Rebuffering ratio is the share of a streaming session the viewer spent stalled rather than watching, defined as total stall time divided by stall-plus-play time and expressed as a percentage. It counts only the mid-playback freezes that occur after the buffer runs dry, with the initial startup wait and user-initiated seeks excluded, so the number is computed from player events under standards such as CTA-2066, never from the pixels. It is the streaming QoE metric most strongly tied to abandonment: a causal study found a stall equal to just 1 percent of a video's length cost about 5 percent of watch time, and buffering ratio carries the largest single effect on engagement across all content types. Its catch is that the ratio alone hides whether one long freeze or many short ones caused it, so it is read alongside rebuffering frequency and duration, and against the bitrate ABR trades for smoothness.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
Rebuffering ratio is the QoE number most tied to viewers leaving, so it is usually the first thing a streaming team should watch. Our seven-volume handbook spans the video stack, and Volume 3 is where to begin for rebuffering: ABR algorithms, buffer-based rung selection, CDN caching, player stall recovery and QoE monitoring. Written by Nikolay Sapunov, CEO at Fora Soft.
Is your rebuffering ratio costing you viewers you could keep?
We will audit your player and ABR settings against real session data and give you a plan to cut stalls. 250+ video products shipped since 2005.
