以下代码使用 Vision 和 AVFoundation 框架在 macOS 上的内置摄像头上启用面部跟踪。在某些情况下，代码会因队列 com.apple.VN.trackersCollectionManagementQueue (serial) 上的工作线程上的 EXC_BAD_ACCESS (code=2) 而崩溃。只要没有检测到人脸，应用程序就会按预期运行，但一旦检测到人脸并尝试通过该方法跟踪它，就会崩溃
[_sequenceRequestHandler performRequests:requests onCVPixelBuffer:pixelBuffer orientation:exifOrientation error:&error]
该方法在AVCaptureVideoDataOutputSampleBufferDelegate方法内部调用
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection)
据我了解，EXC_BAD_ACCESS 意味着我无法访问内存 [1] ，错误代码 (2) KERN_PROTECTION_FAILURE 意味着指定的内存有效，但不允许所需形式的访问 [2] 。 一份(可能已过时的)技术说明解释说，这是由线程尝试写入只读内存引起的。 [3] 。由此，我了解到问题不是由过早释放或内存损坏引起的，而是跨线程的内存访问控制。
我相信该问题是在更新后出现的。在游戏模板项目(Metal、SceneKit 和 SpriteKit)的方案编辑器中选中“调试可执行文件”时，会发生崩溃，但在应用程序和文档应用程序模板中使用时不会崩溃。该代码在适应物理设备上的 iOS 时也能按预期工作。我尝试通过删除尽可能多的代码来隔离问题，并且可以将以下文件添加到任何模板中。
头文件
#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface LSPVision : NSObject <AVCaptureVideoDataOutputSampleBufferDelegate>
@property (nonatomic) AVCaptureVideoPreviewLayer *previewLayer;
- (void)captureFrame;
@end
NS_ASSUME_NONNULL_END
实现文件
#import "LSPVision.h"
#import <Vision/Vision.h>
@implementation LSPVision
{
// AVCapture stuff
AVCaptureSession *_session;
AVCaptureVideoDataOutput *_videoDataOutput;
dispatch_queue_t _videoDataOutputQueue;
CGSize _captureDeviceResolution;
// Vision requests
NSMutableArray *_detectionRequests; // Array of VNDetectFaceRectanglesRequest
NSMutableArray *_trackingRequests; // Array of VNTrackObjectRequest
VNSequenceRequestHandler *_sequenceRequestHandler;
BOOL _frameCapture;
}
- (nonnull instancetype)init
{
self = [super init];
if(self)
{
_session = [self _setupAVCaptureSession];
[self designatePreviewLayerForCaptureSession:_session];
[self _prepareVisionRequest];
_frameCapture = YES;
if (_session) {
[_session startRunning];
}
}
return self;
}
# pragma mark Setup AVSession
- (AVCaptureSession *)_setupAVCaptureSession {
AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice *device;
#if defined(TARGET_MACOS)
if (@available(macOS 10.15, *)) {
AVCaptureDeviceDiscoverySession *discoverySession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionFront];
device = discoverySession.devices.firstObject;
}
#endif
if (device != nil) {
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
if ([captureSession canAddInput:deviceInput]) {
[captureSession addInput:deviceInput];
}
AVCaptureDeviceFormat *lowestResolution = [self _lowestResolution420Format:device];
if (lowestResolution != nil) {
if ([device lockForConfiguration:nil]) {
device.activeFormat = lowestResolution;
[device unlockForConfiguration];
}
}
}
if (device != nil) {
[self _configureVideoDataOutput:device captureSession:captureSession];
return captureSession;
}
NSLog(@"Hold up, something went wrong with AVCaptureSession");
[self _tearDownAVCapture];
return nil;
}
- (AVCaptureDeviceFormat *)_lowestResolution420Format:(AVCaptureDevice *)device {
AVCaptureDeviceFormat *lowestResolutionFormat = nil;
CMVideoDimensions lowestResolutionDimensions = { .height = (int32_t)10000, .width = (int32_t)10000 };
for (AVCaptureDeviceFormat *deviceFormat in device.formats) {
CMFormatDescriptionRef deviceFormatDescription = deviceFormat.formatDescription;
if (CMFormatDescriptionGetMediaSubType(deviceFormatDescription) == (kCVPixelFormatType_420YpCbCr8BiPlanarFullRange | kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange)) {
CMVideoDimensions candidateDimensions = CMVideoFormatDescriptionGetDimensions(deviceFormatDescription);
if ((lowestResolutionFormat == nil) || candidateDimensions.width > lowestResolutionDimensions.width) {
lowestResolutionFormat = deviceFormat;
lowestResolutionDimensions = candidateDimensions;
NSLog(@"Device Format: Width: %d, Height: %d", candidateDimensions.width, candidateDimensions.height);
_captureDeviceResolution.width = candidateDimensions.width;
_captureDeviceResolution.height = candidateDimensions.height;
}
}
}
if (lowestResolutionFormat != nil) {
return lowestResolutionFormat;
}
return nil;
}
- (void)designatePreviewLayerForCaptureSession:(AVCaptureSession *)session {
AVCaptureVideoPreviewLayer *videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
self.previewLayer = videoPreviewLayer;
videoPreviewLayer.name = @"Camera Preview";
}
- (void)_configureVideoDataOutput:(AVCaptureDevice *)inputDevice captureSession:(AVCaptureSession *)captureSession {
AVCaptureVideoDataOutput *videoDataOutput = [AVCaptureVideoDataOutput new];
videoDataOutput.alwaysDiscardsLateVideoFrames = true;
// Create a serial dispatch queue used for the sample buffer delegate as well as when a still image is captured.
// A serial dispatch queue must be used to guarantee that video frames will be delivered in order.
dispatch_queue_t videoDataOutputQueue = dispatch_queue_create("com.example.apple-samplecode.VisionFaceTrack", NULL);
[videoDataOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
if ([captureSession canAddOutput:videoDataOutput]) {
[captureSession addOutput:videoDataOutput];
}
[videoDataOutput connectionWithMediaType:AVMediaTypeVideo].enabled = true;
_videoDataOutput = videoDataOutput;
_videoDataOutputQueue = videoDataOutputQueue;
}
# pragma mark Vision Request
- (void)_prepareVisionRequest {
NSMutableArray *requests = [NSMutableArray array];
VNRequestCompletionHandler handlerBlock = ^(VNRequest * _Nonnull request, NSError * _Nullable error) {
if (error) {
NSLog(@"Handler error: %@", error);
}
VNDetectFaceRectanglesRequest *faceDetectionRequest = (VNDetectFaceRectanglesRequest *)request;
dispatch_async(dispatch_get_main_queue(), ^{
for (VNFaceObservation *observation in faceDetectionRequest.results) {
VNTrackObjectRequest *faceTrackingRequest = [[VNTrackObjectRequest alloc] initWithDetectedObjectObservation:observation];
NSUInteger count = requests.count;
[requests insertObject:faceTrackingRequest atIndex:count];
}
self->_trackingRequests = [requests copy];
});
};
VNDetectFaceRectanglesRequest *faceDetectionRequest = [[VNDetectFaceRectanglesRequest alloc] initWithCompletionHandler:handlerBlock];
_detectionRequests = [NSMutableArray arrayWithObject:faceDetectionRequest];
_sequenceRequestHandler = [[VNSequenceRequestHandler alloc] init];
}
# pragma mark Delegate functions
// AVCaptureVideoDataOutputSampleBufferDelegate
// Handle delegate method callback on receiving a sample buffer.
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
if (_frameCapture == YES) {
NSMutableDictionary *requestHandlerOptions = [NSMutableDictionary dictionary];
CFTypeRef cameraIntrinsicData = CMGetAttachment(sampleBuffer, kCMSampleBufferAttachmentKey_CameraIntrinsicMatrix, nil);
if (cameraIntrinsicData != nil) {
[requestHandlerOptions setObject:CFBridgingRelease(cameraIntrinsicData) forKey:VNImageOptionCameraIntrinsics];
}
CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
if (!pixelBuffer) {
NSLog(@"Failed to obtain a CVPixelBuffer for the current output frame.");
return;
}
#if defined(TARGET_MACOS)
CGImagePropertyOrientation exifOrientation = kCGImagePropertyOrientationLeftMirrored;
#endif
NSError *error;
NSArray *requests;
if (_trackingRequests.count > 0) {
requests = _trackingRequests;
} else {
// No tracking object detected, so perform initial detection
VNImageRequestHandler *imageRequestHandler = [[VNImageRequestHandler alloc] initWithCVPixelBuffer:pixelBuffer orientation:exifOrientation options:requestHandlerOptions];
NSArray *detectionRequests = _detectionRequests;
if (detectionRequests == nil) {
return;
}
[imageRequestHandler performRequests:_detectionRequests error:&error];
if (error) {
NSLog(@"Failed to perform FaceRectangleRequest: %@", error);
}
return;
}
// SequenceRequesthandler results in 10-20% cpu utilization
[_sequenceRequestHandler performRequests:requests onCVPixelBuffer:pixelBuffer orientation:exifOrientation error:&error];
if (error) {
NSLog(@"Failed to perform SequenceRequest: %@", error);
return;
}
// Setup the next round of tracking
NSMutableArray *newTrackingRequests = [NSMutableArray array];
for (VNTrackObjectRequest *trackingRequest in requests) {
NSArray *results = trackingRequest.results;
trackingRequest.trackingLevel = VNRequestTrackingLevelFast;
VNDetectedObjectObservation *observation = results[0];
if (![observation isKindOfClass:[VNDetectedObjectObservation class]]) {
return;
}
if (!trackingRequest.isLastFrame) {
if (observation.confidence > 0.3f ) {
trackingRequest.inputObservation = observation;
} else {
trackingRequest.lastFrame = true;
}
NSUInteger number = newTrackingRequests.count;
[newTrackingRequests insertObject:trackingRequest atIndex:number];
}
}
_trackingRequests = newTrackingRequests;
if (newTrackingRequests.count == 0) {
// Nothing to track, so abort.
return;
}
NSMutableArray *faceLandmarksRequests = [NSMutableArray array];
for (VNTrackObjectRequest* trackingRequest in newTrackingRequests) {
VNRequestCompletionHandler handlerBlock = ^(VNRequest * _Nonnull request, NSError * _Nullable error) {
if (error != nil) {
NSLog(@"Facelandmarks error: %@", error);
}
VNDetectFaceLandmarksRequest *landmarksRequest = (VNDetectFaceLandmarksRequest *)request;
NSArray *results = landmarksRequest.results;
if (results == nil) {
return;
}
// Perform all UI updates (drawing) on the main queue, not the background queue on which this handler is being called.
dispatch_async(dispatch_get_main_queue(), ^{
for (VNFaceObservation *faceObservation in results) {
[self _setEyePositionsForFace:faceObservation];
//NSLog(@"seeing face");
}
});
};
VNDetectFaceLandmarksRequest *faceLandmarksRequest = [[VNDetectFaceLandmarksRequest alloc] initWithCompletionHandler:handlerBlock];
NSArray *trackingResults = trackingRequest.results;
if (trackingResults == nil) {
return;
}
VNDetectedObjectObservation *observation = trackingResults[0];
if (observation == nil) {
return;
}
VNFaceObservation *faceObservation = [VNFaceObservation observationWithBoundingBox:observation.boundingBox];
faceLandmarksRequest.inputFaceObservations = @[faceObservation];
// Continure to track detected facial landmarks.
NSUInteger nr = faceLandmarksRequests.count;
[faceLandmarksRequests insertObject:faceLandmarksRequest atIndex:nr];
VNImageRequestHandler *imageRequestHandler = [[VNImageRequestHandler alloc] initWithCVPixelBuffer:pixelBuffer orientation:exifOrientation options:requestHandlerOptions];
[imageRequestHandler performRequests:faceLandmarksRequests error:&error];
if (error != nil) {
NSLog(@"Failed to perform FaceLandmarkRequest: %@", error);
}
}
}
//_frameCapture = NO;
}
# pragma mark Helper Functions
- (void)captureFrame {
_frameCapture = YES;
}
- (void)_tearDownAVCapture {
_videoDataOutput = nil;
_videoDataOutputQueue = nil;
}
@end
调试
崩溃似乎与 Metal 有关，可能是在多个线程上。当 Vision 框架(来自工作线程)从私有(private)神经网络框架 (Espresso) 执行 Metal Performance Shaders 时，会发生崩溃。在崩溃之前，存在与命令缓冲区相关的死锁。这最终导致地址清理程序报告未知地址上的总线。我认为这就是我收到 KERN_PROTECTION_FAILURE 的原因。其他线程要么正在执行 Metal，要么只是在等待。我不知道信号量是否与 Metal CPU/GPU 同步或其他相关。当代码与App模板一起使用时，Vision框架在主线程上运行，不会发生崩溃。除了提交错误报告之外，我不知道如何以任何有意义的方式解决这个问题。话虽这么说，我的调试技能还有很多不足之处，因此非常感谢任何帮助 - 不仅在解决问题方面，而且在理解问题方面。地址清理程序和线程清理程序已打开以进行以下输出。由于大小限制，可以读取崩溃报告 here 。现在可以从 dropbox 查看和下载崩溃的项目(在我的计算机上)。我的电脑是 2019 MB Pro 16。
控制台输出
ErrorTest1(13661,0x107776e00) malloc: nano zone abandoned due to inability to preallocate reserved vm space.
2020-12-24 09:48:35.709965+0100 ErrorTest1[13661:811227] Metal GPU Frame Capture Enabled
2020-12-24 09:48:36.675326+0100 ErrorTest1[13661:811227] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x6030000b7b50> F8BB1C28-BAE8-11D6-9C31-00039315CD46
2020-12-24 09:48:36.707535+0100 ErrorTest1[13661:811227] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x6030000bb5a0> 30010C1C-93BF-11D8-8B5B-000A95AF9C6A
2020-12-24 09:48:36.845641+0100 ErrorTest1[13661:811227] [] CMIOHardware.cpp:379:CMIOObjectGetPropertyData Error: 2003332927, failed
2020-12-24 09:48:38.717546+0100 ErrorTest1[13661:811794] [logging-persist] cannot open file at line 44580 of [02c344acea]
2020-12-24 09:48:38.717648+0100 ErrorTest1[13661:811794] [logging-persist] os_unix.c:44580: (0) open(/var/db/DetachedSignatures) - Undefined error: 0
2020-12-24 09:48:38.778975+0100 ErrorTest1[13661:811761] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:61:16: warning: unused variable 'input_slice_count'
const uint input_slice_count = (INPUT_FEATURE_CHANNELS + 3) / 4;
^
2020-12-24 09:48:38.779198+0100 ErrorTest1[13661:811812] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:121:24: warning: comparison of integers of different signs: 'int' and 'const constant uint' (aka 'const constant unsigned int')
for(int kd = 0; kd < params.inputFeatureChannels; kd++) // _ID = 3, RGB
~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
2020-12-24 09:48:38.779441+0100 ErrorTest1[13661:811838] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:121:24: warning: comparison of integers of different signs: 'int' and 'const constant uint' (aka 'const constant unsigned int')
for(int kd = 0; kd < params.inputFeatureChannels; kd++) // _ID = 3, RGB
~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
2020-12-24 09:48:39.072518+0100 ErrorTest1[13661:811838] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:61:16: warning: unused variable 'input_slice_count'
const uint input_slice_count = (INPUT_FEATURE_CHANNELS + 3) / 4;
^
2020-12-24 09:48:39.073210+0100 ErrorTest1[13661:811842] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:98:16: warning: unused variable 'fm_group'
const uint fm_group = threadgroup_id.z - splitId * params.simdsPerGroupData;
^
program_source:121:24: warning: comparison of integers of different signs: 'int' and 'const constant uint' (aka 'const constant unsigned int')
for(int kd = 0; kd < params.inputFeatureChannels; kd++) // _ID = 3, RGB
~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
2020-12-24 09:48:39.073538+0100 ErrorTest1[13661:811812] [Metal Compiler Warning] Warning: Compilation succeeded with:
program_source:98:16: warning: unused variable 'fm_group'
const uint fm_group = threadgroup_id.z - splitId * params.simdsPerGroupData;
^
program_source:121:24: warning: comparison of integers of different signs: 'int' and 'const constant uint' (aka 'const constant unsigned int')
for(int kd = 0; kd < params.inputFeatureChannels; kd++) // _ID = 3, RGB
~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
LLDB bt
* thread #5, queue = 'com.apple.VN.trackersCollectionManagementQueue', stop reason = EXC_BAD_ACCESS (code=2, address=0x70000deb1ff8)
frame #0: 0x000000010739db33 libsystem_pthread.dylib`___chkstk_darwin + 55
frame #1: 0x000000010739dafc libsystem_pthread.dylib`thread_start + 20
frame #2: 0x000000010724277b libMTLCapture.dylib`___lldb_unnamed_symbol2507$$libMTLCapture.dylib + 585
frame #3: 0x00007fff29f597be MPSNeuralNetwork`___lldb_unnamed_symbol4427$$MPSNeuralNetwork + 1907
frame #4: 0x00007fff29f5a3c2 MPSNeuralNetwork`___lldb_unnamed_symbol4432$$MPSNeuralNetwork + 756
frame #5: 0x00007fff29f5aa39 MPSNeuralNetwork`___lldb_unnamed_symbol4435$$MPSNeuralNetwork + 83
frame #6: 0x00007fff339e50e8 Espresso`Espresso::MPSEngine::mps_convolution_kernel::recreate_kernel() + 230
frame #7: 0x00007fff339e3c95 Espresso`Espresso::MPSEngine::convolution_kernel_base<Espresso::generic_convolution_kernel>::set_biases(std::__1::shared_ptr<Espresso::blob<float, 1> >) + 455
frame #8: 0x00007fff339e724b Espresso`Espresso::MPSEngine::convolution_kernel_proxy::set_biases(std::__1::shared_ptr<Espresso::blob<float, 1> >) + 103
frame #9: 0x00007fff338b3a8f Espresso`Espresso::generic_convolution_kernel::set_biases(std::__1::shared_ptr<Espresso::blob<float, 1> >, std::__1::shared_ptr<Espresso::abstract_batch>) + 49
frame #10: 0x00007fff338bdee1 Espresso`Espresso::load_network_layers_post_dispatch(std::__1::shared_ptr<Espresso::net> const&, std::__1::shared_ptr<Espresso::SerDes::generic_serdes_object> const&, std::__1::shared_ptr<Espresso::cpu_context_transfer_algo_t> const&, std::__1::shared_ptr<Espresso::net_info_ir_t> const&, bool, Espresso::network_shape const&, Espresso::compute_path, bool, std::__1::shared_ptr<Espresso::blob_storage_abstract> const&) + 5940
frame #11: 0x00007fff338ba6ee Espresso`Espresso::load_network_layers_internal(std::__1::shared_ptr<Espresso::SerDes::generic_serdes_object>, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::shared_ptr<Espresso::abstract_context> const&, Espresso::network_shape const&, std::__1::basic_istream<char, std::__1::char_traits<char> >*, Espresso::compute_path, bool, std::__1::shared_ptr<Espresso::blob_storage_abstract> const&) + 793
frame #12: 0x00007fff338c9294 Espresso`Espresso::load_and_shape_network(std::__1::shared_ptr<Espresso::SerDes::generic_serdes_object> const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::shared_ptr<Espresso::abstract_context> const&, Espresso::network_shape const&, Espresso::compute_path, std::__1::shared_ptr<Espresso::blob_storage_abstract> const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 576
frame #13: 0x00007fff338cb715 Espresso`Espresso::load_network(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::shared_ptr<Espresso::abstract_context> const&, Espresso::compute_path, bool) + 2496
frame #14: 0x00007fff33d9603c Espresso`EspressoLight::espresso_plan::add_network(char const*, espresso_storage_type_t) + 350
frame #15: 0x00007fff33daa817 Espresso`espresso_plan_add_network + 294
frame #16: 0x00007fff30479b9d Vision`+[VNEspressoHelpers createSingleNetworkPlanFromResourceName:usingProcessingDevice:lowPriorityMode:inputBlobNames:outputBlobNames:explicitNetworkLayersStorageType:espressoResources:error:] + 517
frame #17: 0x00007fff3047992d Vision`+[VNEspressoHelpers createSingleNetworkPlanFromResourceName:usingProcessingDevice:lowPriorityMode:inputBlobNames:outputBlobNames:espressoResources:error:] + 151
frame #18: 0x00007fff303ce123 Vision`-[VNRPNTrackerEspressoModelCacheManager espressoResourcesFromOptions:error:] + 417
frame #19: 0x00007fff303ce8c8 Vision`-[VNObjectTrackerRevision2 initWithOptions:error:] + 262
frame #20: 0x00007fff304152df Vision`__54-[VNTrackerManager _createTracker:type:options:error:]_block_invoke + 207
frame #21: 0x00000001072fc0b0 libdispatch.dylib`_dispatch_client_callout + 8
frame #22: 0x000000010730d3b2 libdispatch.dylib`_dispatch_lane_barrier_sync_invoke_and_complete + 135
frame #23: 0x00007fff30414f01 Vision`-[VNTrackerManager _createTracker:type:options:error:] + 261
frame #24: 0x00007fff30414b52 Vision`-[VNTrackerManager trackerWithOptions:error:] + 509
frame #25: 0x00007fff304dda4a Vision`-[VNRequestPerformer trackerWithOptions:error:] + 85
frame #26: 0x00007fff30343ac4 Vision`-[VNTrackingRequest internalPerformRevision:inContext:error:] + 436
frame #27: 0x00007fff3037fb08 Vision`-[VNRequest performInContext:error:] + 885
frame #28: 0x00007fff303cd9a1 Vision`VNExecuteBlock + 58
frame #29: 0x00007fff304dd105 Vision`-[VNRequestPerformer _performOrderedRequests:inContext:error:] + 674
frame #30: 0x00007fff304dd482 Vision`-[VNRequestPerformer performRequests:inContext:onBehalfOfRequest:error:] + 352
frame #31: 0x00007fff304dd586 Vision`-[VNRequestPerformer performRequests:inContext:error:] + 60
frame #32: 0x00007fff304cbf1a Vision`-[VNSequenceRequestHandler _performRequests:onImageBuffer:gatheredForensics:error:] + 293
frame #33: 0x00007fff304cc122 Vision`-[VNSequenceRequestHandler performRequests:onCVPixelBuffer:orientation:gatheredForensics:error:] + 111
frame #34: 0x00007fff304cc0aa Vision`-[VNSequenceRequestHandler performRequests:onCVPixelBuffer:orientation:error:] + 28
* frame #35: 0x0000000106fc5a97 ErrorTest1`-[LSPVision captureOutput:didOutputSampleBuffer:fromConnection:](self=0x0000608000047c20, _cmd="captureOutput:didOutputSampleBuffer:fromConnection:", output=0x00006030000ce770, sampleBuffer=0x0000614000091240, connection=0x00006030000d0c30) at LSPVision.m:246:9
frame #36: 0x00007fff3786b2e0 AVFCapture`__56-[AVCaptureVideoDataOutput_Tundra _render:sampleBuffer:]_block_invoke + 213
frame #37: 0x00000001077ff3bb libclang_rt.asan_osx_dynamic.dylib`__wrap_dispatch_async_block_invoke + 203
frame #38: 0x00000001072fae78 libdispatch.dylib`_dispatch_call_block_and_release + 12
frame #39: 0x00000001072fc0b0 libdispatch.dylib`_dispatch_client_callout + 8
frame #40: 0x00000001073036b7 libdispatch.dylib`_dispatch_lane_serial_drain + 776
frame #41: 0x0000000107304594 libdispatch.dylib`_dispatch_lane_invoke + 449
frame #42: 0x0000000107312217 libdispatch.dylib`_dispatch_workloop_worker_thread + 1675
frame #43: 0x000000010739eb15 libsystem_pthread.dylib`_pthread_wqthread + 314
frame #44: 0x000000010739dae3 libsystem_pthread.dylib`start_wqthread + 15
更新
该错误似乎在 macOS Monterey 12.1 上已得到解决。
最佳答案
这里有更多评论，我正在尝试重现这一点。我按原样采用了您的代码，但必须注释掉 [self _setEyePositionsForFace:faceObservation]; in
for (VNFaceObservation *faceObservation in results) {
//[self _setEyePositionsForFace:faceObservation];
//NSLog(@"seeing face");
}
因为你没有给出它的实现。然而，完成后，我可以毫无问题地运行代码。为了进一步测试，我添加了如下日志。
// SequenceRequesthandler results in 10-20% cpu utilization
NSLog(@"aaa");
[_sequenceRequestHandler performRequests:requests onCVPixelBuffer:pixelBuffer orientation:exifOrientation error:&error];
NSLog(@"bbb");
据我了解，您的问题具体是 [_sequenceRequestHandler PerformRequests:requests onCVPixelBuffer:pixelBufferorientation:exifOrientation error:&error]; ，但我没有遇到麻烦，日志显示了很多重复aaa 和 bbb。为了进一步测试，我还添加了一个 ok 日志，如下所示
if (error != nil) {
NSLog(@"Failed to perform FaceLandmarkRequest: %@", error);
} else {
NSLog(@"ok");
}
并且很高兴地与aaa和bbb一起打印。
我还连接了一个按钮，如下所示
- (IBAction)buttonAction:(id)sender {
NSLog( @"Button" );
self.v.captureFrame;
}
其中 self.v 是(我的)LSPVision 的一个实例，我可以毫无困难地按我想要的按钮。
我认为问题可能出在其他地方，甚至可能在我注释掉的 _setEyePositionsForFace 中，或者您可以提供更多代码，以便我可以在这边重现它？
FWIW 这是日志示例
2020-12-27 09:14:54.147536+0200 MetalCaptureTest[11392:317094] aaa
2020-12-27 09:14:54.184167+0200 MetalCaptureTest[11392:317094] bbb
2020-12-27 09:14:54.268926+0200 MetalCaptureTest[11392:317094] ok
2020-12-27 09:14:54.269374+0200 MetalCaptureTest[11392:317094] aaa
2020-12-27 09:14:54.314135+0200 MetalCaptureTest[11392:316676] Button
2020-12-27 09:14:54.316025+0200 MetalCaptureTest[11392:317094] bbb
2020-12-27 09:14:54.393732+0200 MetalCaptureTest[11392:317094] ok
2020-12-27 09:14:54.394171+0200 MetalCaptureTest[11392:317094] aaa
2020-12-27 09:14:54.432979+0200 MetalCaptureTest[11392:317094] bbb
2020-12-27 09:14:54.496887+0200 MetalCaptureTest[11392:317094] ok
2020-12-27 09:14:54.497389+0200 MetalCaptureTest[11392:317094] aaa
2020-12-27 09:14:54.533118+0200 MetalCaptureTest[11392:317094] bbb
2020-12-27 09:14:54.614813+0200 MetalCaptureTest[11392:317094] ok
2020-12-27 09:14:54.615394+0200 MetalCaptureTest[11392:317094] aaa
2020-12-27 09:14:54.663343+0200 MetalCaptureTest[11392:317094] bbb
2020-12-27 09:14:54.747860+0200 MetalCaptureTest[11392:317094] ok
编辑
谢谢，我得到了 dropbox 项目，它正在这边工作。根本没有崩溃。这是日志。
ErrorTest1(11743,0x10900ce00) malloc: nano zone abandoned due to inability to preallocate reserved vm space.
2020-12-27 10:55:10.445333+0200 ErrorTest1[11743:344803] Metal GPU Frame Capture Enabled
2020-12-27 10:55:10.471650+0200 ErrorTest1[11743:344803] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x6030000aabc0> F8BB1C28-BAE8-11D6-9C31-00039315CD46
2020-12-27 10:55:10.528628+0200 ErrorTest1[11743:344803] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x6030000ae130> 30010C1C-93BF-11D8-8B5B-000A95AF9C6A
2020-12-27 10:55:10.608753+0200 ErrorTest1[11743:344803] [] CMIOHardware.cpp:379:CMIOObjectGetPropertyData Error: 2003332927, failed
2020-12-27 10:55:11.408594+0200 ErrorTest1[11743:344873] [logging-persist] cannot open file at line 44580 of [02c344acea]
2020-12-27 10:55:11.408806+0200 ErrorTest1[11743:344873] [logging-persist] os_unix.c:44580: (0) open(/var/db/DetachedSignatures) - Undefined error: 0
2020-12-27 10:55:17.637382+0200 ErrorTest1[11743:344803] seeing face
2020-12-27 10:55:17.838354+0200 ErrorTest1[11743:344803] seeing face
2020-12-27 10:55:17.987583+0200 ErrorTest1[11743:344803] seeing face
2020-12-27 10:55:18.171168+0200 ErrorTest1[11743:344803] seeing face
2020-12-27 10:55:18.320957+0200 ErrorTest1[11743:344803] seeing face
FWIW 我有最新的操作系统 BS 11.1、最新的 Xcode 12.3 并在 MB Air 2017 上运行它。根据你的描述，我怀疑多线程可能是一个问题，但现在我的重点是在这边重现它。
关于objective-c - VNSequenceRequestHandler 上的 EXC_BAD_ACCESS，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/65436369/