycle(
????????????this as LifecycleOwner,cameraSelector,preview,imageAnalysis
? ? ? ? ? )
? ? val c:CameraInfo =camera.cameraInfo;
// Use the camera object to link our preview use case with the view
? ?preview?.setSurfaceProvider(textureView?.surfaceProvider)
? },ContextCompat.getMainExecutor(this))
? }
/** Convenience method used to check if all permissions required by this app are granted */
private fun hasPermissions(context:Context) =permissions.all {
? ? ContextCompat.checkSelfPermission(context,it) ==PackageManager.PERMISSION_GRANTED
}
override fun onRequestPermissionsResult(
requestCode:Int,
permissions:Array,
grantResults:IntArray
) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults)
if (requestCode ==permissionsRequestCode && hasPermissions(this)) {
bindCameraUseCases()
}else {
finish()// If we don't have the required permissions, we can't run
? ? }
}
4.YUV轉nv21工具
@kotlin.annotation.Retention(AnnotationRetention.SOURCE)
@IntDef(ImageFormat.NV21,ImageFormat.YUV_420_888)
annotation class YuvType
class YuvByteBuffer(image:Image, dstBuffer:ByteBuffer? =null) {
@YuvType
? ? val type:Int
? ? val buffer:ByteBuffer
? ? init {
val wrappedImage = ImageWrapper(image)
type =if (wrappedImage.u.pixelStride ==1) {
ImageFormat.YUV_420_888
? ? ? ? }else {
ImageFormat.NV21
? ? ? ? }
val size = image.width * image.height *3 /2
? ? ? ? buffer =if (
dstBuffer ==null ||dstBuffer.capacity()
dstBuffer.isReadOnly || !dstBuffer.isDirect
? ? ? ? ) {
ByteBuffer.allocateDirect(size) }
else {
dstBuffer
}
buffer.rewind()
removePadding(wrappedImage)
}
// Input buffers are always direct as described in
// https://developer.android.com/reference/android/media/Image.Plane#getBuffer()
? ? private fun removePadding(image:ImageWrapper) {
val sizeLuma = image.y.width * image.y.height
? ? ? ? val sizeChroma = image.u.width * image.u.height
? ? ? ? if (image.y.rowStride > image.y.width) {
removePaddingCompact(image.y,buffer,0)
}else {
buffer.position(0)
buffer.put(image.y.buffer)
}
if (type ==ImageFormat.YUV_420_888) {
if (image.u.rowStride > image.u.width) {
removePaddingCompact(image.u,buffer,sizeLuma)
removePaddingCompact(image.v,buffer,sizeLuma +sizeChroma)
}else {
buffer.position(sizeLuma)
buffer.put(image.u.buffer)
buffer.position(sizeLuma +sizeChroma)
buffer.put(image.v.buffer)
}
}else {
if (image.u.rowStride > image.u.width *2) {
removePaddingNotCompact(image,buffer,sizeLuma)
}else {
buffer.position(sizeLuma)
var uv = image.v.buffer
? ? ? ? ? ? ? ? val properUVSize = image.v.height * image.v.rowStride -1
? ? ? ? ? ? ? ? if (uv.capacity() >properUVSize) {
uv = clipBuffer(image.v.buffer,0,properUVSize)
}
buffer.put(uv)
val lastOne = image.u.buffer[image.u.buffer.capacity() -1]
buffer.put(buffer.capacity() -1,lastOne)
}
}
buffer.rewind()
}
private fun removePaddingCompact(
plane:PlaneWrapper,
dst:ByteBuffer,
offset:Int
? ? ) {
require(plane.pixelStride ==1){
? ? ? ? ? ? "use removePaddingCompact with pixelStride == 1"
? ? ? ? }
? ? ? ? val src = plane.buffer
? ? ? ? val rowStride = plane.rowStride
? ? ? ? var row:ByteBuffer
? ? ? ? dst.position(offset)
for (i in 0 until plane.height) {
row = clipBuffer(src,i *rowStride, plane.width)
dst.put(row)
}
}
private fun removePaddingNotCompact(
image:ImageWrapper,
dst:ByteBuffer,
offset:Int
? ? ) {
require(image.u.pixelStride ==2){
? ? ? ? ? ? "use removePaddingNotCompact pixelStride == 2"
? ? ? ? }
? ? ? ? val width = image.u.width
? ? ? ? val height = image.u.height
? ? ? ? val rowStride = image.u.rowStride
? ? ? ? var row:ByteBuffer
? ? ? ? dst.position(offset)
for (i in 0 until height -1) {
row = clipBuffer(image.v.buffer,i *rowStride,width *2)
dst.put(row)
}
row = clipBuffer(image.u.buffer, (height -1) *rowStride -1,width *2)
dst.put(row)
}
private fun clipBuffer(buffer:ByteBuffer, start:Int, size:Int):ByteBuffer {
val duplicate = buffer.duplicate()
duplicate.position(start)
duplicate.limit(start + size)
return duplicate.slice()
}
private class ImageWrapper(image:Image) {
val width= image.width
? ? ? ? val height = image.height
? ? ? ? val y = PlaneWrapper(width,height, image.planes[0])
val u = PlaneWrapper(width /2,height /2, image.planes[1])
val v = PlaneWrapper(width /2,height /2, image.planes[2])
// Check this is a supported image format
// https://developer.android.com/reference/android/graphics/ImageFormat#YUV_420_888
? ? ? ? init {
require(y.pixelStride ==1){
? ? ? ? ? ? ? ? "Pixel stride for Y plane must be 1 but got ${y.pixelStride}instead."
? ? ? ? ? ? }
? ? ? ? ? ? require(u.pixelStride ==v.pixelStride &&u.rowStride ==v.rowStride){
? ? ? ? ? ? ? ? "U and V planes must have the same pixel and row strides " +
"but got pixel=${u.pixelStride} row=${u.rowStride} for U " +
"and pixel=${v.pixelStride} and row=${v.rowStride}for V"
? ? ? ? ? ? }
? ? ? ? ? ? require(u.pixelStride ==1 ||u.pixelStride ==2){
? ? ? ? ? ? ? ? "Supported" +" pixel strides for U and V planes are 1 and 2"
? ? ? ? ? ? }
? ? ? ? }
}
private class PlaneWrapper(width:Int, height:Int, plane:Image.Plane) {
val width = width
val height = height
val buffer:ByteBuffer = plane.buffer
? ? ? ? val rowStride = plane.rowStride
? ? ? ? val pixelStride = plane.pixelStride
? ? }
}
5.AndroidManifest.xml
<!-- Declare features -->
<uses-feature android:name="android.hardware.camera" />
<!-- Declare permissions -->
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
下載地址:https://download.csdn.net/download/qq_28884137/31845235
