“How much upload bandwidth do I need to live stream?” is a common question addressed by our Support department. It’s also an important question. If you don’t have enough bandwidth for streaming out, then viewers will be unable to view your content and your live stream won’t be successful.
So how much streaming upload bandwidth do you actually need to ensure a successful live broadcast? The answer is… it depends! Understanding factors such as stream quality, encoding settings, and other conditions are essential to configuring a worry-free and reliable live broadcast.
This article was originally published on the Epiphan blog on March 30, 2017. The current version has been updated in July 2019.
What is bandwidth? Streaming upload bandwidth in a nutshell
When streaming out to the Internet, you are consuming upload bandwidth. Examples of uploading include attaching a file to an e-mail, saving a file to Cloud storage, or publishing a live stream. As with download bandwidth, upload bandwidth has a set rate (i.e. “5 Mb/s up”) as dictated by your internet service provider (ISP). Download bandwidth limits are also generally higher than upload limits (e.g. “15 Mb/s down and 5 Mb/s up”). It is essential to know your network’s upload speed because this rate enables (and also limits) the quality of your outgoing streams.
Encode your stream to fit your network
Streamed content needs to be encoded. Video (and to a lesser extent, audio) content that is not compressed consumes far too much upload bandwidth to support a reliable broadcast for viewers. Encoding your content is done with a small program, called a codec, using either software (such as free open-source solution, OBS Studio) or hardware (like “all-in-one” live production mixer, Pearl-2). The goal of encoding is to digitize and compress your video and audio content to a bandwidth-friendly file size without sacrificing quality.
A stream’s video and audio data processed over a period of time is called bit rate. Higher bit rates generally translate into higher quality video and audio. If your stream’s bit rate is too high relative to your upload bandwidth however, then your live stream will be unreliable for viewers. For example, a stream with a 6 Mb/s bit rate doesn’t work on a network with a 5 Mb/s upload bandwidth limit.
It’s important to have your selected bit rate roughly match the resolution (i.e. SD, HD, Full HD, etc) you’ve chosen to publish. If your program’s bit rate doesn’t agree with your frame size, the quality of the stream is reduced until the configured bit rate value is met—usually resulting in dropped frames and poorly encoded visuals. Naturally, the required network bandwidth for 4K streaming will be higher than that for 1080p streaming.
If you have specific resolution in mind for your live stream, you can consult Netflix’s Internet Speed Recommendations page. While the list below is intended for Netflix viewers (so viewers can confirm they have the required download speed to watch a stream), you can nonetheless use the information provided as a ballpark estimate of the bit rates required for each popular resolution. (Note: these values are simply recommendations—they are not necessarily industry standard!)
Above are the general required bandwidth for streaming guidelines. For example, the minimum required upload bandwidth for 1080p streaming is 5 Mbps, while the minimum 4K streaming bandwidth is around 25 Mbps.
Considerations for live streaming success
It’s simple math to realize that if you have 5 Mb/s of upload bandwidth, your stream bitrate should be less than 5 Mb/s. But just how much less? Bandwidth limit is only part of the story! You’ll need to consider some additional factors to ensure the success of your live stream.
1. Always have some extra upload bandwidth available
Ensure you always have enough bandwidth for streaming your broadcast—plus more. This extra “headroom” acts as a buffer to account for any changes to your network. Upload bandwidth can be affected by all forms of user activity on your network, such as Internet uploads, VOiP communication, or gaming.
Use the simple formula below to estimate the required bandwidth for streaming:
We recommend to always have approximately 1.5x your stream’s bit rate available to account for these possible network fluctuations. For example, if your live stream has a bit rate of 5 Mb/s, then ensure you have at least 7.5 Mb/s total upload bandwidth available to ensure a reliable live stream.
You may not need all of the calculated overhead bandwidth for a truly stable network, but it’s always best to be on the safe side and have too much rather than too little!
Note that our “1.5x rule” applies to most live streaming situations—except for when streaming out at a relatively low quality (i.e. less than standard definition). Since your total outgoing bit rate is so low, multiplying by a factor of 1.5 likely won’t provide enough headroom to protect against any unplanned upload activity on your network. In these cases, we recommend you allocate some extra bandwidth just to be safe!
2. Consider your network type
There are many different kinds of Internet connectivity, such as DSL, cable, satellite, cellular data, and more. Each of these options has varying levels of download/upload speed capability and network reliability that should be considered before attempting a live broadcast. For example, DSL tends to have lower maximum upload bandwidth which may limit the bit rate, and therefore quality, of your published stream. Or maybe you live in a rural area and have a satellite connection? In which case it would be wise to consider possible obstructive weather conditions before publishing your stream.
3. Consider ISP upload speeds and data caps
Many ISP’s advertise upload and download bandwidth in terms of a maximum speed.
For example an Internet package might be advertised as “Up to 10 Mb/s up and 30 Mb/s down!”. This particular “up to” phrasing is used because Internet speeds can vary. If using a cable network, for example, you’re sharing Internet with other cable users within a geographical area, so your bandwidth may slow during “peak” periods of Internet activity during the day.
Some ISP also have bandwidth usage maximums—so be aware your live stream doesn’t go beyond your monthly upload cap or you may be charged additional fees.
Not sure of your upload speed offhand? There are plenty of free Internet speed tests online you can use, such as the Google Fiber speed test.
4. Ensure you have additional bandwidth if streaming multiple programs
Multi-streaming is an increasingly popular live streaming strategy that involves publishing your broadcast to more than one content distribution network (CDN) platform simultaneously. Multi-encoding, on the other hand, is a similar technique that involves streaming the same program to the same CDN at different bitrates. Multi-streaming allows live streams to reach a greater audience while multi-encoding helps to ensure accessibility of your live to viewers of all levels of download bandwidth.
If using these techniques, it’s essential to consider that each additional program you publish adds to your total outgoing bit rate and therefore requires additional upload bandwidth availability.
The final word
As you can see, the required bandwidth for streaming for a reliable live broadcast depends on a variety of factors. While there is no “one size fits all” configuration, rest assured that with the right tweaking you can publish a successful and reliable live stream regardless of your network.
And remember—as a general rule of thumb, we recommend your streaming upload bandwidth be at least 1.5x the combined bit rate of all your streamed programs (when streaming in SD or above). Happy streaming!
The post Bandwidth for streaming: how much do I need? appeared first on Epiphan Video.