Play test bandwidth fragment if the internet is slow

[arturo32]

Is there a way of not throwing away the test fragment requested by setting startLevel: -1?

Like, if a user has slow internet, it would be great if the first fragment in the lowest quality requested by HLS.js could be played instead of being requested again.

I'm talking about this configuration:

const hls = new Hls({
      startLevel: -1
})

Resulting in:
[test request of the first fragment in 360p] (HLS.js is testing the bandwidth)
[request of first fragment in 350p to be played] (HLS.js discovered the that the quality is 0! And is making the same request...)
[request of the second fragment in 360p]
...

Instead of:
[test request of the first fragment in 360p] (HLS.js is testing the bandwidth)
[playing the requested first fragment] (HLS.js discovered the that the quality is 0! And is using the already requested fragment!)
[request of the second fragment in 360p]
...

[robwalch]

Is there a way of not throwing away the test fragment requested by setting startLevel: -1?

No. This is the path for loading the bitrate test fragment. It is not selected based on the startPosition, and it is flagged with fragment.bitrateTest so that it is not used for any other purpose:

hls.js/src/controller/stream-controller.ts

Line 1193 in 84e4fbd

private _loadBitrateTestFrag(fragment: Fragment, level: Level) {

[robwalch]

What you can do is start on level 0. Then, once loaded, change current level to throw that first segment out, or do nothing and let it switch later.

const hls = new Hls({
  startLevel: 0
});
hls.once(Hls.Events.FRAG_LOADED, (n, data) => {
  // choose whether to use the segment of not based on data.frag.stats
  // setting `currentLevel` will drop or flush the fragment and make an auto switch. Don't do this if you want to use this segment.
  hls.currentLevel = -1;
});

[arturo32]

Thank you very much for this alternative!