Trim and convert a short video without guessing codecs

Understand the settings

A container is the file wrapper: MP4, MKV and WebM describe how streams are stored together. A codec describes how video or audio is encoded. Changing a filename from .mkv to .mp4 does not change either the wrapper or its codecs. This editor actually decodes and re-encodes the selected clip.

Use MP4 with H.264/AAC for ordinary sharing when broad playback compatibility matters. MKV uses the same H.264/AAC encoding here but a different wrapper. WebM uses VP9/Opus and may take longer to process. MP3 and WAV extract only the first audio track: MP3 is lossy and relatively compact; WAV stores 16-bit PCM and can be much larger. None of these choices restores detail lost in the original.

The editor is intentionally for short jobs: input is limited to 200 MiB, 2000 pixels on either side, 30 fps, and three minutes. A small compressed file can still be expensive to decode, so the worker also checks frame timestamps and dimensions and enforces a processing timeout. High-frame-rate input is rejected rather than automatically accepted because you selected 30 fps output.

Trim values are seconds from the beginning. An end value is an absolute position, not a duration: start 5 and end 12 makes a seven-second clip. Cropping removes a stated number of pixels from each edge before resizing. Output width keeps the cropped aspect ratio and rounds to an even width for codec compatibility. Rotation is applied after that. The tool uses stored pixel orientation and ignores phone rotation metadata; use the rotation control if a phone clip looks sideways.

Step by step

1. Choose one video and select the output preset.
2. For a quick test, set start to 5 and end to 12. Leave cropping at zero.
3. If needed, set a smaller width; the tool will not upscale. Select the output frame rate and any rotation.
4. Press Process clip. The page uploads the file, then shows queued, checking and converting stages. Keep the tab open.
5. Download and play the entire result before sharing it. Use Cancel and delete files to remove the temporary result immediately.

Seven-second sharing clip

Input: a 1920 × 1080, 30 fps, 20-second video. Choose MP4, start 5, end 12, width 1280, and leave crop/rotation unchanged. Expected video dimensions are 1280 × 720 and duration approximately seven seconds. Frame/time rounding may affect the final fraction of a second.

Limits and what to check

• Video is re-encoded with lossy presets. This is not archival lossless conversion.
• Only the main video and first audio track are used. Subtitles, chapters, attachments and other audio tracks are not retained.
• Output is 8-bit 4:2:0. HDR tone mapping and color-managed conversion are not provided; use an SDR source.
• Input and output are private temporary server files. Results expire one hour after upload; cleanup runs while the worker or cleanup timer is active.
• Progress percentages describe stages, not exact elapsed-time estimates. There is no URL-import or arbitrary FFmpeg-argument field.

Troubleshooting