I am using video.js (latest, 8.23.4) on Firefox 148 with a large DASH playlist (30 period tags, 180 adaptation sets/segment templates) and it struggles a lot. I profiled it during the fact and noticed that it was spending inordinate amounts of time on calls to resolveUrl:
In particular, it seems that for my playlist each call to refreshMedia_() triggers about 88200 (!) calls to resolveUrl() from vhs-utils. All of the time is spent in the URL() constructor which is apparently fairly expensive when called 80k times. When refreshMedia_() is called every 500ms, the browser can't parse the URLs fast enough and it hinders playback.
For fun I replaced the logic in resolveUrl() with a very primitive:
baseUrl = baseUrl.replace(/\?.+$/, '');
baseUrl = baseUrl.replace(/\/[^\/]+$/, '');
return baseUrl + "/" + relativeUrl;and suddenly all the performance issues are gone!
I also tried to cache the result of parseMainXml, and while it does manage to make playback good enough, the UI still lags while the thousands of URLs are being parsed.
I am unable to share a link to a reproducer / the stream URL as it is confidential, but here's how a slightly redacted version of the main playlist looks like:
main-redacted.mpd.xml
I am using
video.js(latest, 8.23.4) on Firefox 148 with a large DASH playlist (30 period tags, 180 adaptation sets/segment templates) and it struggles a lot. I profiled it during the fact and noticed that it was spending inordinate amounts of time on calls toresolveUrl:In particular, it seems that for my playlist each call to
refreshMedia_()triggers about 88200 (!) calls toresolveUrl()fromvhs-utils. All of the time is spent in theURL()constructor which is apparently fairly expensive when called 80k times. WhenrefreshMedia_()is called every 500ms, the browser can't parse the URLs fast enough and it hinders playback.For fun I replaced the logic in
resolveUrl()with a very primitive:and suddenly all the performance issues are gone!
I also tried to cache the result of
parseMainXml, and while it does manage to make playback good enough, the UI still lags while the thousands of URLs are being parsed.I am unable to share a link to a reproducer / the stream URL as it is confidential, but here's how a slightly redacted version of the main playlist looks like:
main-redacted.mpd.xml