Adding captions

January 1, 2020 - Doug Sillars in captions Authenticate

Captions allow hearing impaired users to read the words being said in your video. It also improves watch times, and can improve your SEO.

To add captions to your video, you'll need a VTT file for a video already uploaded to api.video.

Learn how to create a VTT Video Caption File

Video Upload Tutorial

Find all details to display your captions in our docs

Authenticate your session

You will need your API key to obtain the access_token. You can find your API key in your dashboard.

First, call the authentication endpoint and get your access token.

Example - Curl Request

curl -X POST \
https://sandbox.api.video/auth/api-key \
-H 'Content-Type: application/json' \
-d '{"apiKey": "your_api_key"}'
Example - Http Request
POST /auth/api-key HTTP/1.1
Host: sandbox.api.video
Content-Type: application/json

{
	"apiKey": "your_api_key"
}

Example - Json Response

{
    "token_type": "Bearer",
    "expires_in": 3600,
    "access_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6ImFiYjcxNmNiY2ZiNmY4MDc2OWEzZmQ1MjlhMjZiZWRkY2EwMzhlYzA3NDk5M2ZiMTA0YjhiZGMwOTI5MzgxN2M3NmNkNzI4ZDIzOGMzZmNlIn0.eyJhdWQiOiJsaWJjYXN0IiwianRpIjoiYWJiNzE2Y2JjZmI2ZjgwNzY5YTNmZDUyOWEyNmJlZGRjYTAzOGVjMDc0OTkzZmIxMDRiOGJkYzA5MjkzODE3Yzc2Y2Q3MjhkMjM4YzNmY2UiLCJpYXQiOjE1MjY1NDgzMDEsIm5iZiI6MTUyNjU0ODMwMSwiZXhwIjoxNTI2NTUxOTAxLCJzdWIiOiJ1c01vbml0b3IiLCJzY29wZXMiOlsibW9uaXRvci5saWJjYXN0LmNvbSJdLCJjb250ZXh0Ijp7InVzZXIiOiJ1c01vbml0b3IiLCJwcm9qZWN0IjoicHJNb25pdG9yIiwibWVtYmVyIjoibWVNb25pdG9yIn19.jWHC18iEur69FzD5dm78wAwNzh2cPKTRvKuspyQNQKPvhEbYa2v4XhqVNh0TTw8JeNxBtcePBTMHl4S9nWsw7pW4KD8zbqzUjCZNYlaYDpu8vu_tmWVO2JccglJIjuQEaiTbkUsfLdgtsb_9DJ3frk1-WgAKuzu0HewhcGb80xivdJPqNYA6I1Ig8GOief9LTUNNJoqqZn1A1-UiGRTXDag7_yODuxzpMFaAzbaisfK0gYti-PnjyHGWhpGwRplMKPPJk6rSAp1d9TWWXVgg-bNqUzz4_sr33ICJTx7_qZzfamMqk5PDZbHOwpIj8L2DBfo3isvt6QliWmgFEOuvog",
    "refresh_token": "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"
}

Add the caption to your video

curl https://ws.api.video/videos/{videoId}/captions/{lang} 
           -H ‘Authorization: Bearer {access_token}’ 
          -F file=@/path/to/caption.vtt

replace {videoId} with the videoId of the video to receive captions; {lang} with the language of the video (ex: en-US for US english); and {access_token} with your access token.

JSON response

{	“uri”:”/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en”,
	”src”:”https://cdn.api.video/vod/vi5UNyaStzuuj0xTAGp7qtjf/captions/en.vtt",
	"srclang":"en",
	"default":false
	}

Make captions default

The JSON response above shows that by default, captions are off. To add them, send a PATCH update command:

curl -X PATCH https://ws.api.video/videos/{videoId}}/captions/{lang}} 
        -H ‘Authorization: Bearer {access_token}’ 
        -d ‘{“default”: true}’

Conclusion

Captions make it easier to watch a video. Not just for hearing impaired users, but for autoplaying videos that begin muted. You users can just read what is happening without sound, and then, if they are interested can un-mute the video. You can also add internationalization by translating the captions to additional languages.

Let us know how you are using captions in our developer community. Happy building!

Doug Sillars

Head of Developer Relations