Free, no watermark, no sign-up
MP3 to MP4 with Your Picture
Convert MP3 to MP4 in seconds: drop in a song, a podcast or a voice memo, and it becomes a video with its own cover art, your picture or a plain color. Pick the shape for where it goes, YouTube, Shorts, Reels or a square feed, and download the MP4. Even an hour-long episode is ready in seconds, and its sound can go in exactly as it was.
Paper Plane Sky, with its cover
A song and its cover art as a 16:9 video for YouTube: the cover whole, a blurred copy of it behind.
1920×1080 · 2:44 · AAC 192 kbps · 8 MB · made in 2.6 s
- no sign-up, no watermark
- Free
- for a 59-minute episode, sound kept
- Under 6 s
- AAC (M4A) sound copied untouched
- As it was
- picture and sound start together
- 0 ms
- 16:9, 9:16, 1:1, 4:5, up to 4K
- 4 shapes
- kept from MP3s, plus description lines
- Chapters
How do I convert MP3 to MP4?
To convert MP3 to MP4, open the studio and drop in the MP3. It uses the song’s own cover if the file has one; otherwise choose a picture or a color. Pick a shape, such as YouTube 16:9 or Shorts 9:16, press Make MP4 and download the video. M4A to MP4 and WAV to MP4 take the same steps. It is free and runs in your browser.
MP3 to MP4 in three steps
For MP3 to video, any sound the browser reads works: MP3, M4A, WAV, FLAC, OGG, or the sound of a video. Drop several at once to make a video for each.
Drop in your audio
One file or a whole album. Each one’s cover, length and chapters show at once.
Choose the picture and shape
The file’s own cover, your picture or a color; the shape for YouTube, Shorts, Reels or a feed; 720p, 1080p or 4K.
Download the MP4
Each video is ready in seconds, with the sound’s chapters and the lines for a video description.
An MP3 to MP4 converter built for long audio
This MP3 to MP4 converter draws the picture once, so length barely matters, and it keeps your sound as it was wherever it can.
An hour-long recording in seconds
The picture is encoded once, two seconds of it, and repeated to the end, so the video’s length costs almost nothing. On our test computer a 59-minute episode became an MP4 in 2.7 seconds with its MP3 kept, 5.1 seconds from M4A, and 18 seconds with the sound encoded to AAC. Drawing and encoding every frame of that hour would take about 10 minutes at the same computer’s measured 184 frames a second.
Your sound, exactly as it was
AAC sound, the usual sound of an M4A, goes into the MP4 packet for packet, copied as it is. An MP3 can go in as it is too, with one switch. Everything else is encoded once: to AAC at up to 256 kbps in Chrome and Edge (192 kbps where the browser’s encoder stops there), which every player and video site reads, and to Opus in Firefox, which has no AAC encoder.
Picture and sound start together
The sound starts on the source’s first sample: 0.00 ms of offset in every check, in Chrome and Firefox. An MP3’s encoder delay is trimmed, and the picture ends with the sound, within one frame, so the video ends when the song does.
Podcast chapters come along
An MP3 with chapter marks keeps them in the MP4, for players that read MP4 chapters. The studio also writes the chapter lines for a video description, starting at 0:00, and says whether they meet the video sites’ rule of three chapters of ten seconds or more.
A whole album at once
Drop several songs together and each becomes its own MP4 with the cover inside its own file. Files without a cover use your picture or color. Download them one by one or all at once.
The shape for where it goes
YouTube 16:9, Shorts, Reels and TikTok 9:16, a square 1:1, a 4:5 feed post, or the picture’s own shape, at 720p, 1080p or 4K. The picture sits whole over a soft blurred copy of itself, fills the frame, or sits on a color you pick.
Audio to video samples
Each video was made from this site’s own songs, episodes and voiceovers by the studio in Chrome, then measured. Open one to make it again with your own changes.
Audio to video guide: sound, shapes and chapters
Which sound to choose for MP3 to MP4
Leave the sound setting as it is for most uses. The MP4 then carries AAC, the sound every phone, player and video site reads. AAC sound, as in most M4A files, is always copied, exactly as it was.
Turn on “Keep MP3 sound as it is” to put an MP3 into the MP4 unchanged. It is the fastest way and nothing is lost, but a few players don’t read MP3 inside an MP4, so test the file where it will play.
A video site encodes your sound again after upload anyway, so the copy matters most for files you keep or share as they are.
Shapes and sizes for each site
Long videos on YouTube use 16:9. Shorts, Reels and TikTok use 9:16. Feeds show 1:1 and 4:5 well. 1080p suits almost everything; 4K makes a sharper picture and a larger file, and 720p a smaller one.
- 1YouTube 16:9: 1920×1080 at 1080p, 3840×2160 at 4K.
- 2Shorts, Reels, TikTok 9:16: 1080×1920.
- 3Square 1:1: 1080×1080. Feed 4:5: 1080×1350.
- 4Same as picture: the picture’s own shape, its long side at 1280, 1920 or 3840 pixels.
Pictures that work
Album covers are square, so in a 16:9 video they sit whole in the middle with a blurred copy of themselves at the sides. Choose “Fill the frame” to crop to the edges instead, or “Whole, on a color” for plain bars.
A picture at least as large as the video looks sharpest: 1920 pixels across for 1080p. Smaller pictures are scaled up and look softer.
Podcasts and chapters
Podcast tools often write chapter marks into the MP3. The MP4 keeps them, and the studio shows them as lines like “0:00 Welcome”. Paste those lines into the video’s description and video sites show them as chapters.
Video sites ask for at least three chapters, each ten seconds or longer, the first at 0:00. The studio moves a first chapter that starts a moment in to 0:00 and tells you when the list falls short.
Long recordings and file sizes
Length is not a problem: an hour takes seconds, because the picture is made once. The file size comes from the sound and from the picture’s detail. On our samples at 1080p, a plain color took 17 kbps and a detailed cover 150 to 490 kbps, beside 192 kbps of AAC sound. A 2:44 song with its cover came to 8 MB; a 59-minute episode came to 165 MB.
The video is written to your device’s storage as it is made, so its size is limited by the space your browser gives this site; the studio works out the size from your picture and checks that space before it starts. A browser that gives sites no storage, or too little for this file (some private windows), builds it in memory instead, up to about 1.5 GB on a computer and 300 MB on a phone. For a smaller file choose 720p, a plain color or a simpler picture.
Browsers and phones
Every number on this page was measured on a computer, in Chrome and Firefox. Firefox has no AAC encoder, so there an MP3 or M4A is copied and other sound becomes Opus, which video sites accept.
On a phone it depends on the browser’s video encoder. Where there is one, the studio runs the same steps; the figures on this page were measured on a computer. A browser without one, such as Firefox on Android, says so at once; open the page on a computer instead.
What people turn from MP3 to video
Songs for YouTube
Put a track on YouTube with its cover art: the song as an MP4 in 16:9, ready to upload.
Podcast episodes
A full episode with its chapters, as a video with a still picture, in seconds even when it runs an hour.
Shorts, Reels and TikTok
A song in 9:16 for vertical feeds, or square for a post.
Stories and voiceovers
A narration or bedtime story on a plain color when there is no picture at all.
Albums and mixtapes
Every song of a release at once, each with the cover inside its own file.
Lessons and voice memos
An M4A lesson or memo as an MP4 to share, its sound as it was.
MP3 to MP4 FAQ
More audio tools
Convert MP3 to MP4
Drop in a song, an episode or a whole album and turn audio to video, each MP4 with its cover, in seconds.