Re: [call for comments] ma:compression vs. ma:coding vs. ma:encoding

Jean-Pierre, ah it's about the name ;-) Okay, in DIA UED (Schema available at [1]) - I know it's about context and not content but anyway - we differentiated between audio, video, image, graphics, scene graphs, and transport coding schemes. As you know one can put, e.g., AVC + AAC into a mp4 or mp2ts (or something else) and the former is video/audio coding scheme and the latter is known as transport scheme. If you'd like to cover all of them within a single property, one needs to allow for multiple entries. The MPEG-21 DID Resource element (Scheme available at [2]) has mimeType, encoding, and contentEncoding. The latter is of type NMTOKENS. Semantics are as follows [3]:
 - mimeType: Specifies the data type of the resource, before any of the content-encodings specified in the CONTENTENCODING attribute were applied to the resource, as a concatenation of MIME media-type, sub-type, and parameters, as defined in IETF RFC 2045.
 - encoding: Specifies the encoding format used to include the
 - contentEncoding: Specifies the content-encoding(s) as defined in IETF RFC 2616. A content-encoding value is used as a modifier to the MIME media-type. When present, its value indicates what additional content-encodings have been applied to the resource.

Name is not (that) important, semantics are. However, I would either opt for coding or encoding.

Best regards,
 -Christian

[1] http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-21_schema_files/dia-2nd/UED-2nd.xsd
[2] http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-21_schema_files/did/didl.xsd
[3] http://standards.iso.org/ittf/PubliclyAvailableStandards/c041112_ISO_IEC_21000-2_2005(E).zip

On Apr 28, 2010, at 2:48 PM, Evain, Jean-Pierre wrote:

> Hello Christian,
>  
> Therefore the question is what name is best? Compression, coding, encoding?
>  
> The list of mime types is by no means as comprehensive as MPEG's list, which is why I took the position expressed in an earlier mail ;-) you have understood I would eliminate MIME in this context.
>  
> By the way, Christian, any need to update http://www.ebu.ch/metadata/cs/ebu_AudioCompressionCodeCS.xml and http://www.ebu.ch/metadata/cs/ebu_VideoCompressionCodeCS.xml , which we had discussed in another life?
>  
> Of course, mpeg codecs may not be the only compression schemes. If you believe that the classifications schemes maintained by EBU are incomplete, please do not hesitate to let me know.
>  
> Regards,
>  
> Jean-pierre
>  
> From: Christian Timmerer (ITEC) [mailto:christian.timmerer@itec.uni-klu.ac.at] 
> Sent: mercredi, 28. avril 2010 14:42
> To: Evain, Jean-Pierre
> Cc: 'Silvia Pfeiffer'; Daniel Park; public-media-annotation@w3.org
> Subject: Re: [call for comments] ma:compression vs. ma:coding vs. ma:encoding
>  
>  
> MPEG has defined URI for its codecs and the list is available at http://mpeg.chiariglione.org/working_documents/general/URI.zip. Latest version (approved last week) is attached. Let me know in case something is missing.
>  
> Best regards,
>  -Christian
> 
> 
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