How to find duplicate videos with different resolutions or re-encodes

Most video libraries end up holding the same footage at several sizes. A camera records in 4K, an editor exports a 1080p version, a phone app saves a compressed copy for messaging, and a backup tool converts something to HEVC along the way. Each copy has a different file size, a different name and often a different container. To a normal duplicate finder they're four unrelated files.

This guide shows why that happens, how to find these copies with free tools, how to decide which version to keep, and how SceneSort Pro does the same job with a side-by-side review.

Why ordinary duplicate finders miss resized copies

Classic duplicate finders compare checksums (hashes) of the file contents. Two files match only when every byte is identical. Re-encoding changes every byte, even when the picture looks the same, so these situations all slip through:

• Downscales: a 3840×2160 original and a 1920×1080 copy of the same clip.
• Re-encodes: an H.264 file converted to HEVC (H.265) or AV1 to save space.
• Bitrate changes: a "for email" or "small" export at the same resolution but a much lower bitrate.
• Frame-rate changes: a 60 fps recording exported at 30 fps.
• Container swaps: MOV to MP4, or MKV to MP4, with or without re-encoding.

To catch these you need a tool that compares what the video looks like. These tools decode frames at set points, shrink them to a small fingerprint, and compare fingerprints. Because the fingerprint is tiny and blurred on purpose, it survives resizing and compression.

Step 1: See what you're dealing with (free, no install)

Before you run any tool, it helps to know how many resolutions are in a folder. File Explorer can show this:

1. Open the folder and switch to Details view (View → Details).
2. Right-click any column header, choose More…, and tick Frame width, Frame height, Length and Total bitrate.
3. Sort by Length. Copies of the same clip usually have the same or nearly the same duration, so they end up next to each other even when names and sizes differ.

This is slow for big folders, but it's a quick way to confirm you really do have the same clip at several sizes before you install anything.

Step 2: Find them by content with a free tool

Two free, open-source tools compare video content on Windows. Both need FFmpeg (and FFprobe) available; each project's page explains how to provide it.

Option A: Video Duplicate Finder

Video Duplicate Finder (VDF) is a dedicated video and image similarity tool. Its README says it finds duplicates that have a different resolution, frame rate and even a watermark.

1. Get the Windows build from the project's GitHub releases page and make sure FFmpeg and FFprobe are available.
2. Add your include folders. Leave the similarity percentage at its default for the first pass.
3. Start the scan. VDF samples frames from each video and groups the ones that look alike.
4. In each group, sort by resolution or size, check the thumbnails, then mark the copies you don't want.

Option B: Czkawka

Czkawka is a free all-round cleaner with a Similar Videos tool. Add your folders, open that tab and run the search. It works best on copies of similar length; a heavily trimmed copy may not group with its original.

Tip for both: if a scan finds too little, raise the tolerance a step. If it groups clips that are genuinely different (same location, same camera), lower it. Review every group yourself before deleting anything.

Step 3: Decide which copy to keep

Once a group is found, the rule of thumb is simple. Work down this list and stop at the first difference:

Watch out for upscales. A 1080p clip that someone converted to 4K is bigger but not better. If the "4K" copy looks soft at full screen, keep the original 1080p file.

Step 4: The faster way with SceneSort Pro

SceneSort Pro is our Windows app for organising a big, messy media library. Its duplicate finder is built for exactly this situation, and it shows each copy's details next to a frame so the "which one to keep" step is quick. FFprobe is bundled, so there's nothing extra to install.

1. Add your folders. Local drives, external drives and network shares such as \\NAS\Videos all work. Subfolders are included.
2. Open Duplicates and pick a match mode. The Match by list goes from a quick name-based pass to lighter and heavier visual passes, plus audio-based modes. For resized and re-encoded copies, start with a visual mode.
3. Adjust Accuracy if needed. The accuracy stepper sets how close two files must be before they're grouped.
4. Review each group. Every file shows a frame plus resolution, duration, size, codec, frame rate and folder. The suggested keeper is marked in green and the others in red; change the ticks however you like, or right-click to mark a pair as "not a duplicate".
5. Delete safely. The bar shows how much space you'll free. Deleted files go to the Recycle Bin, and Undo is always available.

Because the free edition has every feature and works on your first 500 files, you can point it at one messy folder and see exactly what it finds before deciding anything.

Common questions

Will it match a short clip cut from a longer video?

Sometimes. Frame-sampling tools compare sampled moments, so a short excerpt may or may not line up with the full version. Video Duplicate Finder documents a partial-clip feature that uses audio fingerprints. In SceneSort, the audio-based match modes can help when both files have the same soundtrack.

Does this work for vertical phone videos?

Yes, as long as both copies have the same orientation. A clip that was rotated or cropped to a different shape is much harder for any tool to match, so check those by eye.

Is it safe to delete the smaller copies?

Only after you've looked at each group. Two clips filmed at the same place on the same day can look alike to a fingerprint. Deleting to the Recycle Bin first gives you a safety net.

More guides: start with how to organise a big, messy video collection on Windows; how to find duplicate videos with different names; Video Duplicate Finder vs SceneSort Pro; all video library guides.