AVI to MP4 is built for video editing and conversion jobs that fit cleanly into a browser tab. Convert legacy AVI files to modern MP4 (H.264 + AAC) entirely in your browser. Files are processed locally with FFmpeg WebAssembly — no uploads, no sign up, no watermarks. The processing runs in the page itself, which is why the controls update instantly when you change settings and why a freshly loaded page is ready to do real work the moment it becomes interactive.
The engine behind the page is FFmpeg compiled to WebAssembly. It reads your file in-memory and writes the result back into the browser. Supported inputs include MP4, WebM, MOV, MKV, AVI, FLV, and OGV. For 500 MB and below the work usually completes in seconds; larger files mostly depend on how much spare RAM your device has.
AVI to MP4 fits naturally into the workflow of students submitting video assignments and support agents preparing screen recordings, both of whom typically need a fast result inside the browser. There is no learning curve to budget for: anyone who has used a typical web upload form can complete a run on the first try.
The architecture is local-first by design. Once the page is loaded, you can disconnect from the network and the tool still completes the job. The processing stack — FFmpeg compiled to WebAssembly and the small UI shell wrapping it — ships with the page itself, so the tool keeps working in offline conditions, on a captive-portal Wi-Fi, or behind a corporate proxy that limits what the tab can reach.
AVI to MP4 is shaped for the gap between "I'll do it by hand" and "I'll script it." When the job is small enough that automating it would take longer than doing it, but annoying enough to want a focused tool — that is the situation this page is built for.
When the job finishes, AVI to MP4 hands you the result as `{name}-edited.{ext}`. Filenames are derived from your input where possible, so a quick batch of jobs leaves you with a tidy folder rather than a pile of generic "output (3)" files. Nothing is auto-saved on Favtoo's side because nothing was ever sent there.
The hard constraints are easy to remember. Maximum input: 500 MB. Multiple files per run: no — one input at a time, by design, to keep results predictable. The same controls apply on every run.
AVI to MP4 fits naturally next to several adjacent tools. Common companions include MOV to MP4, MKV to MP4, FLV to MP4, and Video Converter — combine them when the job needs more than one transformation. After running AVI to MP4, many users move on to MOV to MP4 and Video Converter. Each tool is a separate page so you can compose the exact pipeline you need.
AVI to MP4 is honest about scope: it handles a single, well-defined video editing and conversion step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
AVI to MP4 is one example of a broader pattern: utility software increasingly works as single-page, client-side experiences. Every page in the catalog is shaped that way, which keeps each tool fast to load and easy to recommend in a single link.
AVI to MP4 is built around the moment of need: a focused page you open when you have a specific task, complete the task, and close. The catalog contains many adjacent tools so the same model serves the surrounding parts of a typical video editing and conversion workflow.
If you want to get the most out of AVI to MP4, three small habits help. Drag-and-drop is faster than the file picker once you get used to it. The keyboard shortcut for downloading the result is whatever your browser uses for "save link as," because the result is a normal download. And if you are working on a sensitive file, processing in an Incognito or Private window is a good extra layer — it leaves no trace in browser history when the tab closes.
For most failure modes, refreshing the page and re-running the job is enough — the engine has no persistent state to corrupt. If the same input fails twice in a row, the input itself is most likely the problem (a truncated file, an unexpected variant of the format, or a stream the engine does not recognise).
If AVI to MP4 solved your problem, sharing the page link with someone who has the same problem is the most useful thing you can do. The catalog grows mostly through word of mouth; visitors arriving through a recommendation tend to be the ones the tool serves best.
A WebAssembly build of FFmpeg loads inside this page and re-encodes your AVI to MP4 using libx264 + AAC. The bytes are read into JavaScript memory, transcoded in your browser, and returned as a downloadable MP4 — they never touch a server.
Server-side tools run multi-threaded native FFmpeg with hardware acceleration. WebAssembly is single-threaded with no GPU encode access, so AVI-to-MP4 transcodes are typically 3–8× slower than a native run. The trade-off is total privacy: your file never leaves your device.
Yes. FFmpeg WASM decodes DivX, Xvid, MJPEG, MPEG-4, MPEG-2, and most other codecs that ever shipped inside an AVI container, then re-encodes the frames to modern H.264.
Old AVIs often use uncompressed video or MJPEG, both of which produce files that are huge by modern standards. The MP4 output uses H.264 — typically 5–20× smaller at equivalent visual quality.
Up to 500MB. Long uncompressed AVIs can blow past that; if so, downscale first with the Video Resolution Reducer or split with the Video Splitter, then convert each piece.
Yes. Audio is re-encoded to AAC at 128 Kbps stereo, the standard for MP4. MP3, AC-3, PCM, and other AVI audio formats are all decoded automatically.
Interlaced AVIs (e.g. from old camcorders) may show combing artifacts in the MP4 output. The High quality preset usually handles them best; if combing remains, deinterlace ahead of time in a desktop tool.
No. The conversion runs entirely in your browser tab. Nothing is transmitted, stored, or logged. Closing the tab erases the file from memory immediately.
AVI to MP4 works in any modern browser released in the last few years — Chrome, Edge, Firefox, Safari, Brave, Arc and the major Chromium derivatives are all supported. The underlying engine relies on widely-supported web APIs, so there is nothing exotic to install. If you are on a very old browser version and the tool fails to load, updating to the latest release of your preferred browser is the only fix needed.
AVI to MP4 accepts MP4, WebM, MOV, MKV, AVI, FLV, and OGV. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.
Most jobs finish in seconds. Speed scales with input size and with how many CPU cycles your browser tab has available — the engine runs in your browser, so it shares resources with whatever else you have open. For inputs near the 500 MB ceiling, expect anywhere from a few seconds to roughly a minute on a typical laptop. Closing other heavy tabs noticeably speeds things up.
AVI to MP4 is built on FFmpeg compiled to WebAssembly, which is the same class of engine used by professional video editing and conversion pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Favtoo keeps no copy of your file because Favtoo never receives your file. AVI to MP4 runs entirely in your browser, the input is held only in your tab's memory, and closing the tab discards it. There is no opt-in cloud history, no "recent jobs" panel synced to an account, and no server-side retention to configure — the architecture simply has nowhere for your file to be stored.
Inputs are capped at 500 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run AVI to MP4 as often as you need; every run produces a full-quality result.
AVI to MP4 is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
No installation is needed. AVI to MP4 runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use AVI to MP4 on any computer you have temporary access to without leaving anything installed on it.
Desktop apps usually have more advanced features but require installation, maintenance and (often) a licence. Paid online tools are convenient but route your file through their servers and gate downloads behind accounts. AVI to MP4 sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common video editing and conversion operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.
Video to GIF
Convert any video clip to an animated GIF entirely in your browser. Pick the start, length, frame rate, and width — your file is processed locally with FFmpeg WebAssembly and never uploaded.
Screen Recorder
Record your screen, a window, or a browser tab directly in your browser. Optionally include system audio and your microphone. Capture, preview, and download the video without installing any app — and without uploading anything.
Webcam Recorder
Record your webcam directly in your browser with optional microphone audio. Pick the resolution (480p, 720p, or 1080p), frame rate, and mirror mode, then capture and download the result without installing any app.
Screen + Webcam Recorder
Record your screen with your webcam composited into a picture-in-picture corner — perfect for tutorials, course videos, demos, and reaction recordings. Pick the camera position, size, and audio sources, then capture and download in your browser.
Video Slideshow Maker
Turn a stack of photos into an MP4 slideshow with per-slide durations, crossfades, and an optional soundtrack. Pick the resolution (up to 1080p), frame rate, and transitions, then download a single MP4 — all processed in your browser with FFmpeg WebAssembly.
Video from Images + Audio
Combine a stack of photos with a music track or narration into a single MP4 video. Pick the resolution, per-slide duration, transitions, and let the slideshow length match the audio. All processed in your browser with FFmpeg WebAssembly.
Video Trimmer
Set precise in and out timestamps, snap to keyframes when needed, and document handles for social-safe cutdowns.
Video Splitter
Split any video into 2–10 equal-length pieces, packaged as a downloadable ZIP. Files are processed entirely in your browser with FFmpeg WebAssembly using lossless stream-copy.