Summary: The default player on your computer (Windows Media Player on the PC, QuickTime on the Mac) will take care of most of your video playing needs. However, we recommend you get a universal player like VLC, which plays a huge variety of files and can even act as a DVD player for your computer.
Playing video on your computer
Windows computers have the Windows Media Player, Apple OS X has the QuickTime Player, and then there is everything else. There are probably hundreds of programs that can play digital video files, but there are numerous video formats that make it hard to have just one player that plays them all. The VLC player comes close, and is one of our favorite universal players because of the numbers of different formats that it plays. And it’s free. There is the occasional new format that appears on the scene, and then there are all the old formats that exist that people still want to play. Thankfully, these software programs can be updated to keep up with the new and still play the old.
The use of the word “format” in the previous paragraph is a generic term that really refers to what type of video encoding is being used on the digital video file. The purpose of video encoding (compression) is generally to reduce the space that a video files takes up, either on a hard drive, or web/file server. Video compression techniques have improved over the years to enable very high quality at relatively small files sizes. Digital video is the display of images in rapid succession. Displaying uncompressed images 30 times per second, not only requires some real computer horsepower, but it would necessitate a really large file. For more information on basic video properties and an example of how big a file could get, here’s an example on Wikipedia.
Containers vs. CODECs
In order to compress a video file, you need to apply a compression algorithm to it. You need to encode it. In order for a player to play a digital video file, it needs to be able to decode the video format. In other words, it needs to decompress the file. Enter the CODEC, which is short for COmpressor/DECompressor, or more correctly enCOder/DECoder. So a player needs to be able to recognize what video codec is being used before it can play it. Since the video file will also likely have an audio component, it needs to be able to recognize the audio codec as well. Digital video files can contain many different combinations of video and audio codecs as well as possible meta data, streaming data, etc. So that data needs to be put in a wrapper or container. In general the containers are identified by their file extensions.
The longtime standard video file container for Windows computers is the AVI (Audio Video Interleaved) file, and for the Macintosh it’s a QuickTime Movie file (MOV). The file extensions are .avi and .mov respectively. Inside these containers can be any number of combinations of video and audio codecs. The Windows Media Player, and the QuickTime Player, come with a standard set of codecs that the players can work with. You can download codec “packs” for additional capabilities such as the K-Lite Codec Pack for Windows, or Perian for the Mac. Again, you could download and use VLC on either Windows or Mac OS and it would play virtually all the video files that the add-on packs would.
Sometimes the line blurs between containers and codecs. There are many iterations of MPEG format video, but the original was MPEG1. This was once a very popular format, but it has since fallen out of favor as a video format. However, MPEG1 lives on in an audio only format, MPEG1 – Layer 3. Also known as MP3 audio. Contrary to popular belief, MP3 does NOT stand for MPEG3. MPEG2 is the format used in DVDs, and some camcorders with built-in hard drives (though MPEG4/h.264 is rapidly taking over). MPEG2 files were not intended to be played directly on a computer, though the VLC program handles them just fine. Though they are not synonymous, MPEG4 and Apple’s QuickTime are often thought of together. QuickTime utilizes both the standard MPEG4 (known as “part 2” and later “part 14”) and h.264 video codecs. The h.264 Codec has one of the best quality to size ratios around. It is known as “part 10” of the MPEG4 standard and is used on many of the tape-less camcorders in the form of AVCHD video. One of the codecs used in Blu-ray video is the h.264 format. It is a licensed codec, similar to MPEG2, so software and hardware that uses h.264 needs to pay a fee to include it. There is an open source version of the encoder that creates h.264 compatible files called x.264. It is used in the popular Handbrake software, and should in no way be considered inferior to h.264.
Another type of video comes from Microsoft, the Windows Media Video format which uses the VC-1 codec (Blu-ray discs could also be encoded using VC-1 as opposed to h.264). It is in many ways the update to AVI. Microsoft standardized on WMV when other platforms were going to MPEG4 (such as Apple). It is a popular format because of the number of Windows users, but it is notorious for not playing well with Mac and Linux machines. Microsoft’s Silverlight technology is their next generation web based video, meant to compete with Adobe’s Flash video. Flash is the video format made popular by YouTube a few years ago, however MPEG4 and h.264 are beginning to surge because of mobile devices such as the iPhone and iPad. If you’re feeling a bit like it’s hard to keep up with, you’re right – it is.
The DivX format began its history as a “hacked” version of Microsoft’s first MPEG4 implementation. It was also known as a format for DVD “rips”, a way to re-encode video from a DVD to a hard drive, resulting in a smaller single digital file of a movie. The file could then be played on a variety of devices including a computer (with DivX player software), DivX certified DVD players (read from a DVD data disc), and some portable devices (notably from Archos). DivX also has a video-on-demand (VOD) version with the requisite digital rights management (DRM) for controlling distribution (i.e. piracy). DivX has recently made a push into the 4K video space and includes a player able to decoded h.265 (!!!) video, also known as HEVC.
And finally, Real video was one of the original compressed video formats for the web. Today, it is quite rare to see any Real video. However, the Real Player is still available as a universal player of many of the formats that we have talked about in this article.