Matching Quality to Bandwidth
Networks fluctuate. Adaptive bitrate streaming encodes the same video at several quality levels and lets the player switch between them as conditions change, avoiding both stalls and wasted bandwidth.
How It Works
- The video is split into short segments, a few seconds each
- Each segment exists at multiple bitrates, called renditions
- A manifest lists the renditions and segment locations
- The player measures throughput and buffer level, then picks the next segment bitrate
When bandwidth drops, the player requests a lower rendition; when it recovers, it climbs back up. Because switching happens at segment boundaries, playback stays smooth.
Why It Matters
- Fewer rebuffering stalls on weak connections
- Higher quality when the network allows
- CDN friendly since segments are static cacheable files
Key idea
Adaptive bitrate streaming encodes video at many bitrates in short segments and lets the player switch renditions based on measured bandwidth, trading quality for stability without stalls.