SubMiner/changes/subsync-stream-tracks.md

type: fixed area: subsync

• Subsync now works when mpv loaded a subtitle track from a URL, which is how Aniyomi extension streams and Jellyfin add theirs. The track is downloaded to a temporary file first — reusing mpv's own request headers, so authenticated and referer-gated hosts stay reachable — instead of being rejected with "Subtitle file not found: https://…". This applies to both the sync target and the alass reference, so a Jimaku or TsukiHime download can be retimed against a stream's own subtitles. Internal tracks of a stream also pass mpv's headers through to ffmpeg.
• Alass now works on tracks that arrive as WebVTT, which is what Aniyomi extension streams serve. Alass picks its parser from the file extension and has no WebVTT support, so it treated a .vtt reference as a video file and failed with "no audio stream in file". Both the target and the reference are rewritten as SRT for alass, keeping the cue text as-is, and the originals are left untouched.
• Leaving subsync.alass_path, ffsubsync_path, or ffmpeg_path empty now actually auto-discovers the binary, as the config help has always claimed. Previously it fell back to a hard-coded /usr/bin/<tool>, which does not exist on macOS and broke subsync for every default-config install there. Discovery searches PATH plus the usual install prefixes (a GUI launch inherits a minimal PATH) and accepts alass-cli as well as alass. An explicitly configured path is still used verbatim and never silently substituted.
• Subsync failures are written to the application log. Previously the only trace was an OSD toast that vanished after a few seconds, leaving nothing to diagnose from.