Crop & Reframe

Crop a video to a new aspect ratio in your browser: open an MP4, MOV or WebM file, pick the source ratio, 16:9, 9:16, 1:1, 4:5 or 4:3, place the crop rectangle with zoom and position, and download the cropped video with its audio. The file is decoded and re-encoded on your device and is never uploaded.

Crop a clip to a preset ratio

Drop a video here

MP4, MOV or WebM, up to 10 minutes and 2 GB. Your video stays on your device.

File: —
Source: —
Duration: —
Crop: —
Export: —
Ratio: —

Verified facts

Inputs: MP4, MOV, WEBM
Output formats: MP4, WEBM
Processing: In your browser. No media upload.
Access: Free · No signup

MP4, MOV and WebM are containers. Decoding depends on the codec and browser/device support; not every file in these containers will open.

How to use it

Use Open video to choose a local file, or Try a sample. MP4, MOV, WEBM are read; whether a given file decodes depends on the codec inside it and on this browser.
Choose a target aspect ratio. Original keeps the shape of the source. 16:9, 9:16, 1:1, 4:5 and 4:3 take a rectangle of that shape out of the frame.
Drag inside the preview to position the crop. You can also use the Horizontal position and Vertical position sliders. Zoom 1 keeps the largest area of the chosen ratio that fits the frame. Zoom 3 selects the smallest area. A crop edge stops at 16 pixels, so a small source reaches this limit before the maximum zoom.
Check the output dimensions and format. Then press Download video. The tool decodes and re-encodes every frame with the same crop. You can stop the export while it runs.

Limitations

One crop rectangle applies to the whole clip. There is no tracking, no trimming and no reframing over time.
Ratios are the source ratio, 16:9, 9:16, 1:1, 4:5 and 4:3. The rectangle is the largest one of that ratio that fits the frame, reduced by the zoom, and moved inside the frame by the horizontal and vertical position.
Zoom runs from 1 to 3. A crop edge stops at 16 pixels, so zoom reaches less far on a small source.
Crop and output dimensions are even numbers, because video encoders require it. On a source with an odd width or height this drops one row or column at the edge. The output is never enlarged, and its longest edge is written at up to 1920 pixels; a larger crop is reduced to fit and the reduced size is reported before the export runs.
The crop rectangle is placed in display pixels, after the rotation and the pixel aspect ratio the file declares. What the preview shows is the region the export writes.
Every frame is decoded and re-encoded, so this is not a lossless copy. Source presentation timestamps are carried through, including variable frame rates, and the frame rate is not changed.
The tool prefers H.264 in MP4 when the source is silent or its AAC or MP3 audio can be copied. Other sources use VP9 or VP8 in WebM. WebM is also the fallback when the browser cannot write the MP4. The tool shows the selected format before export.
The export keeps the primary video and audio tracks. It omits additional audio tracks along with subtitles and chapters. MP4 copies AAC or MP3 audio. WebM copies Opus or Vorbis audio and re-encodes other supported audio as Opus. A source whose audio cannot be kept in either format fails with a message instead of exporting silent video.
MP4 output is written with its metadata at the end of the file rather than at the front, so the whole file has to be present before it plays. That is the case for a download.
Every frame is drawn through a 2D canvas before it is encoded, so the output is written as sRGB with BT.709 primaries. An HDR source is converted by the browser at that step and its colour can shift.
Sources are read up to 2 GB, 10 minutes, 16 megapixels per frame and 16,384 pixels on the longest edge, measured on the display size and on the coded raster. A file past one of these limits is named in the error instead of being opened.
The export stops above 512 MiB of written video, because the file is held in memory until the download starts. This bounds the file. Decoding and encoding hold memory beyond it.
An export can be stopped while it runs. Nothing is uploaded and nothing is saved between visits.
MP4, MOV and WebM are containers. Decoding depends on the codec and browser/device support; not every file in these containers will open.

One rectangle, the whole clip

The crop you place applies to every frame of the video. Position and zoom are set once and do not change over time.

There is no subject tracking, no keyframed movement and no automatic reframe that follows action from shot to shot. Where a subject leaves the rectangle, it leaves the export.

The export keeps the full source duration and frame order. It also keeps the source frame timing. This tool does not trim, split or join clips.

Aspect ratios and output size

The source resolution and crop settings determine the output dimensions. The export uses the cropped pixels without enlarging them. It rounds both edges to even numbers for encoding. The longest output edge is at most 1920 pixels. A larger crop is reduced to fit, and the output size is shown before export.

The rectangle is placed in display pixels, after the rotation and the pixel aspect ratio the file declares. That is why the region in the preview is the region in the file.

Output from a 1920 by 1080 source at zoom 1.
Aspect ratio	Output
Original	1920 × 1080. The whole frame, so there is nothing to move until you zoom in.
16:9	1920 × 1080. The whole frame again on a source already in this shape.
9:16	608 × 1080. A column the full height of the frame, moved left or right.
1:1	1080 × 1080. A square the full height of the frame, moved left or right.
4:5	864 × 1080. Taller than wide, moved left or right.
4:3	1440 × 1080. The sides come off, moved left or right.

What the export writes

The tool decodes and re-encodes every frame. The export adds another generation of compression. It cannot recover detail lost in the source. The export keeps the source presentation timestamps and frame rate. This includes variable frame rates.

The tool selects the output format when you open the video and shows it before export. It prefers H.264 in MP4 when the source is silent or its AAC or MP3 audio can be copied. Other sources use VP9 or VP8 in WebM. WebM is also the fallback when the browser cannot write the MP4. The selected format determines the file extension and MIME type. An MP4 stores its metadata at the end of the file. Download the whole file before playing it.

The export keeps the primary video and audio tracks. It copies AAC or MP3 audio into MP4. It copies Opus or Vorbis audio into WebM. Other supported audio is re-encoded as Opus in WebM. Additional audio tracks are omitted along with subtitles and chapters. The tool warns when the source has more than one audio track.

The tool reads the finished file before starting the download. It checks the video dimensions against the reported output size. If the source has sound, the export must have an audio track. A failed check stops the download and shows an error.

Privacy and processing

Reading, framing and encoding happen locally in this browser. The tool does not upload your video to Avo servers, and no account is required.

The page itself and the optional sample clip are fetched over the network like any website. Local media processing is not an offline mode and is not a statement about site analytics.

Nothing is kept between visits. Replacing the source releases the previous file and its preview; a downloaded export stays wherever you saved it.

Questions

Does it follow the subject?

No. The crop is a fixed rectangle over the whole clip. There is no face, object or motion tracking, and no automatic reframing per shot.

Can the crop move during the clip?

No. Position and zoom have one value each for the entire video. Animated reframing would need keyframes over time, which this tool does not have.

Can I shorten the video here?

No. The export has the same duration as the source. Trimming and splitting are a separate job and are not in this tool.

Does cropping reduce quality?

The tool re-encodes the video and adds another generation of compression. Cropping removes pixels. The export never enlarges the cropped picture. Its longest edge is at most 1920 pixels.

Is the audio kept?

The export keeps the primary audio track. MP4 copies AAC or MP3 audio. WebM copies Opus or Vorbis audio and re-encodes other supported audio as Opus. Additional audio tracks are omitted along with subtitles and chapters. The tool reads the finished file and rejects it if required audio is missing.

Why will my MOV or MP4 not open?