SysDVR 6.0

SysDVR es una modulo experimental del sistema (sysmodule) para Switch que nos permite capturar el juego que se está ejecutando a un PC.

Existen dos versiones, una que hace el stream vía USB y otra que lo hace a través de la red (TCP). Por ahora no es posible usar las dos al mismo tiempo.

Usar mpv player es la opción más recomendada para capturar, así como cualquier otro reproductor que tenga soporte para stream h264 en raw vía tcp o stdin, aunque habría que configurarlo manualmente.

Limitations

• Video quality is fixed to 720p @ 30fps with h264 compression (hardware limit)
• Audio quality is fixed to 16bit PCM @ 48kHz stereo. Not compressed
• Only works on games that have video recording enabled (aka you can long-press the capture button to save a video)
• Video and audio are two different streams, they're likely to desync as they require two different player instances. Vlc does support a secondary audio stream but i didn't manage to get it working properly.
• Only captures game output. System UI, home menu and homebrews running as applet won't be captured
• Video feed is not realtime, there will always be a minimum of ~1 second of delay.
• Stream quality depends heavily on the environment, bad usb wires or low wifi signal can affect it significantly.
• Stream quality is also affected by software configuration, more details at the bottom.
• USB streaming is not available when docked
• Requires firmware >= 6.0.0

Clearly with these limitations this sysmodule doesn't allow "remote play" and does not replace a capture card.

Usage

Setting up the sysmodule

The provided builds already contain the correct file structure, you should just be able to extract them to your sd card.
To remove the sysmodule just delete the atmosphere/titles/00FF0000A53BB665 folder from your sd card.
CFWs other than atmosphere should work but i won't provide support for them.

Network streaming

This is the easiest way to stream, In this mode the sysmodule is completely standalone, you should be able to play the video stream just by running mpv tcp://<switch ip address>:6666 --no-correct-pts --fps=30 and mpv tcp://<switch ip addr>:6667 --no-video --demuxer=rawaudio --demuxer-rawaudio-rate=48000 for audio.
When using network streaming it's not recommended to stream both audio and video at the same time as it may cause slowdowns. In general network streaming has more lag and delay compared to USB, it is worth the time to set it up, especially for gameplay recording.

USB streaming

To stream via usb you need the UsbStream program, it's built using dotnet core 3.0 and is compatible with linux as well.
First of all you should make sure your drivers are set up correctly (only the first time) :

Driver setup on windows

On windows you may get the device not found or unsupported driver errors or very bad performance on the stream, in this case you may have the wrong driver set up, download zadig and install the libusb-win32 driver for the "Nintendo Switch" device. This won't interfere with other application that communicate with the switch via usb as this sysmodule uses a different product id.

Driver setup on linux

On linux you may have errors about loading the libusb-1.0 library, this happens when the file name is different than the one expected by dotnet, you can make a symlink as described on the LibUsbDotNet repo:
sudo find / -name "libusb-1.0*.so*" and then

cd /lib/x86_64-linux-gnu
sudo ln -s libusb-1.0.so.0 libusb-1.0.so

(Example commands, change the paths with the one you find on your pc)

Streaming

UsbStream supports three streaming modes:

• mpv or stdin : pipes the received data directly to a video player via stdin, this will use no caching so you'll have low delay but it may lag. Using mpv will automatically add the needed configuration for mpv, stdin will require you to type the args to pass to the player
• tcp : opens a tcp server so players can connect to it and use their own caching mechanism to remove or reduce lag (at the price of an higher delay)
• file : writes the received data directly to a file so it can be converted to a common format later.

Launch UsbStream like this: UsbStream video <streaming mode> <arg> audio <streaming mode> <arg>
When using mpv the arg is the mpv executable (.com file on windows) path, you have to repeat it twice if using both streams.

The tcp option requires a free port number and the file option the output file path.

To disable a stream just omit the name and its fields.

Example commands:

UsbStream audio mpv C:/programs/mpv/mpv : Plays audio via mpv located at C:/programs/mpv/mpv, video is ignored
UsbStream video mpv ./mpv audio mpv ./mpv : Plays video and audio via mpv (path has to be specified twice)
UsbStream video tcp 1337 audio file C:/audio.raw : Streams video over port 1337 while saving audio to disk

Note that on windows you should use the mpv.com file and not mpv.exe, omitting the extension will automatically use the right one Launching UsbStream without any parameter will display more options and examples.
To connect to the tcp streams you can use: mpv tcp://localhost:<video port> --no-correct-pts --fps=30 for video and mpv tcp://localhost:<audio port> --no-video --demuxer=rawaudio --demuxer-rawaudio-rate=48000 for audio

Tips
To get the most out of this sysmodule you have to do a lot of testing to find the best configuration that works for you, here are some tips and answers to common issues :

• If the video stream doesn't start immediately try moving the camera around in the game, to display something the video player needs to acquire a video keyframe first
• If the stream is very poor try a different usb cable and driver with zadig, for network stream bring your console closer to the router, try using a lan adapter or windows' own hotspot mode.
• An usb 3 wire is slightly better than usb 2, but both should work.
• Quality also depends on the cpu utilization of the game you're running, OC can improve performances.
• Using cache will reduce lags at the cost of an higher delay, for mpv it's on by default (except when using usb stream with mpv mode), if you want to try without it the command line arg for mpv is --cache=no --cache-secs=0. There's a lot of room for experimenting here, try different values to find the combination that works best for you.
• If using no caching when the screen goes full black or white (eg loading screens) it may cause some desync and the stream will start to drop frames, eventually it will fix by itself but it could take some time, the fastest solution is to open the home menu for a few seconds and then resume the game, for usb stream you can try setting the --desync-fix flag (this will introduce glitches).

Known issues/TODOs

• Memory usage is kept as low as possible (512K for usb ver, 3MB for network) but running this with many other sysmodules, or ones particulary heavy like sysftpd will not work or hang your console on boot.
• The usb version stops working when launching another homebrew that requires usb access like nxmtp or goldleaf.
• Implement a key combination to reinitialize usb when this happens (?)
• Merge the usb and network stream versions and make an homebrew app to toggle between the two
• Improve automatic desync detection and fix for UsbStream

Credits

• Everyone from libnx and the people who reversed grc:d and wrote the service wrapper, mission2000 in particular for the suggestion on how to fix audio lag.
• mtp-server-nx for their usb implementation

by exelix11.