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Camera on Tachyon

The Tachyon board supports a variety of camera configurations, including both CSI2 and V4L2 cameras.

  • Internal cameras (including those bundled with the Kickstarter campaign) are fully supported.
  • The Qualcomm chipset includes 4 CSI2 interfaces, with 2 available on the board.
  • V4L2-compatible USB cameras are supported and typically show up as /dev/video2.
  • The Cheese application is pre-installed on the desktop image for easy webcam testing.

Testing the Camera​

These commands assume you are running as root. You can configure proper permissions for video devices later.

1. Set Environment Variable​

Before launching graphical GStreamer applications as root, set the runtime directory:

export XDG_RUNTIME_DIR=/run/user/root

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  1. Display a Test Pattern

Show a test pattern on any connected display (HDMI or DSI):

gst-launch-1.0 videotestsrc ! videoconvert ! waylandsink async=true sync=false

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  1. Stream Live Camera Feed

Stream video from the internal camera to the display:

gst-launch-1.0 qtiqmmfsrc camera=0 name=qmmf ! video/x-raw ! videoflip method=clockwise ! waylandsink fullscreen=true

You can tweak parameters like rotation, resolution, and framerate as needed.

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  1. Record Video to Disk

Save H.264-encoded video from the camera to a file:

gst-launch-1.0 -e qtiqmmfsrc camera=0 name=qmmf \
! video/x-raw,format=NV12,width=640,height=480,framerate=30/1 \
! qtic2venc ! h264parse ! mp4mux ! queue \
! filesink location=/data/misc/camera/video_file_name_here.mp4

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  1. Capture JPEG Snapshot

Capture a still image (single frame) as a JPEG:

gst-launch-1.0 -e qtiqmmfsrc camera=1 name=qmmf \
! video/x-raw,format=NV12,width=640,height=480,framerate=30/1 \
! jpegenc ! multifilesink location=/data/misc/camera/snapshot.jpg

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V4L2 Camera Notes • V4L2 devices (e.g., USB webcams) typically appear at /dev/video2 or higher. • Use a tool like v4l2-ctl to inspect connected devices. • GStreamer commands using v4l2src are also supported for these devices.

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GUI Testing

For simple tests, launch the Cheese webcam application from the desktop environment:

cheese

No additional setup is required for most USB webcams and internal CSI cameras.