我正在尝试使用屏幕上的数据创建一个H.264压缩会话.我已经创建了一个CGdisplayStreamRef实例,如下所示:
displayStream = CGdisplayStreamCreateWithdispatchQueue(0,100,k32BGRAPixelFormat,nil,self.screenCaptureQueue,^(CGdisplayStreamFrameStatus status,uint64_t displayTime,IOSurfaceRef frameSurface,CGdisplayStreamUpdateRef updateRef) { //Call encoding session here });
以下是我目前如何设置编码功能:
- (void) encode:(CMSampleBufferRef )sampleBuffer { CVImageBufferRef imageBuffer = (CVImageBufferRef)CMSampleBufferGetimageBuffer(sampleBuffer); CMTime presentationTimeStamp = CMTimeMake(frameID++,1000); VTEncodeInfoFlags flags; Osstatus statusCode = VTCompressionSessionEncodeFrame(EncodingSession,imageBuffer,presentationTimeStamp,kCMTimeInvalid,NULL,&flags); if (statusCode != noErr) { NSLog(@"H264: VTCompressionSessionEncodeFrame Failed with %d",(int)statusCode); VTCompressionSessionInvalidate(EncodingSession); CFRelease(EncodingSession); EncodingSession = NULL; return; } NSLog(@"H264: VTCompressionSessionEncodeFrame Success"); }
我试图了解如何将数据从我的屏幕转换为CMSampleBufferRef,以便我可以正确调用我的编码功能.到目前为止,我还无法确定这是否可行,或者是我正在尝试做的正确方法.有没有人有什么建议?
编辑:我已经将我的IOSurface转换为CMBlockBuffer,但尚未弄清楚如何将其转换为CMSampleBufferRef:
void *mem = IOSurfaceGetBaseAddress(frameSurface); size_t bytesPerRow = IOSurfaceGetBytesPerRow(frameSurface); size_t height = IOSurfaceGetHeight(frameSurface); size_t totalBytes = bytesPerRow * height; CMBlockBufferRef blockBuffer; CMBlockBufferCreateWithMemoryBlock(kcfAllocatorNull,mem,totalBytes,kcfAllocatorNull,&blockBuffer);
编辑2
更进一步:
CMSampleBufferRef *sampleBuffer; Osstatus sampleStatus = CMSampleBufferCreate( NULL,blockBuffer,TRUE,1,sampleBuffer); [self encode:*sampleBuffer];
解决方法
可能,我有点迟了但是,它可能对其他人有帮助:
CGdisplayStreamCreateWithdispatchQueue(CGMaindisplayID(),CGdisplayStreamUpdateRef updateRef) { // The created pixel buffer retains the surface object. CVPixelBufferRef pixelBuffer; CVPixelBufferCreateWithIOSurface(NULL,frameSurface,&pixelBuffer); // Create the video-type-specific description for the pixel buffer. CMVideoFormatDescriptionRef videoFormatDescription; CMVideoFormatDescriptionCreateForImageBuffer(NULL,pixelBuffer,&videoFormatDescription); // All the necessary parts for creating a `CMSampleBuffer` are ready. CMSampleBufferRef sampleBuffer; CMSampleTimingInfo timingInfo; CMSampleBufferCreateReadyWithImageBuffer(NULL,videoFormatDescription,&timingInfo,&sampleBuffer); // Do the stuff // Release the resources to let the frame surface be reused in the queue // `kCGdisplayStreamQueueDepth` is responsible for the size of the queue CFRelease(sampleBuffer); CFRelease(pixelBuffer); });
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