Appnotes

Encoding OP-47 Teletext

Last Updated June 17, 2021

Introduction

EEG's SDI closed caption encoders default to outputting captions in CEA-608 and CEA-708 formats, which are used throughout North America. However, with a few simple configuration changes, they can encode captions as OP-47/Teletext for use in Europe, Australia, and other regions.

Configuring Output Format

In order to configure your EEG encoder to output OP-47/Teletext data, browse to its web portal by entering its IP address into your web browser. Near the bottom of the page, you will see a version number. If you are running version 0.1.25 or newer, you will see the "CC Output Format" selector at the bottom of the list of settings:

If it is not already selected, choose the "OP-47" option. Your encoder will then output OP-47/Teletext captions, recognizable on a waveform monitor or other VANC monitoring device with DID/SDID 0x4302. Units with web portal software versions 0.1.23 or 0.1.24 will instead display this selector as "Locale", in which case the correct option to choose will be "Australia". If neither of these selectors is shown, please contact EEG Support to obtain an upgrade for your encoder.

Changing the Teletext Page Settings

By default, EEG encoders configured for OP-47/Teletext output will use a Teletext page setting of 801 for the primary caption channel and will not output data for any other Teletext pages. If you would like to change the primary Teletext page or output Teletext data for multiple languages, you can do so via the Startup Settings Editor. In the following screenshot, the encoder is set to encode the primary caption channel (represented by the "F1" argument) on Teletext page 888 (common in the UK) and the secondary caption channel on Teletext page 889:

After entering one or more of these C <page> <channel> commands into the Startup Settings Editor, please make sure to click Save or, if you would like the settings to take effect before the next time you reboot your encoder, Save and Apply Immediately.

Decoding via Auxiliary Output

If your EEG encoder has an auxiliary output that supports open caption decoding, such as the HD492 or AV650, you will need to set it to decode "CC1", rather than the default of "S1", in order to see your primary-language open captions. In order to do this via the unit's web portal, modify the following setting:

Alternatively, you can also modify this setting via the front-panel LCD menu, via Decoder Setup -> Set HD Service.