Merge videos

Mismatched clips

Joining video is only simple when every clip shares a resolution, frame rate and audio layout. They rarely do. This tool sidesteps the problem: every clip is scaled to fit the canvas you choose, letterboxed if the shape does not match, and resampled to one frame rate and one audio format before the join. It costs a full re-encode and it means the join actually works.

The silent clip trap

If any clip has no audio track, leave "every clip has sound" unticked. With it on, the join looks for an audio stream in every input and fails on the one that has none. With it off, the result is silent throughout.

Use the arrows in the file list to set the order before you run.

Why joining video is harder than joining audio

Audio files can be laid end to end almost regardless of what they are, because a resampler fixes any mismatch cheaply. Video has more things that must agree: resolution, frame rate, pixel format, colour range, and the codec and layout of the audio stream alongside it. Two clips off the same phone usually match. Two clips off different devices, or one screen recording and one camera clip, almost never do, and a naive join either fails outright or produces a file that plays the first clip and then falls apart.

The approach here is the reliable one rather than the fast one: everything is decoded, brought to a single canvas, frame rate and audio format, and encoded once as a new file. That is why it works on a folder of clips from four different sources, and why it costs a full re-encode even when the inputs look identical.

Choose the canvas for the largest clip

Every clip is scaled to fit the canvas and padded where the shape does not match. Picking a canvas smaller than your best footage throws away resolution you had; picking one larger scales lesser clips up and makes them soft. Match the canvas to the highest quality source, and let the smaller ones sit inside it.

Mixing portrait and landscape is the case with no good answer: whichever canvas you choose, one set arrives with bars. If they all need to fill a vertical frame, run the landscape clips through make a short first, which fills the background with a blurred copy rather than black bars.

Sound, and the clip that has none

The single most common failure here is a silent clip in the list. With "every clip has sound" ticked, the join expects an audio stream in every input and stops on the one without. Unticking it produces a silent result throughout, which is the right answer if you are laying music over the top afterwards and the wrong one if you wanted the dialogue.

The fix, when only one clip is silent, is to give it an audio track: run it through audio to video or add silence in the editor. The editor is also where to go if you want anything between the clips, since this joins them hard, with no transitions.

Common questions

Further reading

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