Music Recognition Software
Wav-to-Midi Conversion
WAV and MIDI File Formats

Music Recognition

Music Composer

Guitar Assistant

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If you are looking for Midi-to-Wav converter, visit Midi2Wav.com

What is Music Recognition?

In a few words music recognition is mathematical analysis of an audio signal (usually in WAV format) and its conversion into musical notation (usually in MIDI format). This is a very hard artificial intelligence problem. For comparison, the problem of recognition of scanned text (OCR - Optical Character Recognition) is solved with 95% accuracy - it is an average exactitude of recognition of the programs of the given class. The programs of speech recognition already work with 70-80% accuracy, whereas the systems of music recognition work with 60-70% accuracy but only for a single voice melody (one note at a time). For polyphonic music the accuracy is even lower.

To create a MIDI file for a song recorded in WAV format a musician must determine pitch, velocity and duration of each note being played and record these parameters into a sequence of MIDI events. A music recognition software must do the same things. Even for a single instrument song it is not a simple task, because a WAV recording contains waveform signals and doesn't contain any music specific data.

In general cases the variety of music timbres, harmonic constructions and transitions make it impossible to create a mathematical algorithm for precise reconstruction of a music score from the audio sources. It is hard to recognize audio data which contains many instruments, drums and percussions or clipping signals, unstable pitch sounds and background noises. However, in many cases AKoff Music Composer will produce a MIDI material that represents the basic melody and chords of recognized music. You can download and listen to source wav-files and recognized midi-results.

WAV and MIDI Formats

The difference between WAV and MIDI formats consists in representation of sound and music. WAV format is digital recording of any sound (including speech) and MIDI format is principally sequence of notes (or MIDI events). The relations are approximately the same as between sounded speech and printed text.

WAV format
A WAV file is the recording of a sound wave. It is the mix of all the given sounds (instruments, voices, background noises) you could have heard at the moment of recording. So you can record, for example, human voice in WAV format, but you cannot edit any note or change any instrument in music recorded in a WAV file. The Standard Windows PCM WAV format contains only Pulse Code Modulation data without compression. PCM format is the only kind that saves the entire wave completely with no data loss.

There are many other formats for audio recording. They differ from each other by compression algorithms and can be referred to one group. The conversion from one format into another is very simple. There are many sound editors which allow one to do this.

The following is a list of some audio formats with file extensions:

MIDI format
MIDI (Musical Instrument Digital Interface) format is a sequence of commands to control one or more pieces of musical hardware or software such as synthesizers or sequencers. These commands are not sounds, they are instructions to do something (mostly to generate sound). For example: select Instrument #1 (Acoustic Grand Piano), play Note #60 (C5) with Velocity #127. So you cannot represent, for example, human speech in MIDI format, but you can edit any note or change any instrument in music recorded in MIDI file.

MIDI to WAV conversion
Music recorded in MIDI format can be easily transformed to WAV format. You can play MIDI files on an appropriate player and record reproduced music in a sound editor. The size of a WAV file will be larger than the same music file represented in MIDI format. The quality of music will be determined by MIDI capabilities of your sound card and professionalism of the musician creating the source MIDI file. There are programs converting MIDI files into WAVE using only their own timbres of MIDI instruments (WAVE-table synthesis).

The reconversion from WAV to MIDI is the music recognition problem which up until now has no qualitative solution (with 100% accuracy).