Why merging on Clipy "just works"
FFmpeg's concat demuxer needs every input to share the same codec, resolution, frame rate, and audio sample rate. When clips share that shape (e.g., several chunks from the same recorder), a stream-copy concat works and is sub-second. When they don't — different resolutions, mixed codecs, one clip with audio and one without — stream-copy produces a brittle file where only the first segment plays. Our pipeline normalizes each clip to a common H.264 / AAC shape first, then concatenates. The trade-off is a few extra seconds of encode time for a file that actually plays end-to-end every time — no "why is the second half silent" bug reports.
What this tool does, exactly
Each input clip is re-encoded to H.264 video and AAC audio at a common resolution and frame rate, then joined via the concat demuxer into a single MP4 with +faststart for instant playback. Output is always MP4 because it's the universally playable container. The order in which you dropped clips into the page is the order they're joined; use the up/down arrows to reorder before clicking Merge. Audio is preserved across every segment — that's the per-clip normalize step doing its job. If a clip has no audio track, a silent track is inserted so playback timestamps don't drift.
When merging is the right move
An interview cut into Q&A chunks that needs to be one deliverable. A screen recording that auto-split because the recorder hit a duration limit. B-roll plus a main take that should ship as a single video. Multiple speakers each recorded separately on their own machine. Tutorial steps captured in separate takes. Any time the natural deliverable is one continuous video but the raw material is multiple clips, this tool is the join. The biggest gotcha: if the inputs don't share the same aspect ratio, the output ends up letterboxed or pillarboxed wherever the shape changes. Normalize aspect ratios first by running mismatched clips through resize video to a common shape, then merge.
Sister tools
Merging is often step one of a longer pipeline. Need to drop a webcam corner from the joined output? Crop video. Fix a sideways segment first? Rotate video. Stripping audio for an autoplay-muted social embed? Mute video. The merged file got big? Run it through video compressor. Reframing for a vertical feed after merge? Aspect ratio converter.
Record long takes, skip the merge step
If you find yourself merging clips because your recorder kept hitting time limits, Clipy records long takes natively and ships you a shareable link without an upload round-trip. The cleanest way to avoid this whole step is to not need it.