# Camera controls

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The Video SDK for iOS lets you control the _local_ user's camera during a session: switch, mirror, rotate, and set the aspect ratio. These per-device operations run through `ZoomVideoSDKVideoHelper`. For using two cameras at the same time, see [Multiple camera support](/docs/video-sdk/ios/video/multiple-cameras/).

## Get the camera list

To enumerate the cameras available on the device, call `getCameraDeviceList` on the `ZoomVideoSDKVideoHelper`. Each entry carries the `deviceId` you'll need for `switchCamera` and the multi-camera APIs, along with `deviceName`, `isSelectDevice`, `isSelectedAsMultiCamera`, and `isRunningAsMultiCamera`.

```swift
if let cameraList = ZoomVideoSDK.shareInstance()?.getVideoHelper()?.getCameraDeviceList() {
    for camera in cameraList {
        // Each device exposes deviceId, deviceName, isSelectDevice, and more.
    }
}
```

```objectivec
NSArray<ZoomVideoSDKCameraDevice *> *cameraList = [[[ZoomVideoSDK shareInstance] getVideoHelper] getCameraDeviceList];
for (ZoomVideoSDKCameraDevice *camera in cameraList) {
    // Each device exposes deviceId, deviceName, isSelectDevice, and more.
}
```

To read the currently selected camera, use `getSelectedCamera`.

## Switch camera

Call `switchCamera` with no arguments to cycle to the next available camera. On most devices this toggles between the front and back camera.

```swift
ZoomVideoSDK.shareInstance()?.getVideoHelper()?.switchCamera()
```

```objectivec
[[[ZoomVideoSDK shareInstance] getVideoHelper] switchCamera];
```

To switch to a specific camera, pass a `deviceId` from `getCameraDeviceList`.

```swift
let didSwitch = ZoomVideoSDK.shareInstance()?.getVideoHelper()?.switchCamera("cameraDeviceID")
```

```objectivec
BOOL didSwitch = [[[ZoomVideoSDK shareInstance] getVideoHelper] switchCamera:@"cameraDeviceID"];
```

## Mirror the local video

Mirroring is a common convention for the front-facing camera, so the user sees themselves the way they would in a mirror. Use `mirrorMyVideo(true)` to enable and `mirrorMyVideo(false)` to disable. Use `isMyVideoMirrored` to read the current state.

```swift
let videoHelper = ZoomVideoSDK.shareInstance()?.getVideoHelper()
videoHelper?.mirrorMyVideo(true)

let isMirrored = videoHelper?.isMyVideoMirrored()
```

```objectivec
ZoomVideoSDKVideoHelper *videoHelper = [[ZoomVideoSDK shareInstance] getVideoHelper];
[videoHelper mirrorMyVideo:YES];

BOOL isMirrored = [videoHelper isMyVideoMirrored];
```

## Rotate the local video

When the device orientation changes, call `rotateMyVideo` with the new `UIDeviceOrientation` to update the orientation of the locally captured video.

```swift
ZoomVideoSDK.shareInstance()?.getVideoHelper()?.rotateMyVideo(UIDevice.current.orientation)
```

```objectivec
[[[ZoomVideoSDK shareInstance] getVideoHelper] rotateMyVideo:[UIDevice currentDevice].orientation];
```

A common pattern is to observe `UIDevice.orientationDidChangeNotification` and call `rotateMyVideo` with the new value.

## Aspect ratio of the local video

By default, the SDK renders video at the source aspect ratio. To force the original aspect ratio, use `enableOriginalAspectRatio`. Check the current setting with `isOriginalAspectRatioEnabled`.

```swift
ZoomVideoSDK.shareInstance()?.getVideoHelper()?.enableOriginalAspectRatio(true)
```

```objectivec
[[[ZoomVideoSDK shareInstance] getVideoHelper] enableOriginalAspectRatio:YES];
```

## Alpha channel mode

Alpha channel mode lets the SDK render video with a transparent background, useful for compositing a user's video over other UI content (for example, a presenter video overlaid on a slide deck). Both the device hardware and the current session state gate this feature, so capability-check before enabling.

-   `isDeviceSupportAlphaChannelMode`: does the device hardware support it? Check once.
-   `canEnableAlphaChannelMode`: can the mode be toggled in the current session state? Check before each enable call.
-   `enableAlphaChannelMode`: turn the mode on or off.
-   `isAlphaChannelModeEnabled`: read the current state.

```swift
let videoHelper = ZoomVideoSDK.shareInstance()?.getVideoHelper()

if videoHelper?.isDeviceSupportAlphaChannelMode() == true,
   videoHelper?.canEnableAlphaChannelMode() == true {
    videoHelper?.enableAlphaChannelMode(true)
}

let isOn = videoHelper?.isAlphaChannelModeEnabled()
```

```objectivec
ZoomVideoSDKVideoHelper *videoHelper = [[ZoomVideoSDK shareInstance] getVideoHelper];

if ([videoHelper isDeviceSupportAlphaChannelMode] && [videoHelper canEnableAlphaChannelMode]) {
    [videoHelper enableAlphaChannelMode:YES];
}

BOOL isOn = [videoHelper isAlphaChannelModeEnabled];
```

The SDK fires [`onVideoAlphaChannelStatusChanged`](/docs/video-sdk/ios/video/video-events/#alpha-channel-mode) whenever the mode is toggled. To read the per-pixel alpha mask from the raw video pipeline, see [Raw video with alpha channel](/docs/video-sdk/ios/raw-data/raw-video-alpha-channel/).