Streaming Technology
Latency, Jitter and Packet Loss: How They Affect Streaming
Why a fast connection can still stream badly: what latency, jitter and packet loss are, how they affect live and on-demand video, and how to reduce them.
Live channels and on-demand libraries often sit side by side in the same app, so it is easy to assume they work the same way. They do not. On-demand video is a file that already exists; live video is being created and delivered as you watch. That single difference explains why live streams are usually behind real time, why they buffer more readily and why a network that handles films perfectly can struggle with live sport.
Definitions
- Live streaming: video delivered as it is produced or broadcast — news, sport, live channels.
- Video on demand (VOD): pre-recorded content you start, pause and skip whenever you like — films, series, catch-up programmes.
How on-demand delivery works
The full video already exists on the provider’s servers, encoded at several quality levels and split into short segments. When you press play, your player can fetch segments as quickly as your connection allows, building up a buffer of many seconds or even minutes ahead of what you are watching. Short slowdowns are absorbed by that buffer and you never notice them.
How live delivery works
Live video has to be captured, encoded, packaged and distributed continuously. Segments become available only a few seconds before you watch them, so the player cannot build a large buffer. It must stay close to the “live edge” while keeping just enough in reserve to cover small hiccups.
The practical differences
| Live | On-demand | |
|---|---|---|
| Buffer size | Small — seconds | Large — can be much longer |
| Sensitivity to network hiccups | High | Low |
| Delay behind real events | Typically several seconds or more | Not applicable |
| Pause, rewind, skip | Limited or depends on service | Full control |
| Quality switching | Frequent if the connection varies | Less noticeable |
Why live streams lag behind real time
Each step of the live chain adds delay: encoding, packaging into segments, distribution through servers and the player’s own buffer. Delays of several seconds to well over half a minute are common, depending on the service and technology used. That is why a neighbour with a different service — or a broadcast TV — may react to a goal before you see it.
Lower-latency streaming technologies exist and some services use them, but reducing delay usually means a smaller buffer, which makes the stream more sensitive to network problems. It is a trade-off.
Why live streams buffer more readily
Because the buffer is small, a brief drop in connection quality that an on-demand player would hide can empty a live player’s buffer. Jitter and packet loss are especially disruptive. Latency, jitter and packet loss explains these terms.
Popular live events also concentrate many viewers on the same stream at the same moment, which tests the provider’s capacity.
What this means for your setup
If you watch a lot of live content:
- Prioritise stability. Use Ethernet where possible; see Ethernet vs Wi-Fi.
- Reduce competing traffic during big events.
- Keep devices updated; players improve their handling of live streams over time.
- Restart before important events to clear accumulated memory issues.
If live streams buffer while on-demand plays fine, the connection is probably borderline rather than broken. Our guide to fixing buffering covers the steps.
Catch-up and time-shift: the middle ground
Some services let you restart a programme already in progress, pause live TV or watch recent broadcasts later. These features use recorded segments, so they behave more like on-demand: larger buffers and fewer interruptions. Availability depends entirely on the service and the rights it holds.
Which should you choose?
Most people use both. Live streaming suits news, sport and shared moments; on-demand suits films, series and watching at your own pace. When evaluating a service, check which it emphasises and whether it offers features like catch-up. For definitions of the service types themselves, see IPTV vs OTT.
Common questions
Can I pause live TV on a streaming service?
Some services support pausing, rewinding or restarting live programmes for a limited time; others do not. It depends on the service’s features and the rights it holds for each channel.
Why do live streams look slightly worse than on-demand titles?
Live video must be encoded in real time, which leaves less time for the careful compression used on pre-recorded content, and live channels may be encoded at lower bitrates. On-demand titles can be encoded more efficiently in advance.
How can I reduce live-stream delay?
Delay is mostly determined by the service’s technology. You can avoid adding to it by keeping the player at the live edge, using a wired connection and keeping the app updated.
In short
On-demand video can buffer far ahead, so it shrugs off network hiccups; live video must stay near real time with a small buffer, making it more sensitive and slightly delayed. If live content matters to you, invest in a stable connection — it makes more difference than a faster plan.