OER Handbook/educator/Appendices/file formats

The following is a list of the most commonly used files. Preferred OER formats are recommended, although individual circumstances may require you to use proprietary formats.

Audio
AIFF: A proprietary format from Apple. Like WAV, AIFF is uncompressed and is a good choice for audio editing (Apple Computer, Inc., 1991).

MP3: Although MP3 is probably the most widely used audio format on the internet, it has had patent issues which make it less than ideal, for OER creation. Still, there is a large amount of software and hardware designed to use MP3, which may make it a good choice in many situations (BBC News, 2007; Williams, 2007).

OGG Vorbis and FLAC: Open formats that are completely free. Ogg Vorbis is a lossy format, like MP3, while FLAC is similar to WAV and AIFF (Xiph.org, n.d.; Coalson, 2008).

WAV: A proprietary format from Microsoft and IBM. Although WAV format is patented it is commonly used and is part of the European Broadcast Union standard. WAV files are not 'lossy,' which means they do not lose sound quality as they are edited. Although the format is not open, converting to a WAV file makes sense if you are planning to edit audio, as it is the format of choice for many audio editors (Library of Congress, 2005).

Preferred OER formats: FLAC, OGG Vorbis, MP3.

Images
JPEG: The most common image format on the internet. There are some patent concerns with JPEG, although its committee has stated that they intend for the format to be free to use. JPEG is considered a 'lossy' format, meaning that if the photo is continually edited, the image quality will be reduced. Because JPEG is so commonly used on the internet, it is often used as the final format for OER (Lane, 1999; Clark 2002).

PNG: Open format that is similar to TIFF. In the past, some browsers did not support PNG that well, so adoption of the format has been slow. However, all current web browsers, such as Internet Explorer and Firefox, will display PNG files. Growing support for PNG files makes it a good format for OER (W3C, 2003; Microsoft, 2007).

PSD: Photoshop Document file (Adobe Systems Incorporated "Photoshop Format"). PSD files are great for editing, but are only compatible with Photoshop.

SVG: An open format with promising new features, including animation. Unfortunately, SVG support in web browsers is uneven, making it difficult to recommend as a format for OER. Perhaps, in time, SVG will become a recommended format (Zeidner & Gould, 2008).

TIFF: A proprietary format by Adobe. TIFF files are often used when scanning documents. Despite being proprietary, it is not uncommon for TIFF files to be used as a high-quality backup of OER (Library of Congress, 2006).

Preferred OER formats: PNG.

Presentation
SXI: Open format for Open Office, Neo Office and Star Office. Unlikely to be compatible with Microsoft Office (FilExt, "SXI").

ODP: Open Document format. Supported by Open Office, Neo Office, Star Office as well as others (OpenDocument Fellowship, "Application Support").

PPT: Proprietary format from Microsoft (FileInfo.net, "PPT"). Open source presentation programs try to support it with varying degrees of success.

Preferred OER formats: ODP.

Text
ABW: File format used by the open source word processor Abiword (see Office Programs in the Compose OER section for more information). It is based on XML and is therefore easier for other word processors to convert (Various, 2008).

CSV: Stands for "Comma Separated Values." Essentially it is a plain text file that uses commas to separate individual entries. This format is commonly used by spreadsheets and database applications and is very open (Repici, n.d).

DOC: Proprietary format used by Microsoft Word. The actual format has evolved with Word, but has always been closed. Many other word processors can open and save to DOC format, but the resulting document rarely looks exactly as if it were opened in Microsoft Word (FilExt, "DOC").

DOCX: XML format that is used in Microsoft Word 2007. Although the format is open for anyone to use, implementing it in other word processors is difficult and support is lacking in word processors besides Word (FilExt, "DOCX").

DOT: Template document for versions of Microsoft Word before 2007. Compatibility unknown (File.extension "DOT").

DOTX: Template document for Microsoft Word 2007. Compatibility unknown (FileInfo.net, 2006).

HTML: Open format managed by the non-profit organization W3C(World Wide Web Consortium) (Jacobs, 2008).

ODT: Open Document format managed by OASIS industry consortium (OpenDocument Fellowship, n.d.). Supported by many open source word processors, Microsoft Word can open ODT files with a plug-in (Paul, 2007).

PAGES: Format used by Apple's Pages program. Currently there are no other word processors that open files in PAGES format (Apple Inc., n.d.).

RTF: The Rich Text Format (often abbreviated RTF) is a document file format developed by Microsoft in 1987 for cross-platform document interchange. Most word processors are able to read and write RTF documents (http://en.wikipedia.org/wiki/Rich_Text_Format).

STW: Template format used by Star Office, Open Office and Neo Office word processors. Compatibility unknown (FilExt, ".SXW Details").

SXW: Text format used by Star Office, Open Office and Neo Office word processors (FileInfo.net, 2008). May be compatible with open source word processors, but not necessarily proprietary ones such as Microsoft Word.

TXT: generic file format based on several standards. Almost universally compatible with any word processor or text editor (FilExt, ".TXT Details").

WPD: Word Perfect word processor file format. Compatibility unknown (FilExt, n.d.).

WPS: Microsoft Works word processor file format. Some compatibility with open source word processors such as Neo Office (FileInfo.net, 2008).

WPT: Microsoft Works template file format. Compatibility unknown (FileInfo.net, 2007).

WRI: Windows Write word processor file format. Compatibility unknown, but unlikely to be good, as Write hasn't been used since Windows 3.1 (File.extensions, 2008).

XHTML: Update of HTML using features of XML. Eventually XHTML is intended to replace HTML. Can be open by many word processors, but appearance may be different than anticipated (XHTML2 Working Group, 2008).

XML: Open format that is very flexible. Many open formats use XML, at least in part, to make a new open format. Future compatibility with XML should be excellent, though it is rarely a format that people type by hand, and is usually generated by text editors or word processors (W3C, n.d.).

Preferred OER formats: HTML, SXW, TXT, XHTML, XML.

Video
MPEG-2: Format with patents by several companies. MPEG-2 is the standard format for DVDs and is used by the Internet Archive (see General Repositories for more information) (Lo n.d.; Internet Archive, n.d.).

MPEG-4: Format with patents held by the same companies as MPEG-2. MPEG-4 files are capable of a wider variety of resolutions and sizes, making it a very flexible format. As with MPEG-2, MPEG-4 is used by the Internet Archive and is a recommended format for OER (Apple Inc., "MPEG-4"; Internet Archive, n.d.).

Ogg Theora: Completely open lossy video format (Xiph.org, "FAQ"). Some players support Ogg with a free plug-in (Xiph.org "downloads").

QuickTime video (MOV): Format developed by Apple. MOV files are based on MPEG-4, but not as widely supported. Therefore, it is preferable to save OER as MPEG-4 (Apple Inc., 2007).

SWF and FLV: Format owned by Adobe. SWF files can be viewed by the vast majority of web browsers and platforms (Windows, Mac and Linux). Because SWF files can be viewed by so many different people, it is one of the most common formats for video and animation on the internet. Unfortunately, editing SWF files is very difficult and is not recommended for OER development. FLV is the video format that is used for video while developing SWF files. Neither file format is recommended for OER, but may be unavoidable in certain situations. If you must use a SWF for OER, it is recommended that you also make the FLA available (Library of Congress, 2007; Gay, n.d.; Adobe Systems Incorporated, n.d.).

Windows Media File (WMV): Developed by Microsoft, but is an open format. Although WMV files produce good quality with a small file size however, MPEG-2 or MPEG-4 is preferable to WMV (Microsoft, 2008).

Preferred OER formats: MPEG-4, Ogg Theora.