# How to programmatically select a video track quality

This article describes how you can use the API to select a video track quality. If you select a specific quality, you overrule the ABR algorithm.

The VideoTrack API, which is a sub-API of the MediaTrack API, can be used to implement this functionality. Implementing this functionality is a common use-case for developers who want to build their own UI to toggle a specific video quality.

## SDKs

| Web SDK | Android SDK | iOS SDK | tvOS SDK | Android TV SDK | Chromecast SDK |
| ------- | ----------- | ------- | -------- | -------------- | -------------- |
| Yes     | Yes         | Yes     | Yes      | Yes            | Yes            |

## Code examples

The code examples below show how to implement selecting video track qualities across SDKs.

##### Web SDK

The Web SDK leverages the [MediaTrack API](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/api-reference/web/interfaces/MediaTrack).

```js
// enable a specific video track quality
player.videoTracks[0].targetQuality = player.videoTracks[0].qualities[indexOfRequestedVideoTrackQuality];

// do ABR on a set of qualities
player.videoTracks[0].targetQuality = [
  player.videoTracks[0].qualities[indexOfRequestedVideoTrackQuality1],
  player.videoTracks[0].qualities[indexOfRequestedVideoTrackQuality2],
];

// set to default ABR algorithm
player.videoTracks[0].targetQuality = null;
```

##### Android (TV) SDK

The Android SDK leverages the [MediaTrack API](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/api-reference/android/com/theoplayer/android/api/player/track/mediatrack/MediaTrackList).

```java
// enable a specific video track quality
theoplayer.getPlayer().getVideoTracks().getItem(0).setTargetQuality(theoplayer.getPlayer().getVideoTracks().getItem(0).getQualities().getItem(indexOfRequestedVideoTrackQuality));

// do ABR on a set of qualities
ArrayList<VideoQuality> selectedVideoQualities = new ArrayList<>();
selectedVideoQualities.add(theoplayer.getPlayer().getVideoTracks().getItem(0).getQualities().getItem(0));
selectedVideoQualities.add(theoplayer.getPlayer().getVideoTracks().getItem(0).getQualities().getItem(1));
theoplayer.getPlayer().getVideoTracks().getItem(0).setTargetQualities(selectedVideoQualities); // ABR algorithm only executed to qualities belonging to selectedVideoQualities

// set to default ABR algorithm
theoplayer.getPlayer().getVideoTracks().getItem(0).setTargetQualities(Collections.emptyList());
```

##### iOS (/tvOS) SDK

For HESP streams:

```swift
let videoTrack = player.videoTracks[0]
videoTrack.targetQualities = [videoTrack.qualities[indexOfRequestedVideoTrackQuality]]
// or
videoTrack.targetQualities = [videoTrack.qualities[0], videoTrack.qualities[1]]
```

For HLS streams:

The iOS SDK leverages the [ABR API](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/api-reference/ios/Protocols/ABRConfiguration). The underlying AVFoundation stack, which THEOplayer has to use, brings along the technical limitation that you cannot select a specific video quality. Instead, you can set a maximum resolution or bitrate.

```swift
// set preferred peak bitrate
self.theoplayer.abr.preferredPeakBitRate = 200000

// self.theoplayer.abr.preferredPeakBitRate = nil // removes any bitrate limitation

// preferredMaximumResolution supported starting from iOS 11 and above
// self.theoplayer.abr.preferredMaximumResolution = CGSize(width: 1280, height: 720)
// self.theoplayer.abr.preferredMaximumResolution = CGSize.zero // removes any resolution limitation
```

## Remarks

* A related article on building a Chromeless UI is located at [How to build a Chromeless UI](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/how-to-guides/ui/how-to-build-chromeless-ui.md).

## Related articles

* [How to programmatically detect video track qualities](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/how-to-guides/mediatrack/how-to-detect-video-track-qualities.md)
* [How to programmatically detect audio tracks](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/how-to-guides/mediatrack/how-to-detect-audio-tracks.md)
* [How to programmatically detect video track quality changes](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/how-to-guides/mediatrack/how-to-detect-video-track-quality-changes.md)
* [How to programmatically enable or disable audio tracks](https://docs-preview.optiview.dolby.com/pr-863/theoplayer/v10/how-to-guides/mediatrack/how-to-enable-disable-audio-tracks.md)