What is bandwidth for streaming? What’s the difference between bandwidth and speed? How much bandwidth do you need for 1080p streaming? We’ve got answers.
What is bandwidth?
Bandwidth is the capacity of a network to upload and download data. Internet bandwidth is the maximum volume of information you can send and receive in a measured amount of time. It’s generally calculated in megabits per second (Mbps).
When streaming video to the Internet, you are consuming upload bandwidth. It’s essential to know your network’s available upload bandwidth because it enables (and also limits) the quality of your outgoing streams.
Available bandwidth depends on the network router, environment, and most importantly, the connection type. For example, dial-up Internet had a maximum bandwidth of just 56 kilobits per second (kbps). In contrast, more modern connection types like fiber-optic landline (622 Mbps), Gigabit Ethernet (1,000 Mbps), and 4G LTE (100 Mbps) have much higher bandwidths.
Bandwidth vs. speed
Various online speed tests offer to test how fast your network is. But is that the same as bandwidth? Not quite. “Bandwidth” and “speed” are often used interchangeably, yet there is a difference between these two terms.
If bandwidth is the maximum rate for data transfer, speed is how fast data is factually downloaded or uploaded. Like bandwidth, the connection speed is also measured in Mbps.
Since live streaming involves uploading data to the Internet, having ample upload speed is important. In fact, for successful live streaming, you’ll need both sufficient upload bandwidth and upload speed.
As with download speed, upload speed has a set rate (e.g., “5 Mbps upload speed”) as dictated by your Internet service provider (ISP). Because bandwidth sets the upper limit for the data transfer rate, there’s no sense in purchasing Internet speeds from your ISP that exceed your maximum bandwidth.
Bandwidth vs. bitrate
Because raw video and audio are too hefty to upload, streamed content needs to be encoded. Encoding compresses video and audio content into a size and format that’s easy to send to the Internet.
Bitrate is the amount of data encoded per unit of time. When it comes to streaming, it’s usually measured in kKbps, and less frequently in Mbps. Generally speaking, the higher the bitrate, the higher the video quality, and the higher the upload bandwidth required.
The total bitrate consists of the video and audio bitrates. The bitrate setting will depend on the video resolution and frame rate. For higher resolutions and frame rates, you’ll need higher bitrate settings. For example, the recommended encoding settings for 4K streaming at 60 frames per second (fps) will be higher than that for 1080p streaming at 30 fps. Insufficient bitrate will cause your stream to appear choppy.
How much bandwidth do I need for live streaming?
The amount of bandwidth you’ll need depends on your encoding bitrate. For example, if you are encoding at 3,000 kbps, you will need at least 3 Mbps of upload bandwidth. If your stream’s bitrate is too high relative to your upload bandwidth, your live stream will be unreliable for viewers. For example, a stream with a 6,000 kbps bitrate doesn’t work on a network with a 5 Mbps upload bandwidth limit.
Above are the general required bandwidth for streaming guidelines. For example, the minimum bandwidth required for 1080p (HD) streaming is 5 Mbps, while the minimum 4K (UHD) streaming bandwidth is around 25 Mbps.
Different platforms (e.g., YouTube, Twitch, Facebook) have different speed requirements and recommended encoding settings. So be sure to double-check before streaming.
How to ensure you have enough bandwidth for streaming
It’s simple math to realize that if you have 5 Mbps of upload bandwidth, your stream bitrate should be less than 5 Mbps. But just how much less? Bandwidth limitations are only part of the story! You’ll need to consider some additional factors to ensure the success of your live stream.
Always have some extra bandwidth (and upload speed) available
Ensure you always have enough bandwidth for streaming your broadcast – plus more. This additional headroom acts as a buffer to account for any changes to your network. Any user activity on your network (e.g., Internet uploads, VoIP communication, gaming) can affect both bandwidth and upload speed.
Use the simple formula below to estimate the required bandwidth for streaming:
We recommend always having about 1.5x your stream’s bitrate available to account for these possible network fluctuations. For example, if your live stream has a bitrate of 5,000 kbps (5 Mbps), ensure you have at least 7.5 Mbps total upload bandwidth available to provide a reliable live stream. You may not need all of the calculated overhead bandwidth on a stable network, but it’s always best to be on the safe side.
Consider your network and connection type
As we mentioned, there are many different types of Internet connectivity, including fiber-optic, cable, satellite, and cellular data. Before live streaming, consider the varying levels of available bandwidth and network reliability each option offers.
For example, wireless cellular Internet tends to have lower maximum upload bandwidth and reliability, resulting in a lower-quality stream. Or maybe you live in a rural area and have a satellite connection. In that case, you might want to take weather into account before publishing your stream.
Fiber and cable connections generally offer higher speeds, which are best suited for live streaming. For improved reliability, it’s always best to use a hardwired Internet connection over Wi-Fi or cellular.
Consider ISP upload speeds and data caps
Many ISPs advertise upload and download bandwidth in terms of maximum and minimum speed.
For example, an Internet package might be advertised as “Up to 10 Mbps up and 30 Mbps down”. This particular “up to” phrasing is used because Internet speeds can vary. If using a cable network, for example, you’re sharing the Internet with other cable users within a geographical area, so your bandwidth may slow during “peak” periods of Internet activity during the day.
Some ISPs 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.
Running an Internet speed test is also important. You may have enough available bandwidth on your network but not enough upload speed, depending on how many devices are sharing the network and the types of activities on those devices.
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 stream to viewers of all levels of download bandwidth.
Keep in mind that each additional program you publish adds to your total outgoing bitrate and 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!
What are some of the most common issues you’ve experienced with bandwidth for streaming? Let us know in the comments!