Automatically Adjust Quality when streaming

We don't always live in a world with consistent home Wi-Fi or Internet speeds. Maybe the cellular signal varies during the bus ride into work, or your Wi-Fi slows down every time your roommate microwaves a burrito. When your connection quality changes, it's annoying for video players to pause or require you to change a quality setting. In cases like that, it's ideal for players to automatically adapt without interruptions.

To give you the best possible experience, Plex can now automatically adjust the quality of your video based on your connection speed. When auto quality is turned on, videos will start at the quality that you have selected in your app's quality settings, then increase or decrease quality based on your connection speed.

Getting Started

To use auto quality, you'll need:

  • Plex Media Server version v1.8.1 or later
  • a Plex apps that support Automatically Adjust Quality:
    • Plex Web
    • Android mobile
    • Android TV
    • iOS
    • Apple TV
    • (Auto quality is coming soon to Plex apps on other TVs and streaming devices.)

AAutomatically Adjust Quality is disabled in the apps by default. It can be turned on in supported client apps. Here's how to get started:

  1. Update your Plex Media Server to the latest Plex Media Server release (v1.8.1 or later)
  2. Ensure that your supported client app is running the latest release
  3. Sign in to your account in the client app
  4. Open the app settings and enable the Automatically Change Quality setting under the Quality section

Note: Auto quality requires a Plex Media Server capable of transcoding content. That means that some NAS devices, for instance, will not be able to support the feature.

Quality Settings

You can enable auto quality, choose a starting quality, and limit data usage in the Quality section of your client app.

  • Automatically Adjust Quality: Turn on or off the Automatically Adjust Quality feature that increases or decreases video quality based on your connection speed. When enabled, auto quality will be used on servers with Plex Media Server v1.8.1 or later. Playback on older servers will not be affected.
  • Limit Cellular Data: Set the maximum video quality when playing video over a cellular network. An estimate amount of playback time per gigabyte of data used is provided for each setting to help you determine the ideal quality to help you reduce your data usage.
  • Internet Streaming: Set the starting quality for streaming video from a Plex Media Server over the Internet (remote). Auto quality will start with this setting and automatically adjust the video quality as playback continues. If the default quality is set too high, videos will start slowly.
    • Play Smaller Videos at Original Quality: When the original video file's quality (bit rate) is less than the quality that you've selected for Internet Streaming, Plex will try to play the original video without converting (transcoding). In that case, auto quality will not be used. Once a video starts at original quality, it will stay at original quality during playback. This preserves the full quality, but playback may pause frequently if your connection becomes slow.
      To temporarily disable this for a specific video, open the Playback Settings inside of the video player and choose Convert instead of Play Original Quality.
  • Home Streaming: Choose the starting quality for streaming video from a Plex Media Server when your server is on the same network as your player (local). When the original video file's quality (bit rate) is less than the quality that you've selected for Home Streaming, Plex will always try to play the original video without converting (transcoding).

Checking the Auto Quality Level

With auto quality, your video will begin at the starting quality selected in your app's Quality settings (under Internet Streaming or Home Streaming).  After 20-60 seconds, the video will increase or decrease based on your connection speed.  If your connection speed changes later, quality will continue to increase or decrease.

Some apps can show details about the current quality during playback. In the web, iOS, or Android mobile apps:

  1. While playing a video, tap  (on iOS), the gear icon (on Android mobile), or the playback settings app (Web) in the lower right corner of the app
  2. Choose Playback Settings and then Quality
  3. When auto quality is being used, you should see something like Convert Automatically (Now: 1.5 Mbps, 480p) displayed.  This indicates the quality being played at the moment.  In this example, auto quality is playing 480p.

Playback Questions

Are there any disadvantages to using auto quality?

Auto quality is designed to be a better experience in all cases. By adapting to temporary increases and decreases in your connection speed, videos can play at higher qualities than normal without experiencing problems with stalling (buffering). After the preview period, auto quality will be enabled by default in the apps and become available to all users.

The Plex apps only select auto quality in situations where a video already needs to be converted (transcoded) for playback. It does not interfere with playing videos at their original quality (sometimes called Direct Play or Direct Stream).

Note: When a video is being converted with auto quality, the audio will always be converted, too. This allows the audio to change quality based on your connection speed. At high video qualities, the converted audio quality is extremely high and should not cause any perceptible loss of quality. The server resources required to convert audio are very small compared to video conversion.

What are the minimum and maximum qualities?

Auto quality will automatically select streaming qualities between 192 kbps and 20 Mbps.

Other than your connection speed, the top quality is limited by:

  • The Limit Remote Stream Bitrate setting in the Remote Access settings of Plex Media Server
  • The Internet Upload Speed setting in the Remote Access settings of Plex Media Server
  • The Limit Cellular Data setting in your mobile app (defaults to 0.7 Mbps) when using a cellular Internet connection

Quality will always start at the default quality selected for Internet Streaming or Home Streaming in your app settings, then increase or decrease based on connection speed. Auto quality supports a larger number of precise qualities than appear in the list of available manual quality levels.

Related Page: Bandwidth and Transcoding Limits 

Does auto quality affect the audio quality?

Yes, auto quality will automatically adjust the audio quality based on your connection speed, but these changes are usually small and less noticeable.

Why is the bit rate sometimes higher than the original?

When converting, Plex will never increase the resolution of a video. However, bit rate may increase. In order to preserve quality during conversion (transcoding), it's sometimes necessary to convert to a higher bit rate than the original video file. This is to minimize the quality loss that occurs every time that a video is converted.  Using a high bit rate ensures that you can always experience the full quality, even when conversion is required.

When your app's Internet Streaming or Home Streaming quality setting is set to a higher bit rate than the original video file, the original video file will play without conversion.  The bit rate increase described above can only occur when a video is being converted.

If I rewind the video, will it change the quality?

With auto quality, quality is selected before each portion of the video is downloaded. After a portion of video has been downloaded (buffered), it will always play at the same quality.

Is there a server setting for auto quality?

There is no Plex Media Server setting to enable or disable auto quality. Auto quality is available on all servers running version v1.8.1 or later. Auto quality is controlled by the app.

However, server settings can be used to limit the bit rate used by auto quality. To do this, set the Limit Remote Stream Bitrate setting in the Remote Access settings of Plex Media Server.

Related Page: Bandwidth and Transcoding Limits 

Limitations of Auto Quality

  • Plex Cloud does not support auto quality at this time.
  • Music does not use auto quality.  Only video playback supports auto quality at this time.
  • Auto quality only works with Plex Media Server v1.8.1 or later.  Older versions will use manual quality only.
  • Auto quality requires a Plex Media Server that is capable of converting (transcoding). Servers that can't transcode, such as some NAS devices, cannot support auto quality.
  • Auto quality is only used when the video is being converted (transcoded). If a video starts with Play Original Quality, also known as Direct Play or Direct Stream, it will not automatically change quality based on connection speed.  Similarly, if a video starts with Convert Automatically, it will not automatically change to Play Original Quality.

Related PageHow are Direct Play, Direct Stream, and Transcoding different?