IMSC, TTML, and WebVTT (sidecar) output captions - MediaConvert

IMSC, TTML, and WebVTT (sidecar) output captions

If your output captions are IMSC, TTML or WebVTT format, set them up in your outputs according to the following information. For restrictions on IMSC support, see IMSC captions support in AWS Elemental MediaConvert.

Where to specify the captions

Put your captions in the same output group, but a different output from your video.

After you add captions to an output, delete the Video and Audio 1 groups of settings that the service automatically created with the output.

To delete the Video and Audio 1 groups of settings

  1. On the Create job page, in the Job pane on the left, under Output groups, choose the output that contains the groups of settings that you want to delete.

  2. The Video group of settings is automatically displayed in the Stream settings section. Choose the Remove video selector button.

  3. The Audio 1 group of settings is automatically displayed in the Stream settings section. Choose the Remove button.

How to specify multiple captions tracks

Put each captions track in its own output.

Note

The captions track that you specify first in your job is signaled as the default track in the HLS manifest.

Sidecar captions container options

Depending on your output group, you can choose the captions container for IMSC and TTML captions outputs.

For DASH ISO output groups, you can choose from these:

  • Fragmented MP4 (.fmp4)

  • Raw (.xml for IMSC, .ttml for TTML)

For all other output groups, IMSC and TTML files are raw.

To specify the captions container for IMSC and TTML captions in DASH ISO output groups

  1. Set up the outputs in your DASH ISO output group as described in Creating outputs in ABR streaming output groups. Put captions in a separate output.

  2. On the Create job page, in the Job pane on the left, choose the captions output.

  3. In the Output settings section on the right, choose Container settings, and then enable DASH container settings.

  4. For Captions container, keep the default Raw or choose Fragmented MPEG-4.