This should fix regular and multi streams. VODs apparently were still working (although they appear broken on their website).

Btw, their website uses websocket streams instead of HLS streams. I don't know if this was already the case previously when the plugin was implemented, but if not, then this might be an indicator that their HLS backend might be removed in the future once they stop using it as a fallback mechanism for certain web browsers or other clients/etc.

$ streamlink https://picarto.tv/FattyNite best --hls-duration=10 -o /dev/null
[cli][info] Found matching plugin picarto for URL https://picarto.tv/FattyNite
[cli][info] Available streams: 1080p (worst, best)
[cli][info] Opening stream: 1080p (hls)
[cli][info] Writing output to
/dev/null
[stream.hls][info] Stopping stream early after 10
[cli][info] Stream ended
[cli][info] Closing currently open stream...
[download] Written 4.02 MiB to /dev/null (3s @ 1.41 MiB/s)

$ streamlink https://picarto.tv/LambdaKat best --hls-duration=10 -o /dev/null
[cli][info] Found matching plugin picarto for URL https://picarto.tv/LambdaKat
[cli][info] Available streams: 720p (worst, best)
[cli][info] Opening stream: 720p (hls)
[cli][info] Writing output to
/dev/null
[stream.hls][info] Stopping stream early after 10
[cli][info] Stream ended
[cli][info] Closing currently open stream...
[download] Written 1.96 MiB to /dev/null (5s @ 364.02 KiB/s)
$ streamlink https://picarto.tv/anoroth best --hls-duration=10 -o /dev/null
[cli][info] Found matching plugin picarto for URL https://picarto.tv/anoroth
[cli][info] Available streams: 1080p (worst, best)
[cli][info] Opening stream: 1080p (hls)
[cli][info] Writing output to
/dev/null
[stream.hls][info] Stopping stream early after 10
[cli][info] Stream ended
[cli][info] Closing currently open stream...
[download] Written 6.30 MiB to /dev/null (0s)

$ streamlink https://picarto.tv/LambdaKat best -j | jq .metadata
{
  "id": null,
  "author": "LambdaKat",
  "category": "Illustration",
  "title": "Breadbrain Again™ Early stream Edition"
}
$ streamlink https://picarto.tv/anoroth best -j | jq .metadata
{
  "id": null,
  "author": "anoroth",
  "category": "Illustration",
  "title": "Painting dragons and other creatures!"
}