ReplayKit2 屏幕录制

2020-12-01 本文已影响0人 Show_Perry

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

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];
                   }
               }
           }
       }
   }
}

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;
}

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。

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;
}

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
};

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。

ReplayKit2 屏幕录制

ReplayKit2 屏幕录制

ReplayKit2 使用的技巧

踩过的坑

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