Is MP4 an Audio or Video Format? Here’s What Developers Should Know

MP4 files are everywhere embedded in web pages, streamed in players, and passed through APIs. But many developers and content managers still ask the deceptively simple question: Is MP4 an audio format, a video format, or both? The answer can impact how you deliver media, especially when optimizing for performance and compatibility. Let’s break it down.

Hey team,

I’ve been handling a bunch of media files lately, uploading them, converting them, and embedding them in a web app. One thing that keeps coming up in conversations is the MP4 format.

Sometimes people call it a “video format,” but other times I see it used for audio-only files too.

So now I’m wondering: Is MP4 an audio or video format?

And on a related note:

• Can you store just audio in an MP4 file?
• What makes it different from formats like MP3 or MOV?
• How should I handle MP4s when serving them through a platform like Cloudinary?

Would love some technical clarity here!

Great question, and you’re right to dig into it. MP4 is one of those formats everyone uses, but few fully understand. Let’s clear it up.

MP4 stands for MPEG-4 Part 14. It’s not a codec (like H.264 or AAC), it’s a container format. That means it’s designed to hold different kinds of media content:

• Video (e.g., H.264, H.265)
• Audio (e.g., AAC, MP3)
• Subtitles (e.g., SRT or VTT)
• Metadata (e.g., thumbnails, chapters)

So to answer your question: MP4 can be an audio file, a video file, or both. The file extension .mp4 doesn’t tell you what’s inside, just the wrapper being used.

Format	Type	What It Stores	Use Case
MP4	Container	Video + Audio + Subtitles + Metadata	Versatile media storage
MP3	Codec & format	Audio only	Music, podcasts

So while MP3 is strictly audio, MP4 is more flexible. It’s especially popular for streaming because it packages everything you need into one manageable file.

Let’s say you’re working with an .mp4 file in Cloudinary. Whether it’s audio-only or audio and video, Cloudinary detects the contents and delivers it accordingly.

HTML
<video controls width="100%" 

src="https://res.cloudinary.com/demo/video/upload/f_auto,q_auto/sample.mp4">

</video>Code language: HTML, XML (xml)

HTML
<audio controls>

<source src="https://res.cloudinary.com/demo/video/upload/sample-audio.mp4" type="audio/mp4">

</audio>Code language: HTML, XML (xml)

Bonus: You can use f_auto and q_auto to automatically optimize delivery:

• f_auto serves the best supported format for the browser (e.g., WebM, HLS)
• q_auto compresses intelligently to preserve quality while saving bandwidth

Explore Cloudinary’s Video + Audio Transformation Docs →

If you’re only delivering audio, MP4 is still a good choice if:

• You want support for modern streaming and adaptive delivery
• You’re embedding in HTML5 players that accept audio/mp4
• You’re including extra metadata (e.g., cover art or chapters)

Otherwise, MP3 may be simpler for legacy compatibility.

Question	Answer
Is MP4 a video format?	Yes, it supports video tracks.
Is MP4 an audio format?	Also yes, it can contain audio-only files.
Is MP4 a codec?	No, it’s a container.
Should I use MP4 for audio delivery?	Yes, especially for modern browsers and streaming.

MP4 is a flexible media container that can store audio, video, or both! It plays well with modern web standards and platforms.

• What is MP4? — Cloudinary Glossary
• Cloudinary Video Delivery Docs
• Audio in Cloudinary

Want help detecting file types or optimizing MP4 content dynamically? Check out Cloudinary’s transformation API for full control.