Overlength segments cause problems with playlist size and cleanup #164
Description
This applies to both HLS and DASH.
When NGINX is configured to create 2s segments but the incoming stream has a GOP size of 10s, the segments written are 10s long (this is fine).
However, when writing playlists the actual length of the segments is not taken into account. If the playlist length is set to 40s it will always contain 40s/2s = 20 segments, resulting in a playlist 20×10s = 200s long.
Since segment cleanup is independent, cleaning up segments older than two times the playlist length (2×40s = 80s), the cleanup will throw away segments that are still being referenced. The resulting playlist will have 20 - 80s/10s = 12 missing segments.