Media Resource Control Protocol (MRCP) is a communication protocol used by speech servers to provide various services (such as

speech recognition Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ...

and speech synthesis) to their clients. MRCP relies on another protocol, such as

Real Time Streaming Protocol The Real Time Streaming Protocol (RTSP) is an application-level network protocol designed for multiplexing and packetizing multimedia transport streams (such as interactive media, video and audio) over a suitable transport protocol. RTSP is us ...

(RTSP) or Session Initiation Protocol ( SIP) for establishing a control session and audio streams between the client and the server. MRCP uses a similar style of clear-text signaling as

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...

and many other Internet protocols, in which each message contains 3 sections: a first-line, a header and a body. The first line indicates the type of message as well as information such as response codes. The header contains a number of lines, each in the format

: . The body, whose length is specified by the header, contains the details of the message. Like HTTP, MRCP uses a request (usually issued by the client) and response model. Responses may simply acknowledge receipt of the request or give other information regarding its processing. For example, an MRCP client may request to send some audio

data In the pursuit of knowledge, data (; ) is a collection of discrete Value_(semiotics), values that convey information, describing quantity, qualitative property, quality, fact, statistics, other basic units of meaning, or simply sequences of sy ...

for processing (say, for speech recognition), to which the server could respond with a message containing a suitable

port number In computer networking, a port is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system, a port is a logical construct that identifies a specific ...

to send the data, since MRCP does not have support for audio data specifically as this would have to be handled by some other protocol, such as

Real-time Transport Protocol The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applicati ...

(RTP). MRCP protocol version 2 has been approved as an RFC. Version 2 uses SIP for managing sessions and audio streams between the server and the clients, whereas version 1 did not specify the underlying protocol. MRCP has been adopted by a wide range of commercial speech servers, such as Verbio Technologies
Skit.ai's VIVA

Microsoft Speech Server The Microsoft Speech Server is a product from Microsoft designed to allow the authoring and deployment of IVR applications incorporating Speech Recognition, Speech Synthesis and DTMF. The first version of the server was released in 2004 as Micro ...

, LumenVox Speech Engine,

ReadSpeaker is a Japanese company manufacturing optical products such as photomasks, photomask blanks and hard disk drive platters, contact lenses and eyeglass lenses for the health-care market, medical photonics, lasers, photographic filters, medical flex ...

speechServer MRCP, Nuance Recognizer and Vocalizer, Sestek TTS, Sestek Call Steering as well as commercial

Interactive Voice Response Interactive voice response (IVR) is a technology that allows telephone users to interact with a computer-operated telephone system through the use of voice and DTMF tones input with a keypad. In telecommunications, IVR allows customers to interac ...

software such as Blueworx Voice Response..

External links

* , A Media Resource Control Protocol (MRCP) * , Media Resource Control Protocol version 2 (MRCPv2)
UniMRCP
An open source cross-platform MRCP implementation Internet protocols Application layer protocols {{multimedia-software-stub