A file format is the specific way information is encoded so that it can be stored as a computer file. An image might be encoded in the JPG, PNG, GIF or TIF format, among others. A generic text file might be encoded and stored as a TXT file. Every computer application has its own way of encoding and saving files; some of these are proprietary, meaning they are specific to the software application that created it, and can only be opened by that particular application. For example, you can’t use Microsoft Word to open an Adobe Photoshop document (.PSD). Also, even though they are both audio files, an .AUP file can only be opened by Audacity and a .BAND file can only be opened by Garage Band. It is only after the audio files are published and saved in generic file formats like .AIFF, .WAV or .MP3, that other applications can also open and import these files.
There are too many file formats to cover all of them in this post. If you ever come across a file that was saved or published in a file format that you don’t recognize or can’t open, you can always visit the Wikipedia article that provides a list of file formats. It doesn’t tell you every application that can open each file format. But it might be able to help.
Image File Types
EPS is an Encapsulated PostScript file. At one time EPS files were probably the most common file format for saving vector graphics. There may be a few professional printing houses that still prefer to use EPS files. Consequently, if you hire a graphic designer to design or a logo or business for example, some of your published files could possibly be delivered using the EPS file format. In general, the EPS file format is not used to save a continuous tone image (photographs), as there are much better options available. But it is good for text, logos and graphics that are created as vector graphics in programs like Adobe Illustrator.
GIF stand for Graphics Interchange Format. It used to save images for the web. The GIF file format is also quite old and becoming ‘extinct’ because it can only support a maximum of 256 colors, as opposed to millions of colors that JPEGS and PNG files can support.However it can publish small animations known as “animated GIFs.” It can also produce images with a transparent background, although the quality is very inferior compared to PNG files that also support transparent background.
A JPG file format (Joint Photographic Experts Group) is probably the most commonly used file format to save images for the web. The great news about the JPG (or JPEG) file format (as opposed to GIF) is that it supports millions of colors. However, it cannot produce images with a transparent background, and is a “lossy” file format. What “lossy” means is that every time you save a JPEG file, you lose some of the detail, quality and color in that photograph. One way around this is to never save and re-save a JPEG file. Keep a high quality version of the file and work with copies of that file as opposed to constantly opening and re-saving the original file.
A PDF file is also known as a Portable Document Format. It is commonly used to save documents that are published and shared on the Internet because it is virtually impossible to change the content of the file once it has been published.It is also used to send files to printing houses as they quality of the text and images can be very very good. Consequently, if you hire a graphic designer to design a business card, or brochure, etc., you will more than likely receive that file in a PDF format to which you would send it off to the printing house to be printed. A PDF file can be created in applications like InDesign, PhotoShop and even Microsoft Word, and then published as a PDF file.
PNG stands for Portable Network Graphics, and is becoming the most popular file format for publishing images to the Internet. It displays millions of colors like JPEGs and can produce images with transparent backgrounds like GIFs. However, the PNG file format is not “lossy,” meaning you can save and re-save a PNG file and there will be no loss of quality with the image.
TIFF or TIF stands for Tagged Image File Format. It is a another high quality format for saving raster or bitmap images like photographs. It is usually a much higher quality file format over jpg or even PNG, so is often times the file format used for high quality print publications like magazines. However, you cannot publish a TIFF file to the Internet.
Image File Formats Specific Applications
Sometimes you may run across an odd file format that you can’t open and don’t know what to do with. These file could be encoded to open with specific applications and have not yet been published as one of the generic file formats mentioned above. The more common ones are listed below.
An AI file has been created with a vector-based drawing application called Adobe Illustrator. It requires Adobe Illustrator to open and/or edit it. However, you may be able to open a file saved as an AI using the free vector drawing software named Inkscape or import it into Photoshop. If you hire a graphic designer to design a logo, you may receive the logo as an AI file, along with PDFs, EPSs, and PNGs. This is actually something you should require, as it allows the file to be opened and edited in the future, if needed.
A PSD file is created with probably the most common image editing program, Adobe Photoshop or Photoshop Elements. It requires one of these application to open and edit it. You may be able to open a PSD file using a free image editing software called GIMP.
Audio File Formats
An AIFF (Audio Interchange File Format) is a typical uncompressed audio file format used on the Macintosh operating system. Because AIFF files are not compressed, it is not recommended you publish them to the web. Since they aren’t compressed, AIFF’s (and WAV’s) are great for editing audio using and an editor like Audacity or Adobe Audition. However, their file sizes are usually much larger than compressed file formats and are not recommended for sharing or publishing to the web.
An MP3 is a digital file format for encoding audio files. MP3 is a lossy or compressed file format so it is great for publishing to the web. Most modern web browsers can play MP3′s as well as common audio players found on any computers and mobile devices.
An M4A file is an MPEG4- audio file. The M4A is a higher quality file than the MP3, and is compressed to a smaller file size. The advantage that MP3′s have over M4A’s is that since it is an older format for compressing and saving audio, an MP3 is more compatible than an M4A. Of the two (MP3′s and M4A’s), MP3′s are considered more universal, however since it is a compressed file format, it is suitable for publication to the web. M4A’s are becoming more common, but they are still not as common as MP3′s.
Similar to an AIFF file for the Macintosh, a WAV file is the audio file format used on Windows operating systems. However, most Macintosh computers can also open and play these files. WAV files are audio files that are not compressed and can sometimes be quite large – too large for publishing to the web. However, they are great to use in audio editing applications like Audacity and GarageBand.
Software Specific Audio File Formats
There are a few software specific audio file formats that are created by audio editing applications. Until the files are published as one of the generic audio file formats listed above, if you come across one of these files, they must be opened by the application that created them.
.AUD files are Audacity files. Audacity is a free audio editing software that can be used for both the MAC and PC. If you want to use Audacity to publish MP3 files, you’ll also need to download and install the LAME MP3 encoder.
.BAND files are raw audio files created by Apple’s GarageBand, a free audio editing application for the Macintosh operating system.
Video File Formats
AVI is a video file format has been around since the beginnings of digital video, and was introduced by Microsoft. You may have an older video camera that produces the raw and unedited video as an AVI file. But the newer ones will not. If you are a Windows users, you may have several of AVI files on your computer. AVI has become less common in recent years because other file formats can save video at a much higher quality.
One important note about AVI files (and MOV files): they aren’t actually a file format, but actually a container that holds the various ways a video file might be saved. I know this is confusing…and video in and of itself is much more complex that other types of files. When you save a video file, you aren’t just saving it. You have to encode and compress it with what is known as codecs. The problem with codecs is that your computer probably only as a very limited number and type installed on it. Consequently, you can’t open each and every video file you run across because you may not have the correct codecs installed. In terms of AVI files (and MOV), there is a slight chance that you cannot open it because it was published using a codec that you don’t have installed on your computer. Codecs are one of the more confusing aspects about working with video. I talk more about them below.
Codec or Video Codec is a device or software that enables compression or decompression of digital video (Wikipedia). The compression of video using a codec is usually lossy, meaning some quality, detail and sharpness is lost during the compression process. If you think of the file format as a container, that container can hold many different types of data that will control how the audio plays, how the video is compressed, how the 2 sync up with one another, and so on. There are dozens if not hundreds of different codecs out there and unless you are a video editor, I’m fairly certain your computer does not have all of them. Consequently, you may be able to open one MOV or AVI file and not another because of the codec that was used to save and compress the video file.
FLV and F4V are Flash video files used to deliver video on the Internet. They can only be viewed using the Adobe Flash Player. Videos published to webpages using the FLV or F4V formats will not play on most mobile devices.
H.264 is not a file format. However it is probably the most common video codec for publishing videos to the Internet. H.264 is able to compress video for the Internet, and at the same time, produces high definition (HD) video that retains a great deal of detail and sharpness.
MOV files are native to Apple’s QuickTime and can be shared across platform using QuickTime. Like Microsoft’s AVI files, they aren’t really a file format, but more of a container. The files are usually quite large and many people won’t be able to view a MOV file. Consequently, it is not recommended you publish MOV files to the Internet.
MP4 and MPEG-4 files are high-quality compressed video files that are commonly published to the Internet. You should be aware that the MP4 file format is “lossy,” meaning that quality, color and details will be lost during the compression process. Consequently it is not a good idea to save and re-save an MP4 file. Because they are compressed, MP4 files are great for publishing video to the Internet. They are typically much smaller in file size than AVIs and MOVs. MP4s can be viewed by all modern web browsers and most mobile devices.
A WMV file is a Windows Media Video. It is native to the Windows Operating System and consequently should not be used to publish video to the web as not everyone will able to view it. A video file published as a WMV is usually compressed. There can be a huge loss of quality when saving a video file as a WMV and is probably one of the worse file formats if you’re trying to retain quality, sharpness and detail in a video.
Publishing Video to the Web
To summarize, you don’t have to be a video expert to publish video to the web. You just need to understand a few basic rules.
- Not all video file formats are universal or can be viewed by everyone on the Internet
- Even though they are very common, AVI and MOV files are not considered universal, and not recommended for the Interent. However, you may be able to upload these types of files to video hosting websites like YouTube and Vimeo. But they don’t actually publish the video as an AVI or MOV. They convert the file to an MP4.
- FLV and FV4 files are universal file formats for regular Internet viewing on a desktop computer. However, mobile devices cannot typically view these files.
- MP4 and MPEG-4 files are considered “universal” for most modern web browsers and mobile devices. When saving a file as an MP4 or MPEG-4, if at all possible, use the H.264 codec which makes the file size quite small (good for Internet viewing) yet retain its detail and high quality.