File formats - University of Wollongong

This resource will detail the different types of file formats, and what they can be used for.

What is a file format?

A file format is the structure of how information is encoded, or stored, in a computer file. A program that uses the data in a file must be able to recognise and access data within the file. For example a Microsoft Excel file (.xlsx) will not be able to be opened in a webpage as it is not saved as a .html file.

Particular file formats are often indicated as part of a file’s name by the file name extension. The extension is separated by a period from the name and contains three or four letters that identify the format. For example .docx is the extension for a Microsoft Word document, and therefore a file name would appear as ‘Document Name.docx’.

Document file formats

File format extension	File format name	What is it?	Programs that use this format
.doc	Microsoft Word Document	Microsoft Word document file. Cannot be easily opened by other programs. This problem was resolved when Microsoft began using .docx in 2007.	Microsoft Word (all versions, most common in 2003 and earlier)
.docx	Microsoft Word Open XML Document	Advanced version of .doc Compatible with software other than the Office Suite. Easier to send .docx files as attachments in emails.	Microsoft Word 2007 onwards.
.odt	OpenDocument Text Document	Another form of saving a word processing document other than .docx Serves purpose of providing an open XML-based format that is used as part of the Open Office Program.	OpenOffice Writer
.pages	Pages Document	Word processing document created by the Apple ‘Pages’ Program and available under the Apple iWork Office Suite. Contains text and page layout tasks (much like Microsoft Word).	Pages 4.0, 4.1, 4.2 iWork Google Docs
.pdf	Portable Document Format	Fixed layout document (much like an image). Universal among all operating systems. Print-ready and easy to share from any device.	Adobe Acrobat Reader Adobe Acrobat (for publishing)
.pub	Microsoft Publisher Document File	Microsoft publisher file	Microsoft Publisher
.rtf	Rich Text Format	Mix between rich text files and plain text files. Offers only basic formatting features like bold, italic, underline, bullet points and different fonts.	Microsoft Word TextEdit WordPad
.txt	Raw Text File	Contains plain text and is structured in series of lines of text. Corrupted files can be recovered with .txt Little formatting required and universal due to the ability for any text-based program to read .txt files.	Notepad WordPad

Presentation file formats

File format extension	File format name	What is it?	Programs that use this format
.key	Keynote Presentation	Keynote presentation file that contains the slides for the presentation, images, transition information, and text for the presentation.	File Viewer Lite (Windows) Apple Keynote 6.2 (Mac & iOS)
.odp	OpenDocument Presentation File	Used for saving presentation documents in the Open Document Presentation Format. Comparable to Microsoft PowerPoint with a few features that are made accessible in .ppt files or vice versa.	WordPerfect OpenOffice
.pps	PowerPoint Slide Show	Contains slides that feature either text, images, graphs or lists and cannot be edited. Opens directly in presentation mode.	Apple Keynote Microsoft PowerPoint OpenOffice
.ppt	PowerPoint Presentation	PowerPoint presentation file. Cannot be easily opened by other programs. This problem was resolved when Microsoft introduced .pptx in 2007.	Microsoft Powerpoint (all versions, most common in 2003 and earlier)
.pptx	Microsoft PowerPoint 2007 XML	PowerPoint Presentation file that contains slides of images, text, animation, audio, video, transition effects and more. Is an XML-based open source in which can be easily accessible to individuals using a software other than the Office Suite. An extension from .ppt file format.	Apple Keynote Microsoft PowerPoint OpenOffice

Spreadsheet file formats

File format extension	File format name	What is it?	Programs that use this format
.csv	Comma Separated Values File	Flat files which store tabular data through numbers and text in plain-text form. Used to collect data from tables to be transported as input to other table-orientated applications such as Microsoft Excel.	Microsoft Excel OpenOffice Notepad
.ods	OpenDocument Spreadsheet	Used for saving spreadsheet documents under the Open Document Spreadsheet Format. Comparable to Microsoft Excel with a few features that are made accessible in .xlsx files or vice versa.	OpenOffice
.xls	Microsoft Excel Spreadsheet	Microsoft Excel spreadsheet file. Cannot be easily opened by other programs. This problem was resolved when Microsoft introduced .xlsx in 2007.	Microsoft Office (all versions, most common in 2003 and earlier)
.xlsx	Microsoft Excel Open XML Spreadsheet	Is an XML-based open source in which can be easily accessible to individuals using a software other than the Office Suite. Excel file in which it can format and create spreadsheets and graphs, as well as processing complex mathematics queries. An extension from .xls file format.	Microsoft Excel 2007 onwards

Audio file formats

File format extension	File format name	What is it?	Programs that use this format
.aup	Audacity Project File	Created by the Audacity program to save edited audio file and save them in XML format.	Audacity
.mp3	MPEG-1 or MPEG-2 Audio Layer-3	Format for compressing audio. Uses lossy compression.	Apple iTunes Microsoft Windows Media Player
.m4a	MPEG-4 Audio Layer	Popular when using iTunes and can be saved under the extension of .m4a or .mp4 (the difference between the two being that .mp4 is capable of storing video). .m4a files are an improvement on .mp3 files due to the fact that they are capable of undertaking lossless compression as opposed to lossy compression*.	Apple QuickTime Player Apple iTunes Microsoft Windows Media Player
.midi	Musical Instrument Digital Interface	Developed to ease the transfer of MIDI data between applications for musicians and audio developers. Cues, volume, pitch, velocity and other notations information are carried within the .midi file and they help to synchronize the tempo between multiple devices. User is able to play multiple audio channels from one controller and these files offer ease of modification, compactness and choice of instrument. Separated into two versions: Type 0 which contains a single track and Type 1 which contains a multi-track data.	Apple QuickTime Player Microsoft Windows Media Player GarageBand
.wav	WAVE Audio	Contains sounds such as effects, music, and voice recordings. .wav files are larger files thus making them less popular than .mp3. Higher quality compared with .mp3 and .mp4 files and they undertake lossless compression.	Microsoft Windows Media Player CyberLink PowerDirector Roxio Creator 2009
.wma	Windows Media Audio	Capable of the same quality as a .mp3 file. Faster compression rate reaching quality audio at 64kbps (kilobits per second). Files can undertake lossy compression however allows for some form of lossless compression as well.	MPlayer VLC Media Player Microsoft Windows Media Player Microsoft Windows Movie Maker

* Lossless compression means that files that are compressed can be converted back to their original format without any loss of quality. Whereas lossy compression can convert compressed files back to the original form however there is loss of quality as a trade-off for file size.

Video file formats

File format extension	File format name	What is it?	Programs that use this format
.avi	Microsoft Audio Video Interleave	Contains audio and video information in single file thus allows simultaneous audio with video playback. Uses less compression than formats such as .mov and .mpeg. Maximum size is 2GB.	Microsoft Windows Media Player Apple QuickTime Player VideoLAN VLC Media Player
.f4v	Flash MP4 Video File	Flash Video Format. Referred to as a container format as it uses boxes for data storage.	Adobe FlashPlayer 13 Adobe Flash Professional CC VideoLAN VLC Media Player
.m4v	iTunes Video File	Operates in the same way as the .mp4 videos. Plays both video and audio data. Videos that are downloaded from iTunes are obtained in .m4v format.	Apple QuickTime Player Apple iTunes VLC Media Player
.mod	Camcorder Recorded Video (Modul) File	Used and created by Panasonic and JVC for digital video recording with tapeless camcorders. .mod data is recorded onto a hard disk or SD card. Any computer or device that can reproduce .mp2 video files can view .mod files and .mod files can be viewed on DVD players as well.	QuickTime Player VLC Media Player Windows Media Player
.mov	QuickTime Movie	Used to save video files with a proprietary compression algorithm designed by Apple. Capable of holding multiple media types such as videos, video effects, text, images, subtitles and audio.	Apple QuickTime Player
.mp4	MPEG-4 Video Stream (Motion Picture Experts Group File)	Capable of storing multimedia such as audio, video and subtitles. Often used in online streaming of videos.	Real Media Player Windows Media Player iTunes
.swf	Shockwave Flash Movie	Used for displaying animated vector graphics, multimedia and Action Script with text. Files contain animations with varying degrees of interactivity and function.	Adobe Flash Player
.wmv	Windows Media Video	Contained by the Advanced Systems Format (ASF) container. High definition capabilities making them ideal for HD DVD and Blu-ray disks.	MPlayer Microsoft Windows Media Player RealPlayer VideoLAN VLC Media Player

Image file formats

File format extension	File format name	What is it?	Programs that use this format
.ai	Adobe Illustrator File	Represents a vector^ graphic on a single page typically stored in .pdf format. Image quality is not lost if the user enlarges the image.	Adobe Illustrator Adobe Reader Adobe Photoshop
.bmp	Microsoft Windows Bitmap	Represents a raster^^ image that is used for the storage of bitmap digital images separate from the display device. Stored as 2D images of various dimensions, colours, and colour depths. Not compressed or they undertake lossless compression thus making them large files and generally undesirable for uploading, sending or downloading files. The term ‘bitmap’ derives from the computer programming idea of a map of bits.	Adobe Photoshop Microsoft Paint Microsoft Photo Editor
.gif	Graphics Interchange Format	Popular due to their abilities to animate bitmap images. Not all .gif files are animated; many logos and images with sharp, defined lines and edges, and a transparent background utilize the .gif extension. Undertake lossless compression. File can be converted to another file type without loss of quality. The number of colours needed in the image is reduced by removing the colour not being used in the image thus fewer colours lead to more efficient compression of the file.	Adobe Photoshop Microsoft Windows Photo Gallery Viewer Apple Preview
.jpeg	Joint Photographic Experts Group	Provide convenience when sending over the internet due to their lossy compression. Images are reordered in a way that only a small part of the image is downloaded thus presenting a hazy view of the entire image rather than a crisp part or just a small part of the image. The degree of compression can be adjusted to achieve the desired trade-off between file sizes and visual quality.	Adobe Photoshop Corel Paint Shop Pro Apple Preview Microsoft Windows Photo Gallery Viewer
.png	Portable Network Graphics	Is a bitmapped image format that is lossless compressed. Originally formatted to take over the .gif format as they both have the ability to display transparent backgrounds however .png does not support animation.	Microsoft Windows Photos Microsoft Paint Adobe Photoshop CC
.psd	Adobe Photoshop Document	Allows users to edit images using layers. These layers are used to allow elements to be added and removed easily as well as different filter, effects, transparencies and more to be applied to an image. When image is complete, Photoshop allows the user to flatten the layers and converts the flat image into a .jpeg, .gif, .tiff or other non-proprietary file formats so it can shared. Once flattened by conversion it cannot be converted back to the .psd file format.	Adobe Illustrator CS6 Adobe InDesign CS6
.tiff	Tagged Image File Format	Stores raster images and is able to support colour depths from 1-24bits and both lossy and lossless compression.	Microsoft Windows Photos (Windows) Apple Preview (Mac) Adobe Photoshop Elements & Illustrator (Windows & Mac)

^Vector images are based on mathematical formulas that define geometric primitives such as polygons, lines, curves, circles and rectangles. They are best used to represent more structured images such as line art graphics with flat, uniform colours including logos, letterheads, and fonts.

^^Raster images is an image file that is defined by a pixel that has one or more numbers associated with it. The number defines the location, size or colour of the pixels.

Internet related file formats

File format extension	File format name	What is it?	Programs that use this format
.html	Hypertext Markup Language with a client-side image map	HTML is used to create electronic documents (called pages) that are displayed on the World Wide Web and contains hyperlinks that connects other pages. Every web page is written using one version of HTML code and ensures the proper formatting of text and images so that the Internet browser may display them as they are intended to look. HTML provides a basic structure of the page upon which Cascading Style Sheets+ (.css) are overlaid to change its appearance.	Internet Explorer Mozilla Firefox Google Chrome
.jsp	Java Server Page	Allows for the generation of dynamic web pages using the Java Programming Language and is server-generated.	Adobe Dreamweaver (Windows & Mac) Apple Safari (Mac) Mozilla Firefox & Google Chrome (Windows, Mac & Linux)

+Cascading Style Sheets (.css) refers to a language used to specify the presentation of a document on web page thus being able to change the layout, colour, font, images and more. This allows improved content management, flexibility and accessibility of the webpage information. Also a single .css file can be linked to multiple pages allowing the same formatting, organization and appearance of all the pages at the same time.

Compressed file formats

File format extension	File format name	What is it?	Programs that use this format
.7z	7-zip Compressed Archive File	Free, open source software used to compress and uncompress files. Useful for the storage and sending/receiving of large files or groups of files.	7Zip WinRAR WinZip
.rar	Roshal Archive	Used for data compression, error recovery and file spanning. Most common file extensions are .rar (for compressed files) and .rev (for recovery files).	7Zip WinRAR WinZip
.zip	ZIP Compression	Archive file format utilized for the lossless compression of one or more pieces of data. Each file in a Zip compressed folder is compressed individually not as the whole archive.	StuffIt WinRAR WinZip