Video bitrate

What is video bitrate?

Bits are units of data that make up a piece of digital content, like a photo or video. Bitrate refers to how many bits can be transferred or processed within a certain amount of time. Bitrate is usually measured in the number of bits per second. When we’re talking about upload and download speeds, or internet speed in general, what we’re really talking about is bitrate. 

Videos contain a lot more bits than, say, high-res photos or regular old emails. If the bitrate is too low, your video may get compressed. That means even if your video starts out with high resolution and a high frame rate, your viewers may end up seeing a poorer image quality.

Video bitrate measurements 

Bitrate is measured in bits per second, which is often abbreviated as bps. Audio files are typically measured in kilobits per second, but because video files tend to be so large, we sometimes measure them in megabits per second (Mbps).

Avoid mixing up Mbps and MBps, which mean different things. Megabits (Mbps) per second refers to upload and download speeds, while megabytes (MBps) per second refers to the volume of info that gets transferred.

Video bitrate vs. video resolution

An important thing to keep in mind is the difference between bitrate and resolution. Video resolution is the number of pixels that make up an image on your screen; video bitrate is the speed at which data is processed. Resolution is usually written as 720p or 1080p, referring to images that are either 720 pixels wide or 1,080 pixels wide.

How does bitrate affect video quality?

Is a higher bitrate always better? Not necessarily. A higher bitrate results in better quality but also larger file sizes. The larger the file, the more buffering issues it may cause, since the server resources of most viewers can’t process really big files quickly. So finding the best bitrate is a bit of a balancing act. You want it to be high enough that your video is sharp and clear, but not so high that viewers struggle to watch it.

• Facebook Live recommends a max bitrate of 4,000 Kbps, plus a max audio bitrate of 128 Kbps.
• YouTube Live recommends a range between 1,500 and 4,000 Kbps for video, plus 128 Kbps for audio.
• Twitch recommends a range between 3,000 and 6,000 Kbps for video, plus up to 160 Kbps for audio.

Other factors that influence video quality

Consider the other factors besides bitrate that affect your live videos, like frame rate and resolution. 

• Frame rate is a rate at which the images or video frames are played to create motion. The frame rate is measured in frames per second (fps). The standard rate is 24fps for most video formats. But there are also videos with higher frame rates, ranging from 30fps to 60fps. Frame rate plays a significant role in live streaming, especially when it comes to broadcasting high-tempo sports or music events. On this point, higher fps leads to a better output video signal. 
• Resolution indicates the number of pixels that form the video frame and make up its image. Generally, more pixels bring on a sharper look for the frame. The video resolution types often used for broadcasts are represented as 480p, 720p, 1080p, and 4K. Resolution matters when it comes to improving the viewing experience on large displays. 

You also have to take into account several other factors when choosing a bitrate, including:

• Upload speed
• Video compression
• Device compatibility
• Streaming platform you’re broadcasting to

It’s better to have a stable stream with a lower resolution or frame rate than to choose higher values and end up streaming with a delay.

Bitrate and bandwidth limits

When broadcasting, you may experience bandwidth limits for both upload and download transfers. 

Bandwidth refers to the maximum throughput of the network for uploading and downloading data. The larger the data request, the higher bandwidth it needs to pass through. When the bandwidth is insufficient, it induces breakpoints and slows down the transferring process.

The bandwidth, same as speed, can be measured in Mbps. Many internet providers specify how much bandwidth their networks allow. If they provide 100 Mbps for downloads and 5 Mbps for uploads, the network can easily cope with downloading content but may not handle uploads fast enough for quality live streaming. 

How to deal with bandwidth limits

There are a few things both streamers and viewers can do to adapt to bandwidth limits.

• High-efficiency video coding (HEVC) or H.265. This is an extended version of H.264 or AVC, which is the industry standard for video compression. HEVC enables video compression without affecting the quality — it allows for a smaller file size that requires less bandwidth. Plus, viewers whose devices are compatible with H.265 also need less bandwidth; hence, they have a better chance of watching the stream in premium quality.
• Platforms that support adaptive bitrate streaming (ABS). These work well when it is necessary to eliminate downloading limits. Not only do they provide bufferless playback mode, but they also automatically optimize video resolution, which results in more viewing options to choose from. Viewers with higher bandwidth can watch the broadcast in top quality, whereas people with limited bandwidth can watch it with a lower resolution and frame rate to match their restrictions. 

Buffer-free broadcasting: the best video bitrates

Broadcasting usually requires more bandwidth compared to a pre-recorded video that is simply uploaded to a website. Upload speed depends on several factors, including the type of content, encoding, and site you want to stream to, as well as resolution and frame rate.

Let’s say you want to stream on platforms like Facebook, YouTube or Twitch and expect the broadcast to be bufferless. Here are some insights on the best video bitrates to use:

• Full HD Video with a high frame rate (1080p, 60fps): your bitrate should be 4,500 to 6,000 Kbps
• Full HD with a standard frame rate (1080p, 30fps): your bitrate should be 3,500 to 5,000 Kbps
• Regular HD with high frame rate (720p, 60fps): your bitrate should be 3,500 to 5,000 Kbps
• Regular HD with standard frame rate (720p, 30fps): your bitrate should be 2,500 to 4,000 Kbps

Additionally, consider these tips to enhance your upload speed for streaming:

1. Use a wired connection. Since it is more stable compared to Wi-Fi, you can expect no interruptions during the stream and consequently better quality of live video. 
2. Go with a multistreaming service, like Restream. It allows broadcasting to multiple platforms simultaneously and relieves your system by carrying part of the load.
3. Turn on ad-blockers and privacy tools. They will limit the use of upload bandwidth by various unwanted programs. 
4. Make sure to use modern software and hardware. Out-of-date systems slow down your computer and become a real bottleneck for your upload bandwidth, which generally leads to worse streaming quality. 

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