VIDEO TOOLS

Edit video in your browser.

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Free · Local processing

Video compression

Reduce video file size in your browser. Keep the original resolution, choose clearer video or a size limit, and preview before downloading.

File will not leave the device

↥Drag a videoSelect video

Display file information after selecting video

Compression complete

Parameters, example and limits

What does video compression trade off?

A smaller video uses fewer bits to represent the picture and audio. Fine text, rapid motion and faces need a visual check even when the export meets a size ceiling. Browser codec support determines which export options are available.

Step by step

Choose a video and check its dimensions and duration. Keep original resolution for a first comparison.
Start with Clearer video, or choose Fit a size limit when the receiving service specifies a ceiling. Enter the ceiling in decimal MB.
Compress, preview the finished file and inspect text, faces, movement and audio. Download only after checking the reported bytes and dimensions.

Choosing the settings

Option	What changes
Clearer video	Starts from a quality goal. It does not promise a particular percentage reduction or a smaller file for every source.
Fit a size limit	Enforces an output byte ceiling. If the tool cannot fit the chosen settings, increase the limit or reduce output resolution.
Resolution and audio bitrate	720p removes picture pixels compared with a 1080p source. Audio shares the file's bitrate budget, so preserve enough for the content you need.

Example and expected result

A 60-second clip with a 5 MB ceiling has 5,000,000 × 8 ÷ 60 = about 666,667 bits/second for the entire file. At 96 kbps, audio alone uses about 720,000 bytes; video and container overhead share the remaining space. This is a planning calculation, not a promised encoded size or quality score.

If it is not working

The compression worker accepts non-empty inputs up to 192 MiB and caps results at 192 MiB. Device memory and decoding support can still prevent processing below that cap.
For an unreadable format, export a browser-playable source first. For memory errors, cancel and try a shorter clip. A disabled codec option is not supported on the current device.
If a size-limited result looks blurred, raise the limit rather than assuming that a passed size check means acceptable quality.

Creator tools

Change video aspect ratio

Reconstruct horizontal screen material to 9:16 used by TikTok, Reels, and Shorts, and also output 1:1, 4:5, and 16:9.

Do not upload original video

Drag a video Support horizontal and vertical screen materials

Display file information after selecting video

1080 × 1920

Release ratio

Screen fill

Horizontal focus 50%

Vertical focus 50%

Output quality

Aspect ratio conversion complete

9:16

Vertical screen short video

Suitable for YouTube Shorts, TikTok, Instagram Reels.

4:5

Information flow advertising

Obtain a larger visual area in the mobile phone information flow while retaining the main screen.

16:9

Horizontal publishing

Suitable for YouTube, website embedding, presentations, and TV broadcasts.

Parameters, example and limits

Resize for social video

Reconstruct horizontal screen material to 9:16 used by TikTok, Reels, and Shorts, and also output 1:1, 4:5, and 16:9.

Step by step

Select video
Release ratio
Screen fill
Generate short video
Preview and download

Choosing the settings

Option	What changes
Release ratio / Screen fill	Choose an aspect ratio, then decide how to fill it. Move the horizontal and vertical focus to keep the subject in view.

Example and expected result

For a 16:9 clip going to 9:16, crop fills the frame but removes the sides; blur or black borders retain the full picture.

If it is not working

If processing fails: If the format cannot be read, use a browser-playable video or convert the source first. On memory errors, retry with a shorter clip. Check the displayed limits before processing and inspect the result before downloading.
Check the beginning, middle and end of the result, including framing, sound and synchronization where relevant. A sampled report or thumbnail does not verify every frame; inspect the source around each reported timestamp.

Professional quality inspection · Local scanning

Video preflight

Before publishing, scan for black or white frames, frozen shots, long silences, audio clipping, shot pacing and letterboxing. Review issues in a timestamped report.

The original video is not uploaded

Drop a video to check Check visual issues, silence and audio clipping

Display file information after selecting video

Scanning accuracy

Scene change sensitivity

Silence threshold

Minimum silence duration

sec

Simultaneously decode audio tracks and detect long silences and clipping Audio checking can be turned off for very large files to reduce memory usage

—Comprehensive score

Preflight report

Publish Risk Overview

Scoring is used to quickly locate abnormalities and does not replace manual film review.

Visual score—

Number of shots—

Average shot duration—

Sampling—

Long silence—

Peak—

Approximate overall loudness—

Proportion of clipped samples—

Find issues faster

Sample brightness, frame differences and audio levels over time to locate potential issues.

↗

Jump to each issue

Select an issue in the report to review that moment in the source video.

JSON

Export for your workflow

Export a structured JSON report for review, records or later analysis.

Parameters, example and limits

Video preflight

Before publishing, scan for black or white frames, frozen shots, long silences, audio clipping, shot pacing and letterboxing. Review issues in a timestamped report.

Step by step

Select video
Scanning accuracy
Run preflight check
Export JSON report

Choosing the settings

Option	What changes
Scanning accuracy	Click report timestamps to review the source, then export JSON. Whole-track audio analysis is skipped above 64 MiB or 3 minutes; picture analysis can still run. The score is not approval to publish.

Example and expected result

The standard 0.5-second interval samples about 120 frames per minute; brief faults between samples can be missed.

If it is not working

If processing fails: If the format cannot be read, use a browser-playable video or convert the source first. On memory errors, retry with a shorter clip. Check the displayed limits before processing and inspect the result before downloading.
Check the beginning, middle and end of the result, including framing, sound and synchronization where relevant. A sampled report or thumbnail does not verify every frame; inspect the source around each reported timestamp.

Perceptual fingerprint · No need to upload

Duplicate segment detection in two videos

Even if the video is recompressed, the resolution is changed, or slightly cropped, it can still find the same consecutive segments according to the perceptual screen fingerprint, and mark the precise interval in the two videos.

Local comparison content

Upload original video Aas the main timeline

Upload comparison video BCan be an edited version or a re-encoded version

Sampling interval

Similarity threshold

Shortest continuous segment

sec

Time drift tolerance

sec

Content fingerprint

Continuous similar segments

Total matched duration—

A coverage—

B coverage—

Highest similarity—

Number of fingerprint comparisons—

64 bit

Perceptual frame fingerprint

Compares frame structure rather than file bytes, so similar content can still be found after re-encoding and changing resolutions.

2×

Full-frame and center fingerprints

Simultaneously calculate the complete frame and the center area to enhance tolerance to slight cropping, border and watermark changes.

Timeline

Locate the continuous interval

Instead of just saying "similar", give the respective start, end and offset times of videos A and B.

Parameters, example and limits

Duplicate segment detection

Step by step

Upload original video A
Upload comparison video B
Sampling interval
Start comparison

Choosing the settings

Option	What changes
Upload comparison video B	Add videos A and B. A matched range is a visual similarity candidate, not proof of identical files or ownership. Review both timestamps; raise the threshold to reduce false matches.

Example and expected result

Start at a 1-second interval and lower it for short repeats; finer sampling takes longer.

If it is not working

If processing fails: If the format cannot be read, use a browser-playable video or convert the source first. On memory errors, retry with a shorter clip. Check the displayed limits before processing and inspect the result before downloading.
Check the beginning, middle and end of the result, including framing, sound and synchronization where relevant. A sampled report or thumbnail does not verify every frame; inspect the source around each reported timestamp.

Dynamic sidechain compression

Narration automatically lowers background music

Upload a video with human voice and a background music. The music automatically lowers when speaking is detected and resumes naturally when there is a pause, without the need to manually draw volume keyframes.

Native FFmpeg mixing

Upload a video with narrationVideo must have a vocal track Upload background musicAutomatically loop when the music is insufficient

Display file information after selecting video

Music volume between spoken sections

Human voice detection sensitivity

Ducking ratio

Attack time

Release time

Video processing

Fast mode will not reduce the image quality; if the original video encoding cannot be loaded into MP4, please use "compatibility mode" instead.

Voiceover mix complete

Side chain compression

Use the narration track as the control signal to dynamically lower the music only when the vocal appears.

∞

Music automatically loops

If the background music is shorter than the video, it does not need to be edited in advance. It will automatically loop until the end of the video.

0 keyframes

Say goodbye to manual animation keyframes

Interviews, narrations, lessons, and short video narrations can all be done in one go for basic mixing.

Parameters, example and limits

Voiceover mixing

Step by step

Upload a video with narration
Upload background music
Video processing
Create voiceover mix
Preview and download

Choosing the settings

Option	What changes
Upload background music / Video processing	Add a video with narration and a music file. Music loops if shorter than the video. Attack and release set how quickly music lowers and returns; stronger ratios lower it more. Fast mode copies video frames; use H.264 compatibility mode if MP4 export fails. This tool does not separate speech from an existing soundtrack.

Example and expected result

Timing example: use a 60-second narrated video with 20 seconds of music. The music loops to cover the video; ducking lowers it when narration is detected. Check transitions by listening. This does not extract narration from a mixed soundtrack.

If it is not working

If processing fails: If the format cannot be read, use a browser-playable video or convert the source first. On memory errors, retry with a shorter clip. Check the displayed limits before processing and inspect the result before downloading.
Check the beginning, middle and end of the result, including framing, sound and synchronization where relevant. A sampled report or thumbnail does not verify every frame; inspect the source around each reported timestamp.

LOCAL · FREE

Video storyboard contact sheet

Sample a video at evenly spaced times, make a timestamped frame sheet and jump back to any frame.

Video stays on this device

Drop a video here or choose a file your browser can play (up to 128 MiB)

Choose a video to see its duration and format.

Parameters, example and limits

Video storyboard

Sample a video at evenly spaced times, make a timestamped frame sheet and jump back to any frame.

Step by step

Select video
Video sampling frame number
Generate storyboard contact table
Download PNG

Choosing the settings

Option	What changes
Video sampling frame number	Choose 12, 24, 36 or 48 evenly spaced frames. Click thumbnails to seek and download the timestamped PNG. This is not automatic shot detection: short shots can be missed. Maximum 128 MiB and 6 hours; the browser must decode the video.

Example and expected result

For a 60-second clip with 12 frames, sampling starts near 2.5 seconds, then 7.5 seconds.

If it is not working

If processing fails: If the format cannot be read, use a browser-playable video or convert the source first. On memory errors, retry with a shorter clip. Check the displayed limits before processing and inspect the result before downloading.
Check the beginning, middle and end of the result, including framing, sound and synchronization where relevant. A sampled report or thumbnail does not verify every frame; inspect the source around each reported timestamp.

FAQ

Frequently asked questions

Some tasks need the 31 MB media engine. Your browser downloads it once and may cache it for later.

Why is the first opening process slower?＋

Some tasks need the 31 MB media engine. Your browser downloads it once and may cache it for later.

Will processed videos be uploaded to the server?＋

Files and text are processed in your browser, without uploading your input.

Can large files be processed?＋

Browser processing consumes device memory and CPU. The desktop version is more suitable for processing longer videos; the mobile version is recommended to use shorter footage. The browser version of FFmpeg is generally slower than the desktop native software.

ToolRobin Advanced Video Lab

Instead of building another conversion station, we should build a publishing infrastructure for creators.

Video physical examination, content fingerprinting, lens-aware subtitles and automatic mixing can form obvious differences; followed by local speech recognition, face tracking coding and batch workflow.

Free browser video tools

ToolRobin Video Tools helps creators review and prepare footage directly in the browser. Build a timestamped contact sheet from evenly sampled frames, reframe clips for social formats, compare footage and run preflight checks without installing a desktop editor.

Review a long clip at a glance

Choose 12 to 48 evenly spaced frames, inspect the contact sheet and jump back to a frame time in the source video. Short shots between samples may be missed.

Privacy-first workflow

The contact sheet is generated on your device. Video is not uploaded; the browser must support decoding the file.

Audio Tools Subtitle Studio All ToolRobin tools

Edit video in your browser.

Video compression

Change video aspect ratio

Vertical screen short video

Information flow advertising

Horizontal publishing

Video preflight

Publish Risk Overview

Find issues faster

Jump to each issue

Export for your workflow

Duplicate segment detection in two videos

Continuous similar segments

Perceptual frame fingerprint

Full-frame and center fingerprints

Locate the continuous interval

Narration automatically lowers background music

Side chain compression

Music automatically loops

Say goodbye to manual animation keyframes

Video storyboard contact sheet

Contact sheet

Jump to a sampled frame

Frequently asked questions

Instead of building another conversion station, we should build a publishing infrastructure for creators.

Free browser video tools

Review a long clip at a glance

Privacy-first workflow