jsPsych/docs/extensions/record-video.md
2022-07-19 15:05:39 -07:00

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# record-video
This extension records video from the participant's webcam during a trial.
This extension encodes the video data in [base 64 format](https://developer.mozilla.org/en-US/docs/Glossary/Base64).
This is a text-based representation of the video which can be coverted to various video formats using a variety of [online tools](https://www.google.com/search?q=base64+video+decoder) as well as in languages like python and R.
## Parameters
### Initialization Parameters
Initialization parameters can be set when calling `initJsPsych()`
```js
initJsPsych({
extensions: [
{type: jsPsychExtensionRecordVideo, params: {...}}
]
})
```
Parameter | Type | Default Value | Description
----------|------|---------------|------------
*None*
### Trial Parameters
Trial parameters can be set when adding the extension to a trial object.
```js
var trial = {
type: jsPsych...,
extensions: [
{type: jsPsychExtensionRecordVideo, params: {...}}
]
}
```
Parameter | Type | Default Value | Description
----------|------|---------------|------------
*None*
## Data Generated
Name | Type | Value
-----|------|------
record_video_data | base64 string | [Base 64 encoded](https://developer.mozilla.org/en-US/docs/Glossary/Base64) representation of the video data.
## Examples
???+ example "Record video data during a trial"
=== "Code"
```javascript
const init_camera = {
type: jsPsychInitializeCamera
};
const trial = {
type: jsPsychHtmlButtonResponse,
stimulus: `<div id="target" style="width:250px; height: 250px; background-color: #333; position: relative; margin: 2em auto;">
<div class="orbit" style="width:25px; height:25px; border-radius:25px;background-color: #f00; position: absolute; top:calc(50% - 12px); left:calc(50% - 12px);"></div>
</div>
<style>
.orbit {
transform: translateX(100px);
animation: orbit 4s infinite;
}
@keyframes orbit {
0% {
transform: rotate(0deg) translateX(100px);
}
100% {
transform: rotate(360deg) translateX(100px);
}
}
</style>`,
choices: ['Done'],
prompt: "<p>Video is recording. Click done after a few seconds.</p>",
extensions: [
{type: jsPsychExtensionRecordVideo}
]
};
```
=== "Demo"
<div style="text-align:center;">
<iframe src="../../demos/jspsych-extension-record-video-demo1.html" width="90%;" height="500px;" frameBorder="0"></iframe>
</div>
<a target="_blank" rel="noopener noreferrer" href="../../demos/jspsych-extension-record-video-demo1.html">Open demo in new tab</a>