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This article introduces the relevant knowledge of "what is Qt universal hard decoding". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

I. Preface

Hardware decoding is a scheme proposed by graphics chip manufacturers to decode video streams with GPU resources, as opposed to soft solutions, that is, the traditional scheme using CPU to undertake the decoding work; the advantages are high efficiency, low power consumption and low thermal power consumption, while the disadvantages are lack of strong support (including filters, subtitles, etc.), great limitations (for example, energy-saving failure cnq of PC after hardware decoding, etc.), and the setting is more complex. The hardware needs hardware decoding module, related driver cooperation, appropriate playback software and correct setting of playback software. Without one, the hardware decoding function can not be turned on. The mainstream hardware decoding scheme is introduced by Intel, AMD-ATI and Nvdia.

At present, mainstream players support hard decoding, and players without hard decoding are all rogues. Now more and more 2K, 4K or even 8K HD videos, without hard decoding and only soft decoding, will consume a lot of CPU resources, which is very undesirable, and need to be specially handed over to GPU to draw and decode. This can greatly reduce the pressure on CPU, so that CPU can do other work, previously written in the video surveillance system. On the use of excellent decoding and GPU drawing, do not use these two are all empty talk, simply can not bear 64-channel real-time display, vlc, ffmpeg, mpv must be perfect support for hard decoding, of which vlc and mpv settings are the simplest, Haikang sdk does not provide hard decoding by default, the official manual has written to hard decoding library, it is estimated that additional contact to get.

Hard decoding processing in different kernels

Vlc hard decoding: 1.1 set parameters by calling libvlc_media_add_option: parameters supported by avcodec-hw=auto 1.2: none auto any d3d11va dxva2

Ffmpeg hard decoding: 2.1 call av_hwdevice_find_type_by_name to find hard decoding automatically according to name 2.2 call find_fmt_by_hw_type to find the corresponding hard decoding format 2.3callback videoCtx- > get_format = get_hw_format decoder format assignment for hard decoding 2.4call av_hwdevice_ctx_create to create hard decoding device 2.5call avcodec_send_packet avcodec_receive_frame decoding number According to 2.6call av_hwframe_transfer_data to convert hard-decoded data 2.7. supported parameter: none qsv cuvid d3d11va dxva2

Mpv hard decoding: 3.1. parameter supported by calling mpv_set_option to set parameter hwdec 3.2: none auto any d3d11va dxva2

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 bool FFmpegThread::initHWDeviceOther () {# ifdef hardwarespeed / / automatically looks for hard decoding by name QByteArray hardwareData = hardware.toUtf8 (); enum AVHWDeviceType type = av_hwdevice_find_type_by_name (hardwareData.data ()); qDebug ()

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