What a proxy is and why it helps
A proxy is a smaller copy of a source clip that the editor plays while you cut. Shotcut's documentation describes proxy editing as creating and using low-resolution videos and images so the computer has fewer pixels to process in real time, with the originals swapped back in for export. [1] Kdenlive documents proxy clips as generated files for large video and image sources, with settings for their size and encoding. [2]
This guide summarizes the official documentation of those two free editors, checked on 13 October 2026. We have not measured playback or render times. Other editors, including paid ones, offer similar features under different menu names; check your editor's own manual for the exact steps.
Diagnose before you change anything
Shotcut's documentation warns that a proxy can hide a problem with the actual source media, such as frame-accurate seeking issues. [1] If the original file has a defect, find it before relying on smooth proxy playback.
| Symptom | Likely category | Proxy helps? | Next check |
|---|---|---|---|
| Playback stutters only on 4K or high-bitrate clips | Decoding load | Usually the right first step | Generate proxies for those clips |
| Playback stutters on every clip, including small ones | Computer or editor settings | Maybe not | Check free disk space, preview settings and background apps |
| Stutter starts only after adding effects | Effects processing | Partly | Disable effects while cutting; apply them last |
| Export is slow but playback is fine | Render workload | No | Export overnight or simplify effects |
| Audio drifts out of sync over time | Source timing problem | No, and a proxy can hide it | Check the source file's frame rate |
How proxy editing works in two free editors
- Shotcut: a Use Proxy setting turns proxy use on for the current or next project. Adding eligible video or image files to the playlist or timeline can start a proxy job; existing proxies are reused automatically, but missing ones are not created just by opening a project. [1]
- Shotcut: proxy height follows the Preview Scaling setting and falls back to 540p when Preview Scaling is off; files must be larger than 1.3 times the preview scaling resolution to qualify. [1]
- Shotcut: proxies can be stored in a global folder or a project folder. A hardware-encoder option exists, but the documentation says most users should not expect it to significantly improve speed. [1]
- Kdenlive: proxy clips must be enabled in the configuration. You can set a pixel-width threshold for automatic proxy creation and choose encoding profiles, and Kdenlive can use proxy files some cameras record alongside the original. [2]
The export check that matters
Shotcut's documentation says that normally the proxy clips are replaced with their originals when you export, but describes an exception: an advanced export option that uses preview scaling produces a faster rough draft from proxies, which is not intended as final output. It also notes that Export Frame uses the proxy upscaled to project resolution. [1]
So inspect the final file, not the timeline. Open the export in a separate player at full screen and check a frame with fine detail, such as small interface text. If it looks soft compared with the original, the export used proxies or a reduced resolution. Kdenlive's proxy configuration page does not describe export behavior, so check the render settings in its manual before delivering. [2]
Worked example: a fictional course creator
In this invented case, a creator records 4K screen captures for a course and edits on a five-year-old laptop. Playback stutters on every 4K clip but not on 1080p webcam clips. That pattern points to decoding load, so the creator enables proxies, waits for the proxy jobs to finish, and cuts the course at a smooth preview.
Before uploading, the creator exports one lesson, opens it in a player and checks that code on screen is as sharp as in the source. The cost of this route is disk space for the proxy files and the time to generate them. A new laptop would be justified only if playback is still unusable with proxies, or if export times regularly block publishing.
Housekeeping and pitfalls
- Budget disk space for proxies in addition to originals, and know which folder holds them so a cleanup does not delete files you still need. [1]
- Keep original media connected at export; an editor cannot restore full quality from a proxy if the original is missing.
- Do not judge color, sharpness or audio quality from proxy playback.
- When moving a project to another computer, move originals first; proxies can be regenerated.
Questions before you decide
Will proxies make my export faster?
Not for a final export. Shotcut documents that proxies are normally replaced by originals when exporting, so render work is done on full-resolution media. Proxies mainly make editing playback smoother.
Do I need a paid editor for proxy editing?
No. Shotcut and Kdenlive, both free, document proxy settings. Many paid editors have equivalents, so check whether your current editor already supports proxies before switching or upgrading hardware.
Sources & verification
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- Shotcut documentation: Settings > Proxy Editing Accessed 13 Oct 2026
- Kdenlive documentation: Proxy clips configuration Accessed 13 Oct 2026
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