qwindowsvideodevices.cpp

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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qwindowsvideodevices_p.h"
 
#include <QtCore/quuid.h>
#include <QtCore/private/qcomptr_p.h>
#include <QtCore/private/qfunctions_win_p.h>
#include <QtMultimedia/private/qcameradevice_p.h>
#include <QtMultimedia/private/qcomtaskresource_p.h>
#include <QtMultimedia/private/qwindowsmultimediautils_p.h>
 
#include <dbt.h>
 
#include <mfapi.h>
#include <mfidl.h>
#include <mfreadwrite.h>
#include <mferror.h>
#include <ks.h>
 
// MinGW-13.1 workaround
#ifndef KSCATEGORY_SENSOR_CAMERA
static constexpr GUID KSCATEGORY_SENSOR_CAMERA = {
    0x24e552d7, 0x6523, 0x47f7, { 0xa6, 0x47, 0xd3, 0x46, 0x5b, 0xf1, 0xf5, 0xca }
};
#endif
 
QT_BEGIN_NAMESPACE
 
namespace {
 
LRESULT QT_WIN_CALLBACK deviceNotificationWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    if (message == WM_DEVICECHANGE) {
        auto b = (PDEV_BROADCAST_HDR)lParam;
        if (b && b->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
            auto wmd = reinterpret_cast<QWindowsVideoDevices *>(GetWindowLongPtr(hWnd, GWLP_USERDATA));
            if (wmd) {
                if (wParam == DBT_DEVICEARRIVAL || wParam == DBT_DEVICEREMOVECOMPLETE) {
                    wmd->onVideoInputsChanged();
                }
            }
        }
    }
 
    return 1;
}
 
LPCWSTR getWindowsClassName()
{
    // each Qt instance should have its own window class name to prevent name clashes when multiple
    // qt instances are used in the same process.
    // appending a uuid is good enough to ensure that.
    static const std::wstring singleton =
            QString(QStringLiteral("QWindowsMediaDevicesMessageWindow_")
                    + QUuid::createUuid().toString())
                    .toStdWString();
    Q_ASSERT(singleton.size() < 256 && "The maximum length for lpszClassName is 256");
    return singleton.c_str();
}
 
HWND createMessageOnlyWindow()
{
    WNDCLASSEX wx = {};
    wx.cbSize = sizeof(WNDCLASSEX);
    wx.lpfnWndProc = deviceNotificationWndProc;
    wx.hInstance = GetModuleHandle(nullptr);
    wx.lpszClassName = getWindowsClassName();
 
    if (!RegisterClassEx(&wx))
        return nullptr;
 
    auto hwnd = CreateWindowEx(0, getWindowsClassName(), TEXT("Message"), 0, 0, 0, 0, 0,
                               HWND_MESSAGE, nullptr, nullptr, nullptr);
    if (!hwnd) {
        UnregisterClass(getWindowsClassName(), GetModuleHandle(nullptr));
        return nullptr;
    }
 
    return hwnd;
}
 
} // namespace
 
QWindowsVideoDevices::QWindowsVideoDevices(QPlatformMediaIntegration *integration)
    : QPlatformVideoDevices(integration)
{
    qt_win_ensureComInitializedOnThisThread();
 
    m_videoDeviceMsgWindow = createMessageOnlyWindow();
    if (m_videoDeviceMsgWindow) {
        SetWindowLongPtr(m_videoDeviceMsgWindow, GWLP_USERDATA, (LONG_PTR)this);
 
        DEV_BROADCAST_DEVICEINTERFACE di = {};
        di.dbcc_size = sizeof(di);
        di.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
        di.dbcc_classguid = KSCATEGORY_VIDEO_CAMERA;
 
        m_videoDeviceNotification =
                RegisterDeviceNotification(m_videoDeviceMsgWindow, &di, DEVICE_NOTIFY_WINDOW_HANDLE);
        if (!m_videoDeviceNotification) {
            DestroyWindow(m_videoDeviceMsgWindow);
            m_videoDeviceMsgWindow = nullptr;
 
            UnregisterClass(getWindowsClassName(), GetModuleHandle(nullptr));
        }
    }
 
    if (!m_videoDeviceNotification) {
        qWarning() << "Video device change notification disabled";
    }
}
 
QWindowsVideoDevices::~QWindowsVideoDevices()
{
    if (m_videoDeviceNotification) {
        UnregisterDeviceNotification(m_videoDeviceNotification);
    }
 
    if (m_videoDeviceMsgWindow) {
        DestroyWindow(m_videoDeviceMsgWindow);
        UnregisterClass(getWindowsClassName(), GetModuleHandle(nullptr));
    }
}
 
static QString getString(IMFActivate *device, const IID &id)
{
    QComTaskResource<WCHAR> str;
    UINT32 length = 0;
    HRESULT hr = device->GetAllocatedString(id, str.address(), &length);
    if (SUCCEEDED(hr)) {
        return QString::fromWCharArray(str.get());
    } else {
        return {};
    }
}
 
static std::optional<QCameraDevice> createCameraDevice(const QWindowsMediaFoundation &wmf,
                                                       IMFActivate *device)
{
    auto info = std::make_unique<QCameraDevicePrivate>();
    info->description = getString(device, MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME);
    info->id = getString(device, MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK).toUtf8();
 
    ComPtr<IMFMediaSource> source;
    HRESULT hr = device->ActivateObject(IID_PPV_ARGS(source.GetAddressOf()));
    if (FAILED(hr))
        return {};
 
    ComPtr<IMFSourceReader> reader;
    hr = wmf.mfCreateSourceReaderFromMediaSource(source.Get(), NULL, reader.GetAddressOf());
    if (FAILED(hr))
        return {};
 
    QList<QSize> photoResolutions;
    QList<QCameraFormat> videoFormats;
    for (DWORD i = 0;; ++i) {
        // Loop through the supported formats for the video device
        ComPtr<IMFMediaType> mediaFormat;
        hr = reader->GetNativeMediaType((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, i,
                                        mediaFormat.GetAddressOf());
        if (FAILED(hr))
            break;
 
        auto maybeCamera = QWMF::cameraFormatFromMediaType(mediaFormat.Get());
        if (maybeCamera) {
            videoFormats << *maybeCamera;
            photoResolutions << maybeCamera->resolution();
        }
    }
 
    info->videoFormats = videoFormats;
    info->photoResolutions = photoResolutions;
    return info.release()->create();
}
 
static QList<QCameraDevice> readCameraDevices(const QWindowsMediaFoundation &wmf,
                                              IMFAttributes *attr)
{
    QList<QCameraDevice> cameras;
    UINT32 count = 0;
    IMFActivate **devicesRaw = nullptr;
    HRESULT hr = wmf.mfEnumDeviceSources(attr, &devicesRaw, &count);
    if (SUCCEEDED(hr)) {
        QComTaskResource<IMFActivate *[], QComDeleter> devices(devicesRaw, count);
 
        for (UINT32 i = 0; i < count; i++) {
            IMFActivate *device = devices[i];
            if (device) {
                auto maybeCamera = createCameraDevice(wmf, device);
                if (maybeCamera)
                    cameras << *maybeCamera;
            }
        }
    }
    return cameras;
}
 
QList<QCameraDevice> QWindowsVideoDevices::findVideoInputs() const
{
    if (!m_wmf)
        return {};
 
    QList<QCameraDevice> cameras;
 
    ComPtr<IMFAttributes> attr;
    HRESULT hr = m_wmf->mfCreateAttributes(attr.GetAddressOf(), 2);
    if (FAILED(hr))
        return {};
 
    hr = attr->SetGUID(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE,
                       MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_GUID);
    if (SUCCEEDED(hr)) {
        cameras << readCameraDevices(*m_wmf, attr.Get());
 
        hr = attr->SetGUID(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_CATEGORY,
                           KSCATEGORY_SENSOR_CAMERA);
        if (SUCCEEDED(hr))
            cameras << readCameraDevices(*m_wmf, attr.Get());
    }
 
    return cameras;
}
 
QT_END_NAMESPACE