If your working on a video, a song or an image for your Web site, blog, or printed materials, you’ve probably found yourself confronted with multiple acronyms when it came time to save the file. Staring at the options, you may have wondered if it really makes a difference whether the file is saved as a JPEG, MPEG a TIFF, MP3, Quicktime, AIFF an EPS or other format, as long as it looks good or sounds good.
In short, yes. For although it might seem like an inconsequential detail, different file types are best suited to different uses. While some formats are optimal for saving Web-navigation icons, for instance, they may not be the best choice for high-resolution photographs. And just because a certain format works well for online graphics doesn’t always mean it is ideal for print jobs.
As a general rule, as a producer of quality media you want to keep your files uncompressed or in it’s original state until your final render or save.
To help you understand the alphabet soup of image formats, I’ll discuss a few basic factors to consider when choosing a file type, provide an overview of some of the most common formats, and explain why you might choose each one. That way, you’ll be better equipped to make the right decision the next time you find yourself staring at your image-editing, video editing, or music writing software program’s Save As prompt.
Factors to Consider When Choosing Image File Types:
Since image files can be quite large, many formats employ some form of compression, the process of making the file size smaller by altering or removing information.
If you choose a format that uses lossless compression, no data will be removed from the image, resulting in a file that appears almost identical to the orignial, albeit much smaller. On the other hand, if you use a format with lossy compression you permanently eliminate certain information in the image but do so in a way that’s not obvious to most people. Applying larger amounts of lossy compression makes the image smaller but also degrades its appearance, so there’s a trade-off between image quality and file size.
Color depth refers to the amount of colors found in an image and is expressed in bits, the smallest unit of binary measurement. An image’s color depth can range from one bit (black and white) to 24 bits, which provides more than 16 million different colors.
Note that the more colors an image contains, the larger the file size will be. Also, be aware that even if you decide to use 24-bit color for your organization’s Web images, viewers using older hardware may not be able to view it at its intended color depth.
Common Image Formats and Best Uses
Bitmap (BMP) files are the default image format used by Microsoft operating systems and by Windows’ built-in Paint accessory. Like GIFs, JPEGs, PNGs, and TIFFs (see below for more information on these file types) BMPs are raster-based, meaning that they use thousands or millions of pixels to compose an image. Typically, BMPs do not use compression — resulting in very large file sizes— and range in resolution from one bit (black and white) to 24 bits (16.7 million colors)
Best Uses: BMPs are generally not used for Web purposes and should probably be avoided in most cases unless you just want a quick way to save images to your local machine for personal reference.
Encapsulated Post Script (EPS) files are one of the industry-standard formats used in professional printing. Many commercial graphics applications — including Adobe Photoshop (available to qualifying nonprofits for $60 from TechSoup Stock) and Adobe Illustrator (available to qualifying nonprofits for $50 from TechSoup Stock) — will output EPS files, as will free graphics-editing program Inkscape.
Best Uses: EPS is an ideal format for printing vector-based graphics, which build images using geometry rather than pixels. Because vector graphics don’t use pixels like raster graphics do, a print shop can resize them as many times as necessary without worrying that the quality will degrade. An EPS file makes a good choice for printing graphics such as logos or other jobs that don’t contain many photographs. Adobe Illustrator and Inkscape both save vector-based images as EPS files. For more background on vector graphics versus raster graphics, read TechSoup’s article Creating Web Graphics.
Commonly used on Web pages, Graphics Interchange Format (GIF) files are unlike many other popular image formats in that they only support up to 8 bits of color depth (or 256 colors). However, since the GIF format uses lossless compression, it does not noticeably degrade the original image.
Best Uses: Because GIFs contain fewer colors than other image formats, they are best suited for Web graphics with a limited color range, such as site navigational buttons and headers. However, the fact that GIFs use less color than other formats also make them smaller, meaning they’ll load faster in the user’s Web browser.
Joint Photographic Experts Group (JPEG) files provide full 24-bit color but use lossy compression. While most users won’t be able to see much difference between a moderately compressed JPEG and the original uncompressed image, a heavily compressed JPEG will appear blurry and make individual pixels noticeable.
Best Uses: As the “P” in its acronym implies, the JPEG format is optimized for use with photographs, particularly those to be posted on a Web site. Since JPEGs use 24-bit color they can accurately render a photograph’s subtleties, while the lossy compression algorithm helps achieve an economical file size.
While it’s more of a general file type than a dedicated image format, Adobe’s Portable Document Format (PDF) can be put to good use in both print and Web-based projects.
Best Uses: Because they can preserve both textual and graphic information, PDFs can be a good format for converting printed materials — such as your organization’s direct-mail newsletter — into something that’s readable on the Web. And since Adobe’s PDF-reading program, Acrobat Reader, is free to download and use, content saved as a PDF will be accessible to a large percentage of site visitors. PDFs are also efficient for smaller professional print jobs, since you can send all the images, text, and fonts to the print shop in a single document. However, to produce high-resolution PDFs that will appear professional when printed, your organization will need to purchase a program such as Adobe Acrobat Standard (available to qualifying nonprofits for $30 from TechSoup Stock).
Originally developed to replace the GIF format, Portable Network Graphics (PNG) files employ lossless compression. But unlike GIFs, PNG files can be saved in 24-bit mode to achieve a much wider range of color.
Best Uses: PNG can be a better choice than GIF for designing graphics for a site with a design that may change or for creating images that might be repurposed on multiple sites. This is because PNG supports variable transparency, meaning that individual pixels can have different degrees of transparency. Since GIFs only let you have one totally transparent color, the site’s background color must match the transparent color in the GIF. If the background color changes, the GIF will display cosmetic flaws. (Note that Microsoft Internet Explorer does not currently support PNG’s variable transparency feature.)
PSD (Photoshop Document) is the proprietary file format Adobe Photoshop uses to save projects, which can contain can any combination of photographs, graphics, and text. Finalized PSDs are usually saved as another format, such as GIF or TIFF, before being posted to the Web or sent to a professional printer.
Best uses: If your organization works with a freelance or volunteer graphic designer, it might be a good idea to get copies of the PSD files in addition to the final graphics. That way, if you ever need to make changes at some point during the road, you can modify the original files in Photoshop. While you can of course make changes to PSD files using Photoshop, programs such as Adobe InDesign (available to qualifying nonprofits for $60 at TechSoup Stock) and QuarkXPress (discounts available for nonprofits) can also tackle some PSD editing chores.
* When saving PSD’s if you turnoff hidden layers before saving you can greatly reduce file size while still preserving file.
Though Tagged Image File Format (TIFF) files can be saved completely uncompressed for maximum quality, you can also apply a lossless compression algorithm decrease file size. Like PNGs and GIFs, the TIFF format supports full 24-bit color.
Best Uses: Because TIFFs offer a high color depth and an uncompressed option, they are a superior format for printing high-resolution photographs or other pixel-based (raster) images. The vast majority of free and commercial graphics-editing applications allow you to save images in the TIFF format.
Video files are rendered, and within each of these compression types exists many different customizations having to do with internet streaming, quality, bit rate, sound, ect. All of these can be tweaked and need to be tried, to understand how they effect the quality of video and file size.
Flash Video Format (.flv)
Because of the cross-platform availability of Flash video players, the Flash video format has become increasingly popular. Flash video is playable within Flash movies files, which are supported by practically every browser on every platform. Flash video is compact, using compression from On2, and supports both progressive and streaming downloads.
AVI Format (.avi)
The AVI format, which stands for audio video interleave, was developed by Microsoft.
It stores data that can be encoded in a number of different codec’s and can contain both audio and video data. The AVI format usually uses less compression than some similar formats and is a very popular format amongst internet users.
The AVI format is supported by almost all computers using Windows, and can be played on various players.
Some of the most common players that support the avi format are:
Apple QuickTime Player (windows & Mac)
Microsoft Windows Media Player (Windows & Mac)
VideoLAN VLC media player (Windows & Mac)
Quicktime Format (.mov)
The QuickTime format was developed by Apple and is a very common one. It is often used on the internet, and for saving movie and video files.
The format contains one or more tracks storing video, audio, text or effects. . It is compatible with both Mac and Windows platforms, and can be played on an Apple Quicktime player.
MP4 Format (.mp4)
This format is mostly used to store audio and visual streams online, most commonly those defined by MPEG. It Expands MPEG-1 to support video/audio “objects”, 3D content, low bit rate encoding and support for Digital Rights Management.
The MPEG-4 video format uses separate compression for audio and video tracks; video is compressed with MPEG-4 video encoding; audio is compressed using AAC compression, the same type of audio compression used in .AAC files.
The mp4 can most commonly be played on the Apple QuickTime Player or other movie players. Devices that play p4 are also known as mp4 players.
Mpg Format (.mpg)
Common video format standardized by the Moving Picture Experts Group (MPEG); typically incorporates MPEG-1 or MPEG-2 audio and video compression; often used for creating downloadable movies. It can be played using Apple QuickTime Player or
Microsoft Windows Media Player.
Windows Media Video Format (.wmv)
WMV format, short for Windows Media Video was developed by Microsoft. It was originally designed for internet streaming applications, and can now cater to more specialized content. Windows Media is a common format on the Internet, but Windows Media movies cannot be played on non-Windows computer without an extra (free) component installed. Some later Windows Media movies cannot play at all on non-Windows computers because no player is available.
Videos stored in the Windows Media format have the extension .wmv.
3GP File Extension (.3gp)
The 3gp format is both an audio and video format that was designed as a multimedia format for transmitting audio and video files between 3G cell phones and the internet. It is most commonly used to capture video from your cell phone and place it online.
This format supports both Mac and windows applications and can be commonly played in the following:
Apple QuickTime Player
VideoLAN VLC media player
As far as Audio goes for production I’ve always been a fan of using AIFF files, Their a much bigger, uncompressed and offer superb sound when rendered. I think MP3’s are great for you audio devices but I generally stay clear of a file that small in my video project.
Some of the most popular audio file formats are:
.AAC Advanced Audio Coding File was declared the new audio-file standard in 1997, designed to replace its predecessor, MP3. It provides better quality at lower bit rates, and it’s Apple’s standard iTunes and iPod audio format.
.AIF(F) Audio Interchange File Format was developed by Electronic Arts and Apple back in the ’80s. AIFF files contain uncompressed audio, resulting in large file sizes.
Apple Lossless This file format uses lossless compressions (see the definition under the Important Terminology section) for digital music. Since it stores data in a MP4 container, it has an .m4a file extension.
.MID(I) MIDI is not a true audio-file format; rather, it’s a music-device-controlling protocol to control instruments using computers – and vice versa – in real time.
.MP3 MPEG Layer 3 is the most popular digital-audio music format, designed by a team of European engineers in 1991 to conserve the quality of a song while presenting it in a small, compact file.
.OGG Ogg Vorbis compressed audio file is one of the most popular license-free, open-source audio-compression formats. It’s efficient for streaming and file compression because it creates smaller files than MP3 while maintaining audio quality.
.RA(M) Real Audio Media was developed by RealNetworks in 1995. It has a wide variety of uses, from videos to music, but is mainly used for streaming audio such as that from Internet radio stations.
.WAV Windows WAVE sound file is a an IBM- and Microsoft-developed format popular among PC computer users; it can hold both compressed and uncompressed audio.
.WMA Windows Media Audio was designed by Microsoft to be an MP3 competitor, but with the introduction of iTunes and iPods, it’s fallen far behind MP3 in popularity.
Wow there’s a lot of formats out there! It really is important to know all these and the applications they serve. So before you begin saving have a clear idea of what your going to do with your file.