本文描述了在web或其他网站上标记具有创作共用许可协议的作品或专用于公共领域的具有人可读和机器可读通知的作品的最佳实践。卡塔尔vs葡萄牙分析

Although the importance of human-visible attribution and notice is stressed, this primary focus of this article is machine-readable metadata. Best practice for presentation of human-visible attribution and notice in various formats (apart from collocation with machine-readable equivalents) is currently beyond the scope of this article and will be presentedelsewhere. An index of specific technical recommendations, organized by file type, isavailable.

Principles

• Copyright notice should be published on theweb. Offline or peer-distributed works should refer to notice published on the web. A web notice allows content to be found via web search, content owners to be found by viewers of untethered works, may be trusted to the extent a web page may be trusted, and allows for further annotation by the owner and others.
• Copyright notice should bevisibleand unambiguous to humans and computers, especially the former. Human and computer visible notices should be one and the same.Offline or peer-distributed works should not refer to notice published on the web.
• Copyright notice best practices should begeneral而不仅仅适用于在创作共用许可协议下提供的作品。卡塔尔vs葡萄牙分析

Web

A web page is the preferred venue for published copyright notices. Notices published elsewhere should refer to an equivalent notice published on the web.

This text is licensed to the public under the Creative Commons Attribution 4.0 License.

That HTML snippet says that the current document is licensed under CC Attribution 4.0. The current document is the default subject,rel="license"sets the predicate or verb, the URL in thehrefvalue sets the object.

For detailed background on the web metadata model and syntax being used, seeRDFa.

This use follows the aforementioned principles:

• On theweb(obviously, so long as the HTML page in question is published to a website).
• The metadata isvisible-- it is colocated with an actionable link and may further be styled with CSS for human consumption.
• It isgeneral-- the model used can accomodate any sort of statement about anything that has a URI and thelicense谓词可以接受任何具有URI作为对象的许可，而不仅仅是知识共享许可。卡塔尔vs葡萄牙分析

Now we will see how to use the model to further annotate works with licensing-relevant metadata.

Attribution

A licensor can specify how they wish to be attributed for use of their work (see, for example, § 4(b) of//www.familygiver.com/licenses/by/4.0/legalcode). This includes:

1. The title of the work
2. The name of the person, group or organization to attribute the work to
3. The URL to link the attribution to

理想情况下，这些信息还可以作为机器可读的元数据使用。As an example, this could be encoded in the following triples (assuming the work in question is the current document):

1. <> dc:title "Compact Representation of Blank Pages" .
2. <> cc:attributionName "James Roberts" .
3. <> cc:attributionURL <http://example.org/crobp.html> .

Why the new properties?

1. dcterms:rightsHolder and dc:creator don't say which should be attributed -- or if someone else should be; cc:attributionName has the semantics necessary for the task.
2. The attribution URL will often be the current URL, but we need some way to specify that it should be cited; cc:attributionURL provides this.

Fortunately RDFa allows us to annotate human readable notices and include both the custom properties needed for attribution as well as additional useful properties, e.g.

http://example.org/crobp.html" property="dc:title">Compact Representation of Blank Pages by http://example.org/jr.html" property="cc:attributionName">James Roberts, a http://example.org/bps.html">translation of 'Paginas Blancos Si!', is licensed to the public under the //www.familygiver.com/licenses/by/4.0/">Creative Commons Attribution 4.0 License.

This produces the triples above plus these:

1. <> dc:creator <http://example.org/jr.html> .
2. <> dc:source <http://example.org/bps.html> .
3. <> license <//www.familygiver.com/licenses/by/4.0/> .

Included Objects

Objects included in web pages, such as images, should be annotated as above within their "host" web pages. Ideally all included objects should also embed objectformat nativenotice and metadata as described below, but this is only crucial for objects where the publisher intends for or is concerned about distribution outside the context of the "host" web page.

Metadata about include objects that have their own URIs should be qualified withabout, asrel="license"without anaboutattribute makes a statement about the current document (which is the "host" web page). Example:

Photo licensed under cc by 4.0.

See the RDFa Primer onbeyond the current documentfor additional examples.

More Rights

A page may provide any sort of metadata for itself and its included components. The following example has some obviously useful statements:

Audio (cc) 2006. See my store to obtain permissions not granted by the CC license, signed CDs, and concert tickets.

In addition to the familiarlicensestatement anddc:typefrom Dublin Core we havecc:morePermissions. The intention ofcc:morePermissionsis to point to a URL at which one can discover permissions outside the scope of those granted to the public by the licensor via a CC license.

SeeCCPlusfor more information on specifyingcc:morePermissions.

Interoperability with other web-based metadata formats

RDF/XML

RDF/XML is another RDF serialization that can be used to make any statement that can be made with RDFa. RDF/XML may beed in theof a web page orincluded in HTML comments，正如已弃用的CC建议所提倡的那样。

RDF/XML可以与RDFa完美地互操作，但后者更受欢迎，因为它与人类可见的内容搭配在一起。

Microformats

rel=licenseis both anelemental microformat(specificallyrel license) and anRDFastatement. Compound Microformats should be interoperable viaGRDDLorhGRDDL.

Use cases for licensing and related metadata as microformats may be found aton the microformats wiki; they remain hypothetical as microformats, but generalize to use cases for Creative Commons web metadata.

Feeds

RSS 1.0, RSS 2.0, and Atom 1.0 syndication formats each may includelicense annotations. These should also be reflected on web pages referenced by feed items.

Non-Web

Objects not native to the web should adhere to the following principles regarding license notice and metadata.

• To the extent possible copyright notice should bevisibleto users of the licensed object.
• The licensed object should contain aweb referenceto a web page that provides an equivalent licensing notice for the object in question. This makes a non-web object's licesning status as certain as that of a web page's status -- if the web reference does not agree with the non-web object's license notice, ignore the latter.
• To the extent possible license notice provided by non-web objects should use mechanisms and conventions incommon usefor the format of the non-web object in question.

We will now apply these principles to a variety of content formats, after describing two building blocks for Non-Web metadata -- web statement metadata and XMP.

Web Statement

The web page that provides licensing notice equivalent to any included in the object itself may be only human readable. Ideally the web page will publish metadata that is explicitly associated with the object in question. To do this the object must be identified, ideally with a content-derived identifier, such that a client may verify that the web page metadata concerns precisely the object in question. An example of a content-derived identifier is a content hash.

Following is an example of RDFa describing a resource indentified by a hash:

 'Good Dream' is licensed under CC BY. 

Produces the following triple:

<urn:sha1:DATAG7ENBVHFNQPM4W626VDVK25RYECI> license <//www.familygiver.com/licenses/by/4.0/> .

XMP

XMPhas the broadest support of any embedded metadata format (perhaps it is the only such format with anything approaching broad support) across many different media formats. With the exception of media formats where a workable embedded metadata format is already ubiquitous, Creative Commons recommends adopting XMP as an embedded metadata standard and use of the following two fields in particluar:

• Web reference: value ofxapRights:WebStatement
• License: value ofcc:license

Audio

人的可见元数据是不可能的，音频通知在大多数音乐环境中是不可接受的。除了下面的MP3和OGG外，建议使用XMP嵌入式元数据。

MP3

MP3is the primary exception to the XMP recommendation above, as ID3 is widely supported. The following two fields are recommended:

• Web reference: value ofWOAF("official audio file" URL)
• License: value ofWCOP(copyright URL)

OGG

"Vorbis Comments" are widely supported forOGGfiles. The following two fields are recommended:

• Web reference: value ofCONTACT
• License: value ofLICENSE

注意，OGG是一种也支持视频的容器格式。

Still Images

Although possible, visible attribution and copyright notice generally either does not fit in an image due to size or aesthetic limitations. Even where possible human-visible notice will not be collocated with machine-readable metadata (for bitmap formats currently in use).

For embedded metadata XMP is recommended.

Video

Visible attribution and copyright notice is generally provided in video frames (e.g., credit roll) oroverlays.

Preferably relevant regions of the video will be clickable or otherwise interactively linked with web pages.

有许多视频格式，每一种格式都有自己不受支持的嵌入式元数据规范(如果有的话)。卡塔尔vs葡萄牙分析知识共享建议在视频格式中采用XMP, OGG除外(见上面的音频)。

Document formats

"Document" formats meaning word processor, presentation and spreadsheet document files or their output formats such as PDF.

All of these formats are intended for human consumption and all modern versions support web links, sovisibilityis easy -- the license andweb referenceshould be noted in thee document text wherevercommon usedictates a copyright notice would appear. Looks like we just took care of the other principles as well.

Many document formats support some form of embedded metadata that can be accessed, e.g., by selectingFile|Document Propertiesfrom a menu. Where such metadata includes licensing or copyright-relevant fields, these should be populated with first priority to theweb referenceand second priority to the URL of the license the document in question is under.

Ideally these metadata fields should be used to directly populate the human-visible parts of the document, e.g., via a document field, as is typically used to automatically place page numbers and document titles throughout such documents. This gives us the best of both worlds -- any software that indexes embedded metadata can easily find license information, and that information is perfectly reflected in notices humans see.

Details of how metadata may be embedded in specific file formats is availablehere.