diff options
Diffstat (limited to 'pica-client/videodshow.cpp')
| -rw-r--r-- | pica-client/videodshow.cpp | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/pica-client/videodshow.cpp b/pica-client/videodshow.cpp new file mode 100644 index 0000000..394798a --- /dev/null +++ b/pica-client/videodshow.cpp @@ -0,0 +1,172 @@ +/* + (c) Copyright 2012 - 2026 Anton Sviridenko + https://picapica.im + + 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, version 3. + + 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 "mediadevice.h" + +#include <QtGlobal> + +#ifdef Q_OS_WIN + +#include <QDebug> +#include <QList> +#include <QString> + +// INITGUID before the DirectShow headers so CLSID_SystemDeviceEnum and the +// rest get defined here rather than needing strmiids at link time. The GUIDs +// are emitted with DECLSPEC_SELECTANY, so the ones this shares with +// nativeaudio_wasapi.cpp merge rather than clashing. +#define INITGUID +#include <initguid.h> + +#include <windows.h> +#include <objbase.h> +#include <dshow.h> + +static QString wideToQString(LPCWSTR s) +{ + return s ? QString::fromWCharArray(s) : QString(); +} + +// Lists the cameras DirectShow knows about. +// +// Capture itself goes through FFmpeg's "dshow" demuxer rather than through +// DirectShow directly - it does the job and there is no equivalent of the +// audio situation here, where the platform had something we could not reach +// any other way. But the demuxer has no enumeration API: it can only print +// device names to the log with -list_devices, which is no use to a settings +// dialog. So the list is built here, from the same device category the +// demuxer itself walks, and the names handed back are the ones it matches on. +QList<MediaDeviceInfo> pica_enumerate_dshow_video() +{ + QList<MediaDeviceInfo> result; + + // Qt has already put the GUI thread into an apartment; the reference is + // still ours to balance, hence the matching CoUninitialize() below. + bool didInit = false; + HRESULT hr = CoInitializeEx(nullptr, COINIT_MULTITHREADED); + if (SUCCEEDED(hr)) + didInit = true; + else if (hr != RPC_E_CHANGED_MODE) + return result; + + ICreateDevEnum *devEnum = nullptr; + hr = CoCreateInstance(CLSID_SystemDeviceEnum, nullptr, CLSCTX_INPROC_SERVER, + IID_ICreateDevEnum, (void **)&devEnum); + if (FAILED(hr) || !devEnum) + { + qWarning() << "DirectShow: could not create the device enumerator" + << QString("0x%1").arg((quint32)hr, 8, 16, QLatin1Char('0')); + if (didInit) + CoUninitialize(); + return result; + } + + IEnumMoniker *enumMoniker = nullptr; + hr = devEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &enumMoniker, 0); + + // S_FALSE with a null enumerator is how "no cameras at all" comes back. + if (hr != S_OK || !enumMoniker) + { + devEnum->Release(); + if (didInit) + CoUninitialize(); + return result; + } + + int index = 0; + QStringList seenNames; + IMoniker *moniker = nullptr; + + while (enumMoniker->Next(1, &moniker, nullptr) == S_OK) + { + IPropertyBag *bag = nullptr; + if (FAILED(moniker->BindToStorage(nullptr, nullptr, IID_IPropertyBag, (void **)&bag)) || !bag) + { + moniker->Release(); + continue; + } + + QString friendlyName; + QString uniqueName; + + VARIANT var; + VariantInit(&var); + if (SUCCEEDED(bag->Read(L"FriendlyName", &var, nullptr)) && var.vt == VT_BSTR) + friendlyName = wideToQString(var.bstrVal); + VariantClear(&var); + + VariantInit(&var); + if (SUCCEEDED(bag->Read(L"DevicePath", &var, nullptr)) && var.vt == VT_BSTR) + { + // FFmpeg calls this the device's "alternative name" and matches on + // it as well as on the friendly one, after replacing colons - + // which it uses as a separator in its own device strings. + uniqueName = wideToQString(var.bstrVal).replace(QLatin1Char(':'), QLatin1Char('_')); + } + VariantClear(&var); + + bag->Release(); + moniker->Release(); + + if (friendlyName.isEmpty()) + continue; + + MediaDeviceInfo d; + d.humanReadable = friendlyName; + + // The friendly name is the documented way to name a dshow device and + // the one to prefer. It is not required to be unique though, and two + // identical cameras would both answer to it - the demuxer would open + // whichever came first. Later duplicates therefore fall back to the + // device path, which is unique by construction. + if (!seenNames.contains(friendlyName)) + { + d.device = friendlyName; + seenNames << friendlyName; + } + else if (!uniqueName.isEmpty()) + { + d.device = uniqueName; + d.humanReadable += QString(" (%1)").arg(seenNames.count(friendlyName) + 1); + seenNames << friendlyName; + } + else + { + // Same name, no device path to tell them apart. Listing it again + // would just give the user two entries that open the same camera. + continue; + } + + d.index = index++; + + // Left empty deliberately. compressedFormats drives the "prefer + // compressed formats" setting, and working out what a DirectShow + // camera can deliver means walking its output pin's media types + // through IAMStreamConfig - a good deal more work than the v4l2 call + // that fills this in on Linux, and not needed to get a picture. + result << d; + } + + enumMoniker->Release(); + devEnum->Release(); + + if (didInit) + CoUninitialize(); + + return result; +} + +#endif // Q_OS_WIN |