Tag: Windows API

Certificate Enrollment API Adventures

IX509PrivateKey::Export exports key data from COM object, MSDN: strExportType [in] A BSTR value that specifies how the private key is exported. If the key was created by using a CNG KSP (Key Storage Provider), you can specify one of the values allowed by the pszBlobType parameter in the NCryptExportKey function. If the key was created…

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MediaFoundationVideoEncoderTransforms: Detecting support for hardware H.264 video encoders

H.264 (MPEG-4 Part 10 also known as MPEG-4 AVC) video encoding was never packaged into DirectShow filter by Microsoft and instead they offered Media Foundation Transform (MFT) for the job: H.264 Video Encoder. Further development gave us third party video encoders also packaged as MFTs. Hardware backed MFTs became a part of video hardware drivers…

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Fragile MFEnumDeviceSources

As I mentioned in earlier post, Media Foundation video capture capability is internally using undocumented categories with pretty much the same transforms and enumeration applicable to categories documented. Without documenting it as public contract, MFEnumDeviceSources enumerates transforms, builds standard implementation for IMFMediaSource on top of available transform and… voila! Media Foundation offers “lightweight” API for…

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Media Foundation Video/Audio Capture Capabilities

Just like with DirectShow video capture capability information, it is helpful to unerstand what Medfia Foudnation video capture offering is exactly. Specifically: Video and audio sources available with MFEnumDeviceSources and MFCreateDeviceSource Source attributes, streams, media types DirectShow compatible representations H.264 realated attributes in media types might be not so obvious and device might report too…

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CLSID_VideoInputDeviceCategory and Media Foundation

Media Foundation as video capture API is inflexible. At Microsoft – besides standard Media Foundation problems of backward compatibility, availability of developer tools and overall awkwardness – they decided to no longer offer video capture extensibility with Media Foundation. Be happy with MFEnumDeviceSources and don’t go anywhere else. They explain that they already provided support…

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