Including audio accessibility data
In the audio in CMAF Ingest or Microsoft Smooth output groups, you can include accessibility data. This data describes the type of accessibility that the encode represents. For example, an audio track might actually be a spoken description of what's happening in the video. Accessibility data is also known as accessibility signaling.
MediaLive also includes a feature for including accessibility data in captions. For more information, see Including accessibility data in captions.
Supported accessibility data standards
MediaLive supports the following styles of accessibility data.
| Accessibility data style | Specification | CMAF Ingest | Microsoft Smooth |
|---|---|---|---|
| DASH role audio | DASH role scheme (ISO/IEC 23009-1:2022(E)) | Yes | Yes |
| DVB DASH accessibility |
ETSI TS 103 285 Technical Specification, V1.3.1 (2020-02) |
Yes | Yes |
Specifying accessibility data
Note
The information in this section assumes that you are familiar with the general steps for creating or editing a channel.
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In the Create channel or Edit channel page for the channel, in the Channel panel, find the output group that you want to set up. Then find the audio output where you want to configure accessibility data.
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Select the output by its name. The details appear on the right. Go to the Stream settings section and choose the Audio section.
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Open the Additional settings and set the accessibility data fields.
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To include DASH Roles, choose Add dash roles as many times as you want. In DASH Role Audio, choose the style in each role.
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To include DVB DASH accessibility style, in DVB DASH accessibility, choose the applicable description. You can add only one instance of this accessibility style.
You can add more than one style of acessibility data to each encode. For example, you can add Dash Roles and DVB DASH accessibility style. You might want to do this because different downstream systems for these outputs implement different styles.
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Handling of accessibility data
The fields for accessibility data appear in the encode fields in all output group types, including types that don't support this data.
Note
When you set up audio encodes and you plan to include accessibility data, proceed as follows. First create the audio encodes in the CMAF Ingest and/or Microsoft Smooth output groups, and set up the accessibility data. Then create the audio encodes in the other output groups.
Handling in supported output groups
If you aren't implementing shared audio encodes, MediaLive includes the data only in the audio outputs of the CMAF Ingest and Microsoft Smooth output groups that you set up for audio accessibility data.
Handling in shared encodes
You might plan to share audio encodes among several output groups. For example, you might share an audio encode among at least one CMAF Ingest or Microsoft output group, and with other output groups.
If you set up accessibility data in a shared audio encode, MediaLive will handle the data as follows:
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It will include the data in the CMAF Ingest and Microsoft Smooth output groups that share the encode.
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It won't include the data in other output groups, because those output groups don't support this data. Even though the output group is sharing the encode, MediaLive won't include the data.
Handling in other output groups
You might try to set up accessibility fields in an output that doesn't support accessibility data. If you're not implementing encode sharing with a CMAF Ingest or Microsoft Smooth output group, you will get an error message when you save the channel.
