# Fast source switching
Compare how long the player takes to start after changing the source.
Tip: open your browser's developer console and use the `player` and `THEOplayer` variables to interact with this demo.
### Presets
Big Buck BunnyFrame counter 60 fpsAdult Swim
### Custom stream
URLTypeAuto (auto)Load
### Latest TTFF
Waiting for the first measurement.
### Recent switches
| Source | TTFF | Since source |
| ---------------------- | ---- | ------------ |
| No completed switches. | | |
The initial source stays paused until you start playback, so the time since it was set is left blank. When you load another source, the demo measures time to first frame and time since that source was set. It ignores events from superseded switches.
```js
function loadSource(streamUrl) {
player.autoplay = true;
player.source = {
sources: { src: streamUrl, type: 'application/x-mpegurl' },
};
}
```
Code
demo.html
```html
Fast source switching
```