Best Practices for Ultra High-Definition Streaming

Applies To:

HTTP LargeThis platform has been optimized to cache and deliver static content (e.g., HTML, CSS, JavaScript, ISO, multimedia, and software downloads, etc.) over HTTP or HTTPS.

Dynamic Cloud PackagingThis streaming solution facilitates HLS and/or MPEG-DASH playback of live or on-demand content. A live stream may be pushed to this service via RTMP.

This article describes best practices for setting up on-demand streaming of Ultra-High Definition (UHD) media.

What is Ultra High-Definition?

UHD refers to media with:

An aspect ratio of 16:9 or wider.
A minimum resolution of 3840 pixels by 2160 pixels.

Common UHD formats are:

Term	Aspect Ratio	Resolution
4K	16:9	3840 x 2160
4K	17:9	4096 x 2160
8K	16:9	7680 x 4320
8K	17:9	8192 x 4320

Why is streaming UHD content challenging?

UHD consists of a much higher resolution than Standard Definition or High-Definition. This dramatically increases the amount of data that needs to be transferred to the viewer. For example, a 4K video with a 16:9 aspect ratio consists of 9 times the number of pixels than High-Definition (HD).

Format	Resolution	Pixels	Multiplier
Standard Definition	640 x 480	307,200	1x
High-Definition	1280 x 720	921,600	3x
Ultra High-Definition (4K; 16:9)	3840 x 2160	8,294,400	27x
Ultra High-Definition (8K; 16:9)	7680 x 4320	33,177,600	108x

Large bandwidth requirements may create an environment that is conducive to a long start up delay, buffering, stuttering, and other streaming-related issues.

Additional factors that affect the bandwidth required for your on-demand content are the refresh rate (i.e., frames per second) and the bitrate at which it was encoded.

Best Practices

Encode your content using the following configuration:

Setting	Recommendation
Segment duration	2 - 4 seconds Learn more. A segment duration larger than the above recommendation will increase the amount of time it takes to download each segment. This may impact the player's ability to buffer the stream, since it may not be able to download sufficient segments to offset unexpected network issues. Example: A 10 second segment from a 12 Mbps video is approximately 15 MB, while a 2 second segment from the same video is only 3 MB. Downloading a 3 MB file will be noticeably faster than a 15 MB file.
Key frame interval	It should not exceed the segment duration. Learn more. Specifying a key frame interval larger than the segment duration will generate segments larger than expected. Larger segments may impact the player's ability to buffer the stream. Some encoders use variable key frame intervals. This type of configuration is discouraged, since it may result in larger segments.
Bitrate	Leverage dynamic streamingAllows a media player to dynamically switch between bit rate streams of varying quality levels, in order to provide an optimal viewing experience based on a client’s bandwidth and CPU usage. by: Encoding your content using bitrates of varying quality. Our bitrate recommendation for your highest quality video should fall in between the following range: 4K: 15 to 25 Mbps 8K: 30 to 40 Mbps Encoding media at a bitrate that is 50 Mbps or higher may cause a long start up delay, frequent re-buffering, audio/video sync issues, and video streaming interruptions. Identifying each asset within your playback URL. Learn more.

Setting

Recommendation

Segment duration

2 - 4 seconds

Key frame interval

It should not exceed the segment duration.

Bitrate

Leverage dynamic streamingAllows a media player to dynamically switch between bit rate streams of varying quality levels, in order to provide an optimal viewing experience based on a client’s bandwidth and CPU usage. by:

Encoding your content using bitrates of varying quality.

Our bitrate recommendation for your highest quality video should fall in between the following range:
- 4K: 15 to 25 Mbps
- 8K: 30 to 40 Mbps
Encoding media at a bitrate that is 50 Mbps or higher may cause a long start up delay, frequent re-buffering, audio/video sync issues, and video streaming interruptions.
Identifying each asset within your playback URL.

Learn more.

Set up your CDN environment as indicated below.

Setting	Recommendation
Storage location	Store your on-demand content on the web server(s) associated with a customer origin configuration. Serving your content from your web servers allows you to leverage Origin ShieldThis feature provides a layer of protection for a customer origin server by creating an intermediate caching layer between it and our edge servers. This caching layer resides on one or more of our point-of-presence (POPs). Requests that have not been previously cached on a POP will be channelled through the closest origin shield server. The origin shield server will then either serve a cached version of the requested content or retrieve it from a customer origin server. This feature shifts the network load from the customer origin server to the CDN, since most requests will be handled by the origin shield server..
Origin Shield	Enable Origin Shield and set it to the POP closest to the web servers associated with the above customer origin configuration. Leveraging Origin Shield improves delivery performance by reducing the number of requests that need to be served by your web servers.

Setting

Recommendation

Storage location

Store your on-demand content on the web server(s) associated with a customer origin configuration.

Serving your content from your web servers allows you to leverage Origin ShieldThis feature provides a layer of protection for a customer origin server by creating an intermediate caching layer between it and our edge servers. This caching layer resides on one or more of our point-of-presence (POPs). Requests that have not been previously cached on a POP will be channelled through the closest origin shield server. The origin shield server will then either serve a cached version of the requested content or retrieve it from a customer origin server. This feature shifts the network load from the customer origin server to the CDN, since most requests will be handled by the origin shield server..

Origin Shield

Enable Origin Shield and set it to the POP closest to the web servers associated with the above customer origin configuration.

Leveraging Origin Shield improves delivery performance by reducing the number of requests that need to be served by your web servers.