AWS Elemental MediaLive
User Guide

How Captions Are Supported

AWS Elemental MediaLive supports specific captions formats that you can include in your content. For a given input container, the AWS Elemental MediaLive encoder can parse certain captions formats. For a given input captions format, the AWS Elemental MediaLive encoder can create one or more output captions. A given output caption can appear only in specific output containers.

Looking at the rule the other way around, starting from the output container you want to produce:

A given output container supports a given set of output captions formats. So your choice of output captions is constrained by the output container.

Furthermore, each output captions format can be produced only from some input captions formats and not from others. And some input captions formats can appear in some input containers and not in others. So your choice of output captions formats is further constrained by the original input container and format.

When you create an event, job, or profile, you must select a format that is valid for your output captions.