Screencast on Sculpt OS

January 10 2020 by Alexander Böttcher

From time-to-time the screen cast support on Genode pops up. Martin successfully ported avconv and demonstrated it back then in 2016. In the event of Sculpt OS, I lately had the chance to update the port and integrate it with Sculpt OS in form of packages ready for use. The following instructions will guide you through the setup. Additionally a short video recorded running on Sculpt is available.

In order to run the screen cast version of Sculpt OS, you will need to download the experimental branch alex-ab/sculpt_avconv_19_11 and build the Sculpt image yourself. Clone

 git clone https://github.com/alex-ab/genode
 cd genode
 git checkout sculpt_avconv_19_11

and adjust to the rest of the instructions for building the boot image and/or watch the short video about building the Sculpt OS image.

After booting your new sculpt image, you can find the avconv tool via

 +
   -> Depot
      -> alex-ab
        -> Experimental
          -> avconv
          -> avplay

On startup of avonv you will have to connect to a Framebuffer service, choose the raw framebuffer access. Additionally, the avonv component needs a storage location to save the recording. When started successfully, the avconv tool will create a file named out.avi and will record everything you are now doing. You may stop avconv by removing it from the component graph.

If you now want to watch your recording, you may do so by using the avplay package. The avplay component expects a file named mediafile, a GUI service and an audio service. As shown in the video, use the inspect feature to mount the file system and make a copy of the out.avi file and name it mediafile. After installing an audio driver, e.g. shown in the video, you can start avplay. After you connected it to all required services, you may watch your recording finally.

As final note, please consider this version of the Sculpt image as experimental. You may use all provided packages without further changes, but don't use it for productive/daily use

- just for recordings ;-).

The libav, avconv and avplay sources are available in my genode-world repository.

Known issues

If your avconv component does not start and complains about a missing 'vfs_lxfb.lib.so" ROM, then you may have in your backup/restored config/deploy a line about vfs.lib.so. Comment the line out, save your config and reboot your image.

  <common_routes>
    <service name="ROM" label_last="ld.lib.so">  <parent/> </service>
    <!-- <service name="ROM" label_last="vfs.lib.so"> <parent/> </service> -->
    <service name="ROM" label_last="init">       <parent/> </service>
    ...