When you're watching a video that stutters or looks pixelated, chances are you're experiencing the effects of poor video bitrate. Whether you're streaming a film, joining a virtual meeting, or broadcasting live content, video bitrate plays a crucial role in the final experience.
In this guide, we’ll explain what video bitrate is, how it affects video quality and performance, and how to optimise bitrate for streaming. We’ll also compare low-bitrate vs high-bitrate scenarios, explore bitrate vs. resolution, and reveal tips to increase bitrate for better results.
Table of contents
Video bitrate refers to the amount of data transmitted per second in a video stream, usually measured in kilobits per second (Kbps) or megabits per second (Mbps). Simply put, it's the rate at which video data is encoded and transferred from source to viewer.
A higher bitrate means more data is being used to represent each frame, which can translate into better video quality, but also requires more bandwidth.
The bitrate directly impacts how sharp, clear, and smooth your video appears. Here’s how:
Higher bitrate = better quality? Usually, yes. Higher bitrate means more information is preserved during compression, which often results in better visuals.
Low bitrate = poor visuals. Low bitrate can lead to pixelation, blocky artefacts, and stuttering, especially in fast-moving scenes.
Video bitrate also determines how well the video handles complex scenes. Scenes with lots of motion or detail—like sports events or gaming streams—require a higher bitrate to avoid image degradation. If the bitrate is too low, these scenes appear blurry or smeared.
Resolution is the number of pixels in a video frame (e.g. 1080p), while bitrate determines how much data is used to deliver that resolution. You can have a high-resolution video with a low bitrate, and it will still look bad. Bitrate and resolution must work together.
A common misconception is that increasing resolution automatically improves video quality. In truth, if the bitrate isn't raised accordingly, the visual quality can actually worsen due to compression artefacts. Always consider bitrate as a companion metric to resolution.
Several factors determine the optimal bitrate for a video stream:
Video resolution and frame rate: Higher resolutions and faster frame rates demand more data.
Codec efficiency: Modern codecs like HEVC (H.265) offer better compression at lower bitrates compared to older codecs like H.264.
Motion and complexity: Action-heavy or visually complex videos require higher bitrates to maintain quality.
Available bandwidth: Your upload and your viewer’s download speeds can limit how much data can be transmitted.
Platform constraints: Streaming services often impose bitrate caps or use adaptive bitrate streaming to adjust quality based on network conditions.
Bitrate can also be affected by buffer strategies and congestion control algorithms. For example, live video conferencing platforms need to make real-time bitrate adjustments to maintain fluid conversation even when network conditions fluctuate.
In webcam-based video streaming, such as video conference meetings where user movement is typically minimal, encoding can be efficient. The suggested bitrates in the table below are designed to achieve a VMAF (Video Multimethod Assessment Fusion) score of 90, which means the video conference will have high quality.
Additionally, different codecs have varying efficiency levels.
|
Resolution |
H.264 |
VP8 |
VP9 |
AV1 |
|
1920 X 1080 |
2.7 Mbps |
2.0 Mbs |
1.2 Mbps |
900 kbps |
|
1280 X 720 |
1.25 Mbps |
1.0 Mbps |
700 kbps |
550 kbps |
|
960 X 540 |
700 kbps |
600 kbps |
450 kbps |
350 kbps |
|
640 X 360 |
400 kbps |
400 kbps |
270 kbps |
190 kbps |
|
384 X 216 |
170 kbps |
180 kbps |
120 kbps |
90 kbps |
|
320 X 180 |
140 kbps |
160 kbps |
90 kbps |
90 kbps |
|
160 X 90 |
50 kbps |
90 kbps |
35 kbps |
30 kbps |
These bitrate values are particularly relevant for video conferencing or any webcam streaming scenario where the objective is to balance quality with efficient bandwidth usage.
Yes. A high bitrate can tax both the sender’s encoding CPU and the viewer’s decoding capabilities. Too low a bitrate, and video quality suffers. It’s about finding the balance.
Bitrate influences CPU and GPU load. High-bitrate streams require more powerful devices to encode (for broadcasters) and decode (for viewers). It also affects network utilisation. Consistently high bitrates can overload routers or cause contention with other devices on the same network.
For real-time applications like video conferencing, Digital Samba uses optimised bitrate adaptation to ensure low-latency performance without sacrificing quality.
In most cases, bitrate is limited by your device's available bandwidth and storage capacity, which affects the video quality and overall experience of your stream. Plus, different platforms have different settings that can also influence the bitrate.
As such, optimising your video settings for various scenarios is crucial. For instance:
If video quality and viewer experience are crucial to your video streams, there are various techniques you can use. Let's take a look at them.
HEVC, also known as H.265, is an extended version of H.264 (AVC), typical for video compression. HEVC enhances video compression by up to 50% compared to H.264 without sacrificing quality, while allowing smaller file sizes that need less bandwidth. It's ideal for bandwidth constraints since it supports high-resolution streaming, making it efficient for 4K and Ultra HD content.
The bitrate comparison between H.264 and H.265/HEVC codecs reveals a significant difference in bitrate requirements for the same video quality. You can compare this with the table above to see the difference.
|
Resolution |
Bitrate (H.264) |
Bitrate (H.265 or HEVC) |
|
480p (Standard Definition) |
0.5 - 2 Mbps |
0.3 - 1.2 Mbps |
|
720p (High Definition) |
2.5 - 4 Mbps |
1.5 - 3 Mbps |
|
1080p (Full HD) |
3 - 5 Mbps |
2 - 4 Mbps |
|
4K (Ultra HD) |
15 - 25 Mbps |
12 - 20 Mbps |
Adaptive Bitrate Streaming (ABS) adjusts video quality in real-time based on network conditions, eliminating downloading limits and providing bufferless playback mode.
With this, those with higher bandwidth can watch streams at top quality, while those with lower bandwidth can watch them at a lower resolution that matches their bandwidth restrictions. For adaptive bitrate streaming, you can use streaming services like Digital Samba, which allows your users to stream quality videos depending on their bandwidth and internet connection.
Understanding the limitations of bitrate and bandwidth is crucial for delivering high-quality video content. By optimising bitrate settings for different platforms and scenarios, content creators can ensure a smooth and enjoyable viewing experience for their audience.
Looking to enhance your stream quality? Here’s how to increase video bitrate and boost performance:
When comparing low-bitrate and high-bitrate videos, it's essential to consider the trade-offs.
Let’s break it down:
Yes. Bitrate plays a crucial role in determining the clarity and smoothness of a video.
Upgrade your internet upload speed, use more efficient codecs, and adjust your encoding settings.
Not necessarily. Too high a bitrate can cause buffering if the network can't handle it. Aim for balance.
For 1080p at 60fps, aim for 4,500–9,000 Kbps using H.264.
HEVC delivers similar quality at a significantly lower bitrate, making it more efficient.
Does a higher bitrate mean better quality? Often yes—but not always. Video quality depends on more than just bitrate. Codec efficiency, resolution, and your viewers’ internet speed all matter.
For content creators and developers alike, mastering bitrate means delivering better experiences—whether that’s a smooth webinar, a sharp livestream, or a crisp on-demand video.
Optimising your bitrate settings can dramatically improve streaming quality and user experience. Whether you're streaming HD webinars or building a secure, GDPR-compliant video platform with Digital Samba, understanding video bitrate is key.
Digital Samba offers a robust video conferencing API and SDK for businesses seeking to enhance their video communication solutions, empowering them to deliver high-quality video experiences. Sign up today for a free account!