ReplayKit2 屏幕录制
如果你需要录制苹果手机屏幕，ReplayKit肯定需要了解。本文主要介绍Replaykit2 在iOS12后的一些技巧及使用方法。为啥不介绍iOS12前的录制呢，因为操作起来太麻烦了，麻烦到开发的我们使用起来都很不顺手，别说用户使用，而且现在苹果都iOS14了...
ReplayKit2 使用的技巧
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由于系统提供的是个
RPSystemBroadcastPickerView类型的View，需要用户点击这个View才能弹出录制界面。那如何才能优雅的把它给隐藏呢？答案是我们在它上面覆盖一层View，然后把点击事件传递给它达到点击效果。事件类型根据不同系统版本会稍有不同,直接贴代码：@property (nonatomic, strong) RPSystemBroadcastPickerView *sysTemBroadCastPickerView; //录制view @property (nonatomic, strong) UIButton *startPushStreamBtn; //开始录制按钮 - (void)showReplayKitView { if (@available(iOS 12.0, *)) { for (UIView *view in _sysTemBroadCastPickerView.subviews) { if ([view isKindOfClass:[UIButton class]]) { float iOSVersion = [[UIDevice currentDevice].systemVersion floatValue]; UIButton *button = (UIButton *)view; if (button != self.startPushStreamBtn) { if (iOSVersion >= 13) { [(UIButton *)view sendActionsForControlEvents:UIControlEventTouchDown]; [(UIButton *)view sendActionsForControlEvents:UIControlEventTouchUpInside]; } else { [(UIButton *)view sendActionsForControlEvents:UIControlEventTouchDown]; } } } } } }
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如何指定录制应用，是否使用麦克风。注意
BundleID为录制Target的BundleID，和主工程的BundleID区分下。如果不填写，弹窗的录制界面将会带上手机上所有支持录制的应用，是不是很不友好..- (RPSystemBroadcastPickerView *)sysTemBroadCastPickerView API_AVAILABLE(ios(12.0)) { if (!_sysTemBroadCastPickerView) { _sysTemBroadCastPickerView = [[RPSystemBroadcastPickerView alloc] init]; _sysTemBroadCastPickerView.showsMicrophoneButton = NO;//是否显示麦克风 _sysTemBroadCastPickerView.preferredExtension = [MnaConfig replayKitBundleID];//指定录制应用BundleID } return _sysTemBroadCastPickerView; }
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点击开始直播后有个倒计时，倒计时结束后如何优雅的退出录制界面？首先我们需要捕获系统录制弹窗，看弹出效果应该是
presentViewController然后采用Method Swizzling尝试下，发现可以拿到。然后我们可以在录制进程启动后发送进程通知，主进程收到后进行dismiss：代码如下：@implementation UIViewController (MnaPresentSwizzleAdd) + (void)load { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ [self swizzleSelector:@selector(presentViewController:animated:completion:) withAnotherSelector:@selector(mna_presentViewController:animated:completion:)]; }); } + (void)swizzleSelector:(SEL)originalSelector withAnotherSelector:(SEL)swizzledSelector { Class aClass = [self class]; Method originalMethod = class_getInstanceMethod(aClass, originalSelector); Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector); BOOL didAddMethod = class_addMethod(aClass, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod)); if (didAddMethod) { class_replaceMethod(aClass, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod)); } else { method_exchangeImplementations(originalMethod, swizzledMethod); } } #pragma mark - Method Swizzling - (void)mna_presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion { if ([NSStringFromClass(viewControllerToPresent.class) isEqualToString:@"RPBroadcastPickerStandaloneViewController"]) { MnaReplayKitHiddenManager.sharedInstance.replayKitBraodViewControler = viewControllerToPresent; //该管理类监听录制进程启动完成的通知然后进行Dismiss [self mna_presentViewController:viewControllerToPresent animated:flag completion:completion]; } else { [self mna_presentViewController:viewControllerToPresent animated:flag completion:completion]; } } @end更新：iOS14后弹出方法更改，暂时还不知道如何显示，该方法只适用iOS14以下
进程通知，进程间通讯非常麻烦。可以采用
CFNotificationCenterPostNotification进行消息传递，不过有个问题是不能传递数据。不过我们可以使用App Groups可以数据共享的方式来进行传递。推荐一个已经封装好的开源库 MMWormhole
踩过的坑
Extension进程最麻烦的就是调试。如果要查看Log，录制调试可以选择 录制进程->运行->选择主进程。这样启动后可以在终端看到Log，不过以前同事遇到过某些Xcode版本不能运行，并看不了Log。测试可行的Xcode版本:Version 12.1 (12A7403)-
如果你需要打印一些日志保存,进行问题定位，需要保存到
Group共享区。获取方式：[[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:goupName]; 内存限制
50M这个非常重要，因为如果超过这个大小直接被系统杀掉。如果你做推流：必须控制缓冲队列大小,做好内存管理。
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音频输出为大端，如果需要，可以转换下大小端。转换为小端代码如下：
- (NSData *)convertAudioSamepleBufferToPcmData:(CMSampleBufferRef)sampleBuffer { CMBlockBufferRef blockBuffer = CMSampleBufferGetDataBuffer(sampleBuffer); if (blockBuffer == nil) { return nil; } AudioBufferList bufferList; CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampleBuffer, NULL, &bufferList, sizeof(bufferList), NULL, NULL, kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment, &blockBuffer); int8_t *audioBuffer = (int8_t *)bufferList.mBuffers[0].mData; UInt32 audioBufferSizeInBytes = bufferList.mBuffers[0].mDataByteSize; CMFormatDescriptionRef formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer); const AudioStreamBasicDescription *asbd = CMAudioFormatDescriptionGetStreamBasicDescription(formatDescription); // Perform an endianess conversion, if needed. A TVIAudioDevice should deliver little endian samples. if (asbd->mFormatFlags & kAudioFormatFlagIsBigEndian) { //大端 for (int i = 0; i < (audioBufferSizeInBytes - 1); i += 2) { int8_t temp = audioBuffer[i]; audioBuffer[i] = audioBuffer[i + 1]; audioBuffer[i + 1] = temp; } } else { //小端 } NSData *data = [NSData dataWithBytes:audioBuffer length:audioBufferSizeInBytes]; CFRelease(blockBuffer); return data; }
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不管你手机竖屏还是横屏，非常无语的是视频输出，都是竖屏。还好
iOS11后有个方法可以判定当前输出的视频帧方向:CGImagePropertyOrientation oritation = ((__bridge NSNumber *)CMGetAttachment(buffer, (__bridge CFStringRef)RPVideoSampleOrientationKey, NULL)).unsignedIntValue; typedef CF_CLOSED_ENUM(uint32_t, CGImagePropertyOrientation) { kCGImagePropertyOrientationUp = 1, // 0th row at top, 0th column on left - default orientation kCGImagePropertyOrientationUpMirrored, // 0th row at top, 0th column on right - horizontal flip kCGImagePropertyOrientationDown, // 0th row at bottom, 0th column on right - 180 deg rotation kCGImagePropertyOrientationDownMirrored, // 0th row at bottom, 0th column on left - vertical flip kCGImagePropertyOrientationLeftMirrored, // 0th row on left, 0th column at top kCGImagePropertyOrientationRight, // 0th row on right, 0th column at top - 90 deg CW kCGImagePropertyOrientationRightMirrored, // 0th row on right, 0th column on bottom kCGImagePropertyOrientationLeft // 0th row on left, 0th column at bottom - 90 deg CCW };
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由于视频都是竖屏输出，所以需要旋转方向然后再转换为
CVPixelBufferRef进行硬编码。找过很多资料，这块介绍很少。有介绍使用开源库libyuv不过是转换为i420后调用的腾讯云接口无相关涉及。现在使用的是方法：#pragma mark - Rotation default stream - (void)dealWithSampleBuffer:(CMSampleBufferRef)buffer timeStamp:(uint64_t)timeStamp { if (@available(iOS 11.0, *)) { CGImagePropertyOrientation oritation = ((__bridge NSNumber *)CMGetAttachment(buffer, (__bridge CFStringRef)RPVideoSampleOrientationKey, NULL)).unsignedIntValue; CIImage *outputImage = nil; CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(buffer); CGFloat outputWidth = self.session.videoConfiguration.videoSize.width; CGFloat outputHeight = self.session.videoConfiguration.videoSize.height; BOOL isLandScape = self.session.videoConfiguration.landscape; size_t inputWidth = CVPixelBufferGetWidth(pixelBuffer); size_t inputHeight = CVPixelBufferGetHeight(pixelBuffer); CGAffineTransform lastRotateTransform = CGAffineTransformMakeScale(0.5, 0.5); CIImage *sourceImage = nil; CGImagePropertyOrientation lastRotateOritation = oritation; sourceImage = [CIImage imageWithCVPixelBuffer:pixelBuffer]; // 如果是横屏且输入源为横屏（iPad Pro）或者 竖屏且输入源为竖屏 if ((inputWidth > inputHeight && isLandScape) || (inputWidth <= inputHeight && !isLandScape)) { if (oritation == kCGImagePropertyOrientationUp) { lastRotateOritation = kCGImagePropertyOrientationUp; } else if (oritation == kCGImagePropertyOrientationDown) { lastRotateOritation = kCGImagePropertyOrientationDown; } lastRotateTransform = CGAffineTransformMakeScale(outputWidth / inputWidth, outputHeight / inputHeight); } else { if (oritation == kCGImagePropertyOrientationLeft) { lastRotateOritation = kCGImagePropertyOrientationRight; } else if (oritation == kCGImagePropertyOrientationRight) { lastRotateOritation = kCGImagePropertyOrientationLeft; } else { lastRotateOritation = kCGImagePropertyOrientationLeft; } lastRotateTransform = CGAffineTransformMakeScale(outputWidth / inputHeight, outputHeight / inputWidth); } sourceImage = [sourceImage imageByApplyingCGOrientation:lastRotateOritation]; outputImage = [sourceImage imageByApplyingTransform:lastRotateTransform]; if (outputImage) { NSDictionary *pixelBufferOptions = @{(NSString *)kCVPixelBufferWidthKey : @(outputWidth), (NSString *)kCVPixelBufferHeightKey : @(outputHeight), (NSString *)kCVPixelBufferOpenGLESCompatibilityKey : @YES, (NSString *)kCVPixelBufferIOSurfacePropertiesKey : @{} }; CVPixelBufferLockBaseAddress(pixelBuffer, 0); CVPixelBufferRef newPixcelBuffer = nil; CVPixelBufferCreate(kCFAllocatorDefault, outputWidth, outputHeight, kCVPixelFormatType_420YpCbCr8BiPlanarFullRange, (__bridge CFDictionaryRef)pixelBufferOptions, &newPixcelBuffer); [_ciContext render:outputImage toCVPixelBuffer:newPixcelBuffer]; CVPixelBufferUnlockBaseAddress(pixelBuffer, 0); CMVideoFormatDescriptionRef videoInfo = nil; CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, newPixcelBuffer, &videoInfo); CMTime duration = CMSampleBufferGetDuration(buffer); CMTime presentationTimeStamp = CMSampleBufferGetPresentationTimeStamp(buffer); CMTime decodeTimeStamp = CMSampleBufferGetDecodeTimeStamp(buffer); CMSampleTimingInfo sampleTimingInfo; sampleTimingInfo.duration = duration; sampleTimingInfo.presentationTimeStamp = presentationTimeStamp; sampleTimingInfo.decodeTimeStamp = decodeTimeStamp; // CMSampleBufferRef newSampleBuffer = nil; CMSampleBufferCreateForImageBuffer(kCFAllocatorMalloc, newPixcelBuffer, true, nil, nil, videoInfo, &sampleTimingInfo, &newSampleBuffer); // 对新buffer做处理 [self.session pushVideoBuffer:newSampleBuffer timeStamp:timeStamp]; // release if (newPixcelBuffer) { CVPixelBufferRelease(newPixcelBuffer); } if (newSampleBuffer) { CFRelease(newSampleBuffer); } } } else { // Fallback on earlier versions [self.session pushVideoBuffer:buffer timeStamp:timeStamp]; } }
- 推流。可以参考 LFLiveKit ，需要注意的是前面说的缓冲区大小设置，还有就是里面
LibRTMP调整输出块大小，减少CPU消耗。