| An uncompressed digital music file (such
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| | efficient than MP3, and comparable to AAC
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| as that on a music CD) uses 10MB or more
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| | in terms of efficiency and file size
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| per minute (at least 30MB for a 3 minute
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| | reductions. WMA supports DRM, so can have
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| song).
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| | both protected and unprotected audio
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| These files have to be compressed to the
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| | files. Most devices and players support
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| more usual levels of 3-5MB per song.
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| | the unprotected WMA files - Apple iTunes
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| Compression rearranges the sequence of
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| | software can convert them to AAC files.
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| numbers, sometimes throwing away less
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| | Ogg Vorbis
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| significant information, in order to
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| | Unlike the other formats, Ogg Vorbis is a
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| reduce the file size. The way the
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| | completely open-source, patent-free,
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| compression is achieved leads to the many
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| | professional audio encoding and streaming
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| different audio file formats available.
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| | format. There are no licensing fees for
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| Below is a list of the popular formats
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| | using this codec. If you are an artist
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| used by MP3 players.
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| | that's goods news. You won't have to pay
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| MP3 (MPEG Layer 3)
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| | any fees if you distribute your songs,
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| MP3 is a perceptual audio coding
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| | which you would if you use, say, MP3. It
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| algorithm, developed by the MPEG group.
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| | is yet another lossy compression, but
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| Although its a lossy compression, the
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| | much better than MP3. An Ogg Vorbis audio
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| digital audio sounds exactly as, or very
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| | file encoded at 110Kbps gives a smaller
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| close to, the original sound. The
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| | size and sounds better than an MP3 file
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| algorithm attempts to adapt the
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| | encoded at 128Kbps. 160Kbps gives
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| compression to the characteristics of the
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| | very-near-CD-quality audio encoding.
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| human perception of sound. This
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| | Although it's open-source, this codec
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| compression algorithm can handle both
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| | compares very favourably to WMA, AAC, WMA
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| constant and variable bit rate
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| | Pro etc (see Wikipedia for more on this).
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| compressions. For good quality music, a
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| | This format is rising in popularity due
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| bit rate of at least 192Kbps is
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| | to its open-source nature and freedom
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| recommended - this is near CD quality.
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| | from licensing issues.
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| 256Kbps per second is better. There is
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| | MIDI(Musical Instrument Digital
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| very little quality difference between
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| | Interface)
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| 256Kbps and 320Kbps, but the later will
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| | MIDI is one of the old formats, but still
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| have a larger file size. MP3 files have
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| | very much in use today. Its not really a
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| no Digital Rights Management (DRM)
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| | compression algorithm, but a synthesized
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| technology built in - meaning they are
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| | music format. MIDI files consist of lists
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| freely portable. That's not to say its
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| | of commands which tell a synthesizer when
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| legal to move music files from one device
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| | to start/stop playing a specific note of
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| to another.
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| | a specific instrument, and may include
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| AAC (Advanced Audio Coding)
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| | the volume and modulation of the note.
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| A newer, lossy audio compression format
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| | With MIDI you can play a number of
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| developed by the same MPEG group. AAC is
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| | instruments at once, or just play one
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| more efficient than the popular MP3
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| | instrument at a time. These files are
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| format, and requires less processing
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| | generally tiny compared to normal audio
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| power to decode. Its also not backward
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| | files such as MP3, WMA, AAC. Because this
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| compatible with MP3. AAC-compressed audio
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| | is synthesized music, its quality greatly
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| at 96 Kbps generally exceeds the quality
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| | depends on the quality of the synthesizer
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| of MP3-compressed audio at 128 Kbps. AAC
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| | on your PC's sound card or the quality of
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| supports DRM, but you can have both
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| | the synthesized instruments in your
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| protected or unprotected formats. The
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| | software. One application for MIDI files
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| unprotected format is freely portable,
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| | is as mobile phone ring tones.
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| while the protected format is locked by
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| | RealAudio (RM/RAM)
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| the DRM used. Apple uses the AAC format
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| | This format from RealNetworks was at the
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| for its iTunes and in QuickTime. Audio
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| | fore-front of internet audio formats for
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| compressed at 128Kbps using AAC sounds
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| | many years. This format is usually
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| very close to the original sound, which
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| | streamed, rather than downloaded. It can
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| means a smaller file size for the same
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| | be played using the RealPlayer or RealOne
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| audio quality compared to the MP3 format.
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| | software. A good number of internet radio
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| The file will be about 75% of the size an
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| | stations still use this format for their
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| MP3 compression would produce.
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| | broadcasts. The audio can be streamed at
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| WMA (Windows Media Audio)
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| | different bit rates to satisfy bandwidth
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| WMA is another lossy compression format,
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| | constraints. If you are on a dial-up
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| developed and owned by Microsoft, and
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| | internet connection, the music quality
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| used in Windows Media Player for DRM
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| | you get is lower than if you are on
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| management. This compression is more
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| | broadband.
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