Computer File Types COMPUTER FILE EXTENSIONS ..................................................................................................................2 TAKING CONTROL OF DEFAULT FILE PLAYERS ...............................................................................3 AUDIO FILES ......................................................................................................................................................3 UNCOMPRESSED .................................................................................................................................................3 COMPRESSED DOWNLOAD FILES ......................................................................................................................4 STREAMING FILES ..............................................................................................................................................4 VIDEO FILES ......................................................................................................................................................5 UNCOMPRESSED .................................................................................................................................................5 DOWNLOAD FILES ..............................................................................................................................................5 CONTAINER MEDIA FORMATS ..................................................................................................................6 WINDOWS FILE TYPES ..................................................................................................................................7
© NBEC/NWOCA 2006
1
training.nwoca.org
Computer File Extensions Computers use file types to designate which program CREATED the document and which applications can OPEN the Document. Many applications are capable of opening multiple types of files. Each file when downloaded will have an extension which is made up of letters and numbers. e.g. Cat.mp3 When you download a file of this type it will automatically open in the default player. Problems that occur with this usually arise each time you install or update your media player on your computer. You may get a message like "Windows Media Player can be used for multiple file types, do you want to change the default player for the following file types" In this case Windows Media Player is asking to become the default (main) player That will be used whenever that file type is encountered. In the battle for domination in the world of video and audio downloads, there have been 3 main competitors. 1. iTunes – available for Macs and PCs has become popular because of its integration with the Apple iPod and its support of Podcasting and conversion to other file types. It is included with all macs and is free to download from Apple. The underlying technology for iTunes is Apple Quicktime which is installed by default when iTunes is installed on your computer. 2.
Windows Media Player (WMP) is the player from Microsoft, it currently supports the Windows Media 10 format and is the underlying technology used in Windows Movie Maker.
3. The last main Application still popular on websites is Real Player aka Real One
© NBEC/NWOCA 2006
2
training.nwoca.org
Taking Control of Default File Players A good starting point to see which applications are handling which file types is to look in your Windows Media Player or iTunes Options and view the Default File Types options.
Windows Media Player
Quicktime Player
You can manually uncheck some file types that you do not want the player to play. An example of this might be to let iTunes handle MP3s and WAVs while Windows Media Player can do the WMV and ASF / ASX files. Now you can have both these players on your computer. It is up to you to decide which one you prefer.
Audio Files Your computer is capable of playing audio files using one of the players indicated in the previous section. Most of these file types will be container files (see container files below) Audio files can be categorized as compressed or uncompressed and as download files or streaming files.
Uncompressed • •
WAV (RIFF file format, widely used on Windows platform) AIFF (AIFF file format, widely used on Mac OS platform)
© NBEC/NWOCA 2006
3
training.nwoca.org
Compressed Download Files Downloaded files contain the entire song or audio clip and may come in a number of different formats. File Type MPEG-1 Audio Layer 3 MPEG-4 AAC File MIDI Files
Extension .mp3 .mp4 .m4a .m4b .m4p .mid
Players iTunes,, WMP, Real iTunes, WMP, Real iTunes, WMP, Real Quicktime WMP Real
Streaming Files Streaming media is media that is consumed (read, heard, viewed) while it is being delivered. Streaming can be compared to listening to the radio. The music/audio downloads to your computer plays then is deleted. You only have the part you are listening to on your computer. The file is buffered (pre-downloaded) and when enough of the file is downloaded it begins to play the file. As you listen, more of the file is downloaded and the part already played is deleted.
• • •
Apple Quicktime Microsoft Windows Media Real Audio
.mov .asx .asf .ra .ram
The main thing to know about these files is that there is no really easy way of saving the files on your computer to use later. They cannot be embedded directly in a Powerpoint or used in a Movie project.
© NBEC/NWOCA 2006
4
training.nwoca.org
Video Files Video files are much the same in nature as audio files, the exception is that of course the file sizes are much larger. These files can also be compressed or uncompressed and can be download or streaming files.
Uncompressed Video captured without any compression can be very large in file size (approx 200Mb per minute of video) For this reason it is not common to find these files on the internet. Quicktime Digital Video Stream Windows Media Video Stream
.dv .avi
Download Files File Type Quicktime Movie Windows Media Format Macromedia Flash
© NBEC/NWOCA 2006
Extension .mov .wmv .mpeg .swf
5
Players Quicktime WMP Flash Browser Plugin
training.nwoca.org
Container Media Formats A container format is a computer file format that can contain various types of data, compressed by means of standardized codecs. The container file is used to be able to identify and interleave the different data types.
This Quicktime movie shows the codecs used in this file as H.264 (Video) and AAC (Audio) You can also see the size 720 x 480 is the regular widescreen resolution for Final Cut Pro and iMovie HD. Now the file produced in the above example will be a container file format that will play in Quicktime Player. It could be .mov or .mp4 More on Containers (From WIKIPEDIA) You can read some more on containers here. Clicking the links will take you to a WIKIPEDIA page on that topic. Some containers are exclusive to audio: • •
WAV (RIFF file format, widely used on Windows platform) AIFF (AIFF file format, widely used on Mac OS platform)
Other flexible containers can hold many types of audio and video, as well as other media. The most popular multi-media containers are: • • • • • • • • •
AVI (the obsolete standard Microsoft Windows container, also based on RIFF) MOV (standard QuickTime container) MPEG-2 TS (acronym of Transport Stream, standard container for digital broadcasting) MP4 (standard container for the MPEG-4 multimedia portfolio) Ogg (standard container for Xiph.org codecs) ASF (standard container for Microsoft WMA and WMV) RealMedia (standard container for RealVideo and RealAudio) Matroska (not standard for any codec or system, but it is an open standard). 3gp (used by many mobile phones)
© NBEC/NWOCA 2006
6
training.nwoca.org
Windows file types You may find many different file types used on your computer here is a list of some of the most commonly found ones. The bolded ones are used in the NWOCA academy. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
AAC Audio File - .aac AutoIt Version 3 File - .au3 Bitmap Image File - .bmp, .dib, .rle Microsoft Word File - .doc Executable File - .exe Adobe Photoshop Eps File - .eps Macromedia Flash Project File - .fla Hyper Text Markup Language File - .html, .htm Jpeg Image File - .jpg, .jpe, .jpeg, .jfif MPEG Layer 3 file - .mp3 MPEG Layer 4 file - .mp4 Windows movie file - .mpeg Windows Movie Maker Project File - .mswmm Portable Bitmap File - .pbm, .pgm, .ppm, .pnm, .pfn PHP File - .php Pict File - .pict, .pct Pixar File - .pxr Png Image File - .png Microsoft PowerPoint File - .ppt Large Document File - .psb Adobe Photoshop File - .psd, .pdd Adobe Photoshop Raw File - .raw Sim City 4 Save File - .sc4 Scitex CT File - .sct Macromedia Flash Movie File - .swf Targa File - .tga, .icd, .vst, .vda Temporary File - .tmp Tiff Image File - .tif, .tiff Basic Text File - .txt Wave Music File - .wav Xml Structured Data / Databse File - .xml
© NBEC/NWOCA 2006
7
training.nwoca.org
