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Encoding
Configure subtitle

Configure subtitle encoding

Before you start: ensure you have configured a subtitle input stream.

  1. From the Encoding tab, go to the Subtitle encoding section.

  2. Click Add to create a new subtitle processing configuration or click to edit an existing one. The Subtitles encoding window displays.

  3. Select the Codec to define how metadata is processed:

    • Pass-through
    • DVB-Subtitles
    • DVB-Teletext
    • Closed caption CEA 608 (only valid with both IP TV export type and 25i/50p to 29.97i/59.94p frame rate conversion)
    • DVB-TTML (only valid with Internet TV export type)
    • DASHIF-TTML (only valid with Internet TV export type)

Possible values depend on subtitle type.

  1. Depending on the selected codec, specific parameters must be configured.

  2. Click Save and continue or Save and exit to save your changes.

  3. Add the conditioned metadata to the output stream (see Define the output stream composition).

Convert Teletext to Closed Caption

To convert Teletext to Closed Caption, follow these steps:

Add input subtile

From the Input tab, go to the Sources > Input streams selection > Subtitle ID section then Configure input subtitle selection by setting the Type to Teletext.

Check Video adjustment

Go to the Media processing tab then go to the Video processing > Video adjustment section and check that Frame rate conversion is set to 25i/50p to 29.97i/59.94p.

Check export type

Go to the Encoding tab then check that Export type is set to IPTV.

Configure subtitle encoding

Go to the Metadata encoding section to add and configure the subtitle encoding:

  1. Click the Add button then set the Codec to Closed caption CEA 608.

  2. Click the Add button then specify the input teletextMagazine, the Page and the destination CEA 608 Field.

  3. Click OK to validate.

Configure subtitle encoding

Go to the Video encoding section to configure the video encoding.

  1. Go to the Video encoding > Stream metadata setting section.

  2. Tick the Closed caption checkbox then in the Closed caption stream, select the stream created in Step #5.

  3. Click OK to validate.

Add the video stream related to the output

  1. Go to the Output tab.

  2. Go to the Output streams section, then click either the Add button (if no stream has been selected) or in the Actions column.

  3. Select the video stream that you configured in Step #6 that includes the closed caption.

  4. Click OK to validate. You should see the selected streams in the list of output streams.

Convert Teletext to TTML

To convert Teletext to TTML, follow these steps:

Add input subtile

  1. From the Input tab, go to the Sources > Input streams selection > Subtitle ID section and Configure input subtitle selection by setting the Type to Teletext.

Check export type

  1. Check that Export type is set to Internet TV.

Configure the subtitle encoding

  1. Click the Encoding tab then go to the Subtitle encoding section. Teletext subtitle has been added to the Encoding tab. By default Codec is set to Pass-through.

  2. Click to edit the subtitle encoding.

  3. Select the codec used to convert the subtitles, DVB-TTML. A new window let you configure the TTML parameters.

  4. Click Ok once done. You should get the following:

Add the subtitle stream to the output

  1. Click the Output tab.

  2. Go to the Output streams section, then click either the Add button (if no stream has been selected) or the edit button, in the Actions column.

  3. Tick the subtitle stream that you configured in the previous step.

  4. Click OK to validate. You should see the selected streams in the list of output streams.

Convert ARIB B24 to DVB-Teletext

Only available with MPEG-2 TS/UDP input type (or MediaComposer with MPEG-2 TS/UDP source only).

To convert ARIB B24 subtitles to Teletext, follow these steps:

Add an ARIB B24 subtitle at the input

  1. From the Input tab, go to the Sources > Input streams selection > Subtitle ID section.

  2. Click Add then set the Type to ARIB B24 and enter either the PID or Language of the subtitle. You should get the following:

Configure the subtitle encoding

  1. Click the Encoding tab then go to the Subtitle encoding section. ARIB B24 subtitle has been added to the Encoding tab. By default Codec is set to Pass-through.

  2. Click to edit the subtitle encoding.

  3. Select the codec used to convert the subtitles, DVB-Teletext. You should get the following:

Add the subtitle stream to the output

  1. Click the Output tab.

  2. Go to the Output streams section, then click either the Add button (if no stream has been selected) or the edit button, in the Actions column.

  3. Tick the subtitle stream that you configured in the previous step.

  4. Click OK to validate. You should see the selected streams in the list of output streams.

Check that ARIB B24 subtitles are present

. You can check that ARIB B24 subtitles are present in the input by displaying statistics.

. You can check that ARIB B24 subtitles are present in the output by opening the output stream in a player.

Convert DVB-Sub to DVB-Teletext using OCR

This feature relies on an open-source OCR (Optical Character Recognition) engine that extracts printed or written text from images. Once converted to Text, the subtitles are converted to DVB-Teletext.

To convert DVB-Subtitles to DVB-Teletext, follow these steps:

Add a DVB subtitle at the input

  1. From the Input tab, go to the Sources > Input streams selection > Subtitle ID section.

  2. Click Add then set the Type to DVB-Subtitles and enter either the PID or Language of the subtitle. You should get the following:

Configure the subtitle encoding

  1. Click the Encoding tab then go to the Subtitle encoding section. DVB subtitle has been added to the list of subtitles. By default Codec is set to Pass-through.

  2. Click to edit the subtitle encoding.

Usually, there is no need to set the Forced language field because the language is directly retrieved from the input DVB Subtitles. If the language is not set or is wrong in the input DVB subtitle descriptor, it can be set by the "Forced language" field.

  1. Select the codec used to convert the subtitles, DVB-Teletext. You should get the following:

Add the subtitle stream to the output

  1. Click the Output tab.

  2. Go to the Output streams section, then click either the Add button (if no stream has been selected) or the edit button, in the Actions column.

  3. Tick the subtitle stream that you configured in the previous step.

  4. Click OK to validate. You should see the selected streams in the list of output streams.

Check the average OCR confidence

You can display statistics to check the average OCR confidence (in the range 0-100) on the last converted subtitle.

Check that DVB subtitles are present

You can check that DVB subtitles are present in the output by opening the output stream in a player.

Configure audio encodingConfigure subtitle burn-in