RealMedia is a proprietary multimedia container format created by RealNetworks with the filename extension .rm. RealMedia is generally used in conjunction with RealVideo and RealAudio, while also being used for streaming content over the Internet. Typically these streams are in CBR (constant bitrate), but a container for VBR (variable bitrate) streams named RMVB (RealMedia variable bitrate) has been developed.
Overview
A RealMedia file consists of a series of chunks that can be of several different types:
- .RMF: RealMedia file header
- PROP: File properties header
- MDPR: Media properties header
- CONT: Content description header
- DATA: Data header
- INDX: Index header
Supported audio formats
- RealAudio 1.0 (VSELP), IpcJ
- RealAudio 2.0 (LD-CELP), 28_8
- AC3, dnet
- Sipro, sipr
- cook, cook
- ATRAC3, atrc
- RealAudio Lossless Format, ralf
- LC-AAC, raac
- HE-AAC, racp
Supported video formats
- ClearVideo (from helix spec)
- H.263, RV10
- H.263, RV13
- H.263+, RV20
- H.264 precursor, RV30
- H.264 precursor, RV40
- H.263+ (RV20), RVTR
See also
- RealPlayer
- Container format
- Comparison of video container formats
- Comparison of video player software
- RealVideo codecs
- RealAudio codecs
- Helix Community - the free and open source software project from RealNetworks
References
- ^ "System-Declared Uniform Type Identifiers". Uniform Type Identifiers Reference. Apple Inc.