MPEG-1 Audio Layer 3, more commonly referred to as 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.

MP3 is an audio-specific format that was designed by the Moving Picture Experts Group as part of its MPEG-1 standard. The group was formed by several teams of engineers at Fraunhofer IIS, AT&T-Bell Labs, Thomson-Brandt, CCETT, and others. It was approved as an ISO/IEC standard in 1991.

MP3 file provides near-CD quality sound (stereo, 16-bit) in a file roughly 1/10 the size of a .WAV or .AIF file. The quality of an MP3 file depends largely on the bit rate used for compression. Common bit rates are 128, 160, 192, and 256 kbps; higher bit rates result in higher quality files that also require more disk space.

MP3 files can be played by MP3 software. There are a lot of MP3 player software, and most of them are free. The following are some popular MP3 players:

• Microsoft Windows Media Player

• Winamp

• iTunes

• Real Player

MP3 player for portable device:

MP3 files are also supported by most portable music players, such as the Apple iPod and Microsoft Zune. They can also be played on the Amazon Kindle. In addition, Symbian OS mobile phones can play MP3 files using the UltraMP3 program.

By default, Ubuntu (for that mater many Linux distributions) cannot play MP3 audio files. This is because of copyright laws (makes it a restricted format) which prevents MP3 functionality from being bundled with Linux distributions.

This does not mean you cannot play MP3 audio files on Ubuntu, it just means you need to download an encoder first.

You can use Totem, which is the default media player in Ubuntu, and add the codec that will allow playing of MP3 audio files.

The easiest way to get started, is to first download or copy an MP3 file to your desktop and double click on it to open Totem. You will immediately see the following message:

Click on the Search button to allow your system to find the required software.

Next you will see the following results from the search, prompting you to make a selection.

Select the first option that include codecs for playing mp3, sid, mpeg1, mpeg2 formats, and carefully read the pop-up notice about installing restricted software. Click Confirm button to confirm the notice. Then click Install to start the installation.

If prompted, enter you password at the prompt to perform administrative tasks.

Once installation has completed, click the Close button.

The MP3 audio file that you clicked on earlier will start playing.

Next time you click on an MP3 file, Totem will open and will immediately start playing tunes for you!

There is a huge difference between normal audio files (like MP3, WAV, WMA etc.) and MIDI. To put it straight, MIDI are not audio files. They contain description on how to create music, but not music itself.

If you stop and think awhile, you will see that MIDI to MP3 conversion is quite natural. With a MIDI file, the only thing you need to create music is a hardware or software synthesizer. A MIDI file contains precise instructions, a synthesizer is designed to follow those instructions. There is no chance of getting wrong results.

You can compare MIDI to MP3 conversion with a professional musician (or even orchestra) playing sheet music.

MP3 to MIDI is another story. It's like making sheet music out of complex recording. You would need a skillful musician and pretty much time, and there's still no guarantee that you will get every note right.

Here is a program that converts MP3 to MIDI amazingly good. However, don't expect miraculous results, especially on complex music with plenty of different instruments (simple melody using one instrument or voice is better to detect). You will need to play with settings to get your melody the way you want it, even with this excellent and unique tool.

It's WIDI Recognition System Professional.

Step 1: Download and install the program.

Download WIDI Recognition System Professional to a known location. Run setup and follow on-screen instructions to install the application.

Step 2: Launch the program. Select converting method.

Launch WIDI Recognition System Professional. A simple Wizard shows up:

Choose to convert pre-recorded MP3 and click Next.

You can also use the program to recognize a tune that you sing into microphone (as an example).

Step 3: Select MP3 file to convert.

The following window appears:

Click Browse and select MP3 file that you want to convert to MIDI:

Click Open. It will return you to the previous window, but with the path to your file:

Click Next. The program will work on the audio a few seconds:

Step 4: Let the program recognize MIDI sequences.

Now you can change settings for MIDI recognition, or just select a preset from the drop-down list.

You don't use any presets for now. Just click Next.

The program starts to analyze your MP3 file. It will take a few seconds.

When the analysis is finished, you can just close the Wizard:

Step 5: Verify the result. Adjust settings. Save MIDI file.

After the Wizard is closed, you can see the main window of the program:

One window in the workspace represents waveform of the original MP3 file (on the background). The other one shows you results of spectrum analysis. Yellow regions are most probably notes - that's where sound is most intense. The program recognizes notes and highlight them using borders. You can adjust, merge, delete, add new notes directly in this window. It is also possible to adjust instruments and preview the tune.

WIDI Recognition System Professional isn't able to recognize instruments yet, so the whole melody will be played using piano (by default). Use editor to make adjustments.

Finally click Save button to save the resulting MIDI. Trial version of the program will allow you to save only 10 seconds of your tune. You can remove this restriction by purchasing the product and entering your personal key.

If you need to convert some of your MP3 files to WAV format, this tutorial will show you in a few easy steps how to use Winamp 2.64 to accomplish this. Have in mind that this has got to do with some plugins that come with Winamp... (You may use this tutorial for other 2.x versions of Winamp, some of the plugin names referenced in my tutorial may differ in previous versions).

STEP 1: Preparing your mp3 files

So you have found the mp3 files that you would like to decode into WAV format. You can either decode the mp3 files one by one or by making a playlist of all the mp3 you want to decode. Make sure the REPEAT button is switched off (toggle), because we don't want the decoder repeating the decoding process and creating duplicate WAV files. Also turn off the Shuffle button if you are to make a playlist of mp3 to decode.

STEP 2: Configuring the decoding plugin

Now you need to select from the Winamp preferences the decoding plugin which Winamp will use to decode our mp3 files. Press CTRL + P inorder to open Winamp Preferences or open otherwise. Select the Output from the Plug-ins section. Then select the decoder plugin which we will be using, named 'Nullsoft Disk Writer plug-in v1.0 (x86) (OUT_DISK.DLL)'.

Now press the Configure button just below inorder to select the directory you wish to save the WAV files which will be created to. After doing that, press Ok and close the preference's window.

STEP 3: Decoding the mp3 to wav files

Inorder to initiate the decoding process, you simply have to press the PLAY button in Winamp. Note that an mp3 which is 4 mins long will need around 15 seconds to decode. During the decoding process, Winamp will appear to be playing at turbo speed, but without any outputted sound. It is adviced to leave your computer alone while decoding is in progress, inorder to avoid any skips in the outputted WAV file, due to CPU usage.

When the decoding process is complete, you should have in mind that while the Decoding plugin is still loaded, you cannot playback any music files until you switch back to the previous Output plugin, which is called 'Nullsoft WaveOut plug-in v.2.02 (x86) (OUT_WAVE.DLL)'.

So now you must repeat STEP 2 and selecting the default playback plugin which we have just mentioned, or to any other playback plugins you prefer to use.

That is all folks! Your WAV files should now be located in the directory (folder) you selected in STEP 2.

Have in mind that WAV files can be played using Winamp and mainly the fact that they take up lots of disk space; approximately just over 10 mb of disk space per minute of music.