Awesome
Screencapture
This repository has been moved to https://github.com/kirides/go-d3d
Motivation
I wanted to learn more about COM
interop with Go and create a somewhat usable screen sharing tool
Libaries used
This application uses D3D11 IDXGIOutputDuplication
to create a somewhat realtime desktop presentation
github.com/mattn/go-mjpeg
for mjpeg streaminggithub.com/kbinani/screenshot
for comparison with GDIBitBlt
(slightly modified source, to support re-usingimage.RGBA
)golang.org/x/exp/shiny/driver/internal/swizzle
for faster BGRA -> RGBA conversion (see shiny LICENSE)github.com/pixiv/go-libjpeg/jpeg
for fast jpeg encoding- enable with
go build -tag jpegturbo
- enable with
Demo
Just build the application and run it.
It should serve all your monitors on an URL like http://127.0.0.1:8023/watch?screen=N
where screen=N <- N
is the monitor index, starting at zero (0
).
By changing the lines in cmd/example/main.go
regarding the streaming, you can switch between GDI BitBlt
or IDXGIOutputDuplication
// ...
framerate := 10
for i := 0; i < n; i++ {
// ...
// streamDisplay(ctx, i, framerate, stream) // <= USE GDI BitBlt
streamDisplayDXGI(ctx, i, framerate, stream) // <= USE IDXGIOutputDuplication
// captureScreenTranscode(ctx, i, desiredFps)
http.HandleFunc(fmt.Sprintf("/mjpeg%d", i), stream.ServeHTTP)
}
// ...
screen recording with ffmpeg
The code contains the function captureScreenTranscode
which allows you to record the
selected screen directly into ffmpeg and transcode it to h264 in an mp4 container.
Performance
Performance is not optimized to 100%, there are still thing that could be improved.
- only copying the dirty-rectangles (less GPU<->CPU communication)
- faster swizzle implementation using AVX/2 (less time for converting the BGRA texture)
- profile ... profile ... profile
Overall the current implementation is about 2-5x faster than GDI BitBlt
(depending on the resolution,
the higher the bigger the difference) and uses a lot less resources for cases where there arent any changes to the screen.
app.manifest
To make use of IDXGIOutput5::DuplicateOutput1
, an application has to provide support for PerMonitorV2
DPI-Awareness (Windows 10 1703+)
This is usually done by providing an my-executable.exe.manifest file either next to the executable, or as an embedded resource.
In this application there are calls to IsValidDpiAwarenessContext
and SetThreadDpiAwarenessContext
which circumvent the requirement.