A quality preset the source already fits under direct plays the file
since #2152, but a transcode above the source bitrate is sometimes the
point: a device that cannot decode the source (10-bit H.264, AV1, 4:4:4)
wants the server's highest-quality encode, and the shortcut silently
handed it the very file it cannot play smoothly.
A new Quality switch, "Play Smaller Videos at Original Quality" (on by
default), gates the shortcut in PlexClient._presetNeedsTranscode; off
restores the pre-#2152 behavior where any non-original preset always
transcodes. Plex-only by design: MediaBrowser servers make the
equivalent direct-play-vs-transcode call server-side.
close#2193