当我使用 YUV_420_888 Image Reader 作为目标表面时，Camera 2 预览冻结

如何解决当我使用 YUV_420_888 Image Reader 作为目标表面时，Camera 2 预览冻结

我正在开发一个应用程序，该应用程序要求在实时摄像机源中检测对象和面部。为此，我正在使用 MLkit。我已经成功地使用后置摄像头实现了对象检测部分，没有任何问题。 ML kit 建议使用 YUV_420_888，尺寸尽可能小，以获得更好的效果。我使用的是 Camera 2 API，这是我设置 ImageReader 进行处理的代码。

class SelfieCaptureFragment : Fragment(R.layout.fragment_selfie_capture) {

    protected lateinit var characteristics: CameraCharacteristics
    protected lateinit var camera: CameraDevice
    protected lateinit var session: CameraCaptureSession
    protected lateinit var requestPermissionLauncher: ActivityResultLauncher<String>
    protected lateinit var captureImageReader: ImageReader
    protected lateinit var analyzeImageReader: ImageReader
    
    /** [HandlerThread] and [Handler] where all camera operations run */
    private val cameraThread = HandlerThread("CameraThread").apply { start() }
    private val cameraHandler = Handler(cameraThread.looper)

    /** [HandlerThread] and [Handler] where all camera still image capturing operations run */
    private val captureImageReaderThread = HandlerThread("captureImageReaderThread").apply { start() }
    private val captureImageReaderHandler = Handler(captureImageReaderThread.looper)

    private val analyzeImageReaderThread = HandlerThread("imageReaderThread").apply { start() }
    private val analyzeImageReaderHandler = Handler(analyzeImageReaderThread.looper)

    companion object {
        /** Maximum number of images that will be held in the reader's buffer */
        const val IMAGE_BUFFER_SIZE: Int = 3
    }

    private fun configureCamera(selectedCameraId: String) {

        lifecycleScope.launch(Dispatchers.Main) {

            camera = openCamera(cameraManager,selectedCameraId,cameraHandler)

            val previewFraction = DisplayUtils
                .asFraction(previewSize!!.width.toLong(),previewSize!!.height.toLong())

            // Initialize an image reader which will be used to capture still photos
            captureSize = characteristics.get(
                CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)!!
                .getOutputSizes(ImageFormat.JPEG)
                .filter { DisplayUtils.asFraction(it.width.toLong(),it.height.toLong()) == previewFraction }
                .sortedBy { it.height * it.width}
                .reversed()
                .first()

            analyzeImageSize = characteristics
                .get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)!!
                .getOutputSizes(ImageFormat.YUV_420_888)
                .filter { DisplayUtils.asFraction(it.width.toLong(),it.height.toLong()) == previewFraction }
                .sortedBy { it.height * it.width}
                .first()

            if (captureSize != null) {

                captureImageReader = ImageReader.newInstance(
                    captureSize!!.width,captureSize!!.height,ImageFormat.JPEG,IMAGE_BUFFER_SIZE
                )

                analyzeImageReader = ImageReader.newInstance(
                    analyzeImageSize!!.width,analyzeImageSize!!.height,ImageFormat.YUV_420_888,IMAGE_BUFFER_SIZE)

                Log.d(TAG,"Selected capture size: $captureSize")
                Log.d(TAG,"Selected image analyze size: $analyzeImageSize")

                val targets = listOf(
                    binding.cameraSurfaceView.holder.surface,captureImageReader.surface,analyzeImageReader.surface
                )

                session = createCaptureSession(camera,targets,cameraHandler)

                val captureBuilder = camera.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW)
                captureBuilder.set(
                    CaptureRequest.CONTROL_AF_MODE,CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE
                )
                captureBuilder.addTarget(binding.cameraSurfaceView.holder.surface)
                captureBuilder.addTarget(analyzeImageReader.surface)

                session.setRepeatingRequest(captureBuilder.build(),null,cameraHandler)

              
            }
        }
    }
}

此代码与我在后置摄像头中用于为对象检测部分设置图像读取器的代码相同。我还没有实现任何与图像处理相关的逻辑来检测相机流中的人脸。错误出在我设置目标的那一行。 captureBuilder.addTarget(analyzeImageReader.surface) 如果我评论说行相机预览效果很好。当相机预览冻结时，我在 logcat 中一遍又一遍地收到以下错误和警告。

W/libc: Unable to set property "debug.sf.dequeuebuffer" to "1": connection failed; errno=13 (Permission denied)
E/BufferQueueProducer: [ImageReader-256x144f23m3-23007-3](id:59df00000003,api:4,p:4806,c:23007) waitForFreeSlotThenRelock: timeout

我不明白为什么它在前置摄像头中不起作用。从analyzeImageReader 返回的分析图像大小为256x144，这也不是一个很大的分辨率，而且它是YUV_420_888 格式的所有支持大小中最小的。任何帮助将不胜感激。当我实现目标检测部分时，我以为我已经弄清楚了。这是一个非常意外的问题。

编辑：我仍然被这个问题困扰，所以我设置了一个小 project 来展示整个图片。请检查 repo 并帮助我找到解决方案。谢谢。

解决方法

希望这会有所帮助：我在使用一种手机型号（三星 A50）时遇到了类似的问题。我设法通过改变这个来解决它：

captureImageReader.setOnImageAvailableListener(null,null)

致：

captureImageReader.setOnImageAvailableListener({ reader ->
            reader.acquireLatestImage().close()
        },imageReaderHandler)