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Version: Next

Updating SMIL playlist - PULL mode

Updating the Players​

To supply fresh content to a player, one needs to specify Refresh meta attribute in the first SMIL playlist loaded from the server. The syntax is as follows:

<smil>
  <head>
    <!-- How often to refresh the SMIL, values in SECONDS with optional expression -->
    <meta http-equiv="Refresh" content="60" expr="adapi-weekday()=4" onlySmilUpdate="true"/>
  </head>
  ...

</smil>

SMIL player is reaching the SMIL playlist URL and checking Last-modified header. Once you upload a new version of the playlist, it's recognized, downloaded, and played.

  • content - defines the check interval in seconds, mandatory
  • expr - limit the check interval based on expression, optional
  • onlySmilUpdate - with this options set to true, player will only check actual smil file for updates and not media specified within smil file

By using expr you can limit the time when signageOS SMIL Player checks for an update during selected time period, e.g. from 1am to 6am:

expr="compare(time(),'01:00:00')>0 and compare(time(), '6:00:00')<0"

Important: HEAD requests​

SMIL player is doing HEAD request for checking Last-modified instead of GET/POST. The reason is to save bandwidth.

If you are running into CORS issues, check that your CDN/storage have CORS set for HEAD requests as well.

If Refresh information is missing, default value (20 seconds) is used.

Source: a-smil.org