使用CameraX初始化USB摄像头时冷启动缓慢问题求助

我在Orange Pi5上开发基于USB摄像头的帧处理应用，使用CameraX框架时遇到冷启动初始化缓慢的问题。首次启动会多次重试初始化，最终在达到最大重试次数后完成初始化。

初始化代码 #

private fun startCameraPreview() {
    cameraProviderFuture = ProcessCameraProvider.getInstance(requireContext())

    cameraProviderFuture.addListener({
        val cameraProvider = cameraProviderFuture.get()
        bindPreview(cameraProvider)
    }, ContextCompat.getMainExecutor(requireContext()))
}

@SuppressLint("RestrictedApi")
private fun bindPreview(cameraProvider: ProcessCameraProvider) {
    previewView = viewBinding.previewView
    previewView.implementationMode = PreviewView.ImplementationMode.COMPATIBLE
    previewView.scaleX = -1f

    val preview: Preview = Preview.Builder()
        .setResolutionSelector(
            ResolutionSelector.Builder().setResolutionStrategy(
                ResolutionStrategy(Size(1080, 768),
                    ResolutionStrategy.FALLBACK_RULE_CLOSEST_HIGHER)
            ).build())
        .build()

    val selector = selectExternalOrBestCamera(cameraProvider) //For Usb camera Access
    preview.setSurfaceProvider(previewView.surfaceProvider)

    val strategy = ResolutionStrategy(Size(640, 480),
        ResolutionStrategy.FALLBACK_RULE_CLOSEST_HIGHER)

    val imageFrameAnalysis = ImageAnalysis.Builder()
        .setResolutionSelector(ResolutionSelector.Builder().setResolutionStrategy(strategy).build())
        .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
        .setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_RGBA_8888)
        .build()

    imageFrameAnalysis.setAnalyzer(Executors.newSingleThreadExecutor(), frameAnalyser)
    cameraProvider.bindToLifecycle(this as LifecycleOwner, selector!!, preview, imageFrameAnalysis)
}

USB摄像头选择代码 #

fun selectExternalOrBestCamera(provider: ProcessCameraProvider): CameraSelector? {
    val cam2Infos = provider.availableCameraInfos.map {
        Camera2CameraInfo.from(it)
    }.sortedByDescending {
        // HARDWARE_LEVEL is Int type, with the order of:
        // LEGACY < LIMITED < FULL < LEVEL_3 < EXTERNAL
        it.getCameraCharacteristic(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL)
    }

    return when {
        cam2Infos.isNotEmpty() -> {
            CameraSelector.Builder()
                .addCameraFilter {
                    it.filter { camInfo ->
                        // cam2Infos[0] is either EXTERNAL or best built-in camera
                        val thisCamId = Camera2CameraInfo.from(camInfo).cameraId
                        thisCamId == cam2Infos[0].cameraId
                    }
                }.build()
        }
        else -> null
    }
}

首次启动错误日志 #

2024-03-05 15:58:14.010 14845-14906 CameraRepository                              D  Added camera: 0
2024-03-05 15:58:14.012 14845-14906 Camera2CameraInfo                             I  Device Level: INFO_SUPPORTED_HARDWARE_LEVEL_EXTERNAL
2024-03-05 15:58:14.012 14845-14906 CameraValidator                               D  Verifying camera lens facing on rk3588s_s, lensFacingInteger: null
2024-03-05 15:58:14.013 14845-14906 CameraValidator                              E  Camera LensFacing verification failed, existing cameras: [Camera@e0778e4[id=0]]
2024-03-05 15:58:14.014 14845-14906 CameraX                                       W  Retry init. Start time 9251708 current time 9253283
                                                                                    androidx.camera.core.impl.CameraValidator$CameraIdListIncorrectException: Expected camera missing from device.
                                                                                        at androidx.camera.core.impl.CameraValidator.validateCameras(CameraValidator.java:97)
                                                                                        at androidx.camera.core.CameraX.lambda$initAndRetryRecursively$2$androidx-camera-core-CameraX(CameraX.java:334)
                                                                                        at androidx.camera.core.CameraX$$ExternalSyntheticLambda3.run(Unknown Source:10)
                                                                                        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
                                                                                        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
                                                                                        at java.lang.Thread.run(Thread.java:920)
                                                                                    Caused by: java.lang.IllegalArgumentException: No available camera can be found
                                                                                        at androidx.camera.core.CameraSelector.select(CameraSelector.java:94)
                                                                                        at androidx.camera.core.impl.CameraValidator.validateCameras(CameraValidator.java:83)
                                                                                        at androidx.camera.core.CameraX.lambda$initAndRetryRecursively$2$androidx-camera-core-CameraX(CameraX.java:334) 
                                                                                        at androidx.camera.core.CameraX$$ExternalSyntheticLambda3.run(Unknown Source:10) 
                                                                                        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
                                                                                        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
                                                                                        at java.lang.Thread.run(Thread.java:920) 

初始化完成提示 #

The device might underreport the amount of the cameras. Finish the initialize task since we are already reaching the maximum number of retries.

后续初始化日志 #

Added camera: 0
2024-03-05 15:58:15.030 14845-14906 Camera2CameraInfo                             I  Device Level: INFO_SUPPORTED_HARDWARE_LEVEL_EXTERNAL
2024-03-05 15:58:15.031 14845-14906 CameraValidator                               D  Verifying camera lens facing on rk3588s_s, lensFacingInteger: null
2024-03-05 15:58:15.032 14845-14906 CameraValidator                              E  Camera LensFacing verification failed, existing cameras: [Camera@10741b2[id=0]]
2024-03-05 15:58:15.032 14845-14906 CameraX                                      E  The device might underreport the amount of the cameras. Finish the initialize task since we are already reaching the maximum number of retries.
2024-03-05 15:58:15.083 14845-14845 CameraOrientationUtil                        D  getRelativeImageRotation: destRotationDegrees=0, sourceRotationDegrees=90, isOppositeFacing=false, result=90
2024-03-05 15:58:15.085 14845-14845 CameraOrientationUtil                         D  getRelativeImageRotation: destRotationDegrees=0, sourceRotationDegrees=90, isOppositeFacing=false, result=90
2024-03-05 15:58:15.094 14845-14845 DynamicRangeResolver                          D  Resolved dynamic range for use case androidx.camera.core.Preview-1b649f9e-f19f-43f5-8882-7ace2058df35 to no compatible HDR dynamic ranges.
                                                                                    DynamicRange@d8ad747{encoding=UNSPECIFIED, bitDepth=0}
                                                                                    ->
                                                                                    DynamicRange@c2bc286{encoding=SDR, bitDepth=8}
2024-03-05 15:58:15.099 14845-14845 CameraOrientationUtil                         D  getRelativeImageRotation: destRotationDegrees=0, sourceRotationDegrees=90, isOppositeFacing=false, result=90
2024-03-05 15:58:15.101 14845-14845 DeferrableSurface                             D  Surface created[total_surfaces=1, used_surfaces=0](androidx.camera.core.processing.SurfaceEdge$SettableSurface@df18112}
2024-03-05 15:58:15.103 14845-14845 DeferrableSurface                             D  Surface created[total_surfaces=2, used_surfaces=0](androidx.camera.core.SurfaceRequest$2@4e29c5e}
2024-03-05 15:58:15.104 14845-14845 DeferrableSurface                             D  New surface in use[total_surfaces=2, used_surfaces=1](androidx.camera.core.SurfaceRequest$2@4e29c5e}
2024-03-05 15:58:15.104 14845-14845 DeferrableSurface                            D  use count+1, useCount=1 androidx.camera.core.SurfaceRequest$2@4e29c5e

CameraX Gradle依赖 #

// CameraX
def camerax_version = "1.3.1"
implementation "androidx.camera:camera-core:${camerax_version}"
implementation "androidx.camera:camera-camera2:${camerax_version}"
implementation "androidx.camera:camera-lifecycle:${camerax_version}"
implementation "androidx.camera:camera-video:${camerax_version}"

implementation "androidx.camera:camera-view:${camerax_version}"
implementation "androidx.camera:camera-extensions:${camerax_version}"

已尝试方案 #

• 添加@OptIn(ExperimentalCamera2Interop::class)注解，无效果
• 为CameraSelector明确指定镜头朝向.requireLensFacing(LENS_FACING_FRONT/BACK/EXTERNAL)，导致崩溃

问题推测 #

CameraValidator无法接受USB摄像头的镜头参数值，导致多次重试初始化，进而造成冷启动缓慢。

内容的提问来源于stack exchange，提问作者John DoeDoe