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MP4 thus allows streaming over the internet. It also allows multiplexing of multiple video and audio streams in one file, variable frame- and bit-rates, subtitles and still images. Content other than audio and video is called "advanced content" by the MPEG-4 standard.

The formats that can be embedded in MP4 files is limited to:

• Video: MPEG-4, MPEG-2 and MPEG-1
• Audio: AAC, MP3, MP2, MP1 , CELP (speech), TwinVQ (very low bitrates), SAOL (midi)
• Pictures: JPEG, PNG
• Subtitles: xmt/bt text format (means that subtitles have to be translated into xmt/bt)

File extensions MP4 uses:

• . mp4 : official extension, for audio, video and advanced content (see above) files
• . m4a: for audio-only files; can safely be renamed to .mp4, though opinions differ on the wisdom of this.
• . m4p: FairPlayFairPlay is Apple Computer's name for its digital rights management (DRM) built in to the QuickTime multimedia technology and used by the iPod, iTunes and the iTunes Music Store. Every file sold by the iTunes Music Store is protected by FairPlay. It digit protected files
• . mp4v , . m4v : video-only, raw mpeg-4 video streams
• . 3gp3gp is a file format which is used in mobile phones to store media(audio/video). This file format is a simpler version of "ISO 14496-1 Media Format". MOV (used by Quick Time) is also a format whish follows similer file format. This format can carry video, . 3g2 : used by 3G3G (or 3-G) is short for third-generation mobile telephone technology. The services associated with 3G provide the ability to transfer both voice data (a telephone call) and non-voice data (such as downloading information, exchanging email, and instant me mobile phones, can also store content not allowed in .mp4 (H.263, AMR, TX3G)