Converts MKV files to AVI format — advanced video archiving with multiple subtitle tracks, chapters, and audio streams in one file to legacy video compatibility. All conversion happens locally in your browser with no file size limits.
Runs on FFmpeg
Content reviewed October 2026 · About Toolzum
Burn text watermarks into a video with 5 position presets (bottom-right default, fixed 24px white on semi-transparent black box). Brand one clip at a time — local FFmpeg work, unlimited saves.
Cut start/end segments from any video with fast stream-copy trimming in your browser (keyframe-aligned, no re-encode). Remove a 45-second cold open from a 10-minute upload — local FFmpeg work, unlimited saves.
Speed up or slow down video from 0.1x to 10x (presets 0.25x–4x) with pitch-corrected audio via chained atempo filters. Make a 20-minute lecture watchable at 2x — local FFmpeg work, unlimited saves.
Convert AAC to universally compatible MP3 for legacy players and sharing. Reach every device ever made — local FFmpeg work, unlimited saves.
Convert AIFF to WMA for legacy Windows systems that accept nothing else. Serve corporate libraries stuck on old codecs — local FFmpeg work, unlimited saves.
MKV (Matroska Video) uses lossless container encoding and is best for advanced video archiving with multiple subtitle tracks, chapters, and audio streams in one file. AVI (Audio Video Interleave) uses uncompressed or lossy encoding and excels at legacy video compatibility — older software, embedded systems, and archival playback. Converting between them lets you take advantage of each format's strengths — for example, using a compressed format for sharing and a lossless format for editing. All conversion happens locally in your browser with no file size limits.
Car stereos, old TVs, industrial players, and legacy software accept only AVI. Converting modern MKVs keeps old hardware useful.
High-bitrate MPEG-4 video with MP3 audio maximizes legacy compatibility. File sizes grow — legacy costs bytes.
Usually not — AVI subtitle support is poor. Burn subtitles in first for players needing captions.
No — conversion runs locally in your browser with FFmpeg. Saves never touch a meter — downloads on local tools are unlimited.
Video to MP3 Converter
Extracts the audio track from uploaded video files (MP4, MOV, AVI, WebM) and encodes it as a high-quality MP3 file. Free to start with no signup.
Crop Video
Crop the visual area of your MP4 or WebM video directly in the browser with 9:16, 1:1, 16:9 presets or custom dimensions with X/Y offsets. Free to start with no signup.
Video Compressor
Reduces MP4, MOV, and WebM video file sizes with a configurable CRF 20–40 slider (default 28, libx264 fast preset), plus a GIF mode with color-palette control. Videos never leave your device — compression runs locally in your browser with FFmpeg WASM.
Video to GIF
Convert MP4/WebM to GIF animations. Videos up to 250MB. Videos never leave your device — compression and conversion run locally in your browser with FFmpeg WASM.
Subtitle Translator
Translate pasted SRT or VTT subtitle text into 9 languages (Spanish, French, German, Japanese, Chinese, Hindi, Portuguese, Russian, Arabic) while preserving every timestamp — AI-powered with your own API key, text never stored.
Video Watermark Adder
Burn text watermarks into a video with 5 position presets (bottom-right default, fixed 24px white on semi-transparent black box). Brand one clip at a time — local FFmpeg work, unlimited saves.