I don’t know where Tautulli gets the transcode speed data it reports but it has to come from Plex somewhere.
It doesn’t make sense to me though, I’m testing HDR tone mapping right now (QuickSync) and with tone mapping on it reports a speed of 0.8 (80% real time) for one 4K HEVC → 1080P transcode. But, it doesn’t seem to buffer ever. Then if I start a second transcode of the same file in a new window, both are reporting 0.8 transcode speed and neither buffer… logically I expect doubling the load to halve the transcode speed of each stream but this doesn’t seem to be the case? Starting a third transcode stream still doesn’t seem to cause buffering on any of them, even though all are reporting a ratio of less than 1:1 so I don’t know if what is getting reported here is accurate?
I’d expect any stream with a transcode speed reported less than 1 to buffer before long, and piling on multiple additional transcodes to make it worse and worse but my server just seems to keep eating the transcodes regardless of what is reported here. How can I have three transcodes going for any length of time when even the first one is supposedly not transcoding fast enough to be real time according to the data Tautulli is getting.
As far as I know Plex itself (nor Plex Dash) actually exposes any metrics about how fast a transcode is taking place.
