HLS manifests - MediaLive

HLS manifests

Language information

If the captions are embedded captions and the output is HLS, you must include captions language information in the manifest. If you don't include this information, the downstream player won't have information about the embedded captions. To include language information in the manifest:

  1. In the HLS output group in Output groups, for Captions, in Captions language setting, choose Insert. Choosing this option inserts lines in the manifest for each embedded captions language. It inserts as many lines as the mappings that you will add in the next step.

  2. Still in the HLS output group, for HLS settings, in Captions language mappings, choose Add captions language mappings.

  3. Choose Add captions language mappings again to add more mapping groups, one for each embedded captions asset, to a maximum of four groups. For example, if the output embedded languages contain English, French, and Spanish, you need three mapping groups.

  4. Complete each mapping group to identify the CC (caption channel) number and its language. Specify the language as a three-letter ISO language code, as per ISO 639-2. For example, if captions channel 1 is French, then set up the three fields with "1", "fre", and "French".

    The order in which you enter the languages must match the order of the captions in the source. For example, if the captions are in the order French, then English, then Spanish, then Portuguese, then set up CC1 as French, CC2 as English, and so on. If you don't order them correctly, the captions in the manifest will be tagged with the wrong languages.

Accessibility information

When you create an HLS or MediaPackage output, you can designate the captions as accessibility captions. Accessibility captions are used to describe sounds, music, and other audio elements, in addition to the spoken dialog.

  • MediaLive assigns accessibility captions a unique attribute in the EXT-X-MEDIA tag of the HLS manifest:

    CHARACTERISTICS="public.accessibility.describes-spoken-dialog,public.accessibility.describes-music-and-sound"

  • In the HLS or MediaPackage output group, select the specific output and select the caption in Stream settings. Expand the Additional settings section and use the Accessibility option to select IMPLEMENTS ACCESSIBILITY FEATURES. This selection will add the accessibility caption attribute to the HLS manifest.

  • Example EXT-X-MEDIA tag with the accessibility caption attribute:

    #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="captions-group",NAME="accessibility-captions1",LANGUAGE="eng",CHARACTERISTICS="public.accessibility.describes-spoken-dialog,public.accessibility.describes-music-and-sound",AUTOSELECT=YES,DEFAULT=YES,URI="caption-accessibility-eng.m3u8"