Switch Frame Tap 0.7.21.1 streams a CFW Switch to your PC over USB-C at up to 1080p60, no capture card
This Atmosphère module sends video and sound to Windows, Linux, macOS or Android over a cable or the network, with MP4 recording and a webcam mode. It works on firmware 21 to 23, though USB only works in handheld mode.
A capture card inside the console
Switch Frame Tap, by TomasUribe, is a GPL-2.0 system module for Atmosphère. It comes with a manager app on the console, an overlay, and viewers for Windows, Linux, macOS and Android, including Android TV. Besides watching the game, you can record to MP4, grab screenshots or use the picture as a webcam. It builds on earlier work such as exelix11's SysDVR.
Version 0.7.21.1 came out on November 3 and fixes game launches from SwitchU. The releases just before it were betas, several of them not yet tested on a console.
Cable or network
USB-C only works in handheld mode, so docked play has to go over the network. Handheld reaches 720p60, or 1080p60 if you add ReverseNX-RT and SaltyNX, an option limited to official games. The author measures 45 to 60 ms of latency, with about 58 fps in Mario Kart 8 Deluxe and 29 in Breath of the Wild.
There are limits: one viewer at a time, no sound on the HOME menu, and some homebrew can't be streamed.
What you need
You need Atmosphère. The project lists firmware 21 to 23, and users report it running on 23.0.1 with Atmosphère 1.12. To install, unzip the package to the root of the microSD and reboot. Windows needs a one-time WinUSB driver setup with Zadig, and on macOS you have to right-click to open it because it isn't signed by Apple.
The author calls it experimental, tested on few consoles, and warns that a bug can freeze the console.
