c++ - What causes IWICBitmapFrameEncode::SetPixelFormat to return a format different from the requested one? -
i've been using wic encode multiple images jpegxr format. occassionally, program logs error last logassert in following snippet of encode function.
hr = m_pfactory->createencoder(guid_containerformatwmp, null, &pencoder); logassert(succeeded(hr),"failed create encoder. err: 0x%x", hr); hr = pencoder->initialize(poutputstream, wicbitmapencodernocache); logassert(succeeded(hr),"failed initialize encoder. err: 0x%x", hr); hr = pencoder->createnewframe(&pbitmapframe, &ppropertybag); logassert(succeeded(hr),"encoder failed create new frame. err: 0x%x", hr); setencodingproperties(ppropertybag); hr = pbitmapframe->initialize(ppropertybag); logassert(succeeded(hr),"failed initialize pbitmapframe given properties. err: 0x%x", hr); hr = pbitmapframe->setsize(rawwidth, rawheight); logassert(succeeded(hr),"failed set bitmap size. err: 0x%x", hr); wicpixelformatguid formatguid = guid_wicpixelformat24bppbgr; hr = pbitmapframe->setpixelformat(&formatguid); if(failed(hr) || !isequalguid(formatguid, guid_wicpixelformat24bppbgr)) { logassert(false,"failed set pixel format guid_wicpixelformat24bppbgr. err: 0x%x", hr); } i checked dump file , seems returned formatguid guid_wicpixelformat24bpp rgb.
i have following questions:
when setpixel format return different version? factors cause return different guid?
i encoding jpegxr, , applying same properties. why behavior of setpixelformat non-deterministic? shouldn't either succeed, or return guid_wicpixelformat24bpprgb?
if rgb format supported, why isn't bgr? it's change in order.
my code, written of examples here:
http://msdn.microsoft.com/en-us/library/windows/desktop/ee719871(v=vs.85).aspx
this issue can happen concurrent calls setpixelformat. i've heard fixed in windows 8.1.
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