By Ole Arndt

Streaming video is a sequence of “moving images” that are sent in compressed form over the Internet and displayed by the viewer as they arrive. Streaming media is streaming video with sound. With streaming video or streaming media, a Web user does not have to wait to download a large file before seeing the video or hearing the sound. Instead, the media is sent in a continuous stream and is played as it arrives. The user needs a player, which is a special program that uncompresses and sends video data to the display and audio data to speakers. A player can be either an integral part of a browser or downloaded from the software maker’s Web site.

Major streaming video and streaming media technologies include RealSystem G2 from RealNetwork, Microsoft Windows Media Technologies (including its NetShow Services and Theater Server), and VDO. Microsoft’s approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. (The program that does the compression and decompression is sometimes called the codec.) Microsoft’s technology offers streaming audio at up to 96 Kbps and streaming video at up to 8 Mbps (for the NetShow Theater Server). However, for most Web users, the streaming video will be limited to the data rates of the connection (for example, up to 128 Kbps with an ISDN connection). Microsoft’s streaming media files are in its Advanced Streaming Format (ASF).

Streaming video is usually sent from prerecorded video files, but can be distributed as part of a live broadcast “feed.” In a live broadcast, the video signal is converted into a compressed digital signal and transmitted from a special Web server that is able to do multicast, sending the same file to multiple users at the same time.

Streaming media is audio and video that are transmitted on the Internet in a streaming or continuous fashion, using data packets. The most effective reception of streaming media requires some form of broadband technology such as cable modem or DSL. A packet is the unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network. When any file (e-mail message, HTML file, Graphics Interchange Format file, URL – Uniform Recourse Locater request, and so forth) is sent from one place to another on the Internet, the Transmission Control Protocol (TCP) layer of TCP/IP divides the file into “chunks” of an efficient size for routing. Each of these packets is separately numbered and includes the Internet address of the destination. The individual packets for a given file may travel different routes through the Internet. When they have all arrived, they are reassembled into the original file (by the TCP layer at the receiving end).

A packet-switching scheme is an efficient way to handle transmissions on a connectionless network such as the Internet. An alternative scheme, circuit-switched, is used for networks allocated for voice connections. In circuit-switching, lines in the network are shared among many users as with packet-switching, but each connection requires the dedication of a particular path for the duration of the connection. “Packet” and “datagram” are similar in meaning. A protocol similar to TCP, the User Datagram Protocol (UDP) uses the term datagram.

MPEG, the Moving Picture Experts Group, develops standards for digital video and digital audio compression. It operates under the auspices of the International Organization for Standardization (ISO). The MPEG standards are an evolving series, each designed for a different purpose. To use MPEG video files, you need a personal computer with sufficient processor speed, internal memory, and hard disk space to handle and play the typically large MPEG file (which has a file name suffix of .mpg). You also need an MPEG viewer or client software that plays MPEG files. (Note that .mp3 file suffixes indicate MP3 (MPEG-1 audio layer-3) files, not MPEG-3 standard files.) You can download shareware or commercial MPEG players from a number of sites on the Web.

The term codec is an acronym that stands for “compression/decompression.” A codec is an algorithm, or specialized computer program, that reduces the number of bytes consumed by large files and programs. In order to minimize the amount of storage space required for a complicated file, such as a video, compression is used. Compression works by eliminating redundancies in data. Compression can be done for any kind of file, including text, programs, images, audio, video, and virtual reality (VR). Compression can reduce the size of a file by a factor of 100 or more in some cases. For example, a 15-megabyte video might be reduced to 150 kilobytes. The uncompressed file would be far too large to download from the Web in a reasonable length of time, but the compressed file could usually be downloaded in a few seconds. For viewing, a decompression algorithm, which “undoes” the compression, would have to be used.

There are numerous standard codec schemes. Some are used mainly to minimize file transfer time, and are employed on the Internet. Others are intended to maximize the data that can be stored in a given amount of disk space, or on a CD-ROM. Codec’s are used in many popular Internet products, including QuickTime, Netmeeting, Cu-Seeme, and VDOphone.

Flash, is a popular authoring software developed by Macromedia, and is used to create vector graphics-based animation programs with full-screen navigation interfaces, graphic illustrations, and simple interactivity in an antialiased, resizable file format that is small enough to stream across a normal modem connection. The software is ubiquitous on the Web, both because of its speed (vector-based animations, which can adapt to different display sizes and resolutions, play as they download) and for the smooth way it renders graphics. Flash files, unlike animated but rasterized GIF and JPEG, are compact, efficient, and designed for optimized delivery. Known as a do-it-yourself animation package, Flash 4 gives Web designers the ability to import artwork using whatever bitmap or illustration tool they prefer, and to create animation and special effects, and add sound and interactivity. The content is then saved as file with a .SWF file name extension.

Web users with Intel Pentium or Power Macintosh processors can download Flash Player to view Flash content, which performs across multiple browsers and platforms. Flash is lauded for being one of the Web’s most accessible plug-in. According to an independent study cited by Macromedia, over 90 percent of Web users already have Flash Player installed. Macromedia was recently acquired by Adobe in a 3.4 billion dollar deal.

About the Author: Ole Arndt is President of Global Media LLC, in Branchburg NJ.

Correspondence to: oarndt@streamingmediabiz.com

Article Source: http://EzineArticles.com/?expert=Ole_Arndt

By Mansi Aggarwal

The MP3 is a complete godsend for anyone who enjoys and appreciates good music. Not only does it afford users the convenience of purchasing music online and ripping from purchased CDs, it also provides the utmost ease in portability. There are more MP3 players on the market than I can name. These players allow you to download hundreds and in some cases thousands of MP3’s to take along with you anywhere. I create MP3 CD’s containing up to 120 of my favorite songs for my listening pleasure in my car. But how can so many audio files get stored on my 800MB (Megabyte) CD?

MP3 Encoders and MP3 converters are the software that creates MP3s by using an MP3 compression and decompression algorithm. For example, an average 3 minute WAV file can be as large as 15MB. Using MP3 encoders and MP3 converters, a large WAV file can be cut down to a much smaller and more portable MP3 file of about 3MB.

MP3 stands for MPEG Audio Layer 3. At layer 3, psychoacoustics principles are used to find and remove all unnecessary sound data, leaving behind only the crucial audio data. By unnecessary sound data I mean all of the stuff that we humans don’t hear anyway. Most people can’t hear sounds above 16 kHz so why would you want it hogging your disk or hard drive space? Non-music audio such as speeches, sermons, audio books and comedy albums, can be reduced even less based on this.

Compression occurs after the essential data has been separated from the redundant data. At this stage, the same amount of data can be stored using fewer bits and less space. The bit rate is the ratio of the number of bits transferred between two devices per second. The higher the bit rate, the higher the sound quality. The lower the bit rate ratio, the lower the sound quality. 192 Kb/s is the most popular bit rate used in peer-to-peer networks. For the most part, MP3 converters and encoders today use variable bit rates. This allows for much better quality audio because the bit rate conforms to the dynamics of the audio frames being stored which in turn keeps more of the important music data.

There are dozens of MP3 compressor and encoder software programs available online and at stores. Some of the main encoding engines are: LAME, Blade Enc, Fraunhofer Encoders and Xing. Deciding which MP3 encoding engine technology is right for you depends on your individual needs and preferences. Blaze Media Pro is an excellent option if you’re looking for a powerful, yet easy to use, all-in-one multimedia solution.

By Peter Nisbet

FILE FORMATS

There are several audio file formats in common use. There are fewer video file formats, but audio video file extensions can be confusing. This is just a brief description of what the more commonly used audio and video file formats and systems are.

AAC:Advanced Audio Coding This is the audio file format used by Apple for the iTunes Music Store, and it may appear with the M4A filename extension. It is better than MP3 for sound quality. It was developed as part of the MPEG4 group owned by Dolby (see below).

AU: This audio file format is the standard used by Java, Sun and Unix.

MPEG: Moving Pictures Expert Group There are a number of MPEG types now, described below.

MPEG-1: This is used in digital cameras and camcorders for small video clips. VHS quality playback can be expected from MPEG-1.

MPEG-2: Used for digital satellite TV, professional movie recording and recording of home DVD recordings. Provides provision for multi-channel surround sound recordings.

MPEG-3: MPEG-3 was propose as an entity, but eventually merged into MPEG-2.

MPEG-4: This is the newest MPEG system and is used for streaming internet content. It is also used in portable video recorders and for internet downloads. Required for DivX. It improves digital broadcasting and interactive graphics and multimedia.

MP3: Digital audio files, most commonly used to store and playback music. It compresses the files to about 10% of a normal audio file, and a normal music track will be about 5 -6 MB in size. MP3 stands for MPEG-1 Audio Layer 3, not MPEG-3 as many people think. A typical MP3 audio file is near CD quality.

OGG: An audio file format supporting a variety of codecs, the most popular of which is the audio codec Vorbis. However, MP3 files are much more broadly supported than Vorbis.

RA: Real Audio This format is designed for streaming audio over the Internet. It is a self-contained file format with all the audio information stored within the file itself.

WAV: The simplest of the audio file formats, developed by Microsoft and IBM, and built into Windows 95. It is an uncompressed audio file format with large file sizes (10 x MP3), and does not need further processing to play. The WAV file consists of three blocks of information: The RIFF block which identifies the file as a WAV file, The FORMAT block which identifies parameters such as sample rate and the DATA block which contains the actual data, or music sample.

WMA: Windows Media Audio A digital system invented by Microsoft, and is used in portable digital audio players. Using WMA, a file can be programmed so that it cannot be copied, and can be used to protect copyright.

WMF: Windows Media Format These are audio-video files comprising WMA and video codecs. They provide high quality and media security for streaming and download and play applications on computers.

WMV: Windows Media Video Used in the Windows media Player, this is used to stream and download and play audio and video content.

When dealing with audio and video file formats, you will sometimes notice the term ‘codec’. A codec is simply short for encoder-decoder (or compressor – decompressor). A main function of a codec is to compress audio or video data streams so that transmission of digital audio samples and video frames can be speeded up and storage space reduced.

The objective of all codecs is to reduce the file size to a minimum while maintaining audio and video quality. A quick indication of the codec’s place in the path of transmission and reception is:

Video device (e.g. camcorder) – video capture card – video digitized – codec (compresses digital info) – result (MPEG2, AVI, WMV etc) – codec (decompress) – video frames – display device.

Between the two codecs the compressed result is transferred to the display device transmitted, stored on file, etc). So to condense the flow even further, we could basically describe it as:

raw data – codec – transmit – codec – play

This is simplistic, but it shows where the codecs are used. Therefore, in order to play a movie, video or piece of music of a certain format, you need a codec in your computer to allow you to decompress the file and play it.

Here is some free software which checks what codec a video system uses, and what codec your system needs to play it:

Codec Tool.

The different video file formats are required to meet the requirements of various video devices. Similarly, audio file formats are designed to meet the needs of the specific delivery methods and storage and playback devices introduced by large corporations such as Microsoft, Sony and Apple. Thus, Sony invented the UMD (Universal Media Disk) for the PSP (Playstation Portable), and Apple introduced AAC (M4A) for its iPod.

Peter Nisbet is the author of many articles on audio and video file systems, their transmission, playback and conversion. More information is available on his websites http://www.legalandfree.com and http://www.online-free-movies.com

Article Source: http://EzineArticles.com/?expert=Peter_Nisbet