What is the difference between lossless stream copy and full re-encoding?

When cutting standard H.264/MP4 files without visual changes, NanoPix executes a lossless stream copy directly at the packet level in milliseconds with zero quality degradation. If exact non-keyframe cuts or visual filters are required, it switches to frame-accurate hardware/WASM re-encoding.

Why does lossless trimming align to the nearest keyframe?

In stream copy mode, video frames between keyframes rely on preceding I-frames to decode properly. Starting playback on a non-keyframe causes visual artifacts or gray frames. For microsecond frame-accurate cuts, choose full transcode on export.

Are my files uploaded to your servers?

No. NanoPix runs in your browser with WebAssembly. Your video, audio, or image files stay on your device—we never receive them.

Is browser-based editing private?

Yes. Processing happens locally on your machine. Nothing is sent to NanoPix servers for encoding or storage.

Yes. NanoPix tools are free to use in a modern browser. No account is required for basic editing and export.

Online Video Trimmer - Cut Video Locally

About Trim

Trim videos online for free—no upload required. Set in/out points on the timeline, export MP4 on your device. Private, fast, browser-based.

How to Trim Video Files Locally in Your Browser

Cut video clips in 3 simple steps without uploading your private media to any cloud server.

1Open NanoPix Video Trimmer and drop or select your local video file.
2Drag the in/out handles on the filmstrip timeline or enter exact timestamps.
3Click export to generate your trimmed video on-device via WebAssembly.

Tool facts

Processing: Runs locally in your browser. Source files are not uploaded to NanoPix for editing.
Available controls: Fine-grained in/out point controls · Filmstrip thumbnail timeline preview · Fast lossless keyframe stream copy
Output: Export trimmed video locally

Frequently asked questions

What can Trim do?: Trim videos online for free—no upload required. Set in/out points on the timeline, export MP4 on your device. Private, fast, browser-based.
What is the difference between lossless stream copy and full re-encoding?: When cutting standard H.264/MP4 files without visual changes, NanoPix executes a lossless stream copy directly at the packet level in milliseconds with zero quality degradation. If exact non-keyframe cuts or visual filters are required, it switches to frame-accurate hardware/WASM re-encoding.
Why does lossless trimming align to the nearest keyframe?: In stream copy mode, video frames between keyframes rely on preceding I-frames to decode properly. Starting playback on a non-keyframe causes visual artifacts or gray frames. For microsecond frame-accurate cuts, choose full transcode on export.
Are my files uploaded to your servers?: No. NanoPix runs in your browser with WebAssembly. Your video, audio, or image files stay on your device—we never receive them.
Is browser-based editing private?: Yes. Processing happens locally on your machine. Nothing is sent to NanoPix servers for encoding or storage.
Is this tool free?: Yes. NanoPix tools are free to use in a modern browser. No account is required for basic editing and export.