Still image quality significantly degraded upon timeline export in Premiere Pro (25.2.3)

[this_side_up_films]

I posted this issue earlier and it got merged by an Adobe mod into a topic that was not the same issue that I'm experiencing, so I'm asking that this not be merged again (unless the specific issue is really out there, but I haven't seen it upon conducting numerous searches), and then I'm going to give more of the granular specifics here, as well.

I'm in Premiere Pro 25.2.3.

running OSX Sonoma 14.4.1

on a 2023 M2 Ultra Mac Studio w/64GB Memory
Here's a screenshot of my sequence settings:

And the issue is that there is a significant degradation in the quality of still images that I am using in the timeline, when comparing what I see in the Program window (or in fullscreen mode) during normal playback vs what the image looks like in the final video clip upon export.  Attached are the expected, better image (a screenshot of the Prorgam window in Premiere), and a frame of the exported, degraded image (from my h264 output).

This is not the first time I have encountered this problem in the Premiere ecosystem, however in past versions, it was fixable by either changing the "Bitrate Encoding" setting to VBR 1-pass (instead of 2 pass) or rendering the timeline and selecting "Use Previews" in the export settings.

I've now run a battery of export tests and tried all of the flavors of Bitrate Encoding with and without Use Previews turned on, post rendering, and it's not working to address the issue.  Sending to Media Encoder is also not working.

Any guidance/patch would be appreciated.  Thank you!

[Rach McIntire]

Hi @this_side_up_films, 

Thanks for the detailed bug report and screenshots.  I'm sorry the render isn't coming out as expected; that's super frustrating.  Are you exporting straight from Premiere or through AME?  Can you also send what your export settings are?  Is it just the stills that are degraded on export (is there also video rendering fine in the same sequence)?  I hope we can help you soon. Sorry for the frustration! 

[this_side_up_films]

Thanks for taking a look, Rach.  As mentioned, the results are the same via Premiere export and via Media Encoder.  I'll insert screenshots below of export settings for one instance of the issue from Premiere, while just noting again that I've tried all the options for "Bitrate Encoding", with and without "Use Previews" turned on (as well as trying 1080p vs 720p) And to your other question, it's primarily noticeable (and most significant in terms of degradation) in the still images, though there is also some lower res mp4 footage (720p) that also looks noticeably better in the Program window than upon export.  The orignal 4k footatge exports completely as expected (given the 720p or 1080p exports).

I'm sure it's a side effect of things being uprezzed and downrezzed wonkily through the workflow (media dimensions -> timeline dimensions -> export dimensions) and I know it's an issue that has come and gone through Premiere iterations before.  But i don't understand it well enough to diagnose beyond that and the old fixes don't fix it now since updating.

[Rach McIntire]

Sent you a DM

[IanB_360]

Hi @this_side_up_films 
Can you do me a favor and go to the export settings using the UHD sequence and then toggle the export from UHD to 1920x1080? You should see the immediate degradation on the still when you do this. We will look into why you are unable to export an HD format from the UHD sequence without any degradation. For now you can do one of two work arounds. You can make a copy of your timeline and change the sequence settings to 1920x1080 . You will need to resizing on your shots to match and then you can export HD to HD without degrading the stills. Or you can Nest your entire UHD sequence and then make a duplicate of that sequence. Change the settings to 1920x1080 and then resize the nested clip to 50% and all the sizing will match what you had in the UHD sequence. If you export this new nested, 50% , 1920x1080 sequence you will also get no degradation to the stills. 
Here to Help

Ian

[this_side_up_films]

Really appreciate you looking into this!

So to respond to everything in order of your post:
1) Strangely, when I toggle between 1080 or 720p on this current session, it's no longer looking degraded in the Preview window in the Export tab, though it DID look degraded at that step when i submitted my initial post.  HOWEVER, it is still exporting with the degraded quality, regardless of it looking as expected in the Preview window.  And for the record, it won't even allow me to do a UHD output with the presets I was using (h.264). When i try to select UHD export it says "Invalid framesize/framerate for this level.  Please lower the video bounds or frame rate, or increase the Profile and Level and try again")

2) yes, duplicating the sequence and then re-sizing to 1080p does produce an output that looks as expected in regards to the still (so much better than exporting 1080p from the UHD sequence), however this is a small portion of a documentary that's already got hundreds of clips in the timeline, so this isn't practical as a regular output solution for me.  but...

3) The technique of nesting the UHD sequence in a 1080p sequence before exporting a 1080p clip does appear to solve the issue as well.  This also worked for a 720p output (with matching sequence and export settings), which is probably what I'll do to save on my storage space for posting cuts.  So that's a simple, non time-cosuming workaround for me for the moment (and really should be fine for a while).  Thank you!

[this_side_up_films]

One last note for posterity here, and to pass on to the engineers perhaps, @IanB_360 / @Rach McIntire....  doing the workaround appears to not only have drastically improved the quality of the still images in my timeline, but modestly improved the sharpness of .mp4 video footage in the same timeline that was also of smaller native dimensions (720P) than my Sequence Settings (UHD).  The UHD native footage looks the same in either export method.  So seems like the smaller the media, the more drastic the downgrading on export (beyond what you'd normally expect from just using lower resolution media).  Thanks!