Media Type 'audio/vnd.hns.audio' Details

Media Type 'audio/vnd.hns.audio' Details


Basic Info
Media Type audio
subtype vnd.hns.audio
Registered? Yes
See also Swaminathan
Extensions

Tags: (none)

File Formats: (none)

Details

(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)