captions

Normal

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Erikka Innes

Tutorials

If you are creating captions for your videos, sometimes the captions don't appear where you want. Maybe they don't sit on the screen correctly, or maybe you have a creative way you want to present them. As it turns out, captions are adjustable! It will take some fine tuning to get the hang of working with them, but WebVTT is easy to use.

## Prerequisites

For this project you need: 

* api.video account - [Sign up here!](https://dashboard.api.video/register)
* A video you want to caption, uploaded to api.video - [here's a blog about how to upload your video](https://api.video/blog/tutorials/upload-a-video-with-the-api-video-python-client)
* A VTT file for your video - [Learn how to caption a video with Maestra](https://api.video/blog/tutorials/add-captions-to-your-video-with-maestra-and-api-video)

## Moving captions

To move captions, open your VTT file. You'll see captions listed next to their times, like this: 

`00:00:01.000 --> 00:00:02.000 
Hello World!`

Now let's say you don't like where the caption starts from. You can add on to the end to move it horizontally. Like this: 

`00:00:01.000 --> 00:00:02.000 position: 20%
Hello World!`

The screen is divided into percentages, so if you put a lower percentage, your caption moves further to the left. If you choose a higher one, it moves further to the right. Be careful you don't move captions into positions where they can't be seen. 

You can also make the captions go vertical. For that, you'd add: 
`00:00:01.000 --> 00:00:02.000 position: 20% vertical:rl
Hello World!`

And in this case, the position is vertical, so the percentage represents a portion of the vertical. 

You can learn a lot more about how to move captions and what's possible by checking out the [WebVTT Guide](https://www.w3.org/TR/webvtt1/). Just a few things you can do include changing the color of text, adding italics, specifying if something is loud, and much more!

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How to edit  and style your video captions

Captions increase your video's audience. Viewers spend more time watching captioned videos, many people watch videos with the sound off, and you can draw viewers who don't speak the spoken language of your video if you include subtitles. See ["Why You Should Caption Your Videos, Whether They're Classes, Speeches, or Entertainment"](https://api.video/blog/video-trends/why-you-should-caption-your-videos-whether-they-re-classes-speeches-or-entertainm) if you want all the details and statistics for why you should consider captions for your video content. Another great reason to add captions, is it's easy to do with api.video and Maestra! Let's get started. 

## Prerequisites

* [api.video account](https://dashboard.api.video/register)
* Maestra account (click the blue **Get Started Free** button)
* Sample video with spoken audio (we used one of Doug for this - https://www.youtube.com/watch?v=O3C7_kgwrPY, but any video is fine as long as it has clear audio) 

Maestra, auto captions, subtitles, caption a video, subtitle a video

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1. Click **New Subtitle** to bring up the upload panel.
2. On the upload panel under Upload your files, click **My Device**. 
3. For the Select audio language section, we choose **English** because the video is in English. The drop-down offers a 'Most Used Languages' section and an 'All Languages' section. 
4. You can choose different settings. For this walkthrough, we choose **Translate captions to another language** and then for the target language, choose **Spanish**. If you want different settings you can put those instead. 
5. Click **Submit**. 
6. Your video will start transcribing. Once it's complete, click on the title of your video. You can see how well your transcription came out. In this case, it came out pretty well.

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7. The next step is to export a copy of the file with the captions we want. Click the **Export** button in the upper right corner. You'll get a screen listing various choices, including downloading a video with all your captions included. We just want to get a WebVTT file for this walkthrough.
8. Make sure you are on the **Subtitle** tab. 
9. Under Languages, check the **English** and the **Spanish** box. 
10. Click **WebVTT** to download your caption file. The first time you click it, it will say **Ready**. The second time, it downloads a **.zip** file with your information in it. 
11. When you open the **.zip** file, you'll see a caption file in English and one in Spanish. Save these. 

## Add the Video to api.video
We need to add our video to api.video before we can caption it. You have a few choices available to you: 

* [Delegated Uploads for Videos Large and Small](https://api.video/blog/tutorials/delegated-uploads-for-videos-large-and-small-python) - This tutorial shows you how to use a delegated token to upload a large or small file using Python.
* [Upload a Video From Your Computer] - Upload a video under 128 MB from your computer using Python. 
* [Upload a Video with the api.video API Using a Public URL](https://api.video/blog/tutorials/upload-a-video-with-the-api-video-api-using-a-public-url-python) - Transfer a video from a public URL to api.video

You can also use a no-code method:

1. Open the api.video dashboard.
2. Click **My videos**.
3. Click **Upload**. 
4. Add your video. 

## Use the Captions Endpoint to Add Captions to Your Video
We can now take the files Maestra generated for us and add them to our video. Here's the code sample we're going to use to do it: 

The code sample hard codes the videoId - but if you want you can retrieve it programmatically. A design where a VTT file's title somehow matches the video's title and then you grab the videoId might be a good way to go. 

In our demo, everything is set up to try to handle a situation where you have multiple caption files. We assume a naming convention like this: 
```title_language tag.vtt``` 

So samples of this would be: doug_en-GB for English from Great Britain and doug_es-ES for Spanish from Spain. 

The language tag in each case is a BCP 47 tag. The appropriate tag is at the end of each file so that it can be sliced from the file name and used in the caption upload. Using Python's regex and os modules we search for every file in the current directory that ends with '.vtt'. If it ends with this, we then retrieve the language tag from the end of the title, open the file in binary, then append the tag and file to a POST request to add a caption. We also modify the URL - it needs to include the videoId and the language tag for the language we want to add. You can see how that's built in the sample.

We have two caption files, so we loop through our .vtt files and send each one to be added. For each successful addition of a caption file, we get a response that looks similar to this: 

```
{
	'uri': '/videos/vi6FZib80ZrC8q73AekJqNDH/captions/es', 
	'src': 'https://cdn.api.video/vod/vi6FZib80ZrC8q73AekJqNDH/captions/es.vtt', 
	'srclang': 'es', 
	'default': False
}
```

* uri - the unique link that you add to https://ws.api.video to reach the video caption file (you must authenticate to view this, so you can't paste it into a browser to see it) 
* src - the location URL of the file
* srclang - what language you're using, written shorthand (instead of es-ES it would be es) 
* default - whether this is the default language for the video 

If you want to make a particular language the default caption, you can specify the language by updating a caption. 

## Check Your Work
You can retrieve details about your captions, but an easy way to check is to look in your dashboard: 

1. Go into your Videos section and click your video.


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2. Click the **Captions** icon directly under the X. You'll see that you can add English or Spanish captions. Give it a try on your own video! 

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Maestra does fairly well with captions, as long as the audio is clear. They offer a free trial for up to 30 minutes of video, so try them out yourself. Maestra lets you automatically create a variety of caption files, but api.video uses the WebVTT format, so you'll want that for any projects on our platform. 

If you want to create your own WebVTT file from scratch, Doug wrote a great post about how to do this here: [How to Add Captions to your Videos](https://api.video/blog/tutorials/how-to-add-captions-to-your-videos)

## Show a Caption
You can see if a caption was already added with this code: 

## Show All Captions
If you want to see every caption for a video, you can do this: 

## Delete a Caption 
A caption can be removed with the following code: 

## Update a Video Caption
You can update a video caption to make it the default. The code for that would be: 

This is all the basics for using captions. Thanks for tuning in today! 
[Start builind now](https://dashboard.api.video/register)!

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Add Captions to Your Video with Maestra and api.video

Video trends

Captions are required for any content that's aired on TV before. The 21st Century Communications and Video Accessibility Act (CVAA) makes this a requirement for any online video that's previously appeared on TV. You'll notice that your favorite streaming sites, like Hulu, Netflix, Amazon, and others all provide captioning for their content. Look around a bit more, and you'll see that these sites often caption all their content even if it's not required. That's because there are additional benefits to video captioning beyond just meeting legal requirements. 

<center><iframe src="https://giphy.com/embed/izaGDgNARMEegTbNYe" width="480" height="480" frameBorder="0" class="giphy-embed" allowFullScreen></iframe><p><a href="https://giphy.com/gifs/caption-logo-izaGDgNARMEegTbNYe">A GIF Caption</a></p><br></center>

## Statistics That Will Make You Want to Caption Your Content
If you want to reach viewers, captions rule. In fact, Digiday said "85% of Facebook video is watched without sound." If there's a message you're trying to convey that requires more than images, captions are what will make this possible. 

Statistics about captioning, captions, video

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Verizon Media has a similar statistic - they say "69% view video with sound off in public places and 25%  watch with sound off on private places." And that's not all. According to the same study done by Verizon Media, 80% of consumers are more likely to watch an entire video when captions are available and 50% of consumers say captions are important because they watch video with the sound off. 

So while your video or live stream may not end up on TV and require captioning, including captions increases your chance of reaching viewers. What makes no sound so important to viewers? Well as it turns out, there's a few common reasons they might need or prefer captions.

## Watch Without Sound 

watch a video without sound, captions for silent video, captioning

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Captions help the deaf watch video content that might not have been accessible to them otherwise. However, captions can do more than that. For people that hear, they may find themselves in a situation where they want to watch a show, but they don't have a way to control the sound with headphones or similar. In a situation like this, turning the sound off and reading captions can still allow them to watch their shows. Even if they can control sound with headphones, they may be in too noisy a situation, or a situation where they need to listen for certain cues - like somebody waiting for their flight in an airport. 

## SEO 

Boost SEO with captions, caption a video, captioning

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If you include a transcript of your video with your video description, search engines will crawl it. This can result in a better SEO rank than just posting the video alone. If you've posted a class of some kind, including the transcript can help people search for the part of the video they wanted. There are even some tools out there that will highlight the chunk of the transcript that matches what's being said in the video. Viewers can click around on the transcript to move the position in the video forward or backward. A great example of this can be seen on Coursera classes. 

## Increase Audience Comprehension
Captions help people more fully understand what's happening in a video. It can help someone taking an online class retain information or it can help someone better follow the plot of their favorite show. When it comes to entertainment like movies or television, captions can make viewers more aware of the music selected for a scene by including the sung lyrics. Frequently show creators choose music to underline a key theme or plot point. Seeing the lyrics can help make viewers more aware of the subtleties of what they're watching. 

## Draw Viewers Who Speak Other Languages
Subtitles are a type of caption, and when you include them you make your content more globally accessible. You can more easily reach viewers in their native language, and subtitles help you achieve that affordably. Completely dubbing content into another language requires voice actors and careful automated dialogue replacement (ADR). Adding captions makes your video accessible without all of this effort - you only need a good written translation instead. 

## Add Captions to Your Content Today
api.video allows you to caption all your video content using our Captions endpoint. Create a Web Video Text Tracks (WebVTT) file by hand or with an online tool to get started. Then upload it for your video and voila! your video content can start reaping the benefits of captions today. 

We have a tutorial to help you get started - [How to Add Captions to your Videos](https://api.video/blog/tutorials/how-to-add-captions-to-your-videos)
[Start building now](https://dashboard.api.video/register)!


Why you should caption your videos, whether they're classes, speeches, or entertainment

Delegated Upload

Video Status

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Doug Twitter

Doug Sillars

NodeJS

Video captions/subtitles make it easier to follow along with your video. Whether your users have hearing issues or not, sometimes they may not want to have a loud speaker playing the video's audio, and adding captions allows them to understand the video.


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When adding captions to a video, you must create a WebVTT file. We've [written on the process of creating WebVTT files](https://api.video/blog/tutorials/how-to-add-captions-to-your-videos/). The format is not difficult to understand, but they are not simple to create manually, you need to break up a transcription into segments, and add start and stop times for each section.  


```

3
00:00:07.519 --> 00:00:11.759
The little train rumbled over the tracks.

4
00:00:10.880 --> 00:00:15.279
She was a happy little train for She had such

5
00:00:13.439 --> 00:00:16.719
a jolly load to carry.

6
00:00:15.599 --> 00:00:20.480
Her cars were filled full of good things for boys

7
00:00:18.879 --> 00:00:21.199
and girls.

```



In this post, we'll show how using the [Authot](https://www.authot.com/) transcription APIs can help you automatically add video captions to your videos, without the fuss of manually creating the VTT caption file.

Authot will receive the video file, make a transcription of the audio file, and then return a complete webVTT file. api.video can then ingest this file into the same videoID as the video, and the captions are added to the video.

It sounds like magic! To prove that it actually works, we've built a demo application [caption.a.video](https://caption.a.video) that utilizes api.video and Authot to host, stream and auto-caption your videos.  

## How it works

The first step is to upload your video to api.video.  This demo is built on top of a [delegated token upload](https://api.video/blog/product-updates/video-access-management-how-to-create-deliver-and-manage-private-videos-and-what/), meaning that a temporary public token was created that lets us upload right from the browser.



### Upload complete

Once the video is uploaded, api.video begins transcoding into a HLS sstream and an MP4 version of the movie.  To create a transcription, Authot requires the mp4 file, so the application uses the [video status](https://docs.api.video/reference#get-video-status/) endpoint to determine when the mp4 video has been encoded. This endpoint tells us when each video stream is ready for playback. Once the mp4 is encoded, we can submit the file to Authot for transcription.

### Transcription

Once the video has been submitted to Authot, the API returns the ID number of the transcription.  The Status endpoint tells us what state the transcription is in.  

The initial state is 0: Uploading

The final state is 10: transcoded

There are some states in between, including 2: transcribing

### Getting the WebVTT

Once the transcription is complete, (when Authot returns the status "10"),  the Node server requests the VTT file, and then uploads the file to the existing video at api.video.

### Completed

The webpage finally updates the text, saying "success".  Clicking the video link - opens the video, and the user can enable captions and watch them play back.


## Automatic captions!

Of course, automatic captions are not 100% accurate.  You may have a few words incorrectly transcribed.  However, in my testing the Authot API is pretty good, and the captions are of a very high quality.

On the other hand - manually creating captions will either take a lot of time, or cost a lot of money (to pay someone else to do the work).  The ease of use, and low cost makes auto-captioning a compelling choice


## Conclusion

We've described an application that allows you to upload a video and automatically add captions to the video.  Try it out today at [caption.a.video](https://caption.a.video). If you're curious on how we built this app, the code is available on [Github](https://github.com/dougsillars/captionavideo).  Let us know what you think by posting on our [community forum](https://community.api.video/).

Add captions, and watch your video watch time increase!

Auto Caption a video

Videos are a compelling way to share experiences with your customers. The combination of speech, sounds, images and movement allow us to share a more enriching experience.

However, on the web a video can only be autoplayed when it is muted. As a consumer with small children, this is often a blessing: the last thing I want is a website to wake up a sleeping baby. But as a developer, I want everyone to experience everything my videos have to offer, so I want to work around this issue (but of course, while still letting everyone’s babies nap!)

One solution is to add captions. Users can still engage with your video and follow along with the dialogue. Facebook finds that [videos with captions are watched 12%](https://instapage.com/blog/closed-captioning-mute-videos) longer than videos without captions (85% of Facebook videos are watched without audio). Longer video watch time increases [your search rank](https://www.3playmedia.com/2018/12/10/7-ways-video-transcripts-captions-improve-seo/), and the presence of a captions file even improves your site SEO! With all of these advantages, the accessibility improvements of your website almost come as an afterthought.

No matter the reason you choose to add captions to your videos — you are probably wondering how it is done!

## The VTT File

Closed captioning is typically done with a VTT (Video Text Track) file. They=se are text files that simply list the text that should appear over a specified period:

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In the example above, from 15–17.9 seconds, the text “At the left we can see” will appear on the screen, followed a split second later by “at the right we can see.” It is really a pretty straightforward format. But other than manually transcribing your video, how can you create a VTT file?

Let’s walk through 2 ways:

### VTT Creator

[VTT Creator](https://www.vtt-creator.com/) is a web based tool. You simply upload your video, and as it plays the video back, it creates captions for you.

![](https://cdn-images-1.medium.com/max/800/0*0EV4F_2lV2epjlaB)

The website uploads your video and begins the analysis, and the pane on the left fills with the subtitles

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You can download the VTT, and you’re good to go!

### Google Speech to Text

Google Cloud, Azure and AWS all have a speech to text tool. I chose Google’s for this demo, but they all operate in much the same way.

Google has a helpful [QuickStart](https://cloud.google.com/speech-to-text/docs/quickstart-client-libraries#client-libraries-install-nodejs) guide to set up your Google Cloud account for Speech to Text. The first step is to use ffmpeg to strip the audio track (there is no need to upload the video track when doing audio analysis).

I used their Node.js code example with a few changes (Code available on [GitHub](https://github.com/dougsillars/subtitles)). The video I was transcribing was over 1 minute long, so I had to host it on a Google Cloud instance. Rather than using:

There is no need to transcode the video to base64 (as described in the tutorial) if it is hosted on Google Cloud. The sample code from Google writes the transcript into the console:

![](https://cdn-images-1.medium.com/max/800/0*PHDqyWCU_PCA4nR8)

This is super cool, but we want more than a transcription — we need those time stamps. The raw JSON file has an entry for each word with the start and end time for each word:

![](https://cdn-images-1.medium.com/max/800/0*jxIPZw0Mr2CFOVLA)

So I created a function that groups words, using the first word’s start time,and the end time of the last word. The length of the phrase can be varied — in the sample code it is set to 10 words. The script outputs a VTT file to the console.

### Adding Captions to your Video

### HTML5

Adding the VTT file to your video is easy. If you are using HTML5 video, you can add a track attribute pointing to the VTT file.
```html
<video autoplay muted controls>
    <source src=”myvideo.webm”>
    <source src=”myvideo.mp4">
    <track default lang=”en” kind=”captions” src=”myvideo.vtt”>
    <track lang=”es” kind=”captions” src=”muvideo-es.vtt”>
</video>
```
### Video Streaming

If you want to add captions to your [api.video](https://api.video) video, you can use the Captions API.

1.  First you must [authenticate](https://api.video/blog/tutorials/authentication-tutorial) your session to gain an access token.
2.  Determine the videoID of the video you’d like to add the caption to. In this example, I have created captions to [Elephant’s Dream](https://orange.blender.org/) (an Open Source video project). The video ID is: vi5UNyaStzuuj0xTAGp7qtjf

(https://embed.api.video/vod/vi5UNyaStzuuj0xTAGp7qtjf)

3. Make a call to add the [caption](https://docs.api.video/reference/post_videos-videoid-captions-language). Using curl, the request looks like:
```bash
curl [https://ws.api.video/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en-US]
(https://ws.api.video/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en-US) -H ‘Authorization: Bearer {access\_token}’ -F file=@/path/to/google.vtt
```

And we receive a response:
```bash
{“uri”:”/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en”,”src”:”https://cdn.api.video/vod/vi5UNyaStzuuj0xTAGp7qtjf/captions/en.vtt","srclang":"en","default":false}
```

Note that captions are off by default. This is easily resolved by patching the video, setting the default to true. Using curl, this looks like:
```bash
 curl -X PATCH [https://ws.api.video/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en](https://ws.api.video/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/e) -H ‘Authorization: Bearer {access\_token}’ -d ‘{“default”: true}’
```

And we receive a response:
```json
{
  “uri”:”/videos/vi5UNyaStzuuj0xTAGp7qtjf/captions/en”,
  ”src”:”https://cdn.api.video/vod/vi5UNyaStzuuj0xTAGp7qtjf/captions/en.vtt",
  "srclang":"en",
  "default":true
}
```

And watching the movie: success! the captions are turned on by default. To autoplay a video with api.video, simply add #autoplay to the end of the url, and we have an autoplaying video with captions.

Now we can rest assured that our videos will likely have more traction, be watched longer, and shared more often. And, we are making our content more accessible to users who cannot hear.

### Conclusion

Video captions not only make your content accessible, but research shows videos with captions are watched longer, and shared more often. And searchable transcriptions actually increase the SEO of your site!

Often there is reluctance to add captions due to the added work, but with just a few clicks of a button, captions can be generated automatically and uploaded for immediate playback.

[Give it a try](https://dashboard.api.video/register), and share your caption successes on the [api.video community forum](https://community.api.video/).

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How to add captions to your videos

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](https://api.video/blog/tutorials/how-to-add-captions-to-your-videos)

>[Video Upload Tutorial](https://api.video/blog/tutorials/video-upload-tutorial)

> Find all details to display your captions in [our docs](https://docs.api.video/reference/get_videos-videoid-captions-language)

## Authenticate your session
You will need your API key to obtain the access_token. You can find your API key in [your dashboard](https://dashboard.api.video/login).

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

Example - Curl Request

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

### Make captions default

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


## 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](https://community.api.video). Happy building!

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Adding captions

Featured article

# api.video blog

Blog

Follow the api.video Blog to explore tutorials, video use cases, and learn about on-demand and live-streaming video updates.