Poodll covers all sides of the caption/subtitles equation for Moodle.  You can:

Display captions in audio and video players

Using the Poodll filter you can turn subtitled media links and players into players with captions or subtitles. Most video players these days will support a subtitle or caption track.  But Poodll can display them for audio and for video as interactive transcript players.

For video it looks like this.

For audio it looks like this:

To use the interactive transcript player you will need a subtitled audio or video file. You can use Cloud Poodll for Atto to generate the subtitles. Or you can upload a file if you already have subtitles.

Read more about Interactive Transcripts here: 

Interactive Transcript Players for Audio and Video

Create Subtitled Media with Cloud Poodll for Atto

If you use Cloud Poodll for Atto to generate the subtitles then it will add the subtitle track if it is a player, or a data-subtitles attribute if it is a media link. This is a lot easier than doing it manually. Just make sure that before you record or upload, you have enabled subtitling and set the language and embed method. This is all done on the options tab of the Cloud Poodll for Atto popup. Like this:

Read more about Cloud Poodll for Atto here:

Using Cloud Poodll for Atto

Editing captions with Poodll Subtitle for Atto

Subtitle generation is seldom 100% perfect. There can be mistranscriptions and also timing issues. Poodll allows you to edit the captions that you created with another icon on the Atto toolbar.

When a video or audio player/link is selected, tapping the Poodll subtitle icon will open the editor. It will look a bit like this:

For more  information about Poodll Subtitle for Atto see here: