Zkrátit video online

What Zkrátit video does

Trimming keeps the part of a video between a start point and an end point and removes the rest. Zkrátit video offers two methods. By default it re-encodes the selected part as H.264 MP4 with AAC sound at high quality (CRF 20), which cuts at the exact frame you choose.

With fast trim, FFmpeg copies the original video and audio data without encoding. This is very quick and keeps the original quality, but the cut can only start at a keyframe. In both cases the result is saved as an MP4 file.

Jak používat nástroj Zkrátit video

1. Přetáhněte video do pole.
2. Pomocí náhledu nastavte možnosti nástroje „Zkrátit video“.
3. Klikněte na Použít. Video se zpracuje ve vašem prohlížeči.
4. Stáhněte nové MP4.

When to use Zkrátit video

• Cut the silent first minute and the ending of a recorded meeting before sharing it with colleagues.
• Keep only the goal from a long match recording to post it in a team chat.
• Shorten a screen recording to the steps that matter before attaching it to a bug report.
• Cut a clip to under 60 seconds for platforms that limit the length of short videos.

Settings explained

Start and end

Two sliders under the preview that set where the clip begins and ends, in steps of 0.1 seconds. The preview jumps to each point while you drag, so you can check the exact frame.

Fast trim (no re-encoding, cuts at keyframes)

Copies the original streams instead of encoding them, so even long videos finish in seconds with no quality loss. The clip may start slightly before your start point, at the previous keyframe.

Format comparison

Co je MP4?

MP4 (MPEG-4 Part 14) je videoformát z roku 2001, jehož autorem je MPEG. Formát používá ztrátovou kompresi. Soubory mají příponu .mp4.

MP4 is a container format defined in part 14 of the MPEG-4 standard and based on Apple's QuickTime file format. It holds separate video, audio and subtitle tracks. The video is usually H.264 or H.265, sometimes AV1, and the audio is usually AAC. The codecs inside, not the container, decide the quality.

MP4 with H.264 video and AAC audio is the most compatible choice for sharing video. It works well for uploads to social media and video sites, playback on phones and TVs, and video embedded in websites.

Compatibility depends on the codecs inside. An MP4 with H.265 or AV1 video may not play on older devices or in every browser. H.264 and H.265 are patented codecs. Editing and saving again with a lossy codec reduces quality.

MP4 plays in all major web browsers, on Windows, macOS, Android and iOS, on smart TVs and game consoles, and in players such as VLC. H.264 MP4 is the safest choice when you do not know the device.

Co je MOV?

MOV (QuickTime Movie) je videoformát z roku 1991, jehož autorem je Apple. Formát používá ztrátovou kompresi. Soubory mají příponu .mov.

MOV is the QuickTime movie format created by Apple. It is a container with tracks for video, audio, timecode and text. The MP4 format was based on it, so the two are closely related. iPhones record MOV files, usually with H.264 or HEVC video, and professional workflows often use ProRes inside MOV.

MOV is a natural choice for video recorded on Apple devices and for editing in Final Cut Pro, iMovie and other professional tools. With codecs such as ProRes, it keeps high quality during editing and post-production.

MOV files with professional codecs are very large. Some Windows programs, Android devices, browsers and websites do not play MOV, especially when it contains HEVC or ProRes video. Converting to MP4 usually solves compatibility problems for sharing.

MOV plays natively on macOS and iOS in QuickTime Player and Photos. Windows can play many MOV files in its built-in apps or in VLC, depending on the codec. Safari plays MOV, while other browsers support it only partly.

Co je AVI?

AVI (Audio Video Interleave) je videoformát z roku 1992, jehož autorem je Microsoft. Formát používá ztrátovou kompresi. Soubory mají příponu .avi.

AVI is a container format introduced by Microsoft as part of Video for Windows. It is based on the RIFF file structure and stores audio and video data interleaved in chunks. It can hold many codecs, and in the 2000s it was often used with DivX or Xvid video and MP3 audio.

Today AVI is mainly useful for compatibility with older software, older hardware players and some industrial or scientific cameras. For most new videos, MP4 or MKV is a better choice.

AVI is an old format that handles modern codecs and features, such as variable frame rate and subtitles, poorly. Files are often larger than MP4 files at the same quality, and web browsers cannot play AVI.

Windows plays many AVI files in its built-in apps, depending on the codec. On macOS, Linux, Android and iOS, a player such as VLC is usually needed. Browsers cannot play AVI, although many video sites accept it as an upload.

Co je WEBM?

WEBM (WebM) je videoformát z roku 2010, jehož autorem je Google. Formát používá ztrátovou kompresi. Soubory mají příponu .webm.

WebM is an open, royalty-free video format started by Google for the web. It is based on the Matroska container and allows only a few codecs: VP8, VP9 or AV1 for video, and Vorbis or Opus for audio. This restriction makes playback in browsers predictable.

WebM is a good choice for video on websites, short clips with small file sizes, and screen recordings made in the browser. It can also store video with transparency, which an MP4 with H.264 video cannot.

Some older Apple devices, editing programs, TVs and phones cannot play WebM. Encoding VP9 or AV1 is slower than encoding H.264. Some social media sites and messaging apps convert or reject WebM uploads.

Chrome, Edge and Firefox play WebM on all platforms, and recent Safari versions support it on macOS and iOS. Android plays WebM natively. On Windows and macOS, VLC and most modern media players open it.

Proč používat nástroj Zkrátit video od FansBond

Většina online převodníků nahrává vaše soubory na své servery. Nástroj „Zkrátit video“ od FansBond místo toho pracuje přímo ve vašem prohlížeči díky WebAssembly a moderním rozhraním prohlížeče. Soubory zůstávají ve vašem zařízení, což je bezpečnější pro soukromé fotky, smlouvy i nezveřejněnou práci, a často je to i rychlejší, protože se nic nemusí nahrávat ani stahovat.

Žádné fronty, žádné vodoznaky a žádný účet. Jakmile se stránka načte, nástroj funguje i na pomalém připojení.

Tips for the best result

• Use fast trim for MP4 and MOV files from phones and cameras. For WEBM, WMV and other formats, leave it off, because their streams often cannot be copied into MP4.
• The sliders appear only when your browser can play the file. If an AVI, WMV or FLV file shows no preview, convert it to MP4 first.
• Trim before cropping or converting, so later steps have less video to encode. Encoding in the browser runs on one processor thread.
• If a fast-trimmed clip starts a moment too early, move the start point later or turn fast trim off for a frame-exact cut.

How Zkrátit video works in your browser

Video and audio are processed with FFmpeg, the open-source media toolkit behind most video software, compiled to WebAssembly. Video is encoded with H.264 for MP4, MOV and MKV, VP8 for WebM, and audio with AAC, MP3, Vorbis, Opus or FLAC depending on the format.

WebAssembly FFmpeg runs on your device's processor without a server. It is slower than a native desktop app, so a long video can take a few minutes. Keep the tab open until the progress bar finishes.

Privacy and security

Most online converters upload your files to a server, process them there and keep a copy for some time. Zkrátit video works differently: the code is downloaded to your browser once, and your files are read and written only on your device.

You can check this yourself: after the page has loaded, turn off your internet connection and the tool still works. This makes it safe for contracts, IDs, medical records, private photos and unreleased work.