winvideo/video_device_monitor_impl.cpp

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/*
 *  Copyright (C) 2004-2026 Savoir-faire Linux Inc.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program. If not, see <https://www.gnu.org/licenses/>.
 */
 
#include "../video_device_monitor.h"
#include "logger.h"
#include "noncopyable.h"
#include "string_utils.h"
 
#include <dshow.h>
#include <dbt.h>
#include <SetupAPI.h>
 
#include <algorithm>
#include <string>
#include <thread>
#include <vector>
#include <cctype>
 
namespace jami {
namespace video {
 
constexpr GUID guidCamera = {0xe5323777, 0xf976, 0x4f5b, 0x9b, 0x55, 0xb9, 0x46, 0x99, 0xc4, 0x6e, 0x44};
 
class VideoDeviceMonitorImpl
{
public:
    VideoDeviceMonitorImpl(VideoDeviceMonitor* monitor);
    ~VideoDeviceMonitorImpl();
 
    void start();
 
private:
    NON_COPYABLE(VideoDeviceMonitorImpl);
 
    VideoDeviceMonitor* monitor_;
 
    void run();
 
    std::vector<std::string> enumerateVideoInputDevices();
 
    std::thread thread_;
    HWND hWnd_;
    static LRESULT CALLBACK WinProcCallback(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
};
 
VideoDeviceMonitorImpl::VideoDeviceMonitorImpl(VideoDeviceMonitor* monitor)
    : monitor_(monitor)
    , thread_()
{}
 
void
VideoDeviceMonitorImpl::start()
{
    // Enumerate the initial capture device list.
    auto captureDeviceList = enumerateVideoInputDevices();
    for (auto node : captureDeviceList) {
        monitor_->addDevice(node);
    }
    thread_ = std::thread(&VideoDeviceMonitorImpl::run, this);
}
 
VideoDeviceMonitorImpl::~VideoDeviceMonitorImpl()
{
    SendMessage(hWnd_, WM_DESTROY, 0, 0);
    if (thread_.joinable())
        thread_.join();
}
 
std::string
getDeviceUniqueName(PDEV_BROADCAST_DEVICEINTERFACE_A pbdi)
{
    std::string unique_name = pbdi->dbcc_name;
 
    std::transform(unique_name.begin(), unique_name.end(), unique_name.begin(), [](unsigned char c) {
        return std::tolower(c);
    });
 
    auto pos = unique_name.find_last_of("#");
    unique_name = unique_name.substr(0, pos);
 
    return unique_name;
}
 
bool
registerDeviceInterfaceToHwnd(HWND hWnd, HDEVNOTIFY* hDeviceNotify)
{
    // Use a guid for cameras specifically in order to not get spammed
    // with device messages.
    // These are pertinent GUIDs for media devices:
    //
    // usb interfaces   { 0xa5dcbf10l, 0x6530, 0x11d2, 0x90, 0x1f, 0x00, 0xc0, 0x4f, 0xb9, 0x51,
    // 0xed }; image devices    { 0x6bdd1fc6,  0x810f, 0x11d0, 0xbe, 0xc7, 0x08, 0x00, 0x2b, 0xe2,
    // 0x09, 0x2f }; capture devices  { 0x65e8773d,  0x8f56, 0x11d0, 0xa3, 0xb9, 0x00, 0xa0, 0xc9,
    // 0x22, 0x31, 0x96 }; camera devices   { 0xe5323777,  0xf976, 0x4f5b, 0x9b, 0x55, 0xb9, 0x46,
    // 0x99, 0xc4, 0x6e, 0x44 }; audio devices    { 0x6994ad04,  0x93ef, 0x11d0, 0xa3, 0xcc, 0x00,
    // 0xa0, 0xc9, 0x22, 0x31, 0x96 };
 
    DEV_BROADCAST_DEVICEINTERFACE NotificationFilter;
 
    ZeroMemory(&NotificationFilter, sizeof(NotificationFilter));
    NotificationFilter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
    NotificationFilter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
    NotificationFilter.dbcc_classguid = guidCamera;
 
    *hDeviceNotify = RegisterDeviceNotification(hWnd, &NotificationFilter, DEVICE_NOTIFY_WINDOW_HANDLE);
 
    if (nullptr == *hDeviceNotify) {
        return false;
    }
 
    return true;
}
 
LRESULT CALLBACK
VideoDeviceMonitorImpl::WinProcCallback(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    LRESULT lRet = 1;
    static HDEVNOTIFY hDeviceNotify;
    VideoDeviceMonitorImpl* pThis;
 
    switch (message) {
    case WM_CREATE: {
        // Store object pointer passed from CreateWindowEx.
        auto createParams = reinterpret_cast<CREATESTRUCT*>(lParam)->lpCreateParams;
        pThis = static_cast<VideoDeviceMonitorImpl*>(createParams);
        SetLastError(0);
        SetWindowLongPtr(hWnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(pThis));
 
        if (!registerDeviceInterfaceToHwnd(hWnd, &hDeviceNotify)) {
            JAMI_ERR() << "Cannot register for device change notifications";
            SendMessage(hWnd, WM_DESTROY, 0, 0);
        }
    } break;
 
    case WM_DEVICECHANGE: {
        switch (wParam) {
        case DBT_DEVICEREMOVECOMPLETE:
        case DBT_DEVICEARRIVAL: {
            PDEV_BROADCAST_DEVICEINTERFACE_A pbdi = (PDEV_BROADCAST_DEVICEINTERFACE_A) lParam;
            auto unique_name = getDeviceUniqueName(pbdi);
            if (!unique_name.empty()) {
                JAMI_DBG() << unique_name << ((wParam == DBT_DEVICEARRIVAL) ? " plugged" : " unplugged");
                if (pThis = reinterpret_cast<VideoDeviceMonitorImpl*>(GetWindowLongPtr(hWnd, GWLP_USERDATA))) {
                    if (wParam == DBT_DEVICEARRIVAL) {
                        auto captureDeviceList = pThis->enumerateVideoInputDevices();
                        for (auto id : captureDeviceList) {
                            if (id.find(unique_name) != std::string::npos)
                                pThis->monitor_->addDevice(id);
                        }
                    } else if (wParam == DBT_DEVICEREMOVECOMPLETE) {
                        pThis->monitor_->removeDevice(unique_name);
                    }
                }
            }
        } break;
        default:
            break;
        }
        break;
    } break;
 
    case WM_CLOSE:
        UnregisterDeviceNotification(hDeviceNotify);
        DestroyWindow(hWnd);
        break;
 
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
 
    default:
        lRet = DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
 
    return lRet;
}
 
void
VideoDeviceMonitorImpl::run()
{
    // Create a dummy window with the sole purpose to receive device change messages.
    static const char* className = "Message";
    WNDCLASSEX wx = {};
    wx.cbSize = sizeof(WNDCLASSEX);
    wx.lpfnWndProc = WinProcCallback;
    wx.hInstance = reinterpret_cast<HINSTANCE>(GetModuleHandle(0));
    wx.lpszClassName = className;
    if (RegisterClassEx(&wx)) {
        // Pass this as lpParam so WinProcCallback can access members of VideoDeviceMonitorImpl.
        hWnd_ = CreateWindowEx(0, className, "devicenotifications", 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, this);
    }
 
    // Run the message loop that will finish once a WM_DESTROY message
    // has been sent, allowing the thread to join.
    MSG msg;
    int retVal;
    while ((retVal = GetMessage(&msg, NULL, 0, 0)) != 0) {
        if (retVal != -1) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
}
 
std::vector<std::string>
VideoDeviceMonitorImpl::enumerateVideoInputDevices()
{
    std::vector<std::string> deviceList;
 
    ICreateDevEnum* pDevEnum;
    HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pDevEnum));
 
    if (FAILED(hr)) {
        JAMI_ERR() << "Unable to enumerate webcams";
        return {};
    }
 
    IEnumMoniker* pEnum = nullptr;
    hr = pDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEnum, 0);
    if (hr == S_FALSE) {
        hr = VFW_E_NOT_FOUND;
    }
    pDevEnum->Release();
    if (FAILED(hr) || pEnum == nullptr) {
        JAMI_ERR() << "No webcam found";
        return {};
    }
 
    IMoniker* pMoniker = NULL;
    while (pEnum->Next(1, &pMoniker, NULL) == S_OK) {
        IPropertyBag* pPropBag;
        HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
        if (FAILED(hr)) {
            pMoniker->Release();
            continue;
        }
 
        IBindCtx* bind_ctx = NULL;
        LPOLESTR olestr = NULL;
 
        hr = CreateBindCtx(0, &bind_ctx);
        if (hr != S_OK) {
            continue;
        }
        hr = pMoniker->GetDisplayName(bind_ctx, NULL, &olestr);
        if (hr != S_OK) {
            continue;
        }
        auto unique_name = to_string(olestr);
        if (!unique_name.empty()) {
            // replace ':' with '_' since ffmpeg uses : to delineate between sources
            std::replace(unique_name.begin(), unique_name.end(), ':', '_');
            deviceList.push_back(std::string("video=") + unique_name);
        }
 
        pPropBag->Release();
    }
    pEnum->Release();
 
    return deviceList;
}
 
VideoDeviceMonitor::VideoDeviceMonitor()
    : preferences_()
    , devices_()
    , monitorImpl_(new VideoDeviceMonitorImpl(this))
{
    monitorImpl_->start();
    addDevice(DEVICE_DESKTOP, {});
}
 
VideoDeviceMonitor::~VideoDeviceMonitor() {}
 
} // namespace video
} // namespace jami