M4B is an audio filename extension for AAC format, which is developed by Apple Inc. It is mainly used on podcast and audiobook files. Typically, M4B files contain audio and other metadata like images, hyperlinks, and chapter markers. M4B files are DRM copy-protected and can be opened on Apple iTunes and QuickTime Player.
3GP is a digital media container format developed by the Third Generation Partnership Project (3GPP). It stores both audio and video streams that are transmitted via 4G, 3G, and 2G mobiles phones. Here, the video format is saved in H.264/H.253 codec, while audio is streamed in AAC-LC, HE-AAC v1, AMR-NB, AMR-WB, AMR-WB+, or Enhanced aacPlus.
MPLayer AIMP Apple QuickTime Player VLC Media Player