reverse search July 4, 2026 ⏱ 6 min read

Reverse Search: Upload One File, Find Every Copy

Upload any image, video, or audio as a reference. Sakarto scans a folder and finds everything similar to it—crops, resizes, re-encodes, covers, and more. 7 visual + 3 audio algorithms. Reference pinned and protected.

Start here if you want to learn everything about reverse search—upload one file and find every copy.

Finding duplicates normally means scanning a whole folder and grouping everything similar. That’s useful when you’re cleaning up a messy photo or music library and you don’t know what’s in there. But sometimes you know exactly which file you want copies of—a specific product photo, a company logo, a particular song, or a podcast episode you need to find scattered across multiple folders.

That’s where reverse search comes in. Instead of grouping everything, you upload one reference file first. Sakarto processes it immediately, then scans your chosen folder and returns only the files that look or sound like that specific reference. The reference is pinned at the top with a protected badge—it can never be accidentally moved or deleted.

It’s like Google reverse image search, but entirely in your browser, with zero uploads, and with ten different algorithms to choose from across images, videos, and audio.

How reverse search is different

The standard Find Duplicates workflow scans a folder and compares every file against every other file. That’s O(n²) complexity—fine for a few hundred files, but it gets slower as the folder grows.

Reverse Search does something much smarter. It fingerprints your reference once, then compares each folder file only against that reference. That’s O(n) complexity—linear scaling. A folder of 10,000 files takes roughly the same time per file as a folder of 100. The scan speed depends only on the number of files, not how many of them are similar to each other.

This makes reverse search the faster choice for large folders where you already know what you’re looking for.

The reference protection system

The reference file is treated differently from every other file in the scan. When you upload it, Sakarto immediately:

Computes its fingerprint using your chosen algorithm
Shows a thumbnail or audio player preview so you can verify the right file was loaded
Pins it at the top of the results as soon as scanning starts
Displays a blue REFERENCE badge on the card
Prevents it from being moved or deleted—Move and Delete buttons are disabled on the reference card

This last point is critical. If you’re using reverse search to find copies of a file you want to keep, you don’t want to accidentally delete the original. The reference protection system makes that impossible.

Reverse Image & Video Search: 7 Algorithms

For detailed explanations of each algorithm, see our dedicated guide: Seven Ways to Catch a Duplicate

Upload an image or video as your reference, pick a folder, and Sakarto finds everything visually similar. Each algorithm compares your reference against every folder file using a 64-bit hash and Hamming distance—except ORB, which uses keypoint matching.

Quick reference:

Algorithm	Best for	Threshold direction	Speed
Color Signature	Same colour palette, same scene	Lower = stricter	Fast
aHash	Large folders, speed priority	Lower = stricter	Fastest
BlockHash	JPEG-compressed copies	Lower = stricter	Very Fast
dHash	Brightness/exposure-adjusted	Lower = stricter	Very Fast
pHash	All-round reliability	Lower = stricter	Fast
wHash	Speed + quality balance	Lower = stricter	Fast
ORB	Rotated, cropped, perspective	Higher = stricter (inverted)	Slower

Reverse Audio Search: 3 Algorithms

For detailed explanations of each algorithm, see our dedicated guide: Three Ways to Hear a Duplicate

Upload a reference audio file and Sakarto finds every recording that sounds similar. All audio processing continues in the background even when you switch browser tabs.

Quick reference:

Algorithm	Best for	Threshold direction	Speed
Chromaprint	Re-encoded tracks, different bitrates	Lower = stricter	Fastest
Essentia HPCP	Covers, live recordings	Higher = stricter (inverted)	Moderate
Meyda MFCC	Speech, podcasts, sound effects	Lower = stricter	Fast

Reverse Search vs. Find Duplicates: which to use?

	Reverse Search	Find Duplicates
What it does	Finds copies of one specific reference file	Groups all similar files in a folder
Complexity	O(n) — each file compared against reference	O(n²) — all files compared against each other
Speed	Faster for large folders	Slower for large folders
Reference protection	Yes — reference pinned and cannot be deleted	No — all files are treated equally
Best for	You know exactly which file you’re looking for	You want to see every duplicate group in a folder

Recommendation: Use both. Run Find Duplicates to see the big picture. Then use Reverse Search for specific important files to clean up their copies without risking the originals.

Privacy and local execution

Like every other Sakarto tool, reverse search runs entirely in your browser. The reference file is processed locally. The folder scan happens locally. All fingerprinting and comparison happens on your CPU using OffscreenCanvas, Web Workers, and the Web Audio API.

Open DevTools → Network tab during any scan: zero outbound requests. No uploads, no telemetry, no data leaving your device.

The verdict

Reverse search is a fundamentally different workflow from standard duplicate finding. It’s faster for large folders, it protects your reference file, and it gives you a clear, focused view of exactly what you’re looking for.

With seven visual algorithms and three audio algorithms to choose from—each tuned for a different kind of copy—you can match the algorithm to the kind of duplicates you expect to find. If you’re not sure where to start:

For images/videos: start with pHash (best all-round) or aHash (fastest for large folders). Use ORB only if rotation or cropping is involved.
For audio: start with Chromaprint (fastest, no CDN). Use Essentia HPCP for covers and live recordings. Use Meyda MFCC for speech and sound effects.