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How Adaptive Bitrate Streaming Helps with Bandwidth Management?

Rostyslav Pidgornyi
Streaming
September 22, 2024

Adaptive bitrate streaming helps manage bandwidth by automatically adjusting video quality based on the viewer’s internet connection. It ensures smooth playback without interruptions, even on slow networks, by reducing video resolution or switching to a lower bitrate when needed.

So, let’s say you’re watching a high-definition (HD) video, but your Wi-Fi suddenly slows down, or you switch from Wi-Fi to mobile data. With adaptive high bitrate streaming, the video automatically drops down in resolution, reducing the data load without interrupting playback.

Instead of buffering endlessly, your video quality just drops for a moment until your connection stabilizes. This adaptability is what makes it such a powerful tool for bandwidth management.

In 2024, video streaming accounts for a significant portion of global internet traffic, making up around 74-82% of all internet data usage, so just imagine the impact. 

1. Dynamic Bandwidth Utilization

ABR segments the video into small chunks, each encoded at multiple bitrates. These chunks are stored on the server, and during playback, the client device monitors available bandwidth and selects the highest quality chunk it can support at that moment. 

This means if bandwidth dips, the stream will automatically switch to a lower bitrate, avoiding the need for buffering or long pauses. This adaptability allows for continuous playback without overloading the network with more data than it can handle at any given time.

This efficiency directly translates to improved bandwidth management, as only the necessary amount of data is transmitted per user, rather than a one-size-fits-all stream, which can overload a network. 

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2. Chunk-based Control Reduces Bandwidth Spikes

Traditional video streaming (e.g., progressive download) tends to download a large portion of a video upfront, often at the highest quality. In contrast, ABR's chunk-based system ensures that only small, manageable pieces of the video are streamed at any time. 

This smoothens out network traffic and prevents bandwidth spikes that might otherwise occur when multiple users start streaming at once or during high-traffic periods.

For example, if 4K video were sent as a single file, users with slower internet connections or congested networks would face massive delays and buffering issues.

 

But with ABR’s chunked transfer, the system might deliver lower-resolution 1080p or even 720p chunks instead, reducing the burden on the network while maintaining playback, which also makes it more CDN-friendly​.

Example

Let’s assume the following parameters:

  • Chunk duration: 5 seconds per chunk
  • Resolution: 1080p (Full HD)
  • Bitrates: 4 Mbps, 6 Mbps, and 8 Mbps

Chunk Size (MB) = {Bitrate (Mbps) × Chunk Duration (seconds)​} / 8

Chunks per minute = 60 / Chunk Duration (seconds)

Bitrate (Mbps) Chunk Duration (seconds) Chunk Size (MB) Chunks per Minute Bandwidth Usage per Minute (MB)
4 5 2.5 12 30
6 5 3.75 12 45
8 5 5 12 60

This chunk-based approach allows for more efficient bandwidth management, as the system dynamically adjusts the quality of each chunk based on real-time network conditions. So, even if you’re streaming 4k, the dynamic adjustment of the bitrate ensures you can get fine-tuned bandwidth utilization. 

3. Efficient Buffer Management

ABR leverages a sophisticated buffer management system to anticipate bandwidth drops before they affect the user experience. It preloads small chunks into the device’s buffer when bandwidth is sufficient, allowing for a temporary cushion when network conditions worsen. 

This buffer management is a key factor in how ABR prevents video stalls and optimizes the use of available bandwidth.

The player also monitors buffer levels to adjust the bitrate accordingly, preventing the network from getting overwhelmed by unnecessarily high-quality streams when there’s no room in the buffer. This granular control ensures the network is never pushed beyond its limits.

4. Impact on Multi-Device Environments

In households or environments where multiple devices are sharing the same internet connection, ABR really shines. Without ABR, each device would consume a set amount of bandwidth, regardless of how strong or weak the connection was at the time. This could lead to one device hogging all the available bandwidth, leaving others to suffer.

ABR ensures that each device receives a stream tailored to its specific bandwidth constraints, preventing a single device from overloading the network. 

This dynamic allocation of resources is crucial in multi-device environments, where maintaining an optimal balance between devices can prevent network slowdowns and dropped connections.

5. Bandwidth Savings for Content Providers

For content providers, ABR helps reduce the infrastructure costs associated with streaming high-bitrate videos to all users, regardless of their network conditions. 

By delivering lower-bitrate streams to users with limited bandwidth, ABR reduces the overall data transferred, cutting down on the costs of bandwidth usage on the server side. This is particularly useful for mobile streaming, where data caps are a concern.

Resolution Bitrate (Mbps) Bandwidth Utilization (GB per hour) Recommended Internet Speed (Mbps)
480p (SD) 1.5 0.65918 1.875
2 0.878906 2.5
2.5 1.098633 3.125
720p (HD) 2.5 1.098633 3.125
3.5 1.538086 4.375
5 2.197266 6.25
1080p (Full HD) 4 1.757813 5
6 2.636719 7.5
8 3.515625 10
1440p (Quad HD) 8 3.515625 10
12 5.273438 15
16 7.03125 20
4K (Ultra HD) 15 6.591797 18.75
20 8.789063 25
25 10.98633 31.25

Moreover, adaptive bitrate streaming allows content providers to optimize their server load by serving only what’s needed, thus reducing the strain on their data centers, especially during peak usage times​.

6. Reduces Latency in Live Streaming

ABR also plays a key role in live video streaming, where the ability to adapt in real time is even more critical. During live events, bandwidth congestion is a common issue, especially when thousands of viewers are tuning in simultaneously. 

ABR helps manage this by dynamically reducing the video quality for viewers with weaker connections, reducing latency without disrupting the live feed. By serving lower bitrate streams when necessary, the live event continues without buffering, even under heavy network load​.

7. Closed-loop Control for Network Efficiency

In the case of advanced implementations like Dynamic Adaptive Streaming over HTTP (DASH), ABR uses closed-loop control algorithms to monitor network bandwidth and device capabilities. 

This approach helps the system continually learn and adjust to real-time conditions, further optimizing bandwidth use by avoiding network congestion and adjusting quality proactively based on predictive modeling