用CGDisplayStream编码H.264压缩会话
用CGDisplayStream编码H.264压缩会话
提问于 2017-03-10 14:57:07
我正在尝试用我屏幕上的数据创建一个H.264压缩会话。我创建了一个类似于这样的CGDisplayStreamRef实例：
displayStream = CGDisplayStreamCreateWithDispatchQueue(0, 100, 100, k32BGRAPixelFormat, nil, self.screenCaptureQueue, ^(CGDisplayStreamFrameStatus status, uint64_t displayTime, IOSurfaceRef frameSurface, CGDisplayStreamUpdateRef updateRef) {
//Call encoding session here
});下面是我当前如何设置编码函数：
- (void) encode:(CMSampleBufferRef )sampleBuffer {
CVImageBufferRef imageBuffer = (CVImageBufferRef)CMSampleBufferGetImageBuffer(sampleBuffer);
CMTime presentationTimeStamp = CMTimeMake(frameID++, 1000);
VTEncodeInfoFlags flags;
OSStatus statusCode = VTCompressionSessionEncodeFrame(EncodingSession,
imageBuffer,
presentationTimeStamp,
kCMTimeInvalid,
NULL, NULL, &flags);
if (statusCode != noErr) {
NSLog(@"H264: VTCompressionSessionEncodeFrame failed with %d", (int)statusCode);
VTCompressionSessionInvalidate(EncodingSession);
CFRelease(EncodingSession);
EncodingSession = NULL;
return;
}
NSLog(@"H264: VTCompressionSessionEncodeFrame Success");
}我试图了解如何将屏幕上的数据转换为CMSampleBufferRef，以便正确地调用我的编码函数。到目前为止，我还没有确定这是否有可能，或者我试图做的事情的正确方法。有人有什么建议吗？
编辑：我已经将自己的IOSurface转换成了CMBlockBuffer，但还没有想出如何将其转换为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, NULL, 0, totalBytes, 0, &blockBuffer);编辑2
取得更多进展：
CMSampleBufferRef *sampleBuffer;
OSStatus sampleStatus = CMSampleBufferCreate(
NULL, blockBuffer, TRUE, NULL, NULL,
NULL, 1, 1, NULL,
0, NULL, sampleBuffer);
[self encode:*sampleBuffer];回答 1
Stack Overflow用户
发布于 2017-05-17 15:00:51
也许，我有点晚了，但无论如何，这可能对其他人有帮助：
CGDisplayStreamCreateWithDispatchQueue(CGMainDisplayID(), 100, 100, k32BGRAPixelFormat, nil, self.screenCaptureQueue, ^(CGDisplayStreamFrameStatus status, uint64_t displayTime, IOSurfaceRef frameSurface, CGDisplayStreamUpdateRef updateRef) {
// The created pixel buffer retains the surface object.
CVPixelBufferRef pixelBuffer;
CVPixelBufferCreateWithIOSurface(NULL, frameSurface, NULL, &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, pixelBuffer, 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);
});页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/42721360
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