Video playback and Download quality

Key terms

Bitrate
The bitrate is the amount of data that is transferred per second. A higher bitrate means that the video will have a higher quality, but it will also take up more bandwidth.

Resolution
The resolution is the number of pixels that make up the video image. A higher resolution means that the video will have a sharper image, but it will also take up more bandwidth.

Rendition
Rendition refers to a specific version of a video that is encoded at a specific bitrate and resolution. A rendition can be used to deliver a video to a device with limited bandwidth or to a device that cannot support a high resolution.

For example, a video might have a 1080p resolution, but it might also have a 720p rendition and a 480p rendition. The 1080p rendition would be used for devices that can support a high resolution, while the 720p and 480p renditions would be used for devices with limited bandwidth or resolution capabilities.

Setting HLS rendition ladders

When you upload a video to ViewLift, the CMS automatically creates different renditions of the same file at different resolutions, from 90p to 1080p as per your ingest profile defined at the encoder level during initial implementation. 4K streaming is not currently available.

The HLS URL for a video object is an m3u8 file that will list the available renditions of the video. The player will choose the HLS manifest that best meets the user's bandwidth and device capabilities.

The auto option on the ViewLift Player will pick the HLS manifest that best meets the user's needs. The high, medium, and low streaming options in the ViewLift player will also use this HLS URL.

For users, the renditions will appear as streaming quality options in the video controls section of the player as the following screenshot illustrates.

Here is a table that summarizes the few streaming quality options and their effects:

To configure streaming renditions, from AppCMS in the top navigation, click SETTINGS > VIDEO PLAYBACK & DOWNLOAD QUALITY. Support for the playback quality can depend on factors like your viewers' demographics, monetization strategy, and content delivery needs.

Setting download quality for offline viewing

Similarly, you can offer different download quality options for users who want to save the video for offline viewing. In ViewLift Tools, you will find the static MP4 URLs for a video object under the Renditions and Mezz folder of a video object, for example: "https://exampletv.viewlift.com/Renditions/592023_example_video/592023_example_video_720.mp4". This is used for offline download and playback. 

For further reading, we suggest checking out this informative article from AT&T, and also this AWS blog.