By guest blogger Bryce Pedersen, VP Marketing, castLabs
Ideal for events such as sports, interactive TV, and social media, ultra-low latency is beneficial for many use cases and will soon become the new norm for OTT. Plus, there’s no waiting needed as it’s completely achievable now.
Digital terrestrial TV and IPTV can see latency of around 5-10 seconds. Whereas live OTT streaming, on the other hand, has traditionally encountered worse latency compared to conventional broadcasting, in the 30-45 second range. The delivery of video through digital workflows presents a number of bottlenecks contributing to delays that can add up to lengthy latency. The main time-eating culprits include:
- Encoding/packaging: processing of content to create streamable segments
- Transmission: ingest into CDN and delivery to the user’s playback device
- Players: downloading of segments and buffering of at least one segment length
However, OTT workflow latency has recently drastically improved across these elements thanks to the introduction of a new stream segment delivery method.
Chunked Transfer Encoding (CTE)
Instead of producing, sending, and downloading entire segments, CTE creates small self-contained ‘chunks’ within a segment. These chunk lengths can be as small as you desire (even down to one frame per chunk) and are transmitted using an HTTP/1.1 persistent connection. This speeds up delivery by enabling earlier playback as both the CDN and player apps don’t need to wait for a full segment to be available: they can instead use the smaller chunks as soon as they are ready.
Common Media Application Format (CMAF)
CMAF compliant streams can be used for either MPEG-DASH or HLS playback. However, CMAF streams using the MPEG-DASH flavor can best use HTTP’s CTE capabilities through the ‘availabilityTimeOffset’ indicator. This means player apps compatible with CMAF and ultra-low latency are capable of requesting a segment’s chunk data before the full segment is complete, and thus reach closer to the live edge.
castLabs and Anevia together provide an easy route to protected ultra-low latency playback using this new live streaming delivery technology.
1 Encoding & Packaging with Anevia’s Genova Live
At the content preparation stage, Anevia’s Genova Live enables speedy CTE for live playback packaged into CMAF streams. Genova Live’s encoding/packaging solution generates content as quickly as possible to mitigate the impact on latency.
2 Transmission with Anevia’s NEA-CDN
At the content delivery network (CDN) level, Anevia’s highly scalable NEA-CDN technology conveniently supports input and output streaming of CMAF low-latency chunks. A mandatory component of this is chunked stream delivery, which is enabled by transmission via HTTP/1.1.
3 Playback with castLabs’ PRESTOplay
castLabs’ feature-rich PRESTOplay SDKs support CMAF and CTE to offer ultra-low latency playback across Android, iOS, browers, TVs, game consoles, STBs, and native desktop apps. Video player apps built with PRESTOplay are able to receive CTE generated content much sooner than regular OTT live streams, allowing earlier playback. Additionally, with the introduction of segment chunks, players can reduce latency further by buffering using a short chunk length instead of a full segment length.
PRESTOplay SDKs offer additional functionality including synchronising playback times across platforms, catch-up mode if a stream falls too far behind the live-edge, and an artificial buffer to allow ABR switching for an optimal user experience.
Anevia’s encoding, packaging, and CDN solutions create ideal network conditions enabling PRESTOplay to provide blazing fast playback.
|PRESTOplay |||Stream Transmission |||Stream Quality |||Latency|
|Android||France to Germany||2 Mbps||~1.6 seconds|
|iOS||France to Poland||2 Mbps||~1.7 seconds|
Content Security with castLabs’ DRMtoday
Digital rights management (DRM) is often a required component to secure premium content. DRM itself does not contribute to stream latency, with only a marginal moment at playback start for the first licence retrieval. castLabs’ DRMtoday licence delivery network provides complete multi-DRM protection for all screens by supporting Google Widevine, Microsoft PlayReady, and FairPlay Streaming by Apple through a single integration.
OTT streaming services can benefit from Anevia and castLabs easy-to-deploy technology to minimise the camera-to-playback time gap across all screens. Learn how to reduce latency to below 5 seconds by downloading the eBook from Anevia. And contact us today to take advantage of our competitive solutions for high-quality experiences with low stream latency.
or contact castLabs: sales@castLabs.com
Attending NAB 2019? Let’s talk ultra-low latency!
Learn more about ultra-low latency at Anevia’s booth in the French Pavilion, booth #SU4317.
And check out an end-to-end playback demo in action at CastLabs’ NAB booth #SU10712.