ABR adjusts video quality based on network conditions:
How it works: Video encoded at multiple bitrates (p, p, p, K) Split into small segments (- seconds) Client requests segments based on available bandwidth Smooth quality switching mid-playback
Protocols:
- HLS (Apple): Widely supported, higher latency
- DASH: Open standard, more flexible
Client algorithm: Estimates bandwidth from download speed. Buffers ahead. Switches quality to avoid rebuffering.
Trade-off: Higher quality needs more bandwidth. Too aggressive switching causes visual artifacts.