The most important in web interface design are images, audio and video to get attraction from user. The image that use in website should be relatively small and the typical size for a web photo is 640X480 in pixels and 72 dots per inch. We can use the sound effectively in web page because some people like to hear music when they serve the web page. Before a user can play a downloaded sound file, they must have appropriate software for that file format installed on their computer. The most popular standard sound file format :
1) WAV - develop for use with Microsoft Windows
2) MIDI - used for background music in web because of small files
3) AU- designed for used on Sun UNIX system.
4) AIFF - develop for Apple Macintosh
5) MPEG - modern, professional-quality- can be played on Windows, UNIX and Macintosh systems.
6) RA - supplying "streaming" audio over the web.
The most commonly used video file formats on the web are; (1) Quick Time ( filename.mov) used for Windows and Macintosh, (2) AVI (filename.avi) used for windows, (3) MPEG (filename.mpg) professional quality video for all pc.
-Playing streaming video (.mpeg, .avi) and audio (.mp3)
Playing audio and video with graphic
Playing streaming audio and video - RA , RAM, RM
The codec is the algorithm that handles the compression of video or audio, as well as the decompression when it is played. The user must have an appropriated plug in or helper application before they can view the movie clip :
1) Netscape Navigator 3.0 Gold
2) a plug-in for viewing AVI video
3) "streaming" video format (similar to the Real Audio streaming format)
4) "Server push" can deliver real-time live video and no requirement for special browser plug-ins or viewing application.
Images, Audio and Video for Website
Audio Usage in Web Environment
The purpose of audio usage in Web is to show the idea through informative communication process, background sound and to improve navigation system through sound integration, special effect or user guide.
How the audio technology can be use in web development ?
1. Showing through webcasts (life) - such radio channel, games, entertainment, lecture etc.
2. To add attraction with background music, background sound and special effect.
3. e-Commerce - selling MP3, audio CD etc.
4. Audio on demand - talking, lecture and etc.
There are many of audio can be use through web such audio digital (.WAV, .AIF, .AU), integration audio with program development (flash, authorware) and video integration (quicktime, AVI, MPEG). The audio technology through website's are :
MP3 is a patented digital audio encoding format using a form of lossy data compression. It is a common audio format for consumer audio storage, as well as a de facto standard of digital audio compression for the transfer and playback of music on digital audio players. Audio quality for MP3 depends on how many kilobits the file may use per second of audio. Using a lower bit rate provides a relatively lower audio quality and produces a smaller file size. Likewise, using a higher bit rate outputs a higher quality audio, but also results in a larger file. MP3 file 12X smallest than audio conventional file such wav , aiff etc. The MP3 always use for downloading music or song and almost 4mb for each song with 4-5 minutes long.
Real Media is a multimedia container format and it is typically used in conjunction with Real Video and RealAudio and is used for streaming content over the Internet. The file size is smallest than MP3 file but with low quality. It’s always use for music, speech, seminar etc. One of advantage is it can prevent user to downloading available file
MIDI (Musical Instrument Digital Interface) allows computers, synthesizers, MIDI controllers, sound cards, samplers and drum machines to control one another, and to exchange system data. MIDI does not transmit an audio signal or media but it transmits "event messages" such as the pitch and intensity of musical notes to play, control signals for parameters such as volume, vibrato and panning, cues, and clock signals to set the tempo. As an electronic protocol, it is notable for its widespread adoption throughout the industry. MIDI files are very small. Even complex and pretty long MIDI compositions are rarely over 200 Kbytes in size, and many of them are much smaller. Because of small file size, it can be download very fast and always use for background music for website. MIDI files are special. Indeed, they can be used for creating music, but not in the same way as MP3 files. While MP3 files contain digitalized audio data, which allows to store any sound found in the real world (no matter how complex it is), MIDI employs a completely different solution which MIDI can save data in music note only (without sound).
Several factor that influence data rate transfer through website. The first factor is speed of internet line which high speed of internet line will give good quality for user. Second is the file size and audio quality. If the file size of audio big, the time for downloading also take a long time. A high quality of audio can make the file size also high. Third is compression data technique with format file used and the technology of audio. The conventional technology (downloading) should download completely before it can be play by user. But the new technology (streaming), the user can play the audio before the downloading process complete. Several audio that use streaming is MP3, Active Streaming Format (ASF) and Real Audio. Beside of advantages that user can get from audio technology through website, the user also have several problem in audio usage through web. The standard always change with technology development and every technology need to different server.
