Tuesday, 25 December 2012

Introduction of Database

What is Database?

A database is a collection of information that is organized so that it can easily be accessed, managed, and updated. In one view, databases can be classified according to types of content: bibliographic, full-text, numeric, and images.
In computing, databases are sometimes classified according to their organizational approach. The most prevalent approach is the relational database, a tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways. A distributed database is one that can be dispersed or replicated among different points in a network. An object-oriented programming database is one that is congruent with the data defined in object classes and sub classes.
Computer databases typically contain aggregations of data records or files, such as sales transactions, product catalogs and inventories, and customer profiles. Typically, a database manager provides users the capabilities of controlling read/write access, specifying report generation, and analyzing usage. Databases and database managers are prevalent in large mainframe systems, but are also present in smaller distributed workstation and mid-range systems such as the AS/400 and on personal computers. SQL (Structured Query Language) is a standard language for making interactive queries from and updating a database such as IBM's DB2, Microsoft's SQL Server, and database products from OracleSybase, and Computer Associates.

Wednesday, 5 December 2012

What is Multimedia?

Multimedia comes in many different formats. It can be almost anything you can hear or see.
Examples: Pictures, music, sound, videos, records, films, animations, and more.
Modern Web pages have often embedded multimedia elements, and modern browsers have support for various multimedia formats.
In this tutorial you will learn about different multimedia formats.

Browser Support

The first Internet browsers had support for text only, and even the text support was limited to a single font in a single color. Then came browsers with support for colors, fonts and text styles, and support for pictures was added.
The support for sounds, animations, and videos is handled in different ways by various browsers. Some multimedia elements is supported, and some requires an extra helper program (a plug-in).
You will learn more about plug-ins in the next chapters.

Multimedia Formats

Multimedia elements (like sounds or videos) are stored in media files.
The most common way to discover the type of a file, is to look at the file extension. When a browser sees the file extension .htm or .html, it will treat the file as an HTML file. The .xml extension indicates an XML file, and the .css extension indicates a style sheet file. Pictures are recognized by extensions like .gif, .png and .jpg.
Multimedia files also have their own formats with different extensions like: .swf, .wav, .mp3, and .mp4.

Video Formats

Videoformats        MP4 is the new and upcoming format for internet video. It is supported by YouTube, Flash players and HTML5.
AVI.aviAVI (Audio Video Interleave) was developed by Microsoft. AVI is supported by all computers running Windows, and by the most popular web browsers. It is a very common format on the Internet, but not always possible to play on non-Windows computers
WMV.wmvWMV (Windows Media Video) was developed by Microsoft. WMV is a common format on the Internet, but it cannot be played on non-Windows computer without an extra (free) component installed. Some later WMVs cannot play at all on non-Windows computers because no player is available
The MPEG (Moving Pictures Expert Group) format is the most popular format on the Internet. It is cross-platform, and supported by all major browsers
QuickTime.movQuickTime was developed by Apple. QuickTime is a common format on the Internet, but QuickTime movies cannot be played on a Windows computer without an extra (free) component installed.
RealVideo was developed by Real Media. RealVideo allows streaming of video (online video, Internet TV) with low bandwidths. Because of the low bandwidth priority, the quality is often reduced
Flash was developed by Macromedia. Flash requires an extra component to play. This component comes preinstalled with all major browsers
MP4.mp4Mpeg-4 (MP4) is the new format for the internet. YouTube recommends using MP4. YouTube accepts multiple formats, and then converts them all to .flv or .mp4 for distribution

Sound Formats

MP3 is the newest format for compressed recorded music. The term MP3 has become synonymous with digital music. If your website is about recorded music, the MP3 format is the choice.
MIDI (Musical Instrument Digital Interface) is a format for electronic music devices like synthesizers and PC sound cards. MIDI files do not contain sound, but digital musical instructions (notes) that can be played by electronics (like your PC's sound card).Click here to play The Beatles.
Since MIDI files only contains instructions; they are extremely small. The example above is only 23K in size, but it plays for nearly 5 minutes. MIDI is supported by many software systems/platforms. MIDI is supported by all the most popular Internet browsers.
MP3.mp3MP3 files are actually the sound part of MPEG files. MPEG was originally developed for video by the Moving Pictures Experts Group. MP3 is the most popular format for music. The encoding system combines good compression (small files) with high quality
RealAudio was developed Real Media. It allows streaming of audio (online music, Internet radio) with low bandwidths. Because of the low bandwidth priority, the quality is often reduced
WAV.wavWAVE (more known as WAV) was developed by IBM and Microsoft. WAVs are compatible with Windows, Macintosh, and Linux operating systems
WMA.wmaWMA (Windows Media Audio), compares in quality to MP3, and is compatible with most players, except the iPod. WMA files can be delivered as a continuous flow of data, which makes it practical for use in Internet radio or on-line music.

Introduction of Multimedia

What Is Multimedia?

Lecturer Note for chapter 5

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