如何使用iOS sdk記錄設備屏幕視頻？

Question

我做的，我也要把iOS screen video。對於查看其工作正常，但我們的要求是記錄屏幕視頻時的視頻是running.I教程應用程序試圖播放視頻使用UIWebview和MPMoviePlayer。直到玩家開始它正在錄製。但開始玩家後，我只得到黑屏。任何建議。

我跟着這個鏈接：

http://developer.apple.com/library/ios/#qa/qa1703/_index.html

-(void) startRecording { 


    // create the AVAssetWriter 

    NSString *moviePath = [[self pathToDocumentsDirectory] stringByAppendingPathComponent:OUTPUT_FILE_NAME]; 

    if ([[NSFileManager defaultManager] fileExistsAtPath:moviePath]) { 

    [[NSFileManager defaultManager] removeItemAtPath:moviePath error:nil]; 

    } 


    NSURL *movieURL = [NSURL fileURLWithPath:moviePath]; 

    NSError *movieError = nil; 

    [assetWriter release]; 

    assetWriter = [[AVAssetWriter alloc] initWithURL:movieURL 

               fileType: AVFileTypeQuickTimeMovie 

                error: &movieError]; 

    NSDictionary *assetWriterInputSettings = [NSDictionary dictionaryWithObjectsAndKeys: 

     AVVideoCodecH264, AVVideoCodecKey, 

     [NSNumber numberWithInt:FRAME_WIDTH], AVVideoWidthKey, 

     [NSNumber numberWithInt:FRAME_HEIGHT], AVVideoHeightKey, 

     nil]; 

    assetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType: AVMediaTypeVideo 

     outputSettings:assetWriterInputSettings]; 

    assetWriterInput.expectsMediaDataInRealTime = YES; 

    [assetWriter addInput:assetWriterInput]; 


    [assetWriterPixelBufferAdaptor release]; 

    assetWriterPixelBufferAdaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] 

    initWithAssetWriterInput:assetWriterInput 

    sourcePixelBufferAttributes:nil]; 

    [assetWriter startWriting]; 


    firstFrameWallClockTime = CFAbsoluteTimeGetCurrent(); 

    [assetWriter startSessionAtSourceTime: CMTimeMake(0, TIME_SCALE)]; 


    // start writing samples to it 

    [assetWriterTimer release]; 

    assetWriterTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 

    target:self 

     selector:@selector (writeSample:) 

     userInfo:nil 

     repeats:YES] ; 


    } 



    -(void) stopRecording { 

    [assetWriterTimer invalidate]; 

    assetWriterTimer = nil; 


    [assetWriter finishWriting]; 

    NSLog (@"finished writing"); 

    } 

- (UIImage*)screenshot 

{ 

    // Create a graphics context with the target size 

    // On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration 

    // On iOS prior to 4, fall back to use UIGraphicsBeginImageContext 

    CGSize imageSize = [[UIScreen mainScreen] bounds].size; 

CGFloat imageScale = imageSize.width/FRAME_WIDTH; 

    if (NULL != UIGraphicsBeginImageContextWithOptions) 

     UIGraphicsBeginImageContextWithOptions(imageSize, NO, imageScale); 

    else 

     UIGraphicsBeginImageContext(imageSize); 


    CGContextRef context = UIGraphicsGetCurrentContext(); 


    // Iterate over every window from back to front 

    for (UIWindow *window in [[UIApplication sharedApplication] windows]) 

    { 

     if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen]) 

     { 

      // -renderInContext: renders in the coordinate space of the layer, 

      // so we must first apply the layer's geometry to the graphics context 

      CGContextSaveGState(context); 

      // Center the context around the window's anchor point 

      CGContextTranslateCTM(context, [window center].x, [window center].y); 

      // Apply the window's transform about the anchor point 

      CGContextConcatCTM(context, [window transform]); 

      // Offset by the portion of the bounds left of and above the anchor point 

      CGContextTranslateCTM(context, 

            -[window bounds].size.width * [[window layer] anchorPoint].x, 

            -[window bounds].size.height * [[window layer] anchorPoint].y); 


      // Render the layer hierarchy to the current context 

      [[window layer] renderInContext:context]; 


      // Restore the context 

      CGContextRestoreGState(context); 

     } 

    } 


    // Retrieve the screenshot image 

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 


    UIGraphicsEndImageContext(); 


    return image; 

} 

-(void) writeSample: (NSTimer*) _timer { 

if (assetWriterInput.readyForMoreMediaData) { 

// CMSampleBufferRef sample = nil; 



CVReturn cvErr = kCVReturnSuccess; 



// get screenshot image! 

CGImageRef image = (CGImageRef) [[self screenshot] CGImage]; 

NSLog (@"made screenshot"); 


// prepare the pixel buffer 

CVPixelBufferRef pixelBuffer = NULL; 

CFDataRef imageData= CGDataProviderCopyData(CGImageGetDataProvider(image)); 

NSLog (@"copied image data"); 

cvErr = CVPixelBufferCreateWithBytes(kCFAllocatorDefault, 

FRAME_WIDTH, 

FRAME_HEIGHT, 

kCVPixelFormatType_32BGRA, 

(void*)CFDataGetBytePtr(imageData), 

CGImageGetBytesPerRow(image), 

NULL, 

NULL, 

NULL, 

&pixelBuffer); 

NSLog (@"CVPixelBufferCreateWithBytes returned %d", cvErr); 



// calculate the time 

CFAbsoluteTime thisFrameWallClockTime = CFAbsoluteTimeGetCurrent(); 

CFTimeInterval elapsedTime = thisFrameWallClockTime - firstFrameWallClockTime; 

NSLog (@"elapsedTime: %f", elapsedTime); 

CMTime presentationTime = CMTimeMake (elapsedTime * TIME_SCALE, TIME_SCALE); 


// write the sample 

BOOL appended = [assetWriterPixelBufferAdaptor appendPixelBuffer:pixelBuffer withPresentationTime:presentationTime]; 



if (appended) { 

NSLog (@"appended sample at time %lf", CMTimeGetSeconds(presentationTime)); 

} else { 

NSLog (@"failed to append"); 

[self stopRecording]; 

self.startStopButton.selected = NO; 

} 

} 

} 

其中：

NSTimer *clockTimer; 
NSTimer *assetWriterTimer; 
AVMutableComposition *mutableComposition; 
AVAssetWriter *assetWriter; 
AVAssetWriterInput *assetWriterInput; 
AVAssetWriterInputPixelBufferAdaptor *assetWriterPixelBufferAdaptor; 
CFAbsoluteTime firstFrameWallClockTime; 

Answer 1

我從iOS開發庫的樣本應用程序。 AVSimpleEditor.隨着視頻錄製，它可以修剪，旋轉，裁剪和添加音樂。

說明：

AVSimpleEditor是一個簡單的基於AVFoundation電影編輯應用程序，行使AVVideoComposition，AVAudioMix的API，並演示瞭如何可用於簡單的視頻編輯任務。它還演示了它們如何與回放（AVPlayerItem）和導出（AVAssetExportSession）進行交互。該應用程序執行修剪，旋轉，裁剪，添加音樂，添加水印和導出。