go2rtc/internal/v4l2

V4L2

What you should to know about V4L2:

• V4L2 (Video for Linux API version 2) works only in Linux
• supports USB cameras and other similar devices
• one device can only be connected to one software simultaneously
• cameras support a fixed list of formats, resolutions and frame rates
• basic cameras supports only RAW (non-compressed) pixel formats
• regular cameras supports MJPEG format (series of JPEG frames)
• advances cameras support H264 format (MSE/MP4, WebRTC compatible)
• using MJPEG and H264 formats (if the camera supports them) won't cost you the CPU usage
• transcoding RAW format to MJPEG or H264 - will cost you a significant CPU usage
• H265 (HEVC) format is also supported (if the camera supports it)

Tests show that the basic Keenetic router with MIPS processor can broadcast three MJPEG cameras in the following resolutions: 1600х1200 + 640х480 + 640х480. The USB bus bandwidth is no more enough for larger resolutions. CPU consumption is no more than 5%.

Supported formats for your camera can be found here: Go2rtc > WebUI > Add > V4L2.

RAW format

Example:

streams:
  camera1: v4l2:device?video=/dev/video0&input_format=yuyv422&video_size=1280x720&framerate=10

Go2rtc supports built-in transcoding of RAW to MJPEG format. This does not need to be additionally configured.

ffplay http://localhost:1984/api/stream.mjpeg?src=camera1

Important. You don't have to transcode the RAW format to transmit it over the network. You can stream it in y4m format, which is perfectly supported by ffmpeg. It won't cost you a CPU usage. But will require high network bandwidth.

ffplay http://localhost:1984/api/stream.y4m?src=camera1