Take it step by step
- Choose a local video and select MP4 for broad H.264/AAC compatibility, WebM for a web container, or MKV for flexible track storage.
- Start with Encode for an unfamiliar source. Set the maximum width and use a lower CRF for higher visual quality with H.264.
- Select Copy only when the destination supports your existing streams. This skips decode/filter/encode, preserves stream quality and cannot resize the picture.
- Inspect the result in your intended player. If Copy fails, choose Encode rather than changing the filename extension.
A situation to try.
The supplied demo MP4 has a synthetic test pattern and tone. Compare an encoded MP4 with a stream-copy MKV. File sizes can differ because container overhead changes even when the streams are preserved.
Use the tool’s synthetic example first where available. The example here explains a decision; it is not a reported benchmark result.
Before you call it done.
- Copy-mode cuts can start near a keyframe rather than the exact requested time.
- WebM output uses VP8/Vorbis in this build; its settings differ from H.264 CRF.
- HDR colour, rotation tags and unusual subtitles need independent review.
- The cached engine is reused for successful repeat jobs and released after an idle minute. User files are removed from its virtual filesystem after each completed job.
Know the limits.
There is no universal speed or compression claim. WASM encoding can be slower than native desktop software, and output can grow. Our tests establish readable fixture exports, not a win over another service.
This tool’s current boundary: Container copy preserves streams only when the destination supports their codecs. Encoding changes quality.
Evidence and scope
Technical source guidance and task-specific output checks. These do not establish that every file, browser or device passes.
Use the checks above on your own exported result. A source explains the format or mechanism; it is not proof that this export preserved every feature.
Technical reference: FFmpeg: stream copy ↗
Choose the right tool for this step.
Video format converter
Convert MOV, MKV or WebM to MP4, WebM or MKV.
On your deviceWhy use it: Use this task-specific local workspace.
Before you start: Keep your original and review the stated format and device limits.
Media inspection
Inspect codec, duration and other media properties.
On your deviceWhy use it: Use this task-specific local workspace.
Before you start: Keep your original and review the stated format and device limits.
Video container remux
Rebuild a readable video container while copying its streams.
On your deviceWhy use it: Use this task-specific local workspace.
Before you start: Keep your original and review the stated format and device limits.
Mute video
Remove audio tracks without re-encoding the picture.
On your deviceWhy use it: Use this task-specific local workspace.
Before you start: Keep your original and review the stated format and device limits.
Split video into parts
Divide a video into sequential MKV files without encoding its streams.
On your deviceWhy use it: Use this task-specific local workspace.
Before you start: Keep your original and review the stated format and device limits.
Preparation tools process locally. Official service links take you to the authority’s website. Inspect any exported copy before sharing it.