Player: iOS
For an episode of a show I’m watching the aspect ratio is normally 4:3. But Plex stretches this to 16:9 by default.
This is happening for all beta version. The last version this has been working correctly is 2025.12.0 (1009).
How it looks in 2025.18.0 (1098):
How it looks in 2025.12.0 (1009):
If more information is required, please let me know!
Hi,
to correct your Aspect Ratio. while playing a Title.
Using the Vertical Ellipsis ⋮ I have indicated below, Playback options / Aspect Ratio/ Zoom. This will then be Libraries wide till it’s changed.
I can change anything I want, but it never goes into the correct format.
Not in Letterbox, not in Original, not in Zoom and not Stretch.
That likely means your video was not encoded at the proper aspect ratio but using an aspect ratio parameter to change it in players. Unfortunately, the Plex app doesn’t support this, it will play at the ratio that the video was encoded at. The transcoder will change the ratio since the player can’t.
The app does have a stretch feature, but not a unstretch.
The NEW Plex player does not support it, you mean.
I don’t think the old one did either. They both use the same video player so it may be a limitation that still exists.
Well, the OP is posting comparisons showing it is using the correct aspect in an earlier version of the new app. If it didn’t work in the original app I would think they would have said something back then. 
I can’t speak for iOS, but I know the display aspect ratio setting in MKV headers is followed in the Android app, as I have used it to fix playback being wrong for a 4:3 show similar to the OP’s problem. I even remuxed a different series to change a 4:3 series to 5:4, because I noticed the picture seemed to be stretched horizontally in the first few episodes.
Original (4:3):
Retagging in the video aspect corrected it, and resulted in circular image elements (the moon, city lights in bokeh) to all be properly round.
5:4 Aspect:
Interesting. The display aspect ratio used to be ignored. I wonder when that changed. I’ve had to reencode some anamorphic videos because of that. Well if that works now, then that is the simple solution.
If still be interested in seeing the xml for that video. My 4:3 videos look correct so there must be something with the video.
It’s been a while. But the support varies by platform. I would assume it’s been supported on iOS whenever they started using mpv for the player backend. Not sure about the old AV Player.
Just checked here in good ol’ 2025 on a Roku that’s only a month old, and it’s still not supported there. This should be displayed as 16:9, filling the screen:
120132.txt (7.3 KB)
So here is the XML for this particular episode. (in txt format, since it doesn’t allow xml to be uploaded)
Media id="380071" duration="1413686" bitrate="2678" width="1920" height="1080" aspectRatio="1.33" audioChannels="2" audioCodec="aac" videoCodec="av1" videoResolution="1080" container="mkv" videoFrameRate="NTSC" audioProfile="lc" videoProfile="main" hasVoiceActivity="0"
This is a blu-ray rip? It should be pillarboxed with this resolution, so that definitely makes the issue more clear.
This is a special encode of an upscale of this episode in AV1.
The issue might also be that Plex does a wrong interpretation of video file of course. I see in the mkvinfo that the pixel width and height are 1920x1080, but the display width and height are set to 1920x1440.
Lol. That’s one way to call it. Your file lists the aspect ratio as 4:3 then says it’s anamorphic which will stretch it back out. The player might actually be doing the right thing.
See if clearing the anamorphic flag fixes the issue.
I find it weird that VLC and Infuse are both playing it correctly.
I’m just trying to figure out what’s happening here.
Plex doesn’t use every parameter in a file. From what it does use, it appears your file may have conflicting info. If that is the case, is Plex wrong for using the info it got or vlc for ignoring it. 
This encode is messed up in my book. It’s a 16:9 aspect encode from the XML info, but it was never that aspect ratio to start with. If it had been a BD rip it would have been pillarboxed but the encoder cropped those off (which is common), but then your encode stops being 1920 wide at that point. As a DVD upconvert, it would have been a normal DVD resolution like 720x480 or 704x480 from the source.
The app isn’t displaying according to the mkv tags DAR. That hasn’t changed.
One thing I notice is that in the 2025.18.0 (1098) screenshot the video is not being displayed vertically filling your phone screen. It looks like it’s being displayed 16:9 (matching the video resolution) but with letterboxing for some reason. There’s enough horizontal screen resolution to display this at full height.
Getting the same issue on my iPad with an old anime siries.
It displays correctly on all other devices and browsers, even on the iPad.
On the iPad, when streaming as “orignial” the video stretches to the iPad Pro 11" screen size, which is ever so slightly wider thatn 4:3 (10:7?).
Changing the Display Options only very slightly changes what is displayed with all modes keeping the new odd aspect ratio.
