MP3 to MP4 (Audio to Video)
Put a picture to your song, podcast or voice note and get a video any site accepts.
Try before you buy.
- Free preview: the first half of the result (up to 10 seconds) at the settings you chose, with a MySmartCoPilot watermark.
- Locked until you unlock it: download, share and saving to your device.
- Unlock: Pro pass, ₹179 for 30 days, a one-time payment that never renews.
Ways to unlock shows how to get the full result.
Printing this result is locked in the free preview.
Preview
Video settings
No picture: the background colour is used.
Part of the audio, frame rate and sound quality
Your video
Locked in the free preview. Opens the ways to unlock this result.
Locked in the free preview. Batch runs unlock with a pass.
Locked in the free preview. Query results unlock with a pass.
About the MP3 to MP4 (Audio to Video)
Sites like YouTube and Instagram take videos, not sound files. This tool turns an MP3 — or an M4A, WAV, FLAC, OGG file, or the sound of a video — into an MP4 video with a picture: your own photo or artwork, the cover picture stored inside the song, or a plain colour. Add a title and a second line, spectrum bars or a waveform line that move with the sound, and a progress bar — the kind of “audiogram” podcasts post — in 16:9, 1:1 or 9:16.
A still picture is encoded at 1 frame a second with a key frame every 10 seconds, so the video is barely larger than the sound itself; anything that moves gets a normal 30 frames a second. The video is H.264 with AAC sound in an MP4 file, the format YouTube recommends for uploads. Everything is made on your device: nothing is uploaded.
The free preview on this page is the first half of the video (up to 10 seconds) at the settings you chose, with a MySmartCoPilot watermark. With a Pro pass, or after unlocking this one video, you get the whole video.
How to use it
- Drop an audio file on the box or click Choose an audio file. If the file has a cover picture, it is used straight away; the title and artist come from its tags.
- Choose a picture (or keep the cover), the shape — 16:9 for YouTube, 1:1 for feeds, 9:16 for Reels, Shorts, TikTok and Status — and how the picture fills it.
- Add spectrum bars or a waveform line and a progress bar if you like, and type a title and a second line. Press Play to see and hear the preview.
- For a clip, open Part of the audio and set From and To (the sound fades in and out over a second).
- Press Make the video. Without a pass the page makes the free preview — the first half, up to 10 seconds, with a watermark — and Ways to unlock shows how to get the whole video; with a Pro pass, or once this video is unlocked, Download MP4 gives the full file.
Examples
Morning Song.mp3 · 4:05 · its own cover picture · 16:9 · 1080p · no visualiser
Morning Song.mp4 · 1920 × 1080 · 1 frame a second · the picture on a blurred copy of itself · only a little larger than the MP3
episode-12.m4a · From 12:30 To 13:30 · 9:16 · spectrum bars · progress bar · title “Episode 12” · second line “The Weekly Show”
episode-12.mp4 · 1080 × 1920 · 30 fps · one minute with the bars moving to the voice and the sound fading in and out
voice note.ogg · no picture · square · waveform line
A 1080 × 1080 video on the background colour with the waveform following the voice
Why a still picture uses so few frames
A video of a still picture changes nothing from one frame to the next, so 30 frames a second would only make the encoder work 30 times as hard for the same picture. At 1 frame a second the picture is stored in full every 10 seconds (a key frame, so players can jump anywhere) and as an unchanged frame in between, which takes almost no space: the file is mostly its sound. YouTube’s own guidance asks for the frame rate the content was made at and accepts other frame rates; if an app or site refuses a low frame rate, choose 30 fps under Part of the audio, frame rate and sound quality.
Spectrum bars and waveform
The spectrum bars show how loud each range of notes is at that moment — low notes in the middle, high notes at both ends — measured the way the browser’s own audio analyser does it (a Blackman-windowed Fourier transform in decibels). Bars rise at once on a beat and fall back smoothly. The waveform line draws the sound wave itself over a few hundredths of a second, so speech and music show their rhythm. Both are drawn into every frame of the video, exactly as in the live preview.
Sound quality
The sound is encoded as AAC, the codec MP4 players and upload sites expect, at 192 kbit/s by default (128 to 320 kbit/s can be chosen), at the source’s own sample rate (44.1 or 48 kHz; other rates are converted to 48 kHz). Converting from MP3 to AAC re-encodes the sound once; at 192 kbit/s or more the difference is very hard to hear. AAC encoding adds a few hundredths of a second (about 0.04 s) of silence at the very start of the sound, too little for lyrics or captions made for the song to drift out of line.
Limitations
- Making a video with moving bars takes time: the browser draws and encodes every frame, often faster than real time on a computer but slower on a phone, so long podcasts are best made as a still picture or a short clip.
- Files protected by DRM (songs bought or rented from some stores) cannot be decoded.
- The finished video is kept in the browser’s memory until you download it; for recordings of several hours use Save straight to a file in Chrome or Edge on a computer (with a pass: the free preview is always made in memory).
- Browsers without a WebCodecs video encoder (for example Firefox for Android) cannot make videos.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What do I get without a pass?
Without a pass, MP3 to MP4 (Audio to Video) shows the first half of the result (up to 10 seconds) at the settings you chose, with a MySmartCoPilot watermark. Until you unlock it, the result can’t be downloaded, shared or saved to your device. A Pro, Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
How do I upload an MP3 to YouTube?
YouTube needs a video. Make one here with your picture — 16:9 at 1080p is a good choice — then download the MP4 (with a Pro pass, or after unlocking this video) and upload it as a normal video.
Do I need a pass?
To download, share or save the whole video, yes: a Pro pass unlocks every Pro tool. Without a pass you see a free preview of your own video: the first half, up to 10 seconds, at the shape, size and settings you chose, with a MySmartCoPilot watermark, played on the page. An unlock of this one video (Ways to unlock lists how) makes the whole video from the sound still open on the page.
Does my audio get uploaded?
No. The sound is decoded, combined with the picture and encoded into the MP4 by your browser; nothing is sent anywhere.
Why is the video so small?
A still picture is stored only once every 10 seconds and the frames in between say “no change”, so almost all of the file is the sound. With moving bars the picture changes every frame and the file is larger.
Can I use only part of a song?
Yes. Open Part of the audio, frame rate and sound quality and type From and To times such as 1:15 and 1:45. The clip fades in and out over a second so it does not start or stop with a click.
Which shape should I choose?
16:9 for YouTube and computer screens, 1:1 for posts in feeds, 9:16 for Reels, Shorts, TikTok and WhatsApp Status. Picture’s keeps the shape of your picture (between 9:16 and 16:9).