There is no "right" answer to this question. Many different video file formats promise to deliver the highest quality video at the smallest possible size; however, the real issue usually becomes what file format is supported by the majority of your visitors.
Here is a summary of some of the most common video formats along with the pros and cons of each:
Flash Video Format
File Extensions:.swf, .flv
Pros: Flash video is the best choice for web-based video in most cases because it is supported by browsers used by nearly 96% of web users. It can produce high-quality video / audio while maintaining a relatively small file-size, and the Flash plugin installed in your browser offers "client-side streaming" (that is, Flash can manage video buffering within your browser as well as selectively compromise quality to maintain consistent playback) if video files are not being servered from a streaming server.
Cons: You will need to purchase an application to encode / compress your videos in Flash format. If you are encoding your video files in .flv format you will need to have a .swf-based player on your server in order to playback the .flv files.
For information on how to embed Flash video on your pages, please see the following article in our knowlegebase:
File Extensions: .mov
Pros: Produces clear, low-bandwidth video files on par with Flash in terms of quality. All Mac users will have support for Quicktime on their computers. If you have a Mac, you can encode Quicktime videos through iMovie without purchasing a separate application.
Cons:If Windows users do not already have Quicktime installed on their computer, they will have to navigate to Apple's site, download and install Quicktime, then restart their browsers before they can view your video. Worse yet, Apple does not offer Quicktime as a standalone plugin--you must install iTunes as well. Less technically savy users installing either iTunes or Quicktime can inadvertantly set iTunes or Quicktime as their default media player. Also, you will need to purchase an application to encode your videos in Quicktime format if you have a Windows machine. Mac users can use the built-in iMovie application to export Quicktime video files, or for more control, purchase Quicktime Pro.
For information on how to embed Quicktime video on your pages, please see the following article in our knowlegebase:
File Extensions: .wmv
Cons: All Windows users will have support for Windows Media file playback on their computers, though they may be required to update their version depending on the version of Windows Media you use to encode your video. If they do not already have Windows Media Player for Mac installed on their computer, Mac users will have to navigate to a Windows site, download and install Windows Media Player before they can view your video.
For information on how to embed a Windows media-encoded video on your pages, please see the following article in our knowlegebase:
File Extensions: .rm, ram
Pros: Player-based support for multiple formats, including many Quicktime and Flash-encoded videos. Produces high-quality video with small file sizes that can be streamed. Supports SMIL 2.0 for creating interactive multimedia.
Cons: Very few users have Real Player installed, and will need to install it before viewing your video. It is quite easy for a user to inadvertantly assign Real Player as their default media player during the install process. Although Real Player was one of the early web-based media plugins, they have not really kept up with the progress of Flash and Quicktime. You will have to purchase a software to compress your video in Real Media format (Helix).
For information on how to embed Real Media on your pages, please see the following article in our knowlegebase:
Audio Video Interleave (AVI)
File Extensions: .avi
AVI is in fact not a video encoding, but rather a generic file extension that is used to indicate a video file, and it may be encododed in a variety of different ways. Many people mistakenly think that because .avi files may be played by a wide variety of media players they are the best format to use. This could not be further from the truth, however--any player will try to play a .avi file, even if it lacks the proper codec to play it. For example, if you embed a .avi file encoded using DivX on your site, and I visit your site with Windows Media Player installed as the default application for all of my multimedia, Windows Media will try to play the file, then notify me that it does not have the appropriate codec installed to handle the file--even if another player on my machine could play the file.
File Extensions: .avi
Pros: Quality video at a fairly small file size.
Cons: Not a legal CODEC. Supposedly reworked from the stolen source code of a pre-release version of the Windows Media 9 CODEC (Widows version of MPEG-4). Many players do not support this CODEC, but because it utilizes the generic .avi file extension, most media players will try to play it, then fail if they do not have the CODEC installed. DivX is also associated with many applications used to rip and re-encode DVDs. If there is a specific reason you need to utilize a DivX-like CODEC, Xvid offers a completely rewritten, open-source version of the CODEC.