---
id: recording-videos
title: Recording Videos
sidebar_label: Recording Videos
---

import useBaseUrl from '@docusaurus/useBaseUrl'

<div class="image-container">
  <svg xmlns="http://www.w3.org/2000/svg" width="283" height="535">
    <image href={useBaseUrl("img/demo_capture.gif")} x="18" y="33" width="247" height="469" />
    <image href={useBaseUrl("img/frame.png")} width="283" height="535" />
  </svg>
</div>

## Camera Functions

The Camera provides certain functions which are available through a [ref object](https://reactjs.org/docs/refs-and-the-dom.html):

```tsx
function App() {
  const camera = useRef<Camera>(null)
  // ...

  return (
    <Camera
      ref={camera}
      {...cameraProps}
    />
  )
}
```

To use these functions, you need to wait until the [`onInitialized`](/docs/api/interfaces/CameraProps#oninitialized) event has been fired.

## Recording Videos

To start a video recording you first have to enable video capture:

```tsx
<Camera
  {...props}
  video={true}
  audio={true} // <-- optional
/>
```

Then, simply use the Camera's [`startRecording(...)`](/docs/api/classes/Camera#startrecording) function:

```ts
camera.current.startRecording({
  onRecordingFinished: (video) => console.log(video),
  onRecordingError: (error) => console.error(error)
})
```

You can customize capture options such as [video codec](/docs/api/interfaces/RecordVideoOptions#videoCodec), [video bit-rate](/docs/api/interfaces/RecordVideoOptions#videoBitRate), [file type](/docs/api/interfaces/RecordVideoOptions#fileType), [enable flash](/docs/api/interfaces/RecordVideoOptions#flash) and more using the [`RecordVideoOptions`](/docs/api/interfaces/RecordVideoOptions) parameter.

For any error that occured _while recording the video_, the `onRecordingError` callback will be invoked with a [`CaptureError`](/docs/api/classes/CameraCaptureError) and the recording is therefore cancelled.

To stop the video recording, you can call [`stopRecording(...)`](/docs/api/classes/Camera#stoprecording):

```ts
await camera.current.stopRecording()
```

Once a recording has been stopped, the `onRecordingFinished` callback passed to the [`stopRecording(...)`](/docs/api/classes/Camera#stoprecording) function will be invoked with a [`VideoFile`](/docs/api/interfaces/VideoFile) which you can then use to display in a [`<Video>`](https://github.com/react-native-video/react-native-video) component, uploaded to a backend, or saved to the Camera Roll using [react-native-cameraroll](https://github.com/react-native-cameraroll/react-native-cameraroll).

### Pause/Resume

To pause/resume the recordings, you can use [`pauseRecording()`](/docs/api/classes/Camera#pauserecording) and [`resumeRecording()`](/docs/api/classes/Camera#resumerecording):

```ts
await camera.current.pauseRecording()
...
await camera.current.resumeRecording()
```

### Video Codec

By default, videos are recorded in the H.264 video codec which is a widely adopted video codec.

VisionCamera also supports H.265 ([HEVC](https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding)), which is much more efficient in encoding performance as well as an up to 50% smaller file size.
If you can handle H.265 on your backend, configure the video recorder to encode in H.265:

```ts
camera.current.startRecording({
  ...props,
  videoCodec: 'h265'
})
```

### Video Bit Rate

Videos are recorded with a target bit-rate, which the encoder aims to match as closely as possible. A lower bit-rate means less quality (and less file size), a higher bit-rate means higher quality (and larger file size) since it can assign more bits to moving pixels.

To simply record videos with higher quality, use a [`videoBitRate`](/docs/api/interfaces/RecordVideoOptions#videoBitRate) of `'high'`, which effectively increases the bit-rate by 20%:

```ts
camera.current.startRecording({
  ...props,
  videoBitRate: 'high'
})
```

To use a lower bit-rate for lower quality and lower file-size, use a [`videoBitRate`](/docs/api/interfaces/RecordVideoOptions#videoBitRate) of `'low'`, which effectively decreases the bit-rate by 20%:

```ts
camera.current.startRecording({
  ...props,
  videoBitRate: 'low'
})
```

#### Custom Bit Rate

If you want to use a custom bit-rate, you first need to understand how bit-rate is calculated.

The bit-rate is a product of multiple factors such as resolution, FPS, pixel-format (HDR or non HDR), and video codec.
As a good starting point, those are the recommended base bit-rates for their respective resolutions:

- 480p: 2 Mbps
- 720p: 5 Mbps
- 1080p: 10 Mbps
- 4K: 30 Mbps
- 8K: 100 Mbps

These bit-rates assume a frame rate of 30 FPS, a non-HDR pixel-format, and a H.264 video codec.

To calculate your target bit-rate, you can use this formula:

```ts
let bitRate = baseBitRate
bitRate = bitRate / 30 * fps // FPS
if (hdr === true) bitRate *= 1.2 // HDR
if (codec === 'h265') bitRate *= 0.8 // H.265
bitRate *= yourCustomFactor // e.g. 0.5x for half the bit-rate
```

And then pass it to the [`startRecording(...)`](/docs/api/classes/Camera#startrecording) function (in Mbps):

```ts
camera.current.startRecording({
  ...props,
  videoBitRate: bitRate // Mbps
})
```

## Saving the Video to the Camera Roll

Since the Video is stored as a temporary file, you need save it to the Camera Roll to permanentely store it. You can use [react-native-cameraroll](https://github.com/react-native-cameraroll/react-native-cameraroll) for this:

```ts
camera.current.startRecording({
  ...props,
  onRecordingFinished: (video) => {
    const path = video.path
    await CameraRoll.save(`file://${path}`, {
      type: 'video',
    })
  },
})
```

<br />

#### 🚀 Next section: [Frame Processors](frame-processors)
