Video bitrate is a crucial factor in determining the quality of video content, whether for streaming, broadcasting or video conferencing. Bitrate refers to the amount of data transferred per unit of time, affecting the video's size and quality.
This article will explore the concept of video bitrate and its impact on video quality. We will also discuss how bitrate affects resolution and video quality and compare low-bitrate vs high-bitrate video.
Additionally, we will answer common questions about video bitrate and provide recommendations for optimising video quality.
Table of content
In simple terms, video bitrate refers to the amount of video data being transferred in a particular amount of time, in this case, per second. It mainly affects the quality and size of the video. It is measured in kilobits per second (Kbps) or megabits per second (Mbps).
Video bitrate distinctly differs from audio bitrate in that it focuses on the data required for visual information and aspects such as resolution, clarity and smoothness, while audio bitrate deals with the data for sound.
There are two main types of bitrate encoding: constant and variable.
Video bitrate is crucial in determining video quality, and understanding its impact on streaming, broadcasting and video conferencing is essential for content creators and consumers alike.
Bitrate is a crucial factor in determining video quality, as it affects the size and quality of the video. A higher bitrate usually results in better video quality, as more data is used to represent each second of video.
Bitrate affects video quality in several ways, including:
Higher bitrate can result in sharper images, smoother motion and more vibrant colours.
However, higher bitrate also requires more bandwidth and storage, which can cause buffering issues and longer load times. Finding the right balance between bitrate and video quality is essential for a smooth and enjoyable viewing experience.
For example, streaming platforms like YouTube and Facebook Live recommend different bitrate ranges for different video resolutions and frame rates. Understanding how bitrate affects video quality can help content creators optimise their videos for different scenarios and platforms.
In addition to bitrate, several other factors significantly impact video quality. These include lighting, camera quality and encoding settings, all of which can interact with bitrate to affect the overall viewing experience.
For instance, poor lighting can lead to grainy or unclear footage, while high-quality cameras can capture more detail and produce sharper images. Moreover, the encoding settings, such as the codec and compression level choice, can influence the balance between file size and video quality.
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.
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 orHEVC) |
|
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.
When comparing low-bitrate and high-bitrate videos, it's essential to consider the trade-offs.
Low-bitrate video conserves bandwidth but may reduce image quality and visual clarity, especially in fast-paced or complex scenes. On the other hand, high-bitrate video requires more bandwidth but generally delivers better image quality, smoother motion and enhanced detail.
When choosing the right bitrate for different scenarios, such as live streaming, video conferencing and video on demand, it's important to balance between video quality and available bandwidth.
For instance, live streaming at 1080p may require a bitrate ranging from 3,500 to 6,000 Kbps for optimal quality. Understanding the pros and cons of each bitrate option is crucial for delivering the desired viewing experience while efficiently utilising available resources.
In summary, when it comes to video streaming, it's essential to understand the importance of video bitrate. This factor significantly affects both video quality and streaming performance. Grasping the interaction between bitrate, resolution and frame rate allows creators to optimise their videos for different situations and platforms, ensuring users a smooth and enjoyable viewing experience.
For top-quality videos, it's crucial to focus on quality assurance and monitor technical aspects like bitrate, buffer fill, and latency. This helps deliver professional-looking results. To maintain higher standards, it's vital to maintain an appropriate bitrate, frame rate and resolution. By doing so, you can guarantee a consistently excellent viewing experience for your audience.
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