{{ summaryTitle }}
{{ summaryValue }}

{{ summaryLine }}

{{ badge.label }}{{ badge.value }}
MP4, MOV, WebM, or MKV; up to 40 MB, 2 minutes, and 2.1 megapixels.
{{ selectedFile ? selectedFile.name : 'Drop one video here' }}
{{ selectedFile ? sourceMetaLine : 'Drop a file or browse from your device' }}

Ignored {{ ignoredFileCount }} extra {{ ignoredFileCount === 1 ? 'file' : 'files' }}. This tool processes one file at a time.

Even value from 16 to 1920 px.
px
Even value; canvas at most 2.1 MP.
px
Choose whether complete source framing or an edge-to-edge target canvas matters most.
Off preserves source detail. Fill requests that require enlargement remain blocked until you explicitly allow it.
{{ allow_upscale ? 'Upscaling allowed' : 'Never upscale' }}
{{ planTitle }}
{{ planLine }}

{{ workflowMessage }}

Off preserves the existing behavior. The compatibility encoder is always video-only.
{{ remove_audio ? 'Silent output' : 'Preserve source audio' }}
Resized video
{{ row.label }}{{ row.display }}

The chart renderer is unavailable. The same geometry remains in the frame ledger.

SignalValueMeaningCopy
{{ row.label }}{{ row.display }}{{ row.detail }}
Video Bitrate Storage Calculator Plan video storage from bitrate and recording duration, including multiple cameras and copies plus headroom and whole-drive capacity checks.
Field of View Calculator Plan camera framing from active sensor size and focal length at a chosen distance with angle-of-view math, target-fit checks, and comparative lens sweeps.
Lens Equivalence Comparator Match framing across camera formats through exact focal length and depth-of-field look, with crop adjustments and a practical lens choice.
Video Call Sheet Generator Build a one-day video call sheet with staggered crew calls, schedule conflict checks and calendar-ready events for the production day.

Changing video dimensions means choosing what happens when the source and target have different shapes. A 16:9 recording cannot become a square without leaving empty space, removing part of the frame, or stretching the picture. Resizing should keep the source aspect ratio and make that tradeoff explicit.

Choice What remains intact What changes
Fit whole frame Every source edge remains visible. Black padding fills unused target space.
Fill and crop The target canvas is covered edge to edge. A centered crop removes content from two opposing edges.
Exact aspect match The full frame and target canvas align. No padding or cropping is needed.

Upscaling creates a larger pixel grid, but it cannot restore detail that the source never captured. Leaving it off prevents accidental enlargement. Fill may still require enlargement when both target dimensions exceed what the source can cover at its original size, so a blocked fill request is a useful warning rather than a processing failure.

Dimensions are only one part of a video handoff. Encoding changes the video stream, and the result uses an MP4 container with H.264 video. The primary local encoder can preserve one source audio stream by converting it to AAC, or remove audio on request. A compatibility path used outside a secure browser context produces video-only output at 12 frames per second, which is materially different from the primary path.

File size will not scale in exact proportion to pixel count. Motion, frame rate, scene detail, codec settings, duration, and audio all influence the output bytes. A smaller canvas often reduces size, but playback and visual inspection are still needed because a dimension check cannot detect an unwanted crop, soft text, missing audio, or compression artifacts.

The safest target is chosen for the destination first. Confirm its required width, height, orientation, maximum duration, and audio policy before resizing, then keep the source file until the new MP4 has been reviewed in the receiving application.

How to Use This Tool:

Choose one browser-decodable video and decide whether full framing or an edge-to-edge canvas matters more.

  1. Drop or browse for one MP4, MOV, WebM, or MKV file. The limit is 40 MB, 0.2 to 120 seconds, and no more than 2,073,600 source pixels.
  2. Enter even Target width and Target height values from 16 through 1,920 pixels. Their product must not exceed 2,073,600 pixels.
  3. Choose Fit whole frame for black padding or Fill and crop for a centered crop.
  4. Leave Allow upscaling off unless a larger canvas is required. If Fill reports that enlargement is necessary, allow it, choose Fit, or reduce the target.
  5. Choose whether to remove audio, then resize. If processing reports an unsafe intermediate frame, use Fit or select a target aspect ratio closer to the source.
  6. Play the generated MP4 and confirm its dimensions, duration, crop or padding, and audio before downloading it.

Interpreting Results:

The output canvas should match the requested dimensions exactly. Content size reports the scaled frame before padding or cropping, while the horizontal and vertical offsets show how much space is added or removed on each side of the centered image.

A verified width, height, and duration do not prove the edit is suitable. Watch representative frames near the beginning, middle, and end, listen for audio when it should remain, and check that titles, faces, captions, or other edge content survived the chosen framing.

Technical Details:

Resize geometry compares the target-to-source scale on both axes. Fit uses the smaller ratio so neither scaled dimension exceeds the target. Fill uses the larger ratio so neither scaled dimension falls short. The scaled width and height are made even for H.264 compatibility before centered padding or cropping is applied.

Formula Core:

Let source dimensions be Ws and Hs, and target dimensions be Wt and Ht. The scale factor is:

sfit = min(WtWs,HtHs) sfill = max(WtWs,HtHs)

When upscaling is off, Fit caps s at 1. Fill is rejected when its required scale is greater than 1. The centered offset on either axis is half the absolute difference between the target dimension and the even scaled content dimension.

Offsetx = |Wt−Wcontent|2

Transformation Core:

Stage Transformation
Validate Check file size, duration, source pixel count, even target dimensions, target pixel count, and the no-upscale rule.
Scale Resize proportionally to the even content dimensions selected by the Fit or Fill formula.
Frame Fit adds centered black padding; Fill removes a centered strip from the oversized content; matching aspect ratios need neither.
Encode Create H.264 video in MP4. The primary path uses AAC when preserving available source audio and removes metadata, chapters, subtitles, and data streams.
Verify Decode the result and require exact target dimensions plus duration within the greater of 0.2 seconds or 5% of the source duration.

Square output example

A 1,920 × 1,080 source resized to 1,080 × 1,080 uses a Fit scale of 0.5625, producing 1,080 × 606 content after even rounding and 237 pixels of black padding above and below. Fill uses a scale of 1, keeps 1,920 × 1,080 content, and crops 420 pixels from both the left and right edges.

Privacy and Compatibility:

The source file and generated MP4 are processed locally in the browser rather than uploaded for encoding. The encoder code may be downloaded from its configured content delivery source when needed, so the first run can require a network connection.

  • Browser decoding support still determines whether a particular MP4, MOV, WebM, or MKV stream can be opened.
  • Outside a secure browser context, compatibility encoding is video-only at 12 frames per second even when audio preservation was requested.
  • Metadata, chapters, subtitles, and data streams are not carried into the generated MP4.

References: