by Neil Ridgway

FOHM+RTSP:FOHM+RTSP:Applying Open Hypermedia and Applying Open Hypermedia and

Temporal Linking to Audio StreamsTemporal Linking to Audio Streams

ContentsContents

• Introduction• WWW and Audio• Streaming Protocols and RTSP• OHSs and Audio• FOHM• My Research• Conclusion

IntroductionIntroduction

• Both the WWW and OHSs can create links:– to and from text and images– only to temporal media (audio and video)

• The WWW:– streaming media protocols for delivery– embedded links

• OHSs:– no streaming protocols– link information handled separately

WWW and AudioWWW and Audio

• Originally download entire audio file.

• Can now stream audio information to users.

• Synchronised Multimedia Integration Language (SMIL) Version 1 - “PowerPoint” for the Web.

Streaming Media ProtocolsStreaming Media Protocols

• De facto standards: – RFC 1889: Real-time Transport Protocol (RTP)– RFC 2326: Real Time Streaming Protocol (RTSP)

• RTP: encoding of the packets and delivery (usually over UDP).

• RTSP: “network remote control”.

Real Time Streaming ProtocolReal Time Streaming Protocol

OHSs and AudioOHSs and Audio

• Audio domain neglected because:– lack of technology– HCI challenges– audio file formats

• Microcosm’s SoundViewer and HyperWave’s Harmony Audio Player.

Fundamental Open Hypermedia Fundamental Open Hypermedia Model (FOHM)Model (FOHM)

• Derived from Open Hypermedia Protocol.

• Interoperable higher-level data structure.

• Designed to work across multiple domains e.g. navigational hypertext.

• Defined as a XML DTD.

My Research: FOHM+RTSPMy Research: FOHM+RTSP

• New RTSP implementation:– to support IPv6 (future proofing)– to control audio streams

• New RTSP implementation extensions:– to support FOHM linkbases– to provide Open Hypermedia and Temporal Linking

functionality.

Extensions to RTSPExtensions to RTSP

• The new methods:– The AVAILABLE_LINKS method.– The FOLLOW_LINK method.– The CREATE_LINK method.

• Link information stored in separate FOHM linkbases.

ConclusionConclusion

• FOHM+RTSP: mutually beneficial relationship.

• First application of FOHM to stream media.

• Several issues:– preloading the links– infinite streams (radio broadcast)