提高直播用户参与度 – 通过 BytePlus Effects 和 Amazon IVS 实现实时增强现实（AR）效果

//创建广播配置
IVSBroadcastConfiguration *config = [[IVSPresets configurations] 
standardPortrait];

// 设置混合器插槽配置
IVSMixerSlotConfiguration *customSlot = [IVSMixerSlotConfiguration new];
customSlot.size = config.video.size;
customSlot.position = CGPointMake(0.0, 0.0);
customSlot.preferredAudioInput = IVSDeviceTypeUserAudio;
customSlot.preferredVideoInput = IVSDeviceTypeUserImage;
NSError *customSlotError = nil;
NSString * const customSlotName = @"custom-slot";
[customSlot setName:customSlotName error:customSlotError];

// 将此插槽设置为之前创建的广播配置
config.mixer.slots = @[customSlot];

NSError *broadcastSessionError = nil;
// 将摄像头描述符参数设为 nil，让应用逻辑控制摄像头设备
IVSBroadcastSession *broadcastSession = [[IVSBroadcastSession alloc] initWithConfiguration:config descriptors:nil delegate:nil error:&broadcastSessionError];

// 附加自定义音频输入源
id customAudioSource = [broadcastSession createAudioSourceWithName:@"custom-audio"];
[broadcastSession attachDevice:customAudioSource toSlotWithName:customSlotName onComplete:nil];// <连接到 onComplete 回调函数>
self.customAudioSource = customAudioSource;

// 附加自定义图像输入源
id customImageSource = [broadcastSession createImageSourceWithName:@"custom-image"];
[broadcastSession attachDevice:customImageSource toSlotWithName:customSlotName onComplete:nil];// <连接到 onComplete 回调函数>
self.customImageSource = customImageSource;

self.broadcastSession = broadcastSession;

self.imageUtils = [[BEImageUtils alloc] init];
self.manager = [[BEEffectManager alloc] initWithResourceProvider:[BEEffectResourceHelper new] licenseProvider:[BELicenseHelper shareInstance]];
// SDK 初始化
int ret = [self.manager initTask];

BEVideoCapture *capture = [[BEVideoCapture alloc] init];
capture.outputFormat = kCVPixelFormatType_32BGRA;
// 为简洁起见，删除了设置 BEVideoCapture 初始配置的代码
[capture startRunning];

// BEVideoCapture 委托回调
- (void)videoCapture:(id<BEVideoSourceProtocol>)source didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer withRotation:(int)rotation {

// 为简洁起见，删除了实现 GLContext 检查的代码

    CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    CMTime sampleTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
    double timeStamp = (double)sampleTime.value/sampleTime.timescale;
    
// 为简洁起见，删除了为确保线程安全而锁定 BytePlus Effect SDK 的代码，例如：NSRecursiveLock
    [self processWithCVPixelBuffer:pixelBuffer rotation:rotation timeStamp:timeStamp];
}

- (void)processWithCVPixelBuffer:(CVPixelBufferRef)pixelBuffer rotation:(int)rotation timeStamp:(double)timeStamp {

    BEPixelBufferInfo *pixelBufferInfo = [self.imageUtils getCVPixelBufferInfo:pixelBuffer];

    // BytePlus Effect SDK 需要采用 BGRA 格式
    if (pixelBufferInfo.format != BE_BGRA) {
        pixelBuffer = [self.imageUtils transforCVPixelBufferToCVPixelBuffer:pixelBuffer outputFormat:BE_BGRA];
    }
    if (rotation != 0) {
        // BytePlus Effect SDK 所接收的纹理贴图必须是正的，在调用 SDK 之前，需要先旋转一下
        pixelBuffer = [self.imageUtils rotateCVPixelBuffer:pixelBuffer rotation:rotation];
    }
    
    // 设置缓冲的输入图像
    id<BEGLTexture> texture = [self.imageUtils transforCVPixelBufferToTexture:pixelBuffer];
    // 设置缓冲的输出图像
    id<BEGLTexture> outTexture = nil;
    outTexture = [self.imageUtils getOutputPixelBufferGLTextureWithWidth:texture.width height:texture.height format:BE_BGRA];

// self.manager 为 BytePlus Effect SDK 初始化过程中的 BEEffectManager
    // 为便于演示，我们将修正图像的旋转。
    int ret = [self.manager processTexture:texture.texture outputTexture:outTexture.texture width:texture.width height:texture.height rotate:BEF_AI_CLOCKWISE_ROTATE_0
timeStamp:timeStamp];
    if (ret != BEF_RESULT_SUC) {
        // 记录图像处理成功完成
    } else {
        // 记录图像处理未成功完成
    }
    outTexture = texture;

if (self.broadcastSession != nil) {
        // 获取 CVPixelBufferRef
        CVPixelBufferRef outputPixelBuffer = [(BEPixelBufferGLTexture *)outTexture pixelBuffer];

        CMVideoFormatDescriptionRef formatDescription;
        CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, outputPixelBuffer, &formatDescription);

        
        CMSampleTimingInfo timing = { kCMTimeInvalid, kCMTimeInvalid, kCMTimeInvalid };
        CMSampleBufferRef sampleBuffer;
    
        // 转换为 CMSampleBufferRef
CMSampleBufferCreateReadyWithImageBuffer(kCFAllocatorDefault,
                                              outputPixelBuffer,
                                              formatDescription,
                                              &timing,
                                              &sampleBuffer);


        // 将 CMSampleBufferRef 提交至 customImageSource
        [self.customImageSource onSampleBuffer:sampleBuffer];
    }    
// 为简洁起见，删除了在 UI 中设置预览窗口的代码
}

if (self.broadcastSession != nil) {
    
        NSURL *myURL = [NSURL URLWithString:@"<INGEST_URL>"];
        NSString *myKey = @"<STREAM_KEY>";
        
        [self.broadcastSession startWithURL:myURL streamKey:myKey error:nil];
    }