When giving a presentation over Zoom or a similar video conferencing tool, it is often useful to show the presentation screen inside a normal window. This makes it easier to check what is being presented, arrange windows on the desktop, and share only the intended content.
I used to do this with a virtual display driver and raiton. The virtual display acted as an additional monitor, and raiton displayed that monitor in a window. This setup worked, but after looking into it again, I found that ffplay, which is included with FFmpeg, can be a better alternative.
Purpose
The goal is simple: display a secondary or virtual monitor inside a window.
This is useful when presenting slides in PowerPoint or similar software. For example, PowerPoint can show the presentation on a second display, while ffplay shows that display as a window on the main desktop. That window can then be monitored or shared in Zoom.
Using ffplay Instead of raiton
The following command displays the second screen in a window:
ffplay -fflags nobuffer -flags low_delay -framedrop -f lavfi "ddagrab=output_idx=1:framerate=60,hwdownload,format=bgra,format=bgr0"
This uses FFmpeg’s ddagrab source to capture a desktop output and display it with ffplay.
In this command, output_idx=1 means that the second display is captured. If the target display is different, this number may need to be changed.
The options nobuffer, low_delay, and framedrop help reduce preview latency, which is important when using the window during a live presentation.
Performance
In my environment, raiton could display the virtual display at around 15 fps. With ffplay, I was able to display it at 60 fps.
This makes ffplay feel much smoother, especially when slides include animations, cursor movement, or other visual changes.
Virtual Display Driver
For the virtual display, I use ge9/IddSampleDriver.
This provides an additional display output on Windows. Presentation software can use that virtual display as if it were a real monitor, and ffplay can then show that display in a normal window.
Summary
ffplay can be used as a practical replacement for raiton when you want to preview or share a presentation display inside a window.
It requires only FFmpeg, works well with a virtual display driver, and can provide smoother output than raiton in this use case. For presentations over Zoom or similar tools, this is a simple and effective way to handle a separate presentation screen.
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