SReview

This SReview, a video review system. It takes input files, stores their lengths in a database, combines those lengths and their starttime with a schedule it has of an event to see which talks are fully recorded, and creates a preview. After that, magic happens, and eventually a fully transcoded quality video rolls out of the system.

Note that while SReview has been used in production for FOSDEM 2017 and DebConf 2017, there is still some missing functionality in some areas. Patches welcome! :-)

States

SReview is fairly minimalistic; it tries to assume as little as possible about video workflow. There are, however, state machines that you should be aware of. First, there is the main state:

waiting_for_files
cutting
generating_previews
notification
preview
transcoding
uploading
done
broken
needs_work
lost

Next, there is the job state:

waiting
scheduled
running
done
failed

Every talk is in one of the main states as well as in one of the job. The following list explains what each of the main states means:

• waiting_for_files: no files (or not all of them) have been found as of yet. Talks should initially be in this state.
• cutting: the cut_talk script
• generating_previews: the previews script
• notification: a notification needs to be sent to the user responsible for reviewing the talk. This may be the speaker, or someone else.
• preview: the notification was sent. This talk is now ready for review by a human being (the webinterface is necessary for this step).
• transcoding: the transcode script is running, or scheduled to start.
• uploading: the files are being uploaded.
• done: the talk has been fully completed, all files should be published.
• broken: SReview will not automatically switch a talk to this state, but it can be used to mark talks that are lost forever and should not be considered anymore.
• needs_work: Refinement of broken. Can be used by an administrator to mark recordings that need larger amounts of work, but that may be fixed eventually.
• lost: Refinement of broken. Can be used by an administrator to confirm that a recording is broken and cannot be usefully released.

The job states, then, mean:

• waiting: it's waiting for the dispatch script to do something.
• scheduled: the script was picked up by the dispatch script, and has been put into the job scheduler's queue. If a slot is available, it will be started almost immediately; if not, it may need to wait until that's done.
• running: the script is now active and running.
• `done : the script finished successfully
• failed: the script did not finish successfully (note: when that hapens, it doesn't always go into this state, currently).

Components

SReview consists of two major components: a webinterface (written in Perl with Mojolicious), and a backend which consists of another set of perl scripts.

To run the webinterface in a test environment, copy the config.pl.template file in the web directory to config.pl, edit it, run "./sreview daemon", and browse to the URL given. To run the webinterface in production, see Mojo::Server::Hypnotoad (or some of the other guides over there).

To run the backend, it is recommended that you install gridengine first. In theory, the backend should work without gridengine, but that is not tested. Additionally, you will then need to run a dispatcher per CPU, rather than having just one dispatcher in the whole network (which is annoying).

Once gridengine has been installed, copy the config.pl.template file in the scripts directory to config.pl, edit it, and run perl dispatch.

If you want to modify the output formats, you should edit the transcode script where you can add and/or remove ffmpeg command lines.

If you want to modify the look and feel of the webinterface, you should edit the files in the web/templates directory.

If you have any issues with SReview, please file an issue (or better yet, a pull request) on the github issue tracker.

Further reading

See the documentation