Join videos with different resolutions and orientations

Merge portrait and landscape video without stretching

Mixed phone footage is rarely consistent. One clip may be 1080x1920 portrait, another 1920x1080 landscape, and a screen recording may use a third size or frame rate. A simple lossless concat fails when those stream properties do not match.

AntiUpload normalizes mismatched clips to a fixed portrait or landscape canvas. Each video keeps its original proportions, with letterbox padding where needed, so faces and text are not stretched to fill the frame.

When video joining can stay lossless

Clips from the same camera or recording session often share codec, dimensions, frame rate, pixel format, and audio settings. When every required stream property matches, the joiner re-muxes them with stream copy instead of decoding and re-encoding every frame.

If the clips differ, normalization requires a new video encode. The tool can use hardware-backed browser codecs for compatible MP4 inputs and falls back to FFmpeg when needed. The output is compatible, but it is not lossless in that mixed-input path.

Crossfades versus fast hard cuts

A hard cut is the fastest option and preserves the stream-copy path when the inputs match. Adding a crossfade blends frames and audio across each boundary, which always requires re-encoding.

Use a hard cut for consecutive clips from the same recording. Use a short crossfade when the clips come from different moments and the visual transition matters more than export speed.

How to use this workflow

1. 01.Add two or more videosChoose the phone, camera, or screen-recording clips you want and drag them into the correct order.
2. 02.Choose the output orientationPick landscape or portrait. Clips that do not match are scaled to fit and letterboxed instead of being stretched.
3. 03.Join and review the resultThe engine picks the fastest compatible path, then gives you one video to preview and download.

Questions