Private browser video tools
Make a video smaller, trim a clip, change its frame, or save its audio. Choose a task below, then pick a file. Your browser checks format and codec support.
Your video stays on this device. No upload, account, or server-side processing job.
See the size, duration, format, and tracks before editing.
Make a smaller video for sharing or uploading.
Keep the part you need with a start and end time.
Create an MP4 using codecs your browser supports.
Choose a square, portrait, or landscape frame.
Save the audio from a video as an MP3 file.
Check and prepare a video for App Store requirements.
Browser-local workspace
Choose one local MP4, M4V, MOV, or WebM file. JavaScript activates a browser-native preview and capability check; available conversions depend on the codecs supported by this device.
No upload, account, or server-side media job.
Choose a local video, review its observable dimensions, duration, bytes, and playback support, then set one clear goal: make an MP4, reduce its size, trim a clip, change its frame, extract audio, or prepare an App Store Preview. This is not a general timeline editor or a cloud converter.
The local worker inspects first and can retain compatible tracks before a re-encode. When a codec or container cannot be handled on this browser, Aftermath reports that limitation instead of uploading the file to a fallback service.
The first preview uses a local Blob URL and reads the metadata needed for a decision. Processing is deliberately bounded: one output stays in browser memory, so files above 500 MB remain available for inspection but need a smaller clip or a dedicated desktop workflow for output operations.
Private browser processing
Aftermath reads selected video bytes only in the current browser. Unsupported codecs are reported clearly rather than sent to another service. High-resolution conversion can use substantial device battery and processing.
Choose a local video workflow for compression, trimming, MP4 conversion, audio extraction, or read-only inspection. The browser accepts supported MP4, M4V, MOV, or WebM sources and keeps the selected file in this session. Processing routes create a separately downloaded result; inspection reports container, tracks, dimensions, timing, and playback facts without creating output. Output jobs keep one completed result in browser memory and are limited to 500 MB; read-only inspection accepts sources up to 4 GB. Codec and device support vary.
| Need | Focused route | Why it matches |
|---|---|---|
| Reduce file size and measure the completed MP4. | Compress a video and measure the result | Compression owns quality presets and one-pass size budgeting. |
| Keep only one time range from a supported video. | Trim or cut a video by time | The trim route exposes compatible and exact timing consequences. |
| Read tracks, codecs, duration and dimensions without output. | See the video facts before you change anything. | Inspection reports local media facts before a conversion is selected. |
| Create an MP4 from a supported source container. | Convert a supported video to MP4 | The conversion route distinguishes compatible track reuse from re-encoding. |
| Crop, fit, or pad video into a selected frame. | Frame a video for its destination in one deliberate pass. | The crop route reports retained and removed frame geometry before processing. |
| Extract the primary audio track as a separate MP3. | Extract MP3 audio from a video | The audio-only route excludes video frames and verifies the completed MP3 track. |
| Check an App Store Preview against measurable media rules. | Prepare an App Store Preview with a compact local checklist. | The checker separates technical measurements from App Store acceptance. |
| Choose an audio-only operation instead of changing video frames. | Trim, convert & improve audio | The audio hub owns trim, level, format, extraction, silence, and cleanup decisions. |
Choose a local video, review its observable dimensions, duration, bytes, and playback support, then set one clear goal: make an MP4, reduce its size, trim a clip, change its frame, extract audio, or prepare an App Store Preview. This is not a general timeline editor or a cloud converter.
Free Local Video Tools — Compress, Trim & Convert
Selected file bytes and entered browser data remain in the current browser session and are not sent to an Aftermath processing service. How local processing is verified.
Checks the displayed limits and reports or creates a local video report or a separately downloaded video/audio result according to the selected task from one MP4, M4V, MOV, or WebM video supported by the current browser codecs.
A local measurement or export does not guarantee acceptance by an external destination.
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