Continuing the unofficial “Video Streaming 101” theme, it’s time to discuss bitrate and more importantly, your bitrate for streaming. This can be a complicated subject for novices to dip into and is also something that’s going to have a huge impact on your video streaming capability, so we’ll lay out the basics in the sections below.
- What is bitrate?
- What is a good bitrate for streaming?
- What affects bitrate speed for streaming?
- How do I deal with a low bitrate and optimize for better streaming?
What is bitrate?
A dictionary definition of bitrate would call it “the number of bits per second that can be transmitted via a digital network.” Bits being the “1” and “0”, binary digits, the most basic units of data in computing and communications.
Or if you want to take it more technical, bitrate is more descriptively “the number of bits that are conveyed or processed per unit of time.” Bitrate is usually expressed in units of bits per second, and since we live in a high tech, high bandwidth world, also usually with metric prefixes like kilo-, mega-, etc. A megabit per second (scientific notation 1 Mbit/s) is one million bits per second. In a possibly confusing move, bits per second are also commonly expressed in the mainstream (by commercial internet providers and the like) with the abbreviation bps but it amounts to the same thing (1 Mbit/s = 1 Mbps). Bitrate can be relevant in numerous different situations from communication to media encoding.
In practical terms regarding sending media over the internet though, bitrate is effectively going to mean the quality level of the media (audio or video) that you stream and upload, and how quickly it transmits.
For the most part audio bitrates for streaming lock in at 160 kbps (if you weren’t paying attention to the earlier paragraph, that’s160 kilobits per second) or sometimes, depending on the platform, a little lower. So as far as bitrate and your broadcasting, it’s generally the video bitrate you want to focus on.
What is a good bitrate for streaming?
That is a very subjective question to answer! However, the common off-the-cuff advice is that pushing for a high-resolution stream at the expense of playback quality is a bad trade-off.
The main thing you want to look for is a good upload speed from your internet provider. The upload rate, if you’re not familiar with it, is how many bits of data you can send out per second. We’ll get into it a little more below, but anything within the range of 672 kbps to 61.5 Mbps will work for you. Yes, that’s a pretty big range. Also, you may be asking why “higher” isn’t automatically “better”.
Streaming with a high bit rate does not guarantee better quality—in some cases, an excessively high bitrate can lead to an unstable stream. In other words, a smooth, stable video stream at a somewhat lower resolution like 720p is far more watchable than trying to stream out 4K (just for example) and ending up with choppy or frozen video. So, keep in mind that there’s also usually an upper limit of bitrate. At least for “standard” streaming set-ups at the time of this post, you’ll want to stick to a maximum of 6000 kbps. Think about it for now as a universal constant, like the speed of light in a vacuum.
Then, depending on your setup and gear, there might be a guide to optimal stream settings for the platform: for instance, YouTube and Twitch have their own guides for streamers. As a rule of thumb streaming full HD video, depending on the framerate, lands between 3500 and 6000 kbps. 720p HD is more forgiving to an entry-level streaming setup, starting at about a 2500 kbps bitrate and capping at 4000. Check what the requirements are for different resolutions and frame rates and how well your hardware (for encoding, etc.) and your internet connection can accommodate, and, again, remember that viewers will be more likely to judge your broadcast negatively based on broken and frustrating playback than whether its resolution is “Full HD” or higher. There’s no shame in starting with a 720p, 30 frames per second (fps) stream (as we mentioned, clocking a 2500-4000 kbps bitrate).
What affects bitrate speed for streaming?
We pointed out above that a good upload speed is key. You can check the specs your internet provider gives you, of course, but that might not give you the whole story about your actual speeds. The other thing to do is go to speedtest.net and see what your actual performance numbers look like—it’s entirely possible to hit a bottleneck where your upload and/or download speeds aren’t meeting the ISP’s claims. On the other hand, it could be performing as expected, or even faster than you thought. In any case, you have a baseline to set up your streams.
If you’re confident your internet connection is stable, you can try to push your stream settings to the last possible kbps. On the other hand, if it’s likely the speed could fluctuate (particularly if you use a shared connection for streaming, etc.) you’ll want to make sure your bitrate for streaming leaves a 35-40% buffer. So to broadcast a live stream at 720p resolution, 30 fps at an approximate 4160 kbps/4.16 Mbps bitrate, don’t use a connection with only 4 Mbps upload speed. Rather you want something at least around 5.7-6 Mbps so that you’re not immediately pushing your upload to the limit.
The bare minimum necessary is a 5 Mbps upload. If your upload is lower than that, it’s time to check in with your internet provider for a service or hardware upgrade. For video streaming, your upload needs will range from about 3.5 Mbps (the low end for SD video) to 8 or 9 Mbps (the high end for Full HD video. And anyone trying to stream more HD than that (Quad HD, 2K, 4K, and so forth) is probably an experienced broadcaster with a specialized setup, things which are outside the scope of this article.
Aside from that, as we’ve already indirectly covered, resolution and frame rate are going to be the key considerations.
The kind of stream and what kind of content you’re broadcasting will partly determine the ideal resolution and framerate, which in turn affect bitrate. For example, if you’re doing a gaming stream with a lot of fast action, you’ll probably want a higher framerate to make sure the onscreen action is smooth and clear. This is the main reason some Twitch streamers, for instance, stream at higher than 30 fps. On the other hand, if you’re doing a static “talking head” type of shot while speaking directly to the camera and not much else is happening in the frame, it could look absolutely fine at 30 fps and even in lower resolutions. In short, lots of visual information will require a higher bitrate.
Generally, for streams of multiplayer/multi-participant activity (…especially gaming streams!) where you both stream and participate from the same internet connection, remember to leave a little bit of a “buffer” of bandwidth for your own connection. If your entire upload limit is full from broadcasting the live stream and nothing’s left for connecting you to the game server/conferencing app/etc. you’ll be lagging and buffering yourself. (For non-gamers, if you’ve seen someone freeze up in Teams or a Zoom call, that’s what we mean.)
Additionally, what kind of encoder you’re using factors into bitrate–in short, it’ll mean how quickly the computer you’re using can process video. Which encoder works best for you is also a subjective concern, so we won’t get too far in the weeds, but there are a few different options for software encoding at varied prices. Or if you have the budget, you might move on to hardware encoders. This is a more advanced concern for when you’re past mastering the basics and are trying to optimize your streaming setup.
About encoding, don’t pump out video at the highest possible settings and assume just any platform will “take care of it” and downscale your video, especially if it’s live. Unless you’re using a custom service, many consumer-grade streaming platforms can struggle with platform-side encoding/transcoding and drop your video mid-stream, bottleneck, and process the stream with jerky video, and other undesirable outcomes. Best to stay within the boundaries they provide, give it some pre-thought, and be precise with the settings you think work best for your content.
How do I deal with a low bitrate and optimize for better streaming?
Helpfully, most platforms are more than happy to give you a guide to optimize your settings and bitrate for content streaming on the service. (You can check out one of Kaltura’s here.)
As you know, one of the first issues concerning low bitrate lies with your internet service provider. So, make sure that the provider you’re with offers speeds in the range you need—the good news is even residential connection speeds are trending “faster than ever.” However, be warned the faster speed on offer, the higher the bills will be likely to run. Also, be sure to check you’re using the best quality, most reputable service available in your area, and, if budget and circumstances permit, a business-level service usually features higher upload speed.
But what if you’ve got the best connection available and within your price range, and it’s still not quite optimal? Here are a few ways to boost your struggling bitrate:
Use a Wired Connection
Yes, WiFi is the wave of the future, but ask an IT pro or hardcore online gamer—a connection with an ethernet cable is just better. You’ll have less interference and more stability if you’re wired, which should improve your stream quality.
Clear off the Network
Your streaming setup would ideally be the only thing on your network when broadcasting. In the big leagues, they’ll use a dedicated connection. Whenever possible, clear off other devices from your internet connection (and/or shut down their WiFi) so nothing is siphoning upload speed.
Close Unnecessary Apps
(also, check for malware) The only thing that should be uploading during your stream is your encoder—or if you’re a game streamer without a dedicated streaming machine, the encoder and the game connection.
Similarly, malware and ads running in the background can mess with your performance. Do your best to get rid of them, they’re just bad.
Update, Update, Update
Even if you can’t have the most cutting-edge hardware, make sure your drivers and OS are always up to date. Keep things as current as possible, you don’t need anything to slow you down.
Consider Cloud-Based Solutions if Multistreaming
If you need to connect enterprise content to several platforms at the same time (which can be useful and great audience exposure for organizations and content creators) going to a cloud-based service can relieve strain on your hardware and bandwidth. Hey, we might be able to help you with that:
Ready to set up your live stream? Kaltura can help!