AVCaptureSession和摄像头线程不关闭[iOS]
问题
当我停止运行AVCaptureSession时,在我的AVCaptureSession中创建的线程不会关闭。AVCaptureSession和摄像头线程不关闭[iOS]
症状
通常我的dispatch_queue从相机获取帧即刻开始。但是在打开和关闭打开/关闭AVCaptureSession的ViewController大约四次后,dispatch_queue需要大约十秒钟才能启动。
预后
看来,与AVCaptureSession相关的线程不被清除。
后,我关闭AVCaptureSession我看到这些线程保持:
com.apple.coremedia.capturesource.connections(serial) 1 Pending Block
com.apple.coremedia.capturesession.connections(serial) 1 Pending Block
<AVCMNotificationDispatcher: 0x16bce00> serial queue(serial) 4 Pending Blocks
com.apple.avfoundation.videocapturedevice.observed_properties_queue(serial)
com.apple.tcc.cache_queue(serial) 1 Pending Block
com.apple.tcc.preflight.kTCCServiceCamera(serial) 1 Pending Block
并与AVCaptureSession我打开后/关闭的ViewController,同一线程保持,但是这三个线程都增加待定块
数<AVCMNotificationDispatcher: 0x17c441a0> serial queue (serial) 9 Pending Blocks
com.apple.avfoundation.videocapturedevice.observed_properties_queue(serial)
com.apple.tcc.preflight.kTCCServiceCamera(serial) 5 Pending Blocks
代码设置
VideoSource.h和VideoSource.mm
在我的ViewController我初始化这样的:
self.videoSource = [[VideoSource alloc] init];
self.videoSource.delegate = self;
[self.videoSource setResolution:AVCaptureSessionPreset352x288]; // was 640
[self.videoSource startWithDevicePosition:AVCaptureDevicePositionFront];
我开始和停止captureSession如下所示,启动和停止好了。实际的抓图效果非常好。
[self.videoSource.captureSession startRunning];
[self.videoSource.captureSession stopRunning];
VideoSource的相关部分,如果您需要了解更多信息,请告诉我们。
从VideoSource.mm
- (void)dealloc {
NSLog(@"Cleaning Up Video Source");
[_captureSession stopRunning];
AVCaptureInput* input = [_captureSession.inputs objectAtIndex:0];
[_captureSession removeInput:input];
input = nil;
AVCaptureVideoDataOutput* output = (AVCaptureVideoDataOutput*)[_captureSession.outputs objectAtIndex:0];
[_captureSession removeOutput:output];
output = nil;
_captureSession = nil;
_deviceInput = nil;
_delegate = nil;
// [super dealloc]; // compiler handles this for you with ARC
}
- (void) addVideoDataOutput {
// (1) Instantiate a new video data output object
AVCaptureVideoDataOutput * captureOutput = [[AVCaptureVideoDataOutput alloc] init ];
// captureOutput.alwaysDiscardsLateVideoFrames = YES;
NSLog(@"Create Dispatch Queue");
// (2) The sample buffer delegate requires a serial dispatch queue
dispatch_queue_t queue;
queue = dispatch_queue_create("com.name.test", DISPATCH_QUEUE_SERIAL);
[captureOutput setSampleBufferDelegate:self queue:queue];
// dispatch_release(queue); // compiler handles this for you with ARC
// (3) Define the pixel format for the video data output
NSString * key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
NSNumber * value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
NSDictionary * settings = @{key:value};
NSLog(@"Set Video Settings");
[captureOutput setVideoSettings:settings];
NSLog(@"Always Discard Late Video Frames");
[captureOutput setAlwaysDiscardsLateVideoFrames:YES];
// (4) Configure the output port on the captureSession property
[self.captureSession addOutput:captureOutput];
}
而且从VideoSource.h
@interface VideoSource : NSObject
@property (nonatomic, strong) AVCaptureSession * captureSession;
@property (nonatomic, strong) AVCaptureDeviceInput * deviceInput;
@property (nonatomic, weak) id<VideoSourceDelegate> delegate;
- (BOOL)startWithDevicePosition:(AVCaptureDevicePosition)devicePosition;
- (void) setResolution:(NSString*)resolution;
@end
请求
如何确保这些线程关闭的时候我解除分配VideoSource?
解决了!
解决方案:调用startRunning并停止从您用于CaptureOutput的SampleBuffer队列的相同dispatch_queue中运行。
这是我的新格局:
#import "VideoSource.h"
@interface VideoSource() <AVCaptureVideoDataOutputSampleBufferDelegate>
// Session management.
@property (nonatomic) dispatch_queue_t sessionQueue;
@property (nonatomic) AVCaptureSession *captureSession;
@property (nonatomic) AVCaptureDeviceInput *deviceInput;
/*@property (nonatomic, strong) AVCaptureSession * captureSession;
@property (nonatomic, strong) AVCaptureDeviceInput * deviceInput; */
@end
@implementation VideoSource
-(id) init{
if(self = [super init]){
self.captureSession = [[AVCaptureSession alloc] init];
self.sessionQueue = dispatch_queue_create("session queue", DISPATCH_QUEUE_SERIAL);
}
return self;
}
然后使用同样的sessionQueue您setSampleBufferDelegate队列。
[captureOutput setSampleBufferDelegate:self queue:self.sessionQueue];
现在到了最重要的部分,确保从最相同的队列调用startRunning/stopRunning:同样
dispatch_async(self.sessionQueue, ^{
[self.captureSession startRunning];
});
,你可以创建一个不错的小功能来清理和停止captureSession :
-(void)closeCaptureSession {
dispatch_async(self.sessionQueue, ^{
if([_captureSession isRunning])[_captureSession stopRunning];
[_captureSession stopRunning];
// Remove all inputs
for(AVCaptureInput *input1 in _captureSession.inputs) {
[_captureSession removeInput:input1];
}
// Remove all outputs
for(AVCaptureVideoDataOutput *output1 in _captureSession.outputs) {
[output1 setSampleBufferDelegate:nil queue:NULL];
[_captureSession removeOutput:output1];
}
// Set to Nil to make ARC's job a little easier
self.captureSession = nil;
self.deviceInput = nil;
self.delegate = nil;
self.sessionQueue=nil;
});
}
我有同样的问题。我处于更糟糕的情况,因为我正在使用我无法控制的相机库。在用照相机解散所述视图控制器之后,它会导致愚蠢的东西,例如有时候呆在那里。谁知道还有什么。 – mskw
嗨Airman,你是如何看待你目前所有的线程? –
@mskw:查看我的新解决方案 – Airman00