Google's New AI Video Resizing for Performance Max: What to Know Before the September 4 Opt-Out Deadline

If you run Performance Max campaigns and haven't touched your video asset settings in the last two weeks, Google has already started rewriting your video ads for you. On August 17, 2026, Google Ads quietly flipped on a generative AI system that scans every active Performance Max campaign, finds video assets missing certain aspect ratios, and builds the missing versions itself. It is on by default for every Performance Max advertiser, and if you want out, the window to opt out through Google's own process closes on September 4, 2026, which is two days from today.

This is not a hypothetical future feature. It is running against your account right now, whether or not you have looked at it yet.

TL;DR: Google is now auto-generating missing 9:16 and 1:1 video versions from your existing 16:9 Performance Max creative using generative AI, enabled by default, with an opt-out deadline of September 4, 2026. After that date you can still change video settings inside Google Ads, but the proactive opt-out route (account team request or opt-out form) closes. This guide walks through exactly what changed, how to check your account today, how to decide whether to opt out, and what to watch for if you choose to stay opted in. If you would rather control your aspect ratios yourself instead of trusting an algorithm's reframe of a single source clip, Miraflow's cinematic AI video generator and AI Image Generator let you compose genuinely native square, vertical, and landscape assets from the start, which is the practical alternative this post covers in detail below.

What Google Actually Announced on August 17, 2026

Google's announcement, first reported by Search Engine Land and corroborated by Search Engine Watch, Common Thread Co, and PPC News Feed, describes a new "asset optimization" upgrade to Performance Max. The plain-language version: Google's system scans your active Performance Max campaigns, identifies video assets that are missing certain aspect ratios, and uses generative AI to build the missing aspect-ratio versions automatically, without you uploading anything new.

The Mechanism, Not Just the Headline

This is worth understanding at the level of what actually happens to your file, not just the marketing description. Performance Max serves video across seven different surfaces, Search, Shopping, Display, YouTube in-stream, YouTube Shorts, Gmail, and Discover, and each surface favors different video shapes. YouTube Shorts and most Display placements want vertical 9:16 video. Some Discover and Gmail placements want square 1:1. Standard YouTube in-stream wants horizontal 16:9. Google's official "About video enhancements" support documentation confirms the same underlying mechanism has existed for standard video campaigns since 2024: Google AI "intelligently flips or extends your video in new aspect ratios while preserving the video's original content," rather than simply cropping the frame edges off.

What changed on August 17 is the scope and the default. Historically, video enhancements were a toggle advertisers had to actively enable per campaign, or that applied mainly to new campaigns going forward. The August update runs the same generative reframing engine as a retroactive, proactive sweep across every active Performance Max campaign already in your account, whether that campaign started yesterday or two years ago, and it is on by default rather than something you had to opt into. Google's own About video enhancements support page is the closest thing to an official primary source describing the underlying mechanism, even though it covers video enhancements broadly rather than this specific August rollout in isolation.

Which Aspect Ratios Actually Get Generated

Across the sources that describe this in detail, the pattern is consistent. If you have a 16:9 horizontal video already uploaded to a Performance Max asset group, and you are missing a 9:16 vertical version, a 1:1 square version, or both, Google's generative AI builds them from that source clip. The system does not simply letterbox or center-crop; it uses generative extension to intelligently reframe or extend the composition so the subject stays roughly centered and usable in the new shape, similar in spirit to how a photo editor's "generative fill" extends the edges of an image rather than just stretching it. Google's own creative video automation documentation also groups this alongside two related automations that already existed: automatically generating shorter cuts from videos longer than 15 seconds (prioritizing what Google's system judges to be the most engaging first five seconds), and an English-language AI voiceover feature covered in more detail below.

Why This Builds on an Older Feature, Not a Brand New One

It helps to know the history here, because a few outlets have implied this is entirely new when it is really an expansion. Google first introduced opt-in video enhancements for standard video ad campaigns back in May 2024, letting advertisers who wanted more format coverage generate square and vertical versions on request. What August 17, 2026 changed for Performance Max specifically is turning that same underlying capability from an optional, campaign-by-campaign toggle into a default-on, retroactively-applied sweep across every existing PMax campaign in an account. That shift, from opt-in to opt-out, from new campaigns only to a full account scan, is the actual news, not the underlying AI reframing technology itself, which Google has been iterating on for close to two years.

Why This Is Happening Now

Google has been pushing Performance Max advertisers toward full-inventory video coverage for a while, and the reasoning tracks a consistent pattern in Google's own guidance. Google's Performance Max creative best practices documentation states that advertisers who include at least one video in each of horizontal, vertical, and square orientation see roughly 20% more conversions on YouTube inventory compared to horizontal video alone. That statistic has been sitting in Google's own help center for a while, and it explains the underlying business logic: every asset group missing a vertical or square video is an asset group that cannot serve into a meaningful chunk of YouTube Shorts, Display, and Discover inventory, which is exactly the kind of coverage gap Performance Max's algorithm is designed to fill.

From Google's side, the calculation is straightforward. A large share of Performance Max advertisers, especially smaller teams without a dedicated video production budget, upload one horizontal video and stop there. That is a real, measurable inventory gap sitting inside Google's own ad exchange, and generative AI reframing is a cheap way for Google to close it without asking advertisers to do anything. Making it opt-out rather than opt-in maximizes how many accounts actually get the coverage improvement, which is consistent with how Google has rolled out other default-on automations across Google Ads in 2026, including the AI Max Search auto-upgrade and the local inventory ads default change covered elsewhere on this blog.

There is a genuine tension worth naming directly. What is good for Google's total addressable inventory and what is good for a specific brand's creative control are not always the same thing, and this update sits right at that seam. It is a rational move for Google to make. Whether it is the right default for your specific account is a separate question, covered in the next two sections.

The Two Different AI Opt-Outs You Might Be Confusing

If you searched around and found references to a Performance Max AI opt-out deadline back in March, you are not imagining it, but it is a different feature with a different deadline, and conflating the two is an easy, understandable mistake to make right now.

The March 20, 2026 Opt-Out Was for AI Voiceover, Not Video Resizing

Back in February and March 2026, Google rolled out AI-generated voiceovers for Performance Max video ads, reported at the time by Search Engine Land and MediaPost. That feature works by pulling text from your existing headlines and descriptions, generating a synthetic voice narration from that copy, and layering it onto video assets that do not already have spoken narration, existing voiceover, or other dialogue, meaning it specifically targets silent or music-only video clips. Advertisers had until March 20, 2026 to opt out before all eligible video assets became automatically eligible to serve voice-enhanced versions. That deadline has already passed. If you did not opt out back in March, AI voiceovers may already be running on your silent Performance Max videos today, separate from anything covered in this post.

The September 4, 2026 Deadline Is for Aspect Ratio Generation

The feature this post is actually about is different in mechanism, even though it comes from the same underlying "video enhancements" system inside Google Ads. Instead of adding synthetic audio, it generates entire new video files in aspect ratios your account is missing, using generative AI to reframe or extend the visual composition of your existing horizontal video. It has its own separate opt-out deadline, September 4, 2026, two days from today.

Both features share a family resemblance, generative AI, default-on, an opt-out-by-a-hard-date model, and both live under the same "video enhancements" umbrella inside Google Ads settings. But they touch different parts of your creative (audio versus visual composition), launched months apart, and require separate opt-out actions. Opting out of one does not automatically opt you out of the other. If you handled the voiceover opt-out correctly in March, that action has no bearing on whether the aspect ratio generation is currently running against your account.

Exactly How to Check Your Account and Decide

This is the part that actually matters today. Reading about the feature is different from knowing whether it is live on your specific campaigns right now, and whether opting out makes sense for your specific creative.

Step 1: Find Out Which of Your Videos Are Actually Missing Aspect Ratios

Inside Google Ads, open the Performance Max campaign in question, go to Campaigns, then Assets, and review your video asset group. Google's own asset group reporting breaks out enhanced or system-generated assets separately from what you originally uploaded, so look for video entries you do not remember uploading yourself, since those are the AI-generated versions. If a campaign only shows one video orientation in its asset group and you never manually added a second or third orientation, that asset group is a candidate for automatic generation the moment the sweep reaches it, if it has not already.

A quick gut check that takes five minutes: pull up every active Performance Max campaign you run, and for each one, count how many of the three orientations, horizontal, vertical, square, actually have a video you personally uploaded and approved. Any gap in that count is exactly what Google's system is designed to fill in automatically.

Step 2: Decide Whether Your Account Actually Needs to Opt Out

Not every advertiser has an equally strong reason to opt out, and treating this as an automatic "always opt out" decision skips a real judgment call. A few honest questions to work through:

• Does your video creative include on-screen text, a disclaimer, pricing, or a required regulatory statement positioned near the edges of the frame? If yes, a generative reframe into 9:16 keeps roughly a third of the original frame's width, which puts edge-positioned text at real risk of being cropped or distorted, per the specific example Relevant Audience's coverage raised about Thai-language burned-in captions losing meaning when truncated in vertical format.
• Is your brand under strict creative guidelines, a regulated category like finance, health, or supplements, or a franchise system where every asset needs sign-off before it runs? If so, the lack of a pre-approval review step before AI-generated versions start serving is the single biggest practical risk here, since nothing currently stops a generated variant from going live before a human sees it.
• Are you already running a healthy mix of horizontal, vertical, and square video that you produced yourself? If your asset groups are already fully covered across all three orientations, this update mostly does not touch you either way, since there is nothing missing for the system to generate.

If none of those apply and your creative is simple, product-centered, with no critical edge-positioned text, staying opted in and letting Google fill genuine coverage gaps for free is a defensible choice. If any of them apply, especially the regulated-category or franchise-brand-guideline case, opting out and handling aspect ratio coverage yourself is the safer call, and it is the case covered later in this guide.

Step 3: How to Actually Opt Out Before September 4

Google's stated opt-out process has two paths, and neither happens through a single obvious toggle buried in campaign settings, which is part of why this deadline has caught some advertisers off guard:

1. Contact your Google Ads account management team, if you have a dedicated rep, and request that generative AI video aspect ratio generation be turned off for your account before September 4, 2026.
2. Submit Google's opt-out form directly, for advertisers managing their own account without a dedicated rep.

If you want a clean way to make that first request, here is a short template you can copy and adapt for an email or a support ticket to your account team:

Subject: Opt-out request, Performance Max generative AI video resizing
Hi [Account Manager Name],
We would like to opt our account(s) out of the new generative AI video aspect ratio generation feature for Performance Max, announced August 17, 2026, before the September 4 deadline. Please confirm this has been applied at the account level, and let us know if any video assets have already been auto-generated so we can review them in the Assets tab.
Account ID(s): [insert]
Requested by: [name / title]
Thanks,
[Your name]

After September 4 passes, the proactive account-wide opt-out route through account management or the form closes, but you are not permanently stuck either way. Every source covering this consistently confirms that video enhancement settings remain adjustable directly inside individual Performance Max campaign settings going forward, campaign by campaign, at any time. The practical difference is friction: opting out before September 4 through the account-level process is a single action covering your whole account, while managing it after the deadline means going into each Performance Max campaign's asset optimization settings individually and toggling the video enhancement setting off there instead.

If You Stay Opted In: What to Actually Watch For

Plenty of advertisers will reasonably decide staying opted in is fine, and for a lot of simple product ads it is. But "fine most of the time" is not the same as "no monitoring needed." A few concrete things worth checking periodically if you leave this on.

The Edge-Crop Problem Is Real, Not Theoretical

Picture a 16:9 product demo video where your logo sits in the bottom-left corner and a small "results may vary" disclaimer runs along the bottom edge for the full 15 seconds. Reframed into 9:16, that composition does not scale the whole frame down uniformly, it keeps roughly the center third of the original width and extends or reframes around it. A logo or disclaimer positioned at the horizontal edges of the original frame has a real chance of ending up outside the generated vertical crop entirely, or squeezed into an unreadable sliver. This is exactly the scenario Relevant Audience's coverage flagged with Thai-language burned-in text specifically, where a caption that made sense at full width lost its meaning once truncated.

Regulated and Compliance-Sensitive Categories Carry More Risk

If you advertise in a category where a specific disclosure legally has to appear on screen, financial risk statements, supplement or health claim disclaimers, insurance terms, a generative reframe that crops or distorts that text is not just a brand aesthetics problem, it is a compliance exposure. There is currently no pre-approval review step where a human signs off on the AI-generated version before it starts serving, according to Google's own creative automation documentation, which only offers after-the-fact review and removal through the Assets tab in Campaigns, not a gate before publication.

Product Misrepresentation Is the Quieter Risk

Beyond cropping, there is a subtler failure mode worth watching for: generative reframing, especially when extending rather than just cropping, can introduce visual elements that were not in your original footage to fill new frame space, the same general category of risk that comes up whenever generative fill extends an image beyond its original boundaries. For a lifestyle or fashion product where the exact garment color, fit, or packaging design matters, an AI-extended background or reframed composition that subtly shifts how the product reads is worth a manual spot-check, not an assumption that "AI-generated" automatically means "faithful to the source."

A Concrete Scenario Worth Running Through

Say you sell a skincare product and your only Performance Max video is a 20-second horizontal clip: a hand holding the bottle up to camera with the brand name and a small "dermatologist tested" claim printed along the bottom edge, product centered but shot slightly left-of-frame to leave room for that text. Left opted in, Google's system generates a 9:16 version by extending or reframing that composition. If the reframe keeps the product centered but cannot preserve the left-of-frame text placement, that dermatologist-tested claim, arguably the single most important trust signal in the ad, either gets cropped, squeezed, or repositioned somewhere the original creative team never approved. That is a genuinely plausible outcome given how the mechanism works, not a worst-case hypothetical, and it is exactly the kind of gap that a human reviewing the generated asset in the Assets tab would need to catch manually, since nothing stops it from serving first.

The Real Alternative: Compose Native Aspect-Ratio Creative Yourself

If any of the concerns above land for your account, the practical fix is not just opting out and leaving a coverage gap in your asset groups. An asset group with only one video orientation still loses out on that roughly 20% conversion lift Google's own data shows for full-orientation coverage. The better move is opting out of Google's automatic reframe and filling that coverage gap yourself, with video and image assets actually composed for each aspect ratio from the start, rather than reverse-engineered from a single source clip after the fact.

This is the real difference between an algorithm's best-effort reframe and a genuinely composed shot. A generative reframe has to guess where the important parts of your existing 16:9 frame are and extend or crop around that guess. A video or image generated natively for 9:16 from the start puts your product, your text, and your framing exactly where you want them in that specific shape, because the composition decision happens at generation time, not as an automated correction afterward.

Miraflow's cinematic AI video generator supports Veo 3 and Veo 3.1 for producing short cinematic clips built for a specific aspect ratio from the prompt itself, rather than stretched or algorithmically extended from an existing file. For product ads, storytelling clips, and short cinematic scenes destined for a Performance Max asset group, that means you can generate a vertical version with your product, logo, and any required disclaimer text deliberately placed inside the safe area of a 9:16 frame, instead of hoping a generative reframe preserves it.

Native Video Prompts for Each Missing Orientation

Vertical 9:16 product demo, composed natively (not reframed)

Vertical 9:16 product demo video, product held centered in frame with generous safe margin on both sides, brand logo and a short claim text positioned within the vertical safe area rather than at the horizontal edges, soft natural lighting, smooth handheld camera movement, clean simple background, no text baked into the video itself, composed specifically for full-screen vertical playback

Square 1:1 product showcase, composed natively

Square 1:1 product showcase video, product rotating slowly under soft studio light against a clean neutral background, composition centered with equal margin on all four sides so nothing sits near the frame edges, steady smooth camera motion, no text overlay, no people, designed natively for a 1:1 crop rather than adapted from a wider shot

For static image assets in a Performance Max asset group, the same logic applies. Miraflow's AI Image Generator covers text-to-image, image-to-image, and inpainting, which is specifically useful if you already have an approved horizontal hero shot and only need to generate the missing square or vertical companion images without redoing the whole shoot. Inpainting lets you mask and adjust just the parts of a generated variant that need fixing, logo placement, product color accuracy, background elements, rather than accepting whatever an automatic reframe produces.

Landscape 16:9 hero shot, composed natively with edge-safe text placement

Wide landscape 16:9 hero product photo, product placed slightly off-center with clear open space along both edges reserved for a logo and a short disclaimer line, warm even lighting, shallow depth of field, high resolution commercial photography, no readable text baked into the image, composed with edge-safe margins from the start rather than cropped down from a different ratio

A practical middle path exists too, worth naming honestly: you do not have to choose between "let Google auto-generate everything" and "hand-produce every single asset yourself." A reasonable workflow for a lean team is opting out of the automatic generation specifically for asset groups that carry disclaimers, regulated claims, or tight brand guidelines, while leaving simpler, text-free product asset groups on the default setting. That keeps the coverage benefit where the risk is genuinely low and puts human judgment back where the risk is real.

Common Mistakes Advertisers Are Making With This Update

• Assuming this is the same feature as the March voiceover opt-out. It is not. They are separate features with separate deadlines, and opting out of one does nothing for the other. Check both if you have not touched either setting recently.
• Waiting until after September 4 to look at this at all. The account-level opt-out route through your account team or the opt-out form closes on the deadline. You can still adjust settings campaign by campaign afterward, but it is slower and easier to miss a campaign.
• Opting out of everything without checking which asset groups actually need it. Blanket opting out means giving up the roughly 20% conversion lift Google's own data attributes to full-orientation video coverage, even on campaigns where the reframe risk is low. Decide per campaign, not for the whole account by default.
• Opting out but never filling the coverage gap yourself. If you turn off automatic generation and stop there, your asset group is left missing vertical or square video entirely, which is a worse outcome than a slightly imperfect AI-generated version in most cases. Opting out only pays off if you replace the gap with real, natively composed assets.
• Not checking the Assets tab for what has already been generated. If the sweep already reached your account before you read this, generated video versions may already be live in your asset groups right now. Check Campaigns, then Assets, before assuming this is purely a future concern.
• Treating "AI-generated" as automatically low quality. Some accounts' automatically generated versions will look perfectly fine, especially simple, centered, text-free product shots. The risk is concentrated in specific creative types (edge text, disclaimers, regulated claims), not a blanket quality problem with every generated asset.

Where This Fits Inside Miraflow AI

The pattern across nearly every Performance Max update in 2026, this one included, is that Google keeps automating more of the creative production layer, not just the targeting and bidding layer. That makes the actual creative you start with more important, not less, because automation can only extend or reframe what you originally gave it to work with. A single unbalanced horizontal video, missing text-safe margins and shot without any thought for a vertical crop, gives Google's generative reframing a much harder job than a set of assets already composed for their intended shape.

Miraflow AI is built around exactly that gap. The cinematic AI video generator and AI Image Generator let you produce native aspect-ratio video and image assets directly from a text prompt, in the browser, without a full production shoot for every orientation Performance Max needs. If your Performance Max strategy also feeds organic short-form content, Text2Shorts generates vertical shorts built for YouTube Shorts, Reels, and TikTok from a single topic prompt, and AI Clipping can turn an existing long-form video you already have into several vertical, captioned clips scored for viral potential, another way to build up a real library of vertical creative without new production. And once your asset groups are properly filled out, Miraflow's YouTube Thumbnail Maker is worth a look if the same campaigns drive traffic toward organic video content that needs its own click-through optimization.

If you are working through the broader set of Performance Max changes Google shipped this year, not just this one, our guide to Performance Max's new steering, reporting, and negative keyword controls covers the account-level settings side of 2026's updates, and our explainer on Google's AI Max Search auto-upgrade covers a separate default-on change worth checking in the same account audit. If you are also curious how Google's newer AI agent tooling fits into account management day to day, Google's Ask Advisor AI agent is a useful companion read. And if you need ready-made creative prompt starting points beyond Performance Max video specifically, our AI prompts for Google Ads display banners and AI UGC ad prompts for product and lifestyle content round out the creative side of a Performance Max asset group. Browse the full library of marketing guides on the Miraflow AI blog, or start generating assets directly from miraflow.ai.

Frequently Asked Questions

Is this the same feature as the Performance Max AI voiceover opt-out from March 2026? No. The March 20, 2026 deadline covered AI-generated voice narration added to silent or music-only videos. This is a separate feature announced August 17, 2026, that generates entirely new video files in missing aspect ratios (vertical and square) from your existing horizontal footage. They live under the same "video enhancements" system in Google Ads but require separate opt-out actions and have separate deadlines.

What happens if I miss the September 4, 2026 deadline? The proactive, account-wide opt-out route through your Google account team or Google's opt-out form closes on September 4. You are not permanently stuck, though. Every source covering this confirms you can still adjust video enhancement settings directly inside individual Performance Max campaign settings after that date, it just takes more manual effort per campaign instead of one account-level request.

Does opting out remove video versions Google already generated for me? Opting out stops new versions from being generated going forward. To remove an already-generated asset, go to Campaigns, then Assets, find the system-generated video entry in the relevant asset group, and use the edit menu's remove option, according to Google's own creative automation documentation.

Which aspect ratios does Google actually generate? Based on Google's own video enhancements documentation and the coverage of this specific update, the system fills in whichever of 16:9 horizontal, 9:16 vertical, or 1:1 square your asset group is missing, generated from whichever orientation you already have uploaded.

Will this hurt my Performance Max performance if I opt out entirely? Only if you opt out and do not replace the coverage gap. Google's own creative best practices documentation attributes roughly 20% more YouTube conversions to campaigns running video in all three orientations versus horizontal only. Opting out of automatic generation without producing your own vertical and square versions leaves that gap in place, which is the scenario worth avoiding.

Can I opt out of just the video resizing but keep the AI voiceover feature, or vice versa? Yes. They are separate settings with separate opt-out processes, described in this post's comparison section above. Handling one does not automatically handle the other, so check both if brand control matters to your account.

Is there a way to preview what the AI-generated version will look like before it goes live? Not currently, based on Google's own documentation. Generated assets appear in reporting and the Assets tab after they exist, with removal available after the fact, but there is no pre-publication approval step where you sign off on a specific generated variant before it starts serving.

Conclusion

Google's move to default-on generative AI video resizing for Performance Max is a genuinely useful feature for a large share of advertisers, closing a real coverage gap that has quietly limited how much of Google's video inventory a single-orientation asset group can actually reach. But default-on and no pre-approval review is exactly the combination that deserves five minutes of attention before September 4, not because the feature is bad, but because the accounts most likely to get burned, ones with edge-positioned disclaimers, regulated claims, or strict brand guidelines, are the accounts least likely to notice a subtle crop until a customer or a compliance review flags it. Check your Assets tab today, decide campaign by campaign rather than as a blanket account setting, and if you do opt out, close the resulting coverage gap yourself with video and image assets genuinely composed for each aspect ratio rather than leaving it empty. Miraflow's cinematic AI video generator and AI Image Generator are built for exactly that: real control over your Performance Max creative, in the shapes you actually need, without waiting on an algorithm's best guess at what to crop.