Very short segment durations are effective only when latency is more important than quality. Each TS segment must start with a key-frame, and the GOP size can'

Very short segment durations are effective only when latency is more important than quality. Each TS segment must start with a key-frame, and the GOP size can't exceed the duration of a segment (e.g. one second). Lowering the segment duration increases the frequency of key-frames, which has the effect of lowering the quality you can achieve at a given bitrate.