gecko/content/media/wmf/WMFUtils.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "WMF.h"
#include "nsString.h"
// Various utilities shared by WMF backend files.
namespace mozilla {
nsCString
GetGUIDName(const GUID& guid);
// Returns true if the reader has a stream with the specified index.
// Index can be a specific index, or one of:
// MF_SOURCE_READER_FIRST_VIDEO_STREAM
// MF_SOURCE_READER_FIRST_AUDIO_STREAM
bool
SourceReaderHasStream(IMFSourceReader* aReader, const DWORD aIndex);
// Auto manages the lifecycle of a PROPVARIANT.
class AutoPropVar {
public:
AutoPropVar() {
PropVariantInit(&mVar);
}
~AutoPropVar() {
PropVariantClear(&mVar);
}
operator PROPVARIANT&() {
return mVar;
}
PROPVARIANT* operator->() {
return &mVar;
}
PROPVARIANT* operator&() {
return &mVar;
}
private:
PROPVARIANT mVar;
};
// Converts from microseconds to hundreds of nanoseconds.
// We use microseconds for our timestamps, whereas WMF uses
// hundreds of nanoseconds.
inline int64_t
UsecsToHNs(int64_t aUsecs) {
return aUsecs * 10;
}
// Converts from hundreds of nanoseconds to microseconds.
// We use microseconds for our timestamps, whereas WMF uses
// hundreds of nanoseconds.
inline int64_t
HNsToUsecs(int64_t hNanoSecs) {
return hNanoSecs / 10;
}
// Assigns aUnknown to *aInterface, and AddRef's it.
// Helper for MSCOM QueryInterface implementations.
HRESULT
DoGetInterface(IUnknown* aUnknown, void** aInterface);
} // namespace mozilla