CanDoYaRuns entirely in your browser - no upload, no sign-up.
Your clips and joined result stay in this browser tab. Nothing is uploaded.
A video joiner combines two or more clips into one continuous video. Add up to six files, arrange their order, choose MP4 or WebM, and download the merged result. Processing happens in your browser, so your original clips are not uploaded, stored, or marked with a watermark.
This joiner uses a local WebAssembly build of FFmpeg. It normalizes frame size, frame rate, pixel format, and audio before joining, which lets common MP4, MOV, WebM, MKV, and AVI clips share one timeline even when their technical settings differ.
Clips with a different aspect ratio are fitted inside the first clip's shape with black padding instead of being stretched or cropped. The new file is re-encoded, while every source file remains unchanged on your device.
No. Your browser reads each local file and passes it to a WebAssembly video engine running in this tab. The engine files download on first use, but your clips and joined output are not sent to that server, stored in a CanDoYa account, or used after you close the page.
Yes. You can arrange, join, preview, and download the result without an account, subscription, or watermark. The practical limits are browser memory and processing time. The device-aware total is conservative, ranging from 120 MB on mobile or low-memory devices to 600 MB on high-memory desktops.
You can combine between two and six clips in one pass. This keeps the interface clear and limits browser memory use because the source files, video engine, and finished result may all occupy memory at once. For a longer project, join smaller groups first, then combine those results in a final pass.
Yes. Common MP4, MOV, WebM, MKV, AVI, MPEG, and OGG-family files can be mixed when their codecs are supported by the local engine. Every clip is scaled to fit the first clip's aspect ratio and normalized to a common frame rate, pixel format, and audio layout before joining.
The output is re-encoded so mixed clips can share compatible settings, which can cause some quality loss. Choose Higher quality and Keep first clip size when detail matters most. Balanced at 720p is a practical default for sharing. The original files are never modified, so you can retry with another setting.
The first clip sets the output shape. A clip with a different aspect ratio is scaled until it fits and the remaining area is padded with black. This preserves the full picture without stretching faces or cropping the edges. Put a landscape clip first for landscape output, or a portrait clip first for portrait output.
The joiner detects whether each source has an audio stream. When a clip is silent, it creates a matching silent stereo track for that clip before joining. This prevents sound from later clips shifting earlier on the timeline and keeps spoken audio synchronized with the correct picture.
Different files must be decoded, resized, and encoded again on your device. Duration, resolution, motion, codec, quality, and available CPU and memory all affect speed. Keep the tab open during processing. For very long or 4K projects, a desktop video editor is usually faster and less memory constrained.