hls.js tries to download segments when offline

[akkiyan]

hls.js version v1.6.7

Go to https://hlsjs.video-dev.org/demo, open browser dev tools and insert this link:
https://test-streams.mux.dev/x36xhzz/url_6/193039199_mp4_h264_aac_hq_7.m3u8

After clicking play video, in the Network tab in dev tools you need to switch to offline.
What hls.js doing? They trying to download all segments from a playlist even offline.
Why?

hls.js 1.5 works fine, but new version buggin

[hongjun-bae]

Of course, the segment download is not working for me either. It would be helpful if you could include the debugging logs.

[akkiyan]

The log is too big, I recorded a video
https://vimeo.com/1102091493?share=copy#t=0

[robwalch]

HLS.js v1 does not toggle loading based on offline status. You can handle this in your app by calling stopLoad() and startLoad() when navigator.onLine changes.

[robwalch]

The video shows retry logic for the segment that HLS.js needs. It is not trying to load all the segments in the playlist as the title suggests. All versions do this (with some differences in retry logic). This is not a regression.

[akkiyan]

Hi.
I'm using Google Chrome v135.0.7049.96 (win10x64)

hls.js v1.4.13 works correctly. If the next segment can't be downloaded after several attempts - it throws an exception fatal: true

https://16f1932e.hls-js-dev.pages.dev/demo/?src=https%3A%2F%2Ftest-streams.mux.dev%2Fx36xhzz%2Furl_6%2F193039199_mp4_h264_aac_hq_7.m3u8&demoConfig=eyJlbmFibGVTdHJlYW1pbmciOnRydWUsImF1dG9SZWNvdmVyRXJyb3IiOnRydWUsInN0b3BPblN0YWxsIjpmYWxzZSwiZHVtcGZNUDQiOmZhbHNlLCJsZXZlbENhcHBpbmciOi0xLCJsaW1pdE1ldHJpY3MiOi0xfQ==

hls.js v1.6.9 wants to download all segments and will throw an exception fatal: true only on the last segment in the playlist.

https://20f3b13d.hls-js-dev.pages.dev/demo/?src=https%3A%2F%2Ftest-streams.mux.dev%2Fx36xhzz%2Furl_6%2F193039199_mp4_h264_aac_hq_7.m3u8&demoConfig=eyJlbmFibGVTdHJlYW1pbmciOnRydWUsImF1dG9SZWNvdmVyRXJyb3IiOnRydWUsInN0b3BPblN0YWxsIjpmYWxzZSwiZHVtcGZNUDQiOmZhbHNlLCJsZXZlbENhcHBpbmciOi0xLCJsaW1pdE1ldHJpY3MiOi0xfQ==

[robwalch]

hls.js v1.6.9 wants to download all segments and will throw an exception fatal: true only on the last segment in the playlist.

https://20f3b13d.hls-js-dev.pages.dev/demo/?src=https%3A%2F%2Ftest-streams.mux.dev%2Fx36xhzz%2Furl_6%2F193039199_mp4_h264_aac_hq_7.m3u8&demoConfig=eyJlbmFibGVTdHJlYW1pbmciOnRydWUsImF1dG9SZWNvdmVyRXJyb3IiOnRydWUsInN0b3BPblN0YWxsIjpmYWxzZSwiZHVtcGZNUDQiOmZhbHNlLCJsZXZlbENhcHBpbmciOi0xLCJsaW1pdE1ldHJpY3MiOi0xfQ==

I was able to reproduce the issue using this URL. v1.6.9 goes through the normal retry behavior, until a stall occurs, and then instead of failing after the last retry (errorAction: { action: 5 }), attempts another recovery method, stepping through each segment as if it were a gap (frag.gap is set to true for each segment).

• Regression introduced by Fragment 4xx network error handling improvements #6853
  

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

  Lines 1885 to 1888 in d2c81f0

  	if (!retry && noAlternate && isMediaFragment(frag) && !frag.endList) {
  	this.resetFragmentErrors(filterType);
  	this.treatAsGap(frag);
  	errorAction.resolved = true;

This is now intended behavior for 4xx errors and any where the retry policy is permissive as it is when "offline".

[robwalch]

I'm considering whether or not to land a patch in 1.6 or wait until 1.7. Other than the additional logs it produces, what is the issue if the client is offline and nothing can be loaded?