castLabs’ PRESTOplay Video Players Enable Ultra-low Latency for Live Streaming

We’re pleased to support the next advancement in online live video. Our PRESTOplay suite of video player SDKs now features ultra-low latency for live streaming!

Low latency streaming is valuable in a number of different scenarios such as sports, news, betting, conferencing, second-screen experiences, and social media casting. The aim in providing a true live experience is to keep playback as close as possible to real-time recording.

Using our PRESTOplay SDKs, streaming services can build player apps that greatly minimize the camera-to-screen time gap across browsers, desktops, mobiles, and TVs. In many cases, content can be played back over HTTP with less latency compared to traditional broadcasting. For example, typical latency for HD cable TV can be around 5-7 seconds. Our player technology helps to drastically improve on this delay in online streaming scenarios.


Other player vendors can only utilize native iOS playback with standard latency logic. PRESTOplay’s ultra-low latency technology is also available on iOS!

Sub-second Latency with CMAF

The CMAF was developed, in part, to improve live streaming performance by allowing smaller fragments to be used inside of a given stream segment. This is used together with ‘chunked-transfer’ encoding which allows the distribution of the smaller CMAF fragments as soon as they become available (via HTTP 1.1).

Specifically, this allows playback of a stream’s segments to occur before they are completed downloading, or even finished being created in the first place. Streams using this method let compatible video players, like PRESTOplay, receive segments earlier and begin playing content significantly sooner.

Sub-second latency

Apps built with PRESTOplay can achieve <1 second latency when streaming CMAF content using this method!

Low Latency with MPEG-DASH & HLS

MPEG-DASH and HLS formats were not initially conceived with ultra-low latency in mind, however, PRESTOplay apps can attain sub-5 second latency. You also have the ability to manually override standard stream specs such as overcoming the 3-segments latency for HLS in order to get closer to the live edge.

Latency (with 1 second segment) Latency (with 2 second segments)
MPEG-DASH ~2.5 seconds (+/- 0.5) ~5 seconds (+/- 0.5)
HLS ~3 seconds (+/- 0.5)

Quick PRESTOplay Configuration

Configuring low latency across our players is easy! All of our PRESTOplay SDKs feature common API settings offering improved ABR heuristics and buffering, including unique optimizations for low latency. For example, the JSON options below can set latency behavior identically across each of our browser, desktop, Android, iOS, and UWP player technologies.

lowLatencyMode: true

When enabled, the player will stick as close as possible to the live edge. The distance from the live edge can be specified with suggestedPresentationDelayMs.

suggestedPresentationDelayMs: 0

The delay in milliseconds to maintain playback from the live edge.

lowLatencyCatchupMode: speedup|seek|none

Enables dynamic live-edge tracking to determine player behavior if playback position falls behind the current live-edge threshold of lowLatencyCatchupThresholdMs.

seek: playback will jump to the live edge.

speedup: playback speed increases by lowLatencyCatchupRate until reaching the live edge.

none: player will not catch up and continue to play.

lowLatencyCatchupThresholdMs: 3000 If playback falls below this value in milliseconds relative to the live edge then the lowLatencyCatchupMode setting is triggered (for example: when a buffer under-run occurs and the player waits for data).
lowLatencyCatchupRate: 1.1 Multiplier value to speed-up playback until reaching the live edge.

DRM-enabled For Premium Content

Each of our PRESTOplay SDKs also support DRM and key rotation for secured playback of premium live content. If you’re looking for multi-DRM licensing and access control, we provide the extensive DRMtoday license delivery network to simplify content protection.


Posted by

Bryce Pedersen

Bryce Pedersen
Global Marketing Strategy

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