The first thing anyone learns about the MP3 audio format is that it is based on a lossy compression algorithm. Lossy compression means that in order to reduce the file size some of the original audio has been removed which inherently reduces the fidelity of the recording. How much data is removed during the compression process is a based on a combination of factors including user preference, portability requirements, available disk space, etc. In the case of an MP3 download the user little control over how much fidelity has been removed from the audio source. In very simple terms the difference in fidelity can be demonstrated by removing letters from certain words in the following sentence. This is w_at a sentence wo_ld lo_k like if it was compres_ed usi_g a_ imaginary los_y compres_ion algorithm. It doesnt look very good but Im sure you can make out the meaning. Thats lossy compression; enough data is provided in order for you to understand the meaning even though some of the data is missing. So how is one to get the fidelity back? The short answer is you cant or should I say couldnt, until now. There has been a breakthrough in thinking in how to describe audio wave patterns called the Sound Genome Theory. The Theory states that digital representation of sound is not just a series of recorded wave patterns but it is actually made up of sound genes. Similar in concept to DNA a sound spectrogram is made up of discrete, discernable components that can be sequenced and synthesized. This sequence of sound genes is what allows software based on the Sound Genome Theory to reconstruct the missing data from a lossy compressed audio file. Passing our compressed sentence from above through an imaginary Fidelity Amplifier would give us a sentence that looks something like this: This is w_at a sentence would look like if it was compressed usi_g an imaginary lossy compression algorithm. As you can see increased fidelity produces a much more pleasing and accurate representation of the original. The interesting thing about the Sound Genome Theory is that it can also be used to compress audio. Software that is based on the theory can achieve compression comparable or better than todays popular lossy compression algorithms yet still maintain the recorded fidelity. The software can also be used on existing MP3s in order to achieve incremental lossless data reduction. Using software based on the Theory will lower the actual file size or bit rate without loosing fidelity of the original recording. Software based on the Sound Genome Theory is starting to leave the lab now and is available both for playback of streaming and downloaded audio and as a way to losslessly compress digital audio. At this point in its evolution the software is available for use on Windows based PCs. Future versions of the software are destined for portable devices as well as other platforms. |
