| Basic Info | |
|---|---|
| Media Type | audio |
| subtype | vnd.hns.audio |
| Registered? | Yes |
| See also | Swaminathan |
| Extensions | |
Tags: (none)
File Formats: (none)
(Last updated 23 March 2006) Name : Kumar Swaminathan Email : [email protected] MIME media type name : Audio MIME subtype name : Vendor Tree - vnd.hns.audio Required parameters : None Optional parameters : None Encoding considerations : binary This media type may require encoding on transports not capable of handling binary. Security considerations : The media type is not intended for execuatble or active content. Integrity and Privacy are handled at a higher level since the intended application is content delivery services for enterprise applications. The server or sender, receiver or client plays the primary role in call establishment, authentication, and privacy prior to launching the media player. These are not tied to any media type. Other security considerations, if any, have not been assessed. Interoperability considerations : The media subtype is intended for identifying audio content that requires decoding of compressed audio by HNS rendering plugins and libraries that get invoked when using a Real Media Player (on all OS). The audio content would have to be created by an utility that converts the compressed audio payloads to a RM container format (recognized by Real Media Player and developed using RealSystemSDK) and which contains 1. Compressed Audio Payload?s MIME type and specific Audio Decoder Library stored in its Media Properties Header 2. Compressed Audio samples with each sample containing a header that contains information such as its timestamp, its size, and indication of whether it is a key frame. Published specification : Intended for use by HNS products and services. For further information please contact Kumar Swaminathan at 301-428-5705 or [email protected]. Applications which use this media : The intended applications are media content delivery services for enterprise applications. The media payload is expected to be LPCM/WAV PCM/MP3/MPEG-4 AAC based for audio. Other compression formats are not excluded but these are the formats that are being considered at this time. The client player is Real Media Player with the HNS developed rendering plugins and decoding libraries for the various codecs. Additional information : 1. Magic number(s) : N/A 2. File extension(s) : .rm 3. Macintosh file type code : N/A 4. Object Identifiers: N/A The server/sender provides for the conversion of the compressed media payloads to an RM container format that is recognized by any Real Player. The RM container contains 1. Compressed Video Payload?s MIME type and specific Video Decoder Library stored in its Media Properties Header 2. Compressed Audio Payload?s MIME type and specific Audio Decoder Library stored in its Media Properties Header 3. Compressed Video and Audio samples with each sample containing a header that contains information such as its timestamp, its size, and indication of whether it is a key frame. The receiver/client video and audio rendering plug-ins are invoked by the Real Media Player for rendering of video and audio frames from the RM file, encoded at the sender/server. These plug-ins are invoked for rendering frames with mime types ?video/x-pn-hns1video? and ?audio/x-pn-hns1audio? to-day but these extended MIME types will eventually be replaced by "video/vnd.hns.video" and "audio/vnd/hns.audio" after registartion of these media sub-types. When RealPlayer is starting it accesses all rendering plug-ins in the plugins folder and asks them which mime type they support. The HNS video rendering plug-in hnsrvpln responds with ?video/vnd.hns.video? while the HNS audio rendering plug-in hnsrapln responds with ?audio/x-pn-hns1audio? to that request. The header of the every stream of RM file contains mime type. When RealPlayer receives stream header it finds renderer plug-in responsible for that mime type and forward all related stream data to that plug-in. HNS video rendering plug-in hnsrvpln uses the decoder library which is specified in the Video Stream Properties Header of the RM file. For example, a library HnsAvcBpDec has been implemented which corresponds to HNS implementation of MPEG-4 AVC Baseline Profile. Similarly, the HNS audio rendering plug-in hnsrapln uses the decoder library which is specified in the Audio Stream Properties Header of the RM file. For example, the library HnsLpcmDec corresponds to Linear PCM decoder. Person to contact for further information : 1. Name : Kumar Swaminathan 2. Email : [email protected] Intended usage : Limited Use Intended for use by HNS developed products and services. Author/Change controller : Kumar Swaminathan (File created 23 March 2006)