P: H.264 exports appear glitchy when scrubbed in QuickTime Player or Preview in macOS 15.1 or newer.

[magnus atom]

[Moderator: Updated title for clarity and making searching easier. This issue also affects Premiere Pro and Media Encoder.]

A month ago I updated my 2021 MacBook Pro to the latest Mac OS Sequoia 15.0.1 and that's when I began experiencing render issues when rendering H.264 from After Effects (2024 & 2025) or Media Encoder (2024 & 2025). The render plays back okay but when I scrub through, but when I scrub through the timeline, in AE, Quicktime, Frame.io, etc, I notice every 4th or so frame has terrible artifacting.

I've been able to work around this for a month by sending ProRes LT to my clients, however now a client is asking for a H264 so I'm stuck trying to figure this out or encode it on an old MacBook that still has an older MacOS version. 

If it helps at all, I've noticed when turning Audio Off when rendering through Media Encoder, the problem goes away, but obviously that's not a real solution. Anybody else have this issue and found a fix?

I'm sadly debating just buying a new MacBook at this point but not even sure that will solve the issue.

[Sébastien Périer]

Hi @magnus atom ,

I'm Sébastien from the After Effects team.

I'm very sorry you're running into an issue with h264 encoding.

Does the encoding problem persists if you use AME to convert your ProRes into h264, or is it only happening when rendering your AE timeline directly (through RenderQueue and AME).

Would you be able to share the encoding preset and/or customer parameters you are using for encoding?

Last but not least, would you be able to share in a DM a link to a video you exported showing the encoding issue that I could share internally with the team?

All the best,

Sébastien,

Sr. Quality Engineer After Effects 

[magnus atom]

Thanks Sébastien, 

Yes, I get the artifacting whether I'm converting from a ProRes > H264 in AME and when sending it straight from the AE timeline. I'll DM you a link to both files you've requested. Thanks again!

[Darth Jahona]

This issue has been plaguing my team for a few weeks now.  We can't reproduce it all the time.  But some renders come out fine at h.264 and others don't.  It's something in the Adobe Suite.  We've noticed this issue when exporting direct in After Effects, Premiere, and in Media Encoder.

I ran a test using the same ProRes 422 video.  Encoding in Media Encoder using the Match Source - Adaptive High Bitrate H.264 preset.  Hardware encoding causes the glitchy anomaly.  Switching to software encoding seems to work fine.

Converting ProRes to h.264 in Apple Compressor or Handbrake haven't shown any issues.

I can't post examples due to the nature of my work.  But it's very similar to what Magnus atom has posted.

Specs:

MacBook Pro 16-inch, 2023

Chip Apple M2 Max

Memory 96 GB

MacOS Sequoia 15.2

Adobe Software Versions:

Premiere Pro: 25.1.0 (Build 73)

After Effects: 25.1.0 (Build 68)

Media Encoder: 25.1 (Build 65)

[Sébastien Périer]

Hi @Darth Jahona ,

sorry to hear you're having this issue. Would you mind sharing the Prores file with me in a DM so I can investigate further? I've investigated with some footage Magnus Atom shared with me privately, but wasn't able to reproduce on my end.

Sébastien Périer
After Effects Quality Engineering

[Matteastin]

Same thing is happening to me. The strange part is that the files playback normal when when I bring them back into Premiere, or upload to YouTube or Vimeo. They only look glitchy in the Finder or in QuickTime. It's so strange.

[Sébastien Périer]

Hi @Matteastin,

I'm Sébastien from the After Effects team. Would you have one piece of footage that repros the bug that you could share with me in a private message?

Sébastien
After Effects Quality Engineer

[Matteastin]

Hi! I figured out a way to fix it, for now. I always just choose H264 and
select the high bitrate option, and check the boxes for the highest render
settings. Instead, I manually selected a 2 pass VBR and made my own custom
setting. It seems to be working now.

Here’s a link to the export I sent to my client last night when we
discovered the issue:
https://we.tl/t-7w8MR5tZEH

The weird part is that I looks bad when you play it in the Finder, or in
QuickTime, but looks fine when you bring it back into Premiere, or upload
it to YouTube. It’s almost like the file container is bad, or something.

[Darth Jahona]

Hi @Matteastin, question for you, what are your system specs?

[Sébastien Périer]

Hi all, thanks for the patience while I was investigating this issue.

I am able to reproduce the problem on my side, here are my findings and potential workaround:

From a test video, encoded in h264 (1080p, Main/Level4.1) on the same Mac M1 device, it will playback correctly in:

• VLC, Premiere, AE, Frame.io, Quicktime and Preview with Mac OS 14.7
• VLC, Premiere, AE, Frame.io with MacOS 15.3

Thanks to @Matteastin for pointing out it is only failing for them in QT/Preview, which made me focus on that path. 

Now, my test mp4 have been encoded in AME with Hardware Encoding turned on. If I encode them with the exact same parameters but with Software encoder selected instead, the file playback properly in Qt/Preview on 15.3.

As I'm updating the bug on our side, I encourage you to use Software Encoder in AME as a workaround.

Note that this only impacts decoding the file on Mac Arm devices, only in Quicktime/Preview, in MacOS Sequoia. The encoded frames are correct, and it might just be a decompress issue happening on Apple's side.

I've set the bug status to confirmed, and updated the bug on our side.

Sébastien
After Effects Quality Engineer

[magnus atom]

Thanks @Sébastien Périer . I can confirm that switching to software encoding has fixed the problem in both After Effects and Media Encoder. Thank you so much for your help!

[alexandre_2086]

I've been dealing with this problem as well ever since I've bought an M2 computer last summer.  I noticed that the video plays fine but gets blocky when scrubbing. I ruled out quickly that it was just a QT issue.  I always test multiple media players out. That's fine and dandy but beware that software encoding may also cause issues as well.  I've been getting calls about glitches and pausing during playback from various clients.  I've never had that issue until I got the M2 computers.  I've tried various settings and have found myself using the same settings that I've used from my old computer because it seems to be the most reliable.  I'm hoping that I don't get any more calls.  I export a ton of content a month.  I guess 3 complaints isn't so bad but I'm expecting more. 

[Fergus H]

Hi all, 

I'm a product manager in the video team at Adobe and my responsiblties include camea & codec support. I want to provide an update on this issue. 

As Sébastien has mentioned, we've been able to reproduce this issue. It happens when: 

• The export is H.264
• The export is done on macOS 15.1 or later
• The export is viewed using QuickTime Player or via the macOS Preview option (i.e., selecting the file and hitting the space bar)
• The export is scrubbed, either by dragging the playhead or using the arrow keys to navigate. (Note: the issue does not happen during normal playback in QuickTime Player or Preview; only when scrubbing.)

In this scenario, you'll see pixelation starting on the 2nd frame of a video then repeating every fourth frame after. 

As discussed in this thread, workarounds include exporting in a different format, from a different OS, or using software encoding (instead of hardware accelerated encoding). We're aware that none of these workarounds are convenient. 

We are currently working with Apple to identify and fix the cause of this issue. We'll update this post when we have more information, including when we have a fix in beta for you to try. 

We're sorry for the inconvenience this is causing; we know it is frustrating. 

Regards,

Fergus

[DAVID 640]

Just want to report that I've just discovered the exact same issue: Exports have blocky glitches every 4th frame when advancing frame by frame in Quicktime. This does NOT occur when using VLC. When I re-impport the video to Premiere Pro and check it frame by frame, NO glitches. I should also report that during playback in Quicktime, no distortions are evident. Also, playback on Vimeo shows no distortions. Advancing frame by frame on Vimeo (hold down SHIFT key, L / R arrows) shows NO distotions. I have just recently upgraded to a MAC Studio from a 2017 iMac. Problem did NOT occur on the old machine. ALSO: I have also just confirmed that changing the encoding setting from Hardware to Software makes this problem go away in going frame by frame in Quicktime. SO, WHAT is going on? Will this be fixed? What are the downsides to changing from Hardware to Software encoding??? Thanks!

[DAVID 640]

Hmmm... I've just Google-learned that software encoding is generally considerewd "higher" quality, at the expense of speed. True? For my work, I'd be fine with higher quality over speed. Advisable? Thanks...

[Fergus H]

@DAVID 640 As mentioned above, we're very aware of this issue and currently working with Apple on a fix for it. I also mentioned above what you noticed: using software encoding is a workaround. 

In general, we don't recommend software encoding instead of hardware encoding. The differences are usually imperceptible, even in extreme examples (very small type), and while performance differences change based on what hardware you've got, software encoding is much slower. 

Regards,

Fergus

[DAVID 640]

Thanks for getting back to me on this Fergus.

Just to be clear:
You generally *don't* recommend software encoding, but that's the only
option to avoid this weird Quicktime anomaly, correct?

But tell me, is it your or your team's perception that playback in
Quicktime shows NO *perceptible* sign of the anomaly?
I cannot see any hint of a problem on playback in QT.

So the only real problem is if a client for some reason decides to go frame
by frame in Quicktime and notices the issue.
Otherwise, the issue seems to be imperceptible...
Or not?

For me, I think I'm gonna have to go with the software encoding for now,
(being aware of the caveats you note above) because I guess I am
still nervous about some playback issue somewhere else in the pipeline.

I do appreciate that you guys are working with Apple to correct the
problem...

David



--
DAVID SCHULDER

646-642-8381
DLSCHULDER@GMAIL.COM
https://schuldervideo.squarespace.com

[Fergus H]

@david Great questions! Answers below

"You generally *don't* recommend software encoding, but that's the only option to avoid this weird Quicktime anomaly, correct?"

That is correct. 

"So the only real problem is if a client for some reason decides to go frame by frame in Quicktime and notices the issue. Otherwise, the issue seems to be imperceptible..."

That is correct.

[Brett37091033ni8q]

Any updaes on this issue? Backgroudn on why it's happening? Timeline for a fix?

[alexandre_2086]

I can imagine it's going to take some time to fix.  The scrubbing pixelation in QT really isn't a real issue to begin with.  It doesn't do it in other media players. The issue that I'm having is that I'm getting my projects rejected exporting h264, period.  It's a hit or miss and I've even tried Software encoding and would get weird gltiches in the same areas.  Only h264 though.  My Intel machine was solid as can be.  

[Fergus H]

@Brett37091033ni8q We know the cause of the issue and know what we need to do to fix it. We expect the fix will be in the next release of our video products (the issue also affects Premiere Pro). It's likely we will have a beta version of After Efects & Premiere Pro with the fix next week. (I offer that information not as a suggestion that our customers should use a beta for production work but simply as information and to those who might like to check the fix for themselves.)

@alexandre_2086 if you're having a different issue with exports - it sounds like for you they are failing entirely - I would suggest that you start a new thread describing the issue. The issue in this thread has a very specific symptom, only visible in QuickTime Player or macOS Preview. 

Regards,

Fergus

[Brett37091033ni8q]

@Fergus H Thank you for the reply.

As you're aware, none of us working pros can upgrade to a beta or initial release of Premiere or AE until some of its new bugs are patched.

How about a refund on Creative Cloud until the software is working as advertised?

[Fergus H]

@Brett37091033ni8q My apologies: I was not suggesting that you use the beta for production work, merely providing it as information. I've clarified my post.

That are multiple workarounds to this issue available right now but we know that workarounds are not a fix and I apologize for the inconvenience. Adobe's Customer Care organization is the right path if you're looking for a refund. 

Regards,

Fergus

Fergus Hammond  |  Principal Product Manager, Premiere Pro  |  Adobe  

[alexandre_2086]

The Beta released seemed to solve the issue. You'll have to port over your presets and change your keyboard shortcuts though.

[mayjain]

Hi all,

The fix for this issue is now in beta versions of our video apps. We are not suggesting you use beta versions in production but if you would like to test the fix, you can try the beta. 

Thanks,
Mayjain

[Scott.C.]

Did this fix make it into 25.2 including media encoder?