The buffer is the cushion of media the player has downloaded ahead of the current playback position. When the network briefly slows or drops, the player keeps drawing from the buffer so the viewer sees no interruption; rebuffering happens only when the buffer runs dry.
Buffer size is a central design trade-off. A larger buffer is more resilient to network variability but increases latency (especially bad for live) and memory use, and wastes bandwidth if the viewer abandons. ABR algorithms watch buffer level as a key signal - filling it when conditions are good and easing quality before it empties. Tuning buffer targets is one of the most direct levers on the rebuffering that drives QoE.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
The player buffer absorbs network dips, and its size is a trade between fast start, low latency, and fewer stalls. The seven volumes cover the full video stack; for buffer tuning start with Volume 3 on players, buffer-based ABR, and recovery from stalls, then Volume 2 on latency budgets, with segment-friendly encoding in Volume 1. Written by Nikolay Sapunov, CEO at Fora Soft.
Rebuffering complaints on your OTT app? Is the player buffer tuned for your audience?
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