1. Capture and encoding
A channel starts as a broadcast feed. An encoder compresses it into a format suitable for the internet, typically H.264 (AVC) or the more efficient H.265 (HEVC). Compression is a trade-off. Lower bitrates save bandwidth but can show blockiness, especially in fast sport.
Many services encode each channel at several quality levels (for example SD, HD and 4K) so the player can choose the best one for your connection.
2. Packaging
The encoded video is cut into short chunks and packaged in a streaming format, commonly HLS (HTTP Live Streaming) or MPEG-TS. Your app downloads these chunks one after another and stitches them into smooth playback.
3. Origin servers and CDNs
- The origin server holds the master copy of every stream.
- A content delivery network (CDN) copies streams to edge servers close to viewers, so thousands of people are not all pulling from one machine.
A good CDN is what keeps a big live event watchable when demand spikes.
4. Your home connection
The last stretch is your broadband and Wi-Fi. This is where most problems happen:
- Peak-time congestion in the evening affects everything on your line.
- Wi-Fi loses speed through walls and distance.
- Other devices at home share the same bandwidth.
5. The player
Your app requests chunks, keeps a small buffer ahead of what you are watching and, with adaptive bitrate, switches quality up or down as your speed changes. If chunks arrive slower than you watch them, the buffer empties and the picture pauses. That is buffering.
Unicast vs multicast
- Unicast sends a separate stream to each viewer. That is how most internet streaming works.
- Multicast sends one stream that many viewers share, which is efficient but only possible on managed operator networks. See IPTV vs OTT.
What this means at home
Most buffering is in the last stretch, your connection, not the server. Our buffering guide works through the fixes in order, and 4K and HD explains the bandwidth each quality level needs.