IWICPlanarBitmapFrameEncode::WritePixels method (wincodec.h)
Writes lines from the source planes to the encoded format.
Syntax
HRESULT WritePixels(
UINT lineCount,
[in] WICBitmapPlane *pPlanes,
UINT cPlanes
);
Parameters
lineCount
Type: UINT
The number of lines to encode. See the Remarks section for WIC Jpeg specific line count restrictions.
[in] pPlanes
Type: WICBitmapPlane*
Specifies the source buffers for each component plane encoded.
cPlanes
Type: UINT
The number of component planes specified by the pPlanes parameter.
Return value
Type: HRESULT
If the planes and source rectangle do not meet the requirements, this method fails with WINCODEC_ERR_IMAGESIZEOUTOFRANGE.
If the IWICBitmapSource format does not meet the encoder requirements, this method fails with WINCODEC_ERR_UNSUPPORTEDPIXELFORMAT.
Remarks
Successive WritePixels calls are assumed sequentially add scanlines to the output image. IWICBitmapFrameEncode::Initialize, IWICBitmapFrameEncode::SetSize and IWICBitmapFrameEncode::SetPixelFormat must be called before this method or it will fail.
The interleaved pixel format set via IWICBitmapFrameEncode::SetPixelFormat and the codec specific encode parameters determine the supported planar formats.
WIC JPEG Encoder: QueryInterface can be used to obtain this interface from the WIC JPEG IWICBitmapFrameEncode implementation. When using this method to encode Y’CbCr data with the WIC JPEG encoder, chroma subsampling can be configured with encoder options during frame creation. See the Encoding Overview and IWICBitmapEncoder::CreateNewFrame for more details.
Depending upon the configured chroma subsampling, the lineCount parameter has the following restrictions:
| Chroma Subsampling | Line Count Restriction | Chroma Plane Width | Chroma Plane Height |
|---|---|---|---|
| 4:2:0 | Multiple of 2, unless the call covers the last scanline of the image | lumaWidth / 2 Rounded up to the nearest integer. | lumaHeight / 2 Rounded up to the nearest integer. |
| 4:2:2 | Any | lumaWidth / 2 Rounded up to the nearest integer. | Any |
| 4:4:4 | Any | Any | Any |
| 4:4:0 | Multiple of 2, unless the call covers the last scanline of the image | Any | llumaHeight / 2 Rounded up to the nearest integer. |
The full scanline width must be encoded, and the width of the bitmap sources must match their planar configuration.
Additionally, if a pixel format is set via IWICBitmapFrameEncode::SetPixelFormat, it must be GUID_WICPixelFormat24bppBGR.
The supported pixel formats of the bitmap sources passed into this method are as follows:
| Plane Count | Plane 1 | Plane 2 | Plane 3 |
|---|---|---|---|
| 3 | GUID_WICPixelFormat8bppY | GUID_WICPixelFormat8bppCb | GUID_WICPixelFormat8bppCr |
| 2 | GUID_WICPixelFormat8bppY | GUID_WICPixelFormat16bppCbCr | N/A |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 8.1 [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2012 R2 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | wincodec.h |
| Library | Windowscodecs.lib |
| DLL | Windowscodecs.dll |