Read video in a thread

Module XML file: video_thread.xml

Only for Linux devices. To be used in other modules for further processing (e.g. opticflow, QR code, streaming).

• Possibility to save an image(shot) on the internal memory (JPEG, full size, best quality)

Example for airframe file

This example contains all possible configuration options, not all of them are mandatory!

<modules>
  <load name="video_thread.xml">
    <define name="VIDEO_THREAD_CAMERA" value="bottom_camera|front_camera" />
    <define name="VIDEO_THREAD_FPS" value="4" />
    <define name="VIDEO_THREAD_SHOT_PATH" value="/data/video/images" />
    <define name="VIDEO_THREAD_DEVICE" value="/dev/video1" />
    <define name="VIDEO_THREAD_DEVICE_VIDEO_WIDTH" value="1280" />
    <define name="VIDEO_THREAD_DEVICE_VIDEO_HEIGHT" value="720" />
    <define name="VIDEO_THREAD_DEVICE_BUFFERS" value="10" />
  </load>
</modules>

Module configuration options

Define Options

• name: VIDEO_THREAD_CAMERA value: bottom_camera|front_camera
  Description: which camera video config to use
• name: VIDEO_THREAD_FPS value: 4
  Description: Video stream frame rate
• name: VIDEO_THREAD_SHOT_PATH value: /data/video/images
  Description: Path where the images should be saved
• name: VIDEO_THREAD_DEVICE value: /dev/video1
  Description: The video device to capture from (only if VIDEO_THREAD_CAMERA is not defined)
• name: VIDEO_THREAD_DEVICE_VIDEO_WIDTH value: 1280
  Description: Video capture width (only if VIDEO_THREAD_CAMERA is not defined)
• name: VIDEO_THREAD_DEVICE_VIDEO_HEIGHT value: 720
  Description: Video capture height (only if VIDEO_THREAD_CAMERA is not defined)
• name: VIDEO_THREAD_DEVICE_BUFFERS value: 10
  Description: Amount of V4L2 image buffers (only if VIDEO_THREAD_CAMERA is not defined)

Module functions

Init Functions

These initialization functions are called once on startup.

• video_thread_init()

Periodic Functions

These functions are called periodically at the specified frequency from the module periodic loop.

• video_thread_periodic()
  • Frequency in Hz: 1
  • Autorun: TRUE
    Periodic function automatically starts after init.
  • Start function: video_thread_start()
    Executed before the periodic function starts.
  • Stop function: video_thread_stop()
    Executed after the periodic function stops.

Files

Header Files

The following headers are automatically included in modules.h

• video_thread.h

Source Files

• modules/computer_vision/video_thread.c
• modules/computer_vision/cv.c
• modules/computer_vision/lib/vision/image.c
• modules/computer_vision/lib/v4l/v4l2.c
• modules/computer_vision/lib/encoding/jpeg.c
• modules/computer_vision/video_thread_nps.c
• modules/computer_vision/cv.c
• modules/computer_vision/lib/vision/image.c
• modules/computer_vision/lib/encoding/jpeg.c

Raw video_thread.xml file:

<!DOCTYPE module SYSTEM "module.dtd">

<module name="video_thread" dir="computer_vision">
  <doc>
    <description>
      Read video in a thread.
      Only for Linux devices.
      To be used in other modules for further processing (e.g. opticflow, QR code, streaming).

      - Possibility to save an image(shot) on the internal memory (JPEG, full size, best quality)
    </description>
    <define name="VIDEO_THREAD_CAMERA" value="bottom_camera|front_camera" description="which camera video config to use"/>
    <define name="VIDEO_THREAD_FPS" value="4" description="Video stream frame rate"/>
    <define name="VIDEO_THREAD_SHOT_PATH" value="/data/video/images" description="Path where the images should be saved"/>
    <define name="VIDEO_THREAD_DEVICE" value="/dev/video1" description="The video device to capture from (only if VIDEO_THREAD_CAMERA is not defined)"/>
    <define name="VIDEO_THREAD_DEVICE_VIDEO_WIDTH" value="1280" description="Video capture width (only if VIDEO_THREAD_CAMERA is not defined)"/>
    <define name="VIDEO_THREAD_DEVICE_VIDEO_HEIGHT" value="720" description="Video capture height (only if VIDEO_THREAD_CAMERA is not defined)"/>
    <define name="VIDEO_THREAD_DEVICE_BUFFERS" value="10" description="Amount of V4L2 image buffers (only if VIDEO_THREAD_CAMERA is not defined)"/>

  </doc>
  <settings>
    <dl_settings>
      <dl_settings name="video">
        <dl_setting var="video_thread.take_shot" min="0" step="1" max="1" shortname="take_shot" module="computer_vision/video_thread" handler="take_shot">
          <strip_button name="Videothread Save Jpeg" icon="digital-camera.png" value="1" group="cv"/>
        </dl_setting>
        <dl_setting var="video_thread.fps" min="1" step="1" max="25" shortname="fps" module="computer_vision/video_thread" param="VIDEO_THREAD_FPS"/>
      </dl_settings>
    </dl_settings>
  </settings>

  <header>
    <file name="video_thread.h"/>
  </header>

  <init fun="video_thread_init()"/>
  <periodic fun="video_thread_periodic()" freq="1" start="video_thread_start()" stop="video_thread_stop()" autorun="TRUE"/>
  <makefile target="ap">

    <file name="video_thread.c"/>
    <file name="cv.c"/>

    <!-- Include the needed Computer Vision files -->
    <define name="modules/computer_vision" type="include"/>
    <file name="image.c" dir="modules/computer_vision/lib/vision"/>
    <file name="v4l2.c" dir="modules/computer_vision/lib/v4l"/>
    <file name="jpeg.c" dir="modules/computer_vision/lib/encoding"/>

    <!-- Random flags -->
    <define name="__USE_GNU"/>
    <flag name="LDFLAGS" value="lrt"/>
    <flag name="LDFLAGS" value="static-libgcc"/>
  </makefile>
  <makefile target="nps">
    <file name="video_thread_nps.c"/>
    <file name="cv.c"/>
    <define name="modules/computer_vision" type="include"/>
    <file name="image.c" dir="modules/computer_vision/lib/vision"/>
    <file name="jpeg.c" dir="modules/computer_vision/lib/encoding"/>
    <flag name="LDFLAGS" value="lpthread"/>
  </makefile>
</module>