41.6 How do live ingest and segmenting work?

Step 5: Deep dives (10 minutes)

• Contribution: the broadcaster sends a high-quality feed (over dedicated links or protocols like SRT/RTMP) to redundant ingest points.
• Encode: live encoders turn it into the ladder (Chapter 40) in real time; every rendition must line up on the same keyframes so players can switch quality between segments.
• Package: cut into segments, write rolling playlists (the latest few segments), and push to the origin.

Latency is mostly set by segment length and how many segments the player buffers:

Figure: shorter segments cut delay, at the cost of more requests and less cushion against a bad network.

In the chapter's code: 6-second segments with 3 buffered put viewers about 27 seconds behind the stadium; 2-second segments about 11 seconds; low-latency modes with 1-second partial segments (LL-HLS, low-latency DASH) about 6 seconds. Pick based on the product: a few seconds' less delay is worth a lot when neighbours with TV are cheering before your phone shows the six.

Memory code: "Shorter segments, shorter delay, smaller cushion."