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This article mainly explains "how to use Qt audio and video development to achieve general screenshot screenshot", the content of the article is simple and clear, easy to learn and understand, now please follow the editor's ideas slowly in depth, together to study and learn "how to use Qt audio and video development to achieve general screenshot screenshot" bar!

I. Preface

For the callback video channel, screenshots only need to be saved directly on the parsed QImage object. For the handle form, different processing strategies need to be called. For example, vlc needs to pass in the save path with its own api interface function libvlc_video_take_snapshot, mpv kernel executes the screenshot-to-file command to pass in the path parameters, and ffmpeg needs to set the capture flag bit for real-time acquisition and parsing. If the screenshot flag bit is true, you need to change the QImage conversion mechanism to send the image instead of yuv data opengl drawing. Haikang's sdk can call the NET_DVR_CapturePicture function.

Generally speaking, screenshots are saved original images, and the corresponding resolution is also the original resolution, and there is no compression or proportional scaling, so the monitoring kernel of ffmpeg must be the most original captured image, not the final drawn image, because the drawn image is likely to have been scaled.

Sometimes there is a scenario that does not need the original image, but only the size of the current channel. In this case, you need to take screenshots of the current channel and take screenshots in the form of screenshots. In this way, you can take screenshots of OSD and other information set, which is equivalent to QQ screenshots. Qt itself provides the grabWindow method to take a screenshot of the form control with the specified handle, the static method QPixmap::grabWindow in the QPixmap class in Qt4 and the method in QApplication::primaryScreen () in Qt5.

II. Functional features

Supports multi-screen switching, full-screen switching, etc., including 1 "4" 6 "8" 9 "13" 16 "25" 36 "64 screen switching.

Support alt+enter full screen, esc exit full screen.

Custom message box + error box + inquiry box + prompt box in the lower right corner (including multiple formats).

17 sets of skin styles are changed at will, all styles are unified, including menus and so on.

The head dashboard mouse moves up to highlight, and eight directions are accurately identified.

The bottom screen toolbar (screen division switch + screenshot sound, etc.) is moved up to highlight.

You can change the logo+ Chinese software name + English software name in the upper left corner of the configuration file.

Encapsulated Baidu map, view switching, motion trajectory, equipment location, mouse press to obtain longitude and latitude and so on.

Support picture map, the device button can drag freely on the picture map to automatically save location information.

On Baidu Maps and Picture Maps, double-click the video to preview the camera real-time video.

Stack forms, each form is a separate qwidget, making it easy to write your own code.

Top right mouse button menu, can dynamically control the time CPU+ upper left corner panel + lower left corner panel + upper right corner panel + lower right corner panel show and hide, support to restore the default layout.

Toolbars can place multiple small icons and close icons.

The left side and the right side can be dragged and stretched, and the width and height position can be automatically remembered and restored after restart.

Double-click the camera node to automatically play the video, double-click the node to automatically add videos in turn, automatically jump to the next one, and double-click the parent node to automatically add all the videos under that node.

The camera node is dragged to the corresponding form to play the video, and the local file can be dragged to play directly.

The video screen form supports dragging and swapping and instant response.

Double-click the node + drag the node + drag the form to change the position, and the url.txt is automatically updated.

Support loading channel video playback from url.txt, automatically memorizing the video corresponding to the last channel, and automatically opening and playing after the software starts.

Lower right corner volume bar control, lose focus automatically hide, volume bar with mute icon.

Integrate Baidu online map and offline map, you can add the corresponding location of the device, automatically generate the map, support zooming and adding coverings and so on.

Drag the video out of the channel form to automatically delete the video.

The right mouse button can delete the current + all videos and take screenshots of current + all videos.

Video recorder management, camera management, you can add, delete, modify, import and export print information, and immediately apply new equipment information to generate a tree list without restarting.

In the pro file, you are free to open or load the map.

Video playback can be switched freely by two kernels, vlc+ffmpeg, both of which can be set in pro.

You can set 1 "4" 9 "16 screen polling, you can set the polling interval and the polling stream type, etc. Click the start polling button on the right side of the toolbar at the bottom of the main interface, and click stop polling again.

By default, the mouse pointer is automatically hidden without operation for more than 10 seconds.

Support onvif search equipment, support any onvif camera, including but not limited to Haikang Dahuayu Shitian Weiye Huawei and so on.

Support onvif pan control, can move the head camera up and down, including reset and focal length adjustment, etc.

It also supports sqlite, mysql, postsql and other databases.

Can save video, can be selected for storage or single file storage, optional storage interval.

The video stream communication mode tcp+udp can be set, and the video decoding can be set as speed priority, quality priority, balance and so on.

Can set hard decoding type, support qsv, dxva2, d3d11va and so on.

Opengl is used by default to draw video, ultra-low CPU resource consumption, support for yuyv and nv12 two formats to draw, very powerful.

Highly customizable, users can easily derive their own functions on this basis, supporting linux and mac systems.

Third, effect picture

4. The core code QImage FFmpegWidget::getImage () const {# ifdef opengl thread- > snap (); # endif return this- > image;} QPixmap FFmpegWidget::getPixmap () const {/ / takes screenshots in the form of screenshots. In this way, you can take screenshots of the set OSD and other information into # if (QT_VERSION grabWindow (winId (), 0,0, width (), height ()); # endif return pixmap } void VlcThread::snap (const QString & fileName) {if (vlcPlayer! = NULL) {libvlc_video_take_snapshot (vlcPlayer, 0, fileName.toUtf8 (). ConstData (), videoWidth, videoHeight);;} void MpvThread::snap (const QString & fileName) {if (mpvPlayer! = NULL) {command (QVariantList ())

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