File format matters during OER production, and spans all phases of the OER life cycle. Whatever the resource, if it is not in a suitable format, educators and learners might not be able to use it, let alone adapt and remix it to be more effective. This section will outline some of the concepts behind OER and file formats. To check the openness of a particular file format, see List of File Formats in the Appendices.
In general, use formats that are open and approved by appropriate standards organizations for interoperability and to ensure access and editability with FLOSS (free, libre and open source software).
Popularity of a format also influences how easy it is to adapt and 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.
When the file formats are kept open, it prevents the OER from inadvertently being "locked" up.
A teacher wants to make a collage. She imports several PNG photos into Photoshop and creates the collage. She saves the file as a PSD and exports a copy as a PNG to post on the web. While others can edit the PNG, it would be a lot easier to edit the PSD file. However, in order to use PSD files, the person has to have a copy of Photoshop.
In this instance, the teacher had a couple of options. She could:
- Use an open-source alternative to Photoshop (see Images programs section in Compose OER); or
- Use a more open format when making edits, such as TIFF. The scenario above isn't too harmful, because at least the PNG file is available for use, but ideally the OER would also be available in a format that is more conducive to editing.
Sometimes getting locked into a particular format or program is unavoidable.
A teacher wants to create an animation. He uses Adobe Flash to produce it. Although the animation worked perfectly for the lesson, he now realizes that needs to use Flash every time he wants to make a change and that others who want to make changes to the animation need Flash as well.
In the example above, the teacher uses Flash, a popular animation program. While Flash is very powerful, editing Flash files can be difficult/impossible without Adobe's program. Unfortunately, open alternatives to Flash are still in a primitive state and not nearly as widespread. Therefore, it may have been difficult to keep the OER in an open format and compatible with open programs. In situations such as these, the best thing to do is to make an editable version of the file available. For example, the teacher may make the FLA (which is the editable Flash file) available along with the SWF (the file that is typically put in web pages) with a Creative Commons license. While anybody who wants to localize or remix it will still need to use Flash, they will at least have the ability to do so.
There is some disagreement about the necessity of an open formats in OER. Some believe that by definition OER cannot use a closed format because technically nobody beyond the file format copyright owner is allowed to alter the format. Others take a more pragmatic view and acknowledge the benefits of open formats but stress that OER creators need to do what works for them (Joyce, 2007; Various, 2008).
As you develop your OER and use OER produced by others, you will begin to have a sense of how much you value open formats. In some ways, the case for open formats is difficult, because it isn't until you've personally had a problem with a closed format that the problems arise. This handbook advocates a "middle-of-the-road perspective" with regards to the necessity of open formats. As you gain more experience developing OER, you will develop your own opinion about open formats.
Other considerations besides open?
One factor in project planning to consider is the availability of an open format. Some open formats are not very widely known, and some might be hesitant to use them, even though there is nothing wrong with them. Additionally, while open source software is free to download, not everyone may want to use a particular open source program. One example might be the GIMP (see the Images program section). GIMP is an image-editing tool that can do many of the things Photoshop can. However, the GIMP user interface is different from Photoshop, which means it may take a little time to learn. The GIMP user interface also looks less polished than Photoshop, which tends to give users the impression that program is of poor quality.
Another factor to consider is that open source software tend to be "works in progress" and can have bugs. Try using the program a few times to make sure it is stable. If possible, you should also determine whether or not the open source software has all the capabilities necessary for your project. If you are working on a project with other educators, make sure you've talked about which programs and formats you will use before starting.
File formats and quality
It is impossible to come up with definitive statements about which formats are optimal for OER development because there are so many possible goals and 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. Below is some guidance on optimizing quality in some media files.
Which formats are better than their rivals is a subject of multiple discussions on the internet (e.g., Ozer 2006; Tsabury, 2007; Microsoft, n.d.). For example, there have been several people who have done tests on audio formats (for example ExtremeTech, 2004; Coalson, n.d.). 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 quality 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, 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 TIFF or PSD to save the files, but the final image might be in JPEG or PNG 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 LMS). 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.
Content packaging and exchange format standards are relevant for OER 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 to 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 opencourseware 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 it finds relatively little support among open source software projects or OpenCourseWare initiatives.
- 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.
What do all these content packages mean for me?
Many LMS programs such as Moodle, Blackboard and WebCT include the ability to export IMS Content 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. You could also use the RELOAD, an open source packaging editor to create standard IMS Content Packages with accompanying metadata.
- Such as the ISO, World Wide Web Consortium, OASIS, IMS Global Learning Consortium, etc.
Cross, J. (2004, April 2). Audio Codec Quality Shootout. ExtremeTech. Retrieved June 29, 2008, from http://www.extremetech.com/article2/0,1558,1560783,00.asp
Coalson, J. (Last Updated 2008, May 14). FLAC - Free Lossless Audio Codec. Retrieved May 23, 2008, from http://flac.sourceforge.net/
Joyce, A. OECD forum final report. UNESCO Virtual University. Retrieved March 21, 2008, from http://www.unesco.org/iiep/virtualuniversity/forumsfiche.php?queryforumspages_id=33
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
Tsabury, E. (2007 May 20). A Survey of Audio Coders for Electronic-Art Music. eContact!. Retrieved June 29, 2008, from http://cec.concordia.ca/econtact/9_4/tsabary.html
Various. FOSS solutions for OER - summary report. (2008, March 5). OER Wiki. Retrieved March 21, 2008, http://oerwiki.iiep-unesco.org/index.php?title=FOSS_solutions_for_OER_-_summary_report#OER_developers_should_commit_to_open_licenses