Add Scanner AV Streaming on VM in Unraid

Scanner-AV-Streaming-on-VM-in-Unraid.md

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+This article will go through my setup for hosting a scanner A/V stream from an Ubuntu Server VM.
+
+#Stack
+* UnRAID 6.12 running on an old Alienware desktop
+* Ubuntu 20.04.6 LTS Virtual Machine
+* ALSA
+* ffmpeg
+* mediamtx
+* Radioshack Pro-651 (any scanner with headphone-out should work)
+* Logitech C90 webcam
+
+#Guide
+##Assign devices to VM
+(This is only necessary if your sound card is PCI-connected)
+1. In UnRAID go to Tools -> System Devices
+2. Check the box(ex) for the IOMMU group(s) for your audio card
+3. Reboot the server
+
+##Set up the VM
+1. Download Ubuntu Server ISO to UnRAID server
+2. Create an Ubuntu VM in UnRAID
+* Pass through a few CPU cores, at least to start with, this will make installation faster
+* Choose 2048-4096MB min ram, at least. Again can be scaled back after installation
+* 10GB vdisk should be enough, 20GB is what I used.
+* Leave graphic card as is, you'll need VNC to complete the initial installation
+* Assign the sound card to the VM
+* Assign the USB webcam to the VM
+3. Start up the VM and proceed through installation of Ubuntu Server
+4. (Optional) Shutdown the VM and adjust the specs back to minimal (1G RAM, 1-2CPU cores)
+
+##Set up the Software Stack
+1. Run these commands
+```
+sudo apt update && sudo apt upgrade -y
+sudo apt install ffmpeg
+wget https://github.com/bluenviron/mediamtx/releases/download/v1.8.4/mediamtx_v1.8.4_linux_amd64.tar.gz
+tar -xvf mediamtx_v1.8.4_linux_amd64.tar.gz
+sudo mv mediamtx /usr/local/bin/
+```
+2. Edit mediamtx.yml and remove the `paths:` at the end, replacing with:
+```
+paths:
+  scanner:
+    source: publisher
+    runOnInit: ffmpeg -f v4l2 -i /dev/video0 -f alsa -i hw:0 -c:v libx264 -preset veryfast -tune zerolatency -pix_fmt yuv420p -f rtsp rtsp://localhost:8554/scanner
+```
+
+### Paths Section:
+- **paths**: This section contains the definitions for different streaming paths.
+  - **scanner**: This is the name of the path. You can name it whatever makes sense for your use case, such as `scanner`, `camera`, or `stream`.
+
+### Path Configuration:
+- **source: publisher**: This specifies that the stream for this path will be published by an external source. In this case, the source is the FFmpeg command specified in `runOnInit`.
+- **runOnInit**: This directive tells MediaMTX to run the specified command when the server starts. The command provided here will initialize the stream.
+
+### FFmpeg Command Explanation:
+- **ffmpeg**: This is the command-line tool used to handle multimedia data.
+- **-f v4l2 -i /dev/video0**: This tells FFmpeg to use the Video4Linux2 (v4l2) input format to capture video from the device `/dev/video0`, which is your USB webcam.
+- **-f alsa -i hw:0**: This specifies the ALSA input format to capture audio from the device `hw:0`.
+- **-c:v libx264**: This sets the video codec to H.264 using the `libx264` encoder.
+- **-preset veryfast**: This option sets the encoding preset to `veryfast`, balancing compression efficiency and encoding speed.
+- **-tune zerolatency**: This tuning option minimizes latency, which is crucial for real-time streaming.
+- **-pix_fmt yuv420p**: This sets the pixel format to `yuv420p`, which is widely compatible with most players and devices.
+- **-f rtsp rtsp://localhost:8554/scanner**: This sets the output format to RTSP and specifies the RTSP URL where the stream will be available, in this case, `rtsp://localhost:8554/scanner`.
+
+
+
+This configuration sets up MediaMTX to serve RTSP and HLS streams, with the `scanner` path specifically set up to capture and stream video and audio using FFmpeg.