Le mer. 26 mai 2021 à 14:11, Lars Knoll <lars.kn...@qt.io> a écrit : > > Hi all, > > After 5 months of work, I am now preparing to merge the new API and > implementation for Qt Multimedia back into the development branch. > > You can find the first iteration of a merge commit here: > https://codereview.qt-project.org/c/qt/qtmultimedia/+/351108 > > With this, Qt Multimedia is probably the module that is changing most between > Qt 5 and Qt 6. The reason for that is that we had large issues maintaining Qt > Multimedia during the Qt 5 lifetime, and never really got to a point where it > offered a consistent experience across all platforms. > > The hope is that we can change that for Qt 6. To make this possible, we have > changed not only parts of the public API, but completely redone its internal > architecture, especially how multimedia connects to the platform specific > backends. Apart from cleaning up the backend API and greatly simplifying it, > I also chose to make it private and remove the plugin architecture around it. > The backend is now selected at compile time, and we’re now only supporting > one backend per platform. > > The architectural cleanup lead to huge simplifications in the code base. The > module went from 140k LOC in 5.15 to 73k LOC in Qt 6, while keeping 90% of > the functionality we had in 5.15 and adding a few things that were missing > there. This should make it significantly easier to maintain and further > develop the module over the lifetime of Qt 6. > > Here’s the list of largest changes (copy from the commit log of the merge > commit above): > > * New QMediaDevices API to discover available input/output devices > and get notifications about changes > * New QMediaFormat API to query for supported codecs and file formats > * Refactored playback API, QMediaPlayer and playlist handling are > fully separated (and can be connected on the app level) > * Simplified QMediaPlayList API to use QUrl instead of the > QMediaContent/QMediaResource pair. > * Support for multiple audio/video/subtitle streams when playing back > media > * Better meta data support for audio/video files and individual streams > inside the file > * New QMediaCaptureSession API as a central class to handle media capture > * QCamera, QMediaEncoder and QMediaImageCapture are to be used together > with the capture session to define a capturing pipeline > * Removed QCameraFocus, QCameraExposure and QCameraImageProcessing > and merged those features into QCamera itself > * New QMediaEncoder class to connect to a capture session for encoding > captured audio/video. > * new QMediaEncoderSettings class to define the audio/video codecs and > file format to be used when encoding. > * Larger changes to the QML API, it is not symmetric to the C++ API, > and to the largest part simply uses the public C++ classes > * Rewritten video output pipeline. The new QVideoSink class is the > main interface between the media player/capture session and an > output surface. > * Built in support for rendering more uncompressed video formats > (RGB and YUV), both through QPainter and shaders > * Support for conversion of video frames in all formats to a QImage > * Support for HW accelerated rendering through RHI for the QML > VideoOutput element > * Support for HW accelerated decoding in many cases > * Cross platform support for audio decoding through QAudioDecoder > * The backend API is now private, so we can adjust it as needed to > implement new functionality > * Removed the QMediaService/QMediaObject abstraction > * Removed the plugin architecture for backends, backends are now > chosen at compile time > * Removed the QAudioProve/QVideoProbe APIs > * Removed QSound. Use QSoundEffect instead. > * Removed the Radio API > * Removed QAudioRecorder. Use QMediaCaptureSession/QMediaEncoder > or QMediaRecorder instead. > * Removed QAbstractVideoFilter. For filtering QML video, use > shader effects instead. > * Removed QAbstractVideoSurface. QVideoSink replaces it. > * QVideoSurfaceFormat has been renamed to QVideoFrameFormat. > * Significantly reduced the API surface of the backend API (from > ~40 to 13 classes) > * Fully rewritten gstreamer backend that only relies on base and good > plugins plus codecs. > * Windows uses WMF exclusively, added camera support through WMF > > There are still open issues and gaps in the implementation that need fixing, > but the code is now in a decent enough shape to merge it back to dev and > continue on that branch. We will however now have everything ready in Qt > Multimedia for the 6.2 feature freeze, and will be working with an exception > on this module. Especially the support for camera and media capture on > Windows and the Android backend still need more work. The gstreamer backend > for Linux and AVFoundation for iOS and macOS should be in a pretty decent > shape. QNX support is missing right now, and is planned after 6.2. > > Volker has done a smaller API review round already, but I’d now appreciate > more eyes on the code base, both on the API side and implementation. Let me > know what you think, and also what doesn’t work.
Hi Lars, Thanks for the updates. One feature that I've always waited for is the possibility to list and select audio/subtitle tracks from qml. Now that the feature is implemented in C++, it seems not much would be missing to also support this officially in QML. Is this planned ? Regards, -Arnaud > > Cheers, > Lars > > _______________________________________________ > Development mailing list > Development@qt-project.org > https://lists.qt-project.org/listinfo/development _______________________________________________ Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development
