MP3 or MP4
Most downloadable music on the Internet is currently available in the MP3 format. MP3 is a file format that allows computer users to download and store music in a relatively small amount of hard drive space. As a general rule, one minute of music requires 1 MB of storage space. The technology is used widely by aspiring musicians who wish to distribute their music to a global audience. It is also used by individuals who wish to copy their existing audio CD into a digital format for playback on their computer or a portable music device.
MP3 is an audio-specific compression format. It provides a representation of pulse-code modulation-encoded audio in much less space than straightforward methods, by using psychoacoustic models to discard components less audible to human hearing, and recoding the remaining information in an efficient manner. Similar principles are used by JPEG, a lossy image compression format.
The MP3 format uses a hybrid transformation to transform a time domain signal into a frequency domain signal:
32-band polyphase quadrature filter
36 or 12 tap MDCT; size can be selected independent for sub-band 0...1 and 2...31
Aliasing reduction postprocessing
MP3 audio can be compressed with different bit rates, providing a range of tradeoffs between data size and sound quality.
The term MP4 has been claimed as a brand name by Internet company Global Music Outlet (GMO). The company is probably benefiting from confusion among Web music fans who seek an upgrade to MP3. While GMO's own MP4 technology does offer improved compression and audio over the popular MP3 standard, it is not the official successor to MP3. That title goes to the MPEG-4 audio standard developed by the International Standards Organization.
The MPEG-4 standard, which was completed in October 1998, is an object-based format that encompasses much more than music. It also addresses the next generation of digitally delivered multimedia, including video and 3D applications.
What is an MP4?
Just like MP3s work by compressing music and audio files without affecting the audio quality, MP4 files are compressed video files. MP4 is also known as MPEG-4 AVC, or advanced video coding. This new technology is going to make video files decrease in size so that they are easier to work with and support. What used to be massive video files of motion and audio are now compressed versions of the same material, called MP4s.
How MP4 Technology Works
MP4 files work through compression; similar to how MP3 audio files are compressed, except these are more complex. The way these videos are compressed into very small files without affecting the quality is through dealing with specific coding issues, minimizing certain aspects, such temporal and spatial redundancies, transforming motion estimation and intra estimation into the frequency domain, and generally through compression and decompression, commonly referred to as codec.
The MP4 player works in a very simple manner. You simply purchase the ?sold separately? electronic device and attach it to your computer, notebook, or TV. It?s that easy.
Advantages of MP4 Technology
MP4s produce videos of DVD-quality at less than 1 Mbps through a broadband connection. This means that with an MP4 player, you can retrieve videos through an Internet connection and watch them with your MP4 player. MP4 players can also play lower MP versions, such as audio MP3s.