vImageConvert_ChunkyToPlanar8(_:_:_:_:_:_:_:_:)

Declaration

func vImageConvert_ChunkyToPlanar8(_ srcChannels: UnsafeMutablePointer<UnsafeRawPointer?>, _ destPlanarBuffers: UnsafeMutablePointer<UnsafePointer<vImage_Buffer>?>, _ channelCount: UInt32, _ srcStrideBytes: Int, _ srcWidth: vImagePixelCount, _ srcHeight: vImagePixelCount, _ srcRowBytes: Int, _ flags: vImage_Flags) -> vImage_Error

Parameters

• srcChannels:

  An array that contains pointers to the start of each channel in the source buffer.

• destPlanarBuffers:

  An array that contains channelCount destination planar vImage buffers. Each source buffer must be the same height and width, but they may have different Rowbytes values.

• channelCount:

  The number of channels in the source image.

• srcStrideBytes:

  The number of bytes between consecutive pixels in a channel in the same row.

• srcWidth:

  The width, in pixels, of the source channels and the destination planar buffers.

• srcHeight:

  The height, in pixels, of the source channels and the destination planar buffers.

• srcRowBytes:

  The distance, in bytes, between the corresponding pixels in consecutive rows in the source buffer, including any unused space between them.

• flags:

  The options to use when performing the operation. If your code implements its own tiling or its own multithreading, pass Kvimagedonottile; otherwise, pass Kvimagenoflags.

Return Value

kvImageNoError; otherwise, one of the error codes in Data Types and Constants.

Discussion

Use this function to deinterleave formats that either aren’t supported by the vImage library or are only known at runtime.

The following code interleaves a 4 x 1 interleaved 2-channel buffer into two 4 x 1 planar buffers:

let width = 4
let height = 1
let size = vImage.Size(width: width,
                       height: height)

let cbCrBuffer = vImage.PixelBuffer(pixelValues: [10, 20,   11, 21,   12, 22,   13, 23],
                                    size: size,
                                    pixelFormat: vImage.Interleaved8x2.self)

let cbBuffer = vImage.PixelBuffer(size: size,
                                  pixelFormat: vImage.Planar8.self)

let crBuffer = vImage.PixelBuffer(size: size,
                                  pixelFormat: vImage.Planar8.self)

cbCrBuffer.withUnsafeVImageBuffer { cbcr in
    cbBuffer.withUnsafePointerToVImageBuffer { cb in
        crBuffer.withUnsafePointerToVImageBuffer { cr in
            
            var srcChannels = [
                UnsafeRawPointer(cbcr.data),
                UnsafeRawPointer(cbcr.data.advanced(by: MemoryLayout<Pixel_8>.stride))
            ]
            
            var dstPlanarBuffers = [Optional(cb), Optional(cr)]
            
            let channelCount = 2
            
            _ = vImageConvert_ChunkyToPlanar8(
                &srcChannels,
                &dstPlanarBuffers,
                UInt32(channelCount),
                MemoryLayout<Pixel_8>.stride * channelCount,
                vImagePixelCount(width),
                vImagePixelCount(height),
                cbcr.rowBytes,
                vImage_Flags(kvImageNoFlags))
            
        }
    }
}

// Prints "[10, 11,    12, 13]".
print(cbBuffer.array)

// Prints "[20, 21,    22, 23]".
print(crBuffer.array)