Just wondering why this has never been implemented? If I have 2 copies of a movie in my library (4K and 1080p), why does Plex decide to transcode the 4K version instead of playing a 1080p version when sharing remotely?
This seems like it should be a fairly easy fix in whatever decision making process PMS does.
For example, I have “Limit remote stream bitrate” set to 10 Mbps (1080p). Plex should see that I have a 1080p version sitting in my library already instead of transcoding a 4K version down to 10 Mbps.
This is just a guess, but I’m wondering if its because of the 10Mbps setting. Because many of my 1080p versions are lower bitrate (for example, 2-4 Mbps), Plex thinks it can transcode the 4K version down to 10-ish Mbps and provide a better version than the existing 1080p file?
Ideally they should change their decision tree to identify if there’s a 1080p file already existing and if needed they could still transcode down from that file.
Are these shown under the same listing in your library, with the “Play Version” option available in the overflow menu? (I.E., someone could manually choose the 1080p version over the 2160p version? Not suggesting they should have to.)
If so, my guess would be that the lower bitrate version may need to be transcoded for another reason (incompatible video/audio codec, burning subtitles, etc…). In that scenario it might just decide to transcode from the best version available to preserve quality.
At any rate, debug server logs would likely be necessary get to the bottom of this. And likely the XML info for such an item in your library.
Yes, both versions are showing in my library with the Play Version option. Maybe if Plex could provide some info about how it determines which version to use, that would be helpful.
I just did a quick test - my 1080p version plays Direct Play on my phone (iOS) if I specifically select it. However, if just hit Resume, it will transcode the 4K version down, even when testing with various quality options on the iOS app (4/8/12 Mbps respectively).
I think this has always been the case (from reading other posts on Reddit at least).
I took a quick look at the server logs myself, and I think the issue is that it never even bothers to check and see if there is a more compatible version already there…from what I can see in the logs, it just uses whatever file is shown first/by default in the client.
For example, the client by default shows the specs for the 4K version in Video/Audio. So when you click Resume, it uses that version to play.
Now I wonder how it works if you use the Optimize function…going to test that out. Sort of thinking maybe a person could drop 1080p versions in the same folder that Plex stores the Optimized versions in? Have to do some testing…
I’m beginning to think there’s a bug in the iOS client. I created an Optimized Version of a movie and in Plex Web I set quality to 3 Mbps. It played the Optimized version (at least from what I can tell - it didn’t transcode the 4K version).
However, on iOS, I made the exact same changes and it still transcoded the 4K version, even though I can direct play the optimized version without issue.
In both instances I just clicked Play and let the app/client select the version.
What changes? If you created an optimized version already, you shouldn’t need to do it again. The optimized version exists and should be playable by any client.
Different clients have different capabilities. You haven’t shown any real data about the different versions you’re attempting to play. There might be real differences which could cause a specific source to be chosen for the transcode.
I’ve tried with the latest New Experience version (2025.32.0) on my iPhone, but also went back to 8.45 on my iPad - neither seems to want to direct play an “optimized IOS version” that I created.
To test, I started with a 10.5 Mbps 1080p movie, creating an iOS 4 Mbps 720p version as shown below.
So it won’t play the Optimized version for some reason. One thing I do see is that the Optimized version that was created is HEVC format, in MP4 container. However, I did confirm that both the original 1080p version and the optimized 720p version will direct play if I change video quality.
Here’s an example of it direct playing the Plex optimized version:
ok what i did was have a movie folder and added another 4k movie folder so if i am after the lower quilaty or for streaming outside the home ie family then i only allow excess to the movie folder not the 4k folder also if its myself away from home i just select the movie folder the same with tv programs i keep the 1080p tv in 1 folder and 4k tv another folder
Yeah I’ve done the same thing. Just trying to get away from having 2 libraries. And the whole purpose of “Optimized” versions is exactly for this reason. Just not sure it really even works (doesn’t seem to).
So seeing that nobody from Plex has responded…does that mean that Optimize versions is pretty much useless? Seems to me that their selection criteria never grabs the optimized file to play.
Thanks for replying back…I hadn’t tried anything for a couple of days and now when I look again, I wonder if it’s actually an issue with the Optimizer on the server itself.
I had optimized the movie shown below, set to 4 Mbps. However, when I look in the Plex Experience app on IOS, it indicates the file is actually 4.5 Mbps
And when I look in Media info, I see that 4520 Kbps bitrate for the entire file (with 3999 Kbps for the video part and 260 Kbps for each audio track). So taking 3999 + 260 (2x) = 4519 Kbps.
I had my IOS settings set to 4 Mbps, so it either tries to transcode my 1080p version down to 4 Mbps, or if I deliberately select to play the 720p, 4520 Kbps version, it transcodes that down to 4000 Kbps.
Going to try optimizing to 3 Mbps and see if I run into the same issue.
And just as I thought - I optimized the original file again with a 3 Mbps setting. The video portion ended up having a bitrate of 3000 Kbps, but the entire file is showing as 3530.
And since that is higher than what I set IOS to (3000), it ends up transcoding
@Atomatth Any thoughts on my 2 latest posts? It seems that the Optimize versions doesn’t actually create files in the bitrate that would match a client app. Therefore it always ends up transcoding.
I did file an issue for the player not requesting the optimize version when it should. As for the follow up questions about the optimizer itself, I’ll have to ask around. IIRC the quality profiles are not hard ceilings and we allow for some small variances but I could definitely be wrong .
Just for clarity. You are testing by:
Setting the Optimizer quality profile to 3 mbps
Setting the player quality profile (cellular, local, Wi-Fi) al to 3 mbps
Starting playback while specifically selecting the optimized version (3 mbps) and playback is transcoding. Is that all correct?
Correct! Tried again this morning with the same results. Not sure if it’s on the player side or server side, or maybe a combo of both?
These are the available versions that get created with a Optimizer setting of 3 Mbps (notice that they all say 3.5 Mbps). Guessing that the player doesn’t see one that matches so it has to transcode down (which it always does from the highest version - that’s been an issue for awhile now from what I read).
I’ve filed 2 issues. One for the client not requesting the correct optimized version when available. The second issue is PMS optimizing above the quality profile which can impact the client issue. These issues have a relationship to one another but will probably be handled separately. Thanks for reporting and providing all the details.
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