Cached Fragments increase BandwidthEstimate causing suboptimal quality selection

What version of Hls.js are you using?

1.4.12

What browser (including version) are you using?

Chrome 117.0.5938.48

What OS (including version) are you using?

Windows 11

Test stream

No response

Configuration

default

Additional player setup steps

No response

Checklist

• The issue observed is not already reported by searching on Github under https://github.com/video-dev/hls.js/issues
• The issue occurs in the stable client (latest release) on https://hlsjs.video-dev.org/demo and not just on my page
• The issue occurs in the latest client (main branch) on https://hlsjs-dev.video-dev.org/demo and not just on my page
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream

Steps to reproduce

1. Open a page with a hls.js-video and have it load some fragments into the cache.
2. Reload the page with a throttled connection and watch the bandwidthEstimate
3. When cached fragments are used, the bandwidthEstimate shoots up and causes the quality level to go up, even though the connection is actually bad. This causes the video to stall, when loading big fragments with a bad connection

Expected behaviour

Disregard cached fragments in the calculation of the bandwidthEstimate

What actually happened?

Cached fragments are being treated as if they were loaded over the network

Console output

Will paste more tomorrow, but will just show the bandwidthEstimate increasing to over 6Mb/s even though the connection is set to 1Mb/s.

This is from my logs in the console:

BandwidthEstimate: 404816640
BandwidthEstimate: 6228293.959612044

Even Though the connection is set to 1Mb/s

Chrome media internals output

No response

Reproduce the issue using the listed Chrome, Windows 11, hls.js 1.4.12 setup and a throttled connection, then trace how bandwidthEstimate is updated when cached fragments are used. Confirm that cached fragments are excluded from network bandwidth measurement and that quality selection no longer rises incorrectly or causes stalls.