MP3 to MP4 Converter
Turn audio into a shareable video with an optional cover image — runs in your browser, no upload.
Tool hub3 tools
Audio & Video Tools Hub
Free, browser-based audio and video utilities that work without uploading files to a server. Convert audio to video for social platforms, extract audio tracks from video recordings, and generate spoken audio from text — all running locally with the MediaRecorder, Web Audio, and Speech Synthesis APIs.
MP4 to MP3 Converter
Extract lossless audio from MP4, WebM, or MOV videos using the Web Audio API. No upload, no signup.
Text to Speech
Generate spoken audio from any text using browser-native speech synthesis voices. Free, instant.
When to use a browser tool vs. a desktop converter
Browser-based audio and video converters have one major trade-off compared to desktop tools like FFmpeg or HandBrake: they run in real time. A 30-minute podcast recording takes 30 minutes to convert from MP3 to MP4 via the browser, because MediaRecorder captures the audio at playback speed. FFmpeg can do the same conversion in 30 seconds. So when do you actually want the browser version?
- You need it done once, right now. The browser tool requires zero setup. FFmpeg is free but takes 5-10 minutes to install and learn for a first-time user.
- The file is private. Unreleased music, draft podcast episodes, internal lectures — anything you do not want to upload to a stranger's server. Browser tools keep the file on your device.
- The file is short. Under 10 minutes, the real-time recording penalty is negligible.
- You are on a managed device. Corporate laptops often restrict installing CLIs and desktop tools but always allow browser-based workflows.
When the file is long, the format requirements are strict (true MP3 codec for legacy players, specific bitrate for ad networks), or you are doing batch jobs of dozens of files, the right answer is FFmpeg or a paid converter. The tools on this hub are deliberately scoped to the “one file, right now” use case.
Common conversion workflows
Podcast → YouTube
Take your final MP3 episode, drop it into MP3 to MP4 Converter, add the show artwork as the cover image, and download. YouTube accepts both MP4 and WebM uploads — no re-encoding needed.
Zoom recording → audio-only archive
Zoom saves meetings as MP4 with the speaker view baked in. To archive the call as a listen-only version (or to feed it into a transcription tool like Whisper), use MP4 to MP3 Converter to extract a lossless WAV of the audio track.
Article → spoken summary
Use Text to Speech to generate a quick voiced version of a blog post or newsletter. Output is browser-native — quality varies by OS voice — but it is fast enough to ship as an “audio version” on a content site without recording yourself.
Privacy and processing model
Every tool on this hub uses browser-native APIs that never leave your device. There is no upload, no telemetry of the file contents, and nothing is stored on a server. Closing the tab discards the working buffer immediately. This makes the hub safe for unreleased media, internal recordings, and any content you cannot risk sharing with a third party.