Client Questions: What is MPEG4?

Definition of MP4 and MPEG-4

We have many clients who wish to understand the difference between MP4 and MPEG-4.  To put it simply; MPEG-4 stands for “Moving Pictures Expert Group 4,” a standard for audio and video coding compression. The method reduces the size of an audio or a video file while retaining its fidelity or quality. 

This large format is great for editing videos or viewing on a larger screen. MP4s are a universal file format compatible with most streaming platforms and their compressed nature makes them smaller and easier to handle. To share videos, it's often necessary to convert from an MOV to an MP4.

To figure out the difference between MP4 and MPEG-4, we have to understand two basic terms first: video codec and media container. It can be shown with the following formula:

Media Container = video format (video codec) + audio format (audio codec) + subtitle + chapter-information + meta-data

Then, we will go through the definition of MP4 and MPEG-4.

What is MPEG-4

MPEG-4 is a method of defining compression of audio and visual digital data (Audio/Visual Objects). With the development of MPEG-4, it is divided into a number of parts (each part covers a certain aspect of the whole specification) including MPEG-4 part 2 (e.g. XviD video codec), MPEG-4 part 3 (e.g. AAC audio codec), MPEG-4 part 10 (H.264 video codec), MPEG-4 part 14 (MP4 media container) and others.

MPEG-4 is a complex thing that includes knowledge in various aspects. To know more further, go to Wikipedia: MPEG-4.

What is MP4

MP4 is an abbreviated term for MPEG-4 part 14. MPEG-4 part 14 is one of the parts of the MPEG-4 compressing algorithm. It is a digital multimedia format (container format) that used to store video, audio, images and such like data. That is to say, MP4 can be a video file extension (.mp4), as well as a container format.

The only official file extension of MPEG-4 part 14 is .mp4. But it also has other file extensions such as .m4v, .m4p, .m4b and m4a. You can refer to this page to know more about these MPEG-4 Part 14 filename extensions.

#MP4 vs MPEG-4: The Differences between MP4 and MPEG-4

MP4: It can be a file extension, a video format, and a media container.

MPEG-4: It's a compression method of the MPEG group, specially designed for low-bandwidth (less than 1.5MBit/sec bitrate) video/audio encoding purposes. 

MP4 is one of the media container formats for MPEG-4. Except for it, videos encoded in MPEG-4 also has other media container formats like Matroska (MKV), AVI, MXF, OGG and QuickTime (MOV).

Now, let's see some examples to make the relationship more intuitive.

MP4 (.mp4) = MPEG-4 video codec (H.264/XviD) + MPEG-4 audio codec (AAC)

MP4 (.mp4) = MPEG-H video codec (H.265) + Dolby Digital audio codec (AC3)

AVI (.avi) = MPEG-4 video codec (H.264/DivX) + MPEG-2 audio codec (MP3)

To Sum Up

MP4 is not necessarily encoded by MPEG-4 video and audio. MPEG-4 video and audio encoding are not necessarily to be packaged in MP4 container. They can also be packaged into other containers such as AVI, MKV, etc.