Komprese videa online

What Komprese videa does

Compressing a video makes the file smaller by encoding it again with stronger settings. Komprese videa re-encodes the picture with H.264 at a lower constant quality level, scales it down to 720p by default, and re-encodes the sound as AAC at a low bitrate. The result is always an MP4 file.

Most of the saving comes from the lower resolution and quality, which remove detail that is hard to see on a phone or laptop screen. If the new file is not smaller than the original, you get the original back.

Jak používat nástroj Komprese videa

1. Přetáhněte soubory, které chcete zmenšit.
2. Zvolte úroveň komprese, nebo ponechte doporučené nastavení.
3. Klikněte na Komprimovat a porovnejte původní a novou velikost souborů.
4. Stáhněte zmenšené soubory.

When to use Komprese videa

• Shrink a phone video so it fits under the attachment limit of an email service, which is often 20 to 25 MB.
• Reduce a screen recording before uploading it to a support ticket, a learning platform or a shared drive with limited space.
• Make a 4K clip from a drone or action camera small enough to send through a chat app.
• Save storage on a phone or laptop by compressing old videos you want to keep but rarely watch.

Settings explained

Video quality

Sets how much detail the H.264 encoder keeps. The default, Low (CRF 30), gives small files that still look fine on phones. Medium or High keep more detail, and Smallest file suits previews and drafts.

Resolution

Sets the maximum height of the video. The default of 720p is sharp on phones and laptops, while 480p or 360p gives much smaller files. Original keeps the size, and videos are never enlarged.

Bitrate

Sets the audio bitrate: 64, 96 or 128 kbps AAC. The default of 96 kbps is clear for speech and acceptable for music. Audio is usually a small part of a video file, so this changes the size little.

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 Komprese videa od FansBond

Většina online převodníků nahrává vaše soubory na své servery. Nástroj „Komprese videa“ 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

• Lower the resolution first. Going from 1080p to 720p removes more than half of the pixels and usually saves more space than any quality setting.
• For a strict size limit, compress once, check the size, then step down the quality or resolution. There is no setting for a target file size.
• Long videos take time because the encoder runs on a single processor thread in the browser. Keep the tab open and plug in your laptop.
• Do not compress the same video again and again. Each pass loses detail, so start from the original with stronger settings instead.

How Komprese videa 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. Komprese videa 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.