Can I use my own cover image?

Not yet — the background is a solid colour with the title. Upload the MP4 to YouTube and set a custom thumbnail there, or use a video editor for album art.

Why is the video only 1 fps?

A still picture does not need more frames; 1 fps keeps the file tiny and every platform accepts it. Audio quality is unaffected.

Does YouTube accept this file?

Yes — H.264 video with AAC audio in MP4 is YouTube’s recommended upload format.

Is my audio uploaded?

No. ffmpeg runs inside your browser; nothing is sent to a server.

Video Converters

MP3 to MP4

YouTube, Instagram and most social apps will not take an audio file. This tool wraps your MP3 in an MP4 with a clean background and the title in the middle, so a podcast episode, a song or a voice memo can be posted like any video.

Runs in your browser — files never leave your device.

Drop supported file here

or click to browse · paste from clipboard · up to 200 MB

Select file

Options

Background

Show the file name as a title

Resolution

Bitrate

About MP3 to MP4

A video file needs a picture track, so the converter renders a still frame (background colour plus the file name) at one frame per second and muxes it with your audio re-encoded to AAC. The result is small — a 5-minute track is about 8 MB — because a still image compresses to almost nothing.

Encoding uses ffmpeg compiled to WebAssembly, running in your browser; the audio never leaves your device. Expect roughly 10–20 seconds of processing per minute of audio on a laptop.

How to convert files to MP4

Drop the MP3 (or other audio file) onto the page.
Pick a background colour and resolution, and whether to show the title.
Click Convert and download the MP4.

About the formats

MP3 · MPEG-1 Audio Layer III · .mp3

The audio format everything can play: cars, phones, old players, websites. Lossy, but at 192–320 kbps close to indistinguishable from CD.

All MP3 patents expired in 2017; the format is now free to use.
128 kbps is the classic “good enough” rate; 320 kbps is the maximum.
MP3 cannot store multichannel surround or lossless audio.

WAV · Waveform Audio · .wav

Uncompressed PCM audio, the studio and archival standard: perfect quality, about 10 MB per minute at CD quality.

WAV is a container; almost all WAVs hold uncompressed 16- or 24-bit PCM.
A 4 GB file-size limit applies to standard WAV; long recordings use RF64 or BWF.
Because nothing is compressed, converting WAV to MP3 is the fastest way to shrink audio 10×.

M4A · MPEG-4 audio (AAC) · .m4a

Apple’s audio format from iTunes, Voice Memos and the Music app: AAC audio in an MP4 container, better than MP3 at the same bitrate.

M4A usually holds AAC; the .m4a from Apple Music purchases may be ALAC (lossless) instead.
Voice Memos on iPhone save M4A; many transcription and Android apps prefer MP3.
M4A supports chapters and cover art metadata.

FLAC · Free Lossless Audio Codec · .flac

Lossless compressed audio, about half the size of WAV with bit-identical playback; the format of choice for music archives and hi-fi downloads.

FLAC is open and royalty-free and supports up to 32-bit, 8 channels and 655 kHz.
Decoding FLAC is light, so most phones and players handle it; some car stereos and iTunes do not.
Converting FLAC to MP3 is lossy; keep the FLAC as the master.

Related conversions

More in Video Converters · All converters