Improving Video Startup Quality with Adaptive Streaming

Blog 3 min read | May 2, 2018 | JW Player


With JW 8.3,

 you won’t have to choose between startup quality and speed

Publishers with premium or co-sponsored content seek both startup speed and video quality.  In the past, this has meant trading off video quality for speed: to maintain fast startup times, our player doesn’t wait for an initial quality estimation before downloading segments and beginning playback. Instead, our player has always defaulted to the lowest quality setting in the manifest, sometimes resulting in negative impacts to viewer experience and brand integrity.

To help customers with these challenges, JW 8.3 improves adaptive streaming, avoiding the lowest quality setting altogether if the viewer’s available bandwidth and the player size can support a higher quality start.

The player maintains the viewer’s bandwidth between videos, allowing the second and subsequent videos to benefit from a higher quality start at the beginning. If the viewer is watching the player embed’s first video, the player can start up at the last known bandwidth when a viewer returns to a site on the same device and browser. All players 8.3.0 and higher will benefit from improved startup quality out of the box.

We often hear from publishers that their own proprietary data suggests that the majority of their viewerbase is accessing content from high-speed connections. As a result, many publishers want to force the player to start their content at the highest quality possible. While we trust our publisher’s judgement, we also want to maintain the “no buffer” experience for which we’re known, and protect viewers on poor connections. Our new configuration option, “defaultBandwidthEstimate” represents a middle ground for publishers. This option can be used with any custom setup block.

This configuration option enables publishers to provide an initial bandwidth estimate (in bits, as is standard for video bandwidth estimation) across all viewers. This estimate can be used when the player has no other information about the viewer’s bandwidth (e.g. in case of a first-time visitor). The player’s saved bandwidth information or the viewer’s manually-selected quality level always takes precedence over the default bandwidth estimate setting.

By default, the player’s initial bandwidth estimate for all viewers is 500000, or 500 kilobits per second download speed. But if you know your viewers tend to watch your content on broadband connections of at least 5 mb/s, you may want to set your “defaultBandwidthEstimate” to “5000000,” which will tell the player to choose an initial quality level of 5 mb/s bandwidth. Need to convert your estimate into bits? Here’s a handy calculator our engineering team uses!

One important thing to know is that the default bandwidth estimate affects the first estimate only. After the first segment, the player dynamically adjusts the viewer’s quality up or down to avoid viewers experiencing rebuffer events. The algorithm never requests a quality threshold that exceeds the width of the video player, which saves bandwidth and improves viewer experience.

For more information, see our support article about adaptive bitrate streaming, and for implementation details for the bandwidth configuration option, see our configuration reference. JW 8.3.0 is now available on the beta channel and for self-hosting and will be generally available tomorrow. We would love any feedback that you have to share.


To learn more about JW 8.3, schedule time to speak with a video expert.


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