Scrubbing an Emby video showed no preview thumbnails on the timeline
while Plex and Jellyfin both worked: Emby's scrubThumbnails capability
was off, so the player never attempted a load. It was off because the
4.9.5 test server answered the preview endpoints with empty payloads —
its extraction task had not run.
Emby's preview transport is a Roku-format BIF at
/Videos/{id}/index.bif?Width=320, the same wire format Plex serves, so
the existing BIF parser handles it unchanged. Enable the capability and
route Emby previews through the shared BifThumbnailService, whose load
now takes a bytes callback instead of a Plex-typed client. MediaBrowser
sources also carry videoAspectRatio from the video stream so the
tooltip sizes itself to the stream. A server without extracted frames
still answers a header-only BIF, which parses to zero frames and keeps
the tooltip suppressed.
close#1930
edde746