I've been using ErsatzTV with Jellyfin for a couple years with all HLS Direct channels, no issues.
After upgrading to Jellyfin 10.11.2 (recently released), playback fails for ErsatzTV channels using AndroidTV and browser. This error shows up in the Jellyfin logs:
ffmpeg version 7.1.2-Jellyfin Copyright (c) 2000-2025 the FFmpeg developers
[...]
[hls @ 0x14e2c46b4000] Skip ('#EXT-X-VERSION:3')
[hls @ 0x14e2c46b4000] Skip ('#EXT-X-DISCONTINUITY')
[hls @ 0x14e2c46b4000] URL http://redacted:8409/iptv/hls-direct/11?index=1 is not in allowed_segment_extensions
[in#0 @ 0x14e2c461d300] Error opening input: Invalid data found when processing input
Error opening input file http://redacted:8409/iptv/channel/11.m3u8?mode=hls-direct.
Error opening input files: Invalid data found when processing input
This might be caused by this change in ffmpeg:
https://github.com/FFmpeg/FFmpeg/commit/b753bac08f6881b2d3dea8f1ab84c81550f35897
The ffmpeg change seems to disallow playback of HLS streams if the URL doesn't end with one of these extensions: "3gp,aac,avi,ac3,eac3,flac,mkv,m3u8,m4a,m4s,m4v,mpg,mov,mp2,mp3,mp4,mpeg,mpegts,ogg,ogv,oga,ts,vob,wav"
The ErsatzTV URL doesn't look like it has ANY extension, just the channel number.
Someone else reported the bug to Jellyfin here but no movement yet. Jellyfin might be able to fix it on their end, but I figured I would report it here as well.