New Polistream Software Release v3.7.0.74

BroadStream is pleased to announce a new software release for Polistream. Since the acquisition of Screen in late 2018 one of our goals has been to double-down on product improvements on all Screen products and you will begin to see new releases on a regular basis. Our two software teams in the UK and Croatia have successfully merged and now work together as one team.

This new release for Polistream provides an initial release of support for DVB-TTML, which is DVB’s new specification for text-based subtitles. The new TTML delivery specification will provide a transitional path to a common TTML subtitle format for both broadcast and Internet-delivered services. This means subtitles used for broadcast can be re-used later for video-on-demand services over DASH/CMAF.

DVB-TTML is especially suited for high resolution content like 4K and higher resolution programming that will be produced in the future. It is also closely aligned with other TTML-based systems including the EBU-TT-D specification, which was adopted for both DVB-DASH and HbbTV. You can learn more about DVB-TTLM here.

Initial Release of support for EBU-TT Live input and output uses Websockets. EBU‑TT can be used in a broadcasting environment to carry subtitles that are created in real time (“live” or from a prepared file) from an authoring station to an encoder prior to distribution, via intermediate processing units. EBU-TT Live Part 3 is carried over Websocket allowing input and output as Client or Server. You can learn more about EBU-TT here.

This new Polistream release includes:

• Support for text backgrounds (TTML tts:backgroundColor attribute)
• We’ve also added an EBU-TT-D text background selector on the UI Options page. This can be set to OFF, ON, or AUTO which enables backgrounds to be “forced off or on”, or it can be controlled by the box attributes in the subtitle.
• When backgrounds are “ON”, the background color is black by default at the start of each row and may be set to other colors by the “new background” control codes embedded in the subtitle text.

Customers with an active support contract can contact Support(at)BroadStream.com for access to this software upgrade.