Configure HLS Segments
When a video is transcoded, it is cut into many small pieces (.ts segments). The HLS segment duration controls how long each of those pieces is. It used to be fixed at 4 seconds — it is now configurable per library, and the new default is 6 seconds.
Why it mattersA longer segment produces fewer files, and therefore fewer requests to the CDN and to storage — it is a cost lever. Moving from 4s to 6s reduces the number of files per video by about 33%.
It does not reduce bandwidth in GB — the bitrate is the same. It can slightly increase time-to-first-frame and reduce seek precision.
The field
| Name | Type | Min | Max | Default | Required |
|---|---|---|---|---|---|
hls_segment_duration | integer | 4 | 15 | 6 | no |
Values outside the range, non-integer, or non-numeric return 400.
Where it lives
| Endpoint | Role of the field |
|---|---|
GET /library | returns hls_segment_duration |
GET /library/{library_id} | returns hls_segment_duration |
PUT /library/{library_id} | accepts hls_segment_duration |
Applies to new videos onlyChanging this configuration does not reprocess anything. Videos that are already converted keep the segments they have; the new value applies to the next upload or reencode.
Good to know
- You cannot choose the duration per upload. The value always comes from the library configuration. To vary it, change the configuration between uploads, or use separate libraries.
- The value is read when the upload finishes, not when it starts. Changing the configuration in the middle of a long upload makes the new value take effect.
- Configuration is currently available via the API only.