|OER Handbook for Educators - Adapt OER|
|Adapt OER||Quality | OER Translation | Offline Versions | Accessibility | Perspectives|
When localizing and remixing files from different OER, it is important to keep file formats in mind. Some formats are easier to edit, and therefore remix and localize, than others. When remixing OERs, keep in mind the information about file formats found in the Get OER section. The more open a file format is, the less expensive (and possibly easier) it will be for people to remix the files. Popularity of a format also influences how easy it is to remix. For example, WMV, though not an open format, is very common and there are many tools to convert WMV files to MPEG-4 or MOV, though it should be noted that these conversion tools are rarely free.
It is impossible to come up with definitive statements about which formats are optimal for remixing because there are so many differing local circumstances. If you are in doubt about which formats to use, check an OER repository that has resources similar to the one you are creating and see which format they use.
Which formats are better than their rivals is a subject of multiple discussions on the internet (ex: Jordan, 2006; Karrer 2007; Microsoft Inc., n.d.). For example, there have been several people who have done tests on audio formats (ExtremeTech, 2004; Coalson, n.d.; Ozer, 2006). Along with the sheer number of formats, some formats are being replaced, improved or changed, making the task of choosing one even harder. The task of a format to use can seem daunting, especially when determining something as subjective as "quality."
However, despite all the discussion about quality in formats, the difference is negligible with regards to OER. That is not to say that there is not a difference between WMV and MPEG-4, or OGG and MP3 audio. Some of these formats do indeed have sharper images and clearer audio. But the most important purpose of OER is pedagogic - to educate and inform. Aesthetic quality, to a certain extent, takes a secondary role. By keeping this perspective and focusing on openness and popularity of the format, the task of selecting a format should be easier.
Media production programs (e.g. Photoshop, Adobe Premiere, etc.) can seem remarkable in their ability to do virtually anything. Still, it saves a great deal in time and mental anguish to think about quality from the very beginning. As an example, it is much easier to use a premium camera with a good flash when taking pictures, than it is to use Photoshop to adjust lighting and bring out detail. This same principle works with audio as well. It is much easier to use audio equipment that captures clean, crisp sound than it is to use audio filters in an editing program to clear up fuzzy, quiet audio. As the old saying goes, "An ounce of prevention is worth a pound of cure."
Many multimedia formats have multiple settings to control quality. These settings can be a better indicator of quality than the choice of format. Programs vary widely in which settings are available for adjustment and how they are changed. When remixing you will want to use high quality files, even though the final file might be at a lesser quality. This is most important when dealing with "lossy" file formats, such as JPEG and MP3. With both of these formats, each time you save, a little bit of quality is lost (see the File Format section under Find OER for more information), similar to making a photocopy of a photocopy. Therefore, when doing the actual localizing and remixing before publishing, it is important to use a lossless format or at least high-quality settings with lossy formats. For example, when using Photoshop to create an OER you would want to use a PSD or TIFF to save the files, but the final image might be in JPEG or GIF format. Ideally, you'll be able to make the original high-quality files, along with the final files, available in case others wish to localize or remix your work.
Image or video size is also a factor in localizing and remixing. Images or video can be shrunk in size using a variety of programs. However, enlarging images or video results in a loss of quality, though small increases in size should not be too detrimental. When working with video or images it is recommended that you work at a size or two larger than the size at which you intend the final OER to be rendered.
The following is a list of settings that are well-suited to remixing:
- At least 640px x 420px
- Lossless file type (TIFF, RAW, PNG)
Make sure you keep multiple backups of files if you plan on using many filters or making adjustments.
- At least 640px x 420px
- DV, HDV formats
Avoid re-compressing the footage as much as possible.
- At least 128kps VBR (Variable Bit Rate)
- WAV, AIFF
Avoid excessive audio filters that unnecessarily distort audio.
Standards and interoperability
Technical standards affect the ability to exchange and share information and content between systems (e.g., between repositories and LMSs). For small projects, such as single file OER, using the appropriate technical standards isn't extremely difficult. But packaging whole courses to be compatible with major LMS means paying particular attention to these standards. You are not expected to know how to convert your course to these standards, but you should be aware of what these standards mean and when they are used.
Standards are relevant for OER projects in a number of areas:
- Content packaging and exchange formats – This is an issue most relevant for projects publishing whole courses, who want to enable users to download the courses into their local learning management systems or exchange OpenCourseWare between projects. IMS Content Packaging (IMS CP) is the standard for course materials that was informally agreed by the OpenCourseWare Consortium. Unfortunately, different software applications implement the IMS CP standard in slightly different ways – this means software must be specifically programmed for packages coming from different providers. Some example providers include: the proprietary WebCT / Blackboard learning management system, the MIT OpenCourseWare repository, and the eduCommons courseware platform. In addition, there are conversations about the benefits of the new IMS Common Cartridge standard (IMS CC), and it is expected that many OpenCourseWare projects will eventually move towards it. SCORM is another content packaging standard but due to the complexity of the standard it finds relatively little support among open source software project or OpenCourseWare initiatives.
What do all these content packages mean for me?
Many LMS programs such as Blackboard, WebCT, Moodle include the ability to export IMS packages for easier uploading to programs like eduCommons. However, because IMS packages vary so much in implementation, it is rare to have a course upload perfectly. That means you should be prepared to spend time fixing errors that creep in during the import process. If you are creating a course from scratch without the benefit of an LMS, do the best you can in organizing and labeling your course, including the file names and folder organization.
"Materials are being developed in XHTML that enables them to be transformed into different formats, and learning design and technical specifications include adherence to accessibility standards." Richard Wyles, New Zealand OER Project case-study (2007)
- Metadata – Metadata is information that describes something, in this case a course or OER - like the way the information on the label of a soup can describes the soup in the can. A number of metadata schemas exist for use with educational content. The OpenCourseware Consortium members agreed on the Dublin Core specifications. With regards to educational taxonomies there is no agreed standard for OERs, and as social tagging and bookmarking services become more prevalent, and specialized search engines are being developed, their might be less need for agreed taxonomies in the future. The JISC commissioned a Vocabulary Management Technologies Review as part of wider review of pedagogical vocabularies which gives a good overview of all the main metadata schemas used in education. Applications that can be used to create or host content should provide functions to add metadata and automatically make it available within the HTML pages of the content.
- RDF – Resource Description Framework (RDF) defines a way of storing descriptive information of a resource in a way that a computer can understand. In the OER context, RDF is usually mentioned with respect to storing metadata about a course (for example, using the Dublin Core set of definitions for metadata), or embedding Creative Commons licensing information in a resource. Usually learners do not have to worry about dealing with RDF.
Coalson, J. (n.d.). FLAC - comparison. Retrieved May 28, 2008, from http://flac.sourceforge.net/comparison.html
ExtremeTech. (2004). Audio Codec Quality Shootout. Retrieved May 28, 2008, from http://www.extremetech.com/article2/0,1558,1560785,00.asp
Jordan, L. (2006, June). Technique: Choosing the Best Video Codec. Retrieved May 28, 2008, from http://www.larryjordan.biz/articles/lj_video_codec.html
Karrer, T. (2007, October 16). Video format comparison - Flash video format - WMV format - QuickTime - Real. Retrieved May 28, 2008, from http://elearningtech.blogspot.com/2007/10/video-format-comparison-flash-wmv.html
Microsoft, Inc. (n.d.). Choosing the best graphic format for the job. Retrieved May 28, 2008, http://office.microsoft.com/en-us/help/HA010563051033.aspx
Ozer, J. (2006, March 22). Choosing a codec. Retrieved May 28, 2008, from http://www.streamingmedia.com/article.asp?id=9259&page=1&c=8