MP3 TERMINOLOGY
MP3 Terminology
WinAMP plugins, what do they do?
It takes the sound and creates animations based on the oscilloscope or spectrum analyzer in Winamp.
DSP (Digital Sound Processing) plug-in. This type of plugin can change the way your MP3s sound.
Input plugin, enables Winamp to read additional formats like for example RealAudio or SID music files.
More on Plug-Ins.
Plug-ins are a great way to make your experience in WinAMP more fun. The most common type of plugin is the VIS (visualization) Plug-in. It takes the sound and creates animations based on the oscilloscope or spectrum analyzer in Winamp. Some of them look absolutely amazing, so be sure to check out our Winamp VIS Plug-in archive. Sonique (another mp3 player) also supports plugins, but they are not compatible with Winamp's.
Another plugin type is the DSP (Digital Sound Processing) plug-in. This type of plugin can change the way your MP3s sound. You can add effects like echo and 'surround'. DSP plug-ins are sometimes VERY CPU intense, so try to close any other running programs if your computer can't handle it.
Yet another plug-in type, the input plugin, enables Winamp to read additional formats like for example RealAudio or SID music files. There are also 'general purpose' plug-ins, such as control plugins. One of them enables you to control winamp with your joystick/joypad for example.
How to install the different types of plug-ins:
- Download the plugin.
- Unzip it to your Winamp\plugins directory (typically C:\Program Files\Winamp\Plugins).
- Start WinAMP.
Visualization plugins:
- Start playing an MP3.
- Press CTRL+K to bring up the Select Plugin window.
- On the right hand side of the new window, select the plugin that you just installed.
- Click "Configure" to configure the plugin.
- Click "Start" to load the plugin. The plugin should now start. Refer to the text file that was included with the plugin if something goes wrong. Also make sure that you have met any hardware/software demands that might exist (possibly a recent DirectX version, a 3D card etc). Don't give up right away if it doesn't work.
DSP/Effect plugins:
- Press CTRL+P to bring up the preferences window.
- On the left hand side of the new window, select DSP/Effect (double-click on "plug-ins" if you cant see it.
- On the right hand side of the window, select the plugin you just installed.
- Using the pull-down menu at the bottom of the window, select which 'part' of the plug-in you want to use.
- Press "Configure" to configure the plugin.
- Start playing an MP3, and hear the difference. Maybe there will be a window opened by the plugin where you can change the settings. If there is not, then you will have to click "Configure" to change them.
Input plugins:
- Just load a file of the specified type the same way you load MP3s.
General purpose plugins:
- Read the documentation that came with the plugin.
What are 'skins', and how do I use them?
Using skins is a way to change the way WinAMP looks. There are thousands of great skins to choose from and some of the finest ones are listed in our skin archive.
After you have downloaded a skin, all you have to do is to unzip them into a subdirectory of your WinAMP\Skins directory (using for example WinZip). Typically the name of the directory would be C:\Program Files\Winamp\Skins\[name of your skin]
After that, press ALT+S while running Winamp (or right-click Winamp to bring up a menu and select Options/Skin Browser...) and select the skin you want to use. If the skin does not appear, then make sure that you placed it in the skins directory. You may have to deselect the "Use folder names" checkbox in WinZip's extract dialogue.
Since WinAmp 2.0, skins may now also change the look of the playlist and equalizer window (recently this feature has been added to the minibrowser window the minimized equalizer window). Old skins do not take advantage of this, so they may look pretty weird. A skin takes up to 1 MB of space on your hard drive, so dont start downloading TOO many of them if you are low on disk space. If you want to save space, then you can try just placing the zipped skin in the skins directory. That way winamp will only unzip the skin when it is used.
(LINK TO DOWNLOAD SKINS)
What is Shoutcast?
Shoutcast is a system for 'streaming' MP3s (MP3s that are downloaded while playing). It works like a radio station, where you 'tune in' by entering an URL in your player (press CTRL+L in winamp). Many stations can be found at the official Shoutcast site. In the later versions of WinAMP, you press ALT+T to open the 'minibrowser', and then locate and click "Shoutcast Top 50" in the drop down menu at the bottom of the browser for a list of the most popular shoutcast stations.
Shoutcast is a very cool way of listening to new songs, but unfortunately you still need a pretty fast connection to be able to listen to any of the high quality streams. For it to be of any use at all you need at the very least a 56k modem.
Bitrate
A term widely used in audio compression is bitrate. It is the average number of bits that one second of audio data will consume. The unit used is kbps (1000 bits/s). (from mp3.now)
VBR
Variable Bit Rate encoding is an encoding method that ensures consistently high audio quality throughout an encoded file by making intelligent bit-allocation decisions during the encoding process. Use VBR encoding when consistent audio quality is the top priority and predictable encoded mp3 file size is not critical Not all mp3 players support Variable Bit Rate encoding.
CBR
Constant Bit Rate Encoding is a method that ensures a consistent bit rate throughout an encoded file, potentially at the expense of audio quality and/or Encoder efficiency.
Use CBR encoding when you need to limit the size of the MP3 file or produce consistent file sizes. Generally, files encoded faster than 128kbps, will have little or no sound quality improvement. Constant Bit Rate encoded files will be smaller than Variable Bit Rate encoded files, of a comparable encoding speed.
Encoder
A program that is used to transform wave files to mp3 files. This is done by using a compression algorithm.
Decoder
A program used to transform an mp3 file to a wave file. This is done by using a decompression algorithm.(from mp3now)
CD-ripper
A CD Ripper copies the audio data digitally from an audio CD to your hard drive. The reason you will want to do this is that when the song(s) have been copied your computer, you will be able to convert (encode) it to an MP3.
>MPEG (1)
Moving Picture Experts Group, working under the joint direction of the International Standards Organization (ISO) and the International Electro-Technical Commission (IEC). This group works on standards for the coding of moving pictures and audio. MPEG has created its own homepage, providing information on the what, where, when and how of the standards.
MPEG (2)
Describes the compression of audio signals using high performance perceptual coding schemes. It specifies a family of three audio coding schemes, simply called Layer-1, Layer-2, and Layer-3. From Layer-1 to Layer-3, encoder complexity and performance (sound quality per bitrate) are increasing.
The three codecs are compatible in a hierarchical way, i.e. a Layer-N decoder may be able to decode bitstream data encoded in Layer-N and all Layers below N (e.g., a Layer-3 decoder may accept Layer-1,-2,-3, whereas a Layer-2 decoder may accept only Layer-1 and -2.)
MP3
Short for MPEG-1 or MPEG-2 audio, layer 3. MP3 is a format that allows you to compress and store music files on your computer.
Player(1)
A program that can be used to playback mp3 files in your computer.
Player(2)
A portable hardware device(smaller in size than a walkman) that is capable of storing music in mp3 format in special memory cards, hence playback of music is then achieved without any moving parts.
Technical Details
(adapted from Frauhofer and MP3tech websites)
MPEG Layer-3
A perceptual audio coding scheme that analyses the audio signal and applies a psychoacoustic model using the properties of the human ear trying to maintain the original sound quality as far as possible. In more detail some of the techniques used in mp3 are the following: The masking effect: This system is based on masking properties of the human ear.
I explain:
During strong sounds, you do not hear the weakest sounds. Take for example a piece of organ: when the organist does not play, you hear the breath in the piping, and when he plays, you no longer hear it because it is masked. It is not therefore necessary to code all the sounds. For this the MP3 encoder uses a psychoacoustic model modelising the behavior of the human ear.
The minimal audition threshold:
The minimal audition threshold of the ear is not linear. It is represented, according to the law of Fletcher and Munsen, by a curve dug between 2Khz and 5Khz. It is not therefore necessary to code sounds situated under this threshold, because they will not be perceipt. The reservoir of bytes: Often, some passages of a musical piece can not be coded to a given rate without altering the musical quality. The mp3 uses then a short reservoir of bytes that acts by using passages that can be coded to an inferior rate to the given flow as a buffer.
The Joint Stereo:
Under a given frequency the human ear no longer able to locate the spacial origin of sounds. The mp3 format can therefore (in option) exploit this trick by using what is called joint stereo. Some frequencies are then recorded as a monophonic signal accompanied by some informations so as to restore a minimum of spatialisation.
The Huffman coding:
The MP3 also uses the classic technique of the Huffman algorithm. It acts at the end of the compression to code information, this is not therefore an algorithm of compression in self but well a coding method. This coding creates variable length codes on a whole number of bits. Higher probability symbols have shorter codes. Huffman codes have the property to have a unique prefix, they can therefore be decoded correctly in spite their variable length. The decoding is very rapid (via a correspondance table). This kind of coding allows to earn on the average a bit less of 20% of space. It is a perfect complement to the perceptual coding: During big polyphonys, the perceptualcoding is very efficient because many sounds are masked or lessened, but few information being identical, the Huffmann algorithm is very few efficient. During "pure" sounds there are few masking effects, but Huffman is then very efficient because digitalised sound contains many redundant bytes, that will then be replaced by shorter codes.
Who Devised MP3?
IIS devised a very powerful algorithm that is standardized as ISO-MPEG AudioLayer-3 (IS 11172-3 and IS 13818-3). BitrateA term widely used in audio compression is bitrate. It is the average number of bits that one second of audio data will consume. The unit used is kbps (1000 bits/s).The bitrates/quality of various audio signals are as follows
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