CMSampleBufferCreateForImageBuffer(allocator:imageBuffer:dataReady:makeDataReadyCallback:refcon:formatDescription:sampleTiming:sampleBufferOut:)

Creates a sample buffer with an image buffer and a callback to make the data ready for use.

Declaration

func CMSampleBufferCreateForImageBuffer(allocator: CFAllocator?, imageBuffer: CVImageBuffer, dataReady: Bool, makeDataReadyCallback: CMSampleBufferMakeDataReadyCallback?, refcon makeDataReadyRefcon: UnsafeMutableRawPointer?, formatDescription: CMVideoFormatDescription, sampleTiming: UnsafePointer<CMSampleTimingInfo>, sampleBufferOut: UnsafeMutablePointer<CMSampleBuffer?>) -> OSStatus

Parameters

allocator:
The allocator to use for allocating the CMSampleBuffer object. Pass kCFAllocatorDefault to use the default allocator.
imageBuffer:
CVImageBuffer for the media data. This can be a CVImageBuffer whose content hasn’t yet been rendered, or a CVImageBuffer that already contains the media data (in which case dataReady should be true). May not be NULL.
dataReady:
Indicates whether or not the CVImageBuffer already contains the media data.
makeDataReadyCallback:
Callback that Cmsamplebuffermakedataready(_:) should call to make the data ready. Can be NULL.
makeDataReadyRefcon:
Refcon Cmsamplebuffermakedataready(_:) should pass to the callback.
formatDescription:
A description of the media data’s format. See discussion above for constraints. May not be NULL.
sampleTiming:
A CMSampleTimingInfo struct that provides the timing information for the media represented by the CVImageBuffer.
sampleBufferOut:
On output, points to the newly created CMSampleBuffer that contains a CVImageBuffer.

Return Value

A result code. See Sample Buffer Error Codes.

Discussion

Unlike a CMBlockBuffer which can reference many samples, a CVImageBuffer is defined to reference only one sample; therefore this routine has fewer parameters than CMSampleBufferCreate. Sample timing information, which is a vector for CMSampleBufferCreate, consists of only one value for this routine. The concept of sample size doesn’t apply to CVImageBuffers. As such, CMSampleBufferGetSampleSizeArray(_:entryCount:arrayToFill:entriesNeededOut:) returns kCMSampleBufferError_BufferHasNoSampleSizes, and CMSampleBufferGetSampleSize(_:at:) returns 0.

Because CVImageBuffers hold visual data, the format description provided is a CMVideoFormatDescription. The format description must be consistent with the attributes and formatting information attached to the CVImageBuffer. The width, height, and codecType must match (for CVPixelBuffers the codec type is given by CVPixelBufferGetPixelFormatType(pixelBuffer); for other CVImageBuffers, the codecType must be 0). The format description extensions must match the image buffer attachments for all the keys in the list returned by CMVideoFormatDescriptionGetExtensionKeysCommonWithImageBuffers. If absent in either they must be absent in both.

Topics

Callbacks

CMSampleBufferMakeDataReadyCallback