【需求】帧率可配置。

project/iPhone/LWAVFoundation/LWAVFoundation/AVFoundation/LWVideoCaptureSession.m

@@ -23,8 +23,10 @@
 
 #pragma mark private
 - (void)initAVCaptureSession {
+    NSError* error = nil;
     self.session = [[AVCaptureSession alloc] init];
     
+    // 设置视频分辨率
     if (![self.session canSetSessionPreset:self.config.preset]) {
         if (![self.session canSetSessionPreset:AVCaptureSessionPresetiFrame960x540]) {
             if (![self.session canSetSessionPreset:AVCaptureSessionPreset640x480]) {
@@ -40,7 +42,7 @@
     }
     [self.session setSessionPreset:self.config.preset];
     
-    [self.session beginConfiguration];
+    // 获取系统设备信息
     AVCaptureDeviceDiscoverySession* deviceDiscoverySession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera] mediaType:AVMediaTypeVideo position:self.config.position];
     NSArray* devices = deviceDiscoverySession.devices;
     for (AVCaptureDevice* device in devices) {
@@ -50,17 +52,38 @@
         }
     }
     
-    NSError* error = nil;
+    // 设置帧率
+    BOOL frameRateSupport = NO;
+    NSArray* ranges = [self.device.activeFormat videoSupportedFrameRateRanges];
+    for (AVFrameRateRange* range in ranges) {
+        if (CMTIME_COMPARE_INLINE(self.config.duration, >=, range.minFrameDuration) &&
+            CMTIME_COMPARE_INLINE(self.config.duration, <=, range.maxFrameDuration)) {
+            frameRateSupport = YES;
+        }
+    }
+    
+    if (frameRateSupport && [self.device lockForConfiguration:&error]) {
+        [self.device setActiveVideoMaxFrameDuration:self.config.duration];
+        [self.device setActiveVideoMinFrameDuration:self.config.duration];
+        [self.device unlockForConfiguration];
+    }
+    
+    // 开始配置参数
+    [self.session beginConfiguration];
+    
+    // 从设备中创建输入，之后需要设置到session
     self.videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:self.device error:&error];
     if (error) {
         NSLog(@"%s:%d init input error!!!", __func__, __LINE__);
         return;
     }
     
+    // 设置session的输入
     if ([self.session canAddInput:self.videoInput]) {
         [self.session addInput:self.videoInput];
     }
     
+    // 配置session的输出
     self.videoOutput = [[AVCaptureVideoDataOutput alloc] init];
     self.videoOutput.alwaysDiscardsLateVideoFrames = NO;
     [self.videoOutput setVideoSettings:@{
@@ -73,12 +96,16 @@
         [self.session addOutput:self.videoOutput];
     }
     
+    // 设置连接器
     AVCaptureConnection* connect = [self.videoOutput connectionWithMediaType:AVMediaTypeVideo];
+    // 设置图片的位置
     connect.videoOrientation = self.config.orientation;
     if ([connect isVideoStabilizationSupported]) {
         connect.preferredVideoStabilizationMode = AVCaptureVideoStabilizationModeAuto;
     }
     connect.videoScaleAndCropFactor = connect.videoMaxScaleAndCropFactor;
+    
+    // 提交采集相关配置
     [self.session commitConfiguration];
     
     self.captureLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];

project/iPhone/LWAVFoundation/LWAVFoundation/Model/LWVideoCaptureConfig.h

@@ -5,6 +5,8 @@
 
 typedef NS_ENUM(NSUInteger, AVCaptureOutputPixelBufferType) {
     kAVCaptureOutputPixelBufferType_420v = kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
+    kAVCaptureOutputPixelBufferType_420f = kCVPixelFormatType_420YpCbCr8BiPlanarFullRange,
+    kAVCaptureOutputPixelBufferType_bgra = kCVPixelFormatType_32BGRA,
 };
 
 @interface LWVideoCaptureConfig : NSObject
@@ -21,6 +23,9 @@ typedef NS_ENUM(NSUInteger, AVCaptureOutputPixelBufferType) {
 // 视频的方向
 @property (assign, nonatomic) AVCaptureVideoOrientation orientation;
 
+// 设置每一帧的时间间隔，其的分子为时间，单位秒，分母为帧率。
+@property (assign, nonatomic) CMTime duration;
+
 - (instancetype) init;
 
 @end

project/iPhone/LWAVFoundation/LWAVFoundation/Model/LWVideoCaptureConfig.m

@@ -13,6 +13,7 @@
         self.preset   = AVCaptureSessionPreset1280x720;
         self.pixelBufferType = kAVCaptureOutputPixelBufferType_420v;
         self.orientation = AVCaptureVideoOrientationPortrait;
+        self.duration = CMTimeMake(1, 30);
     }
     return self;
 }

project/iPhone/LWAVFoundation/LWAVFoundation/View/LWCheckBoxView.m

@@ -56,11 +56,11 @@
             [self.btnItems addObject:[[LWCheckBoxButton alloc] init]];
             self.btnItems[i].contentMode = UIViewContentModeScaleAspectFit;
             self.btnItems[i].delegate = self;
+            self.btnItems[i].tag = i;
             
             [self.labelItems addObject:[[UILabel alloc] init]];
         }
         
-        self.btnItems[i].tag = i;
         self.btnItems[i].image = [self.btnNoSelectImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
         self.btnItems[i].frame = CGRectMake(checkBoxItemX, checkBoxItemY, 30, 30);
         
@@ -93,7 +93,7 @@
     self.selectItem = self.items[index];
     
     if (self.delegate && [self.delegate respondsToSelector:@selector(onSelect:item:)]) {
-        [self.delegate onSelect:index item:self.items[index]];
+        [self.delegate onSelect:index item:self.selectItem];
     }
 }
 

project/iPhone/LWAVFoundation/LWAVFoundation/ViewController/CaptureViewController.m

@@ -36,6 +36,7 @@
     self.checkBoxView = [[LWCheckBoxView alloc] initWithItems:array];
     self.checkBoxView.frame = CGRectMake(checkBoxViewX, checkBoxViewY, checkBoxViewW, checkBoxViewH);
     self.checkBoxView.displayType = kLWCheckBoxViewDisplayType_LR;
+    self.checkBoxView.delegate = self;
     [self.view addSubview:self.checkBoxView];
     
     self.captureTypeLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, checkBoxViewY, 100, 30)];
@@ -59,9 +60,6 @@
     [self.stopBtn setBackgroundColor:[UIColor whiteColor]];
     [self.stopBtn addTarget:self action:@selector(stopSender:) forControlEvents:UIControlEventTouchUpInside];
     [self.view addSubview:self.stopBtn];
-    
-    self.captureSessionConfig = [[LWVideoCaptureConfig alloc] init];
-    self.captureSession = [[LWVideoCaptureSession alloc] initWithConfig:self.captureSessionConfig];
 }
 
 - (void)viewDidDisappear:(BOOL)animated {
@@ -69,6 +67,9 @@
 }
 
 - (IBAction)startSender:(id)sender {
+    self.captureSessionConfig = [[LWVideoCaptureConfig alloc] init];
+    self.captureSession = [[LWVideoCaptureSession alloc] initWithConfig:self.captureSessionConfig];
+    
     [self.captureSession startCapture];
     
     AVCaptureVideoPreviewLayer* layer = [self.captureSession layer];
@@ -84,6 +85,7 @@
     [layer removeFromSuperlayer];
     
     [self.captureSession stopCapture];
+    self.captureSession = nil;
 }
 
 #pragma mark LWVideoCaptureSessionDelegate