Standard MIDI Files Research Articles

Standard MIDI file production as the focus of a broad computer science course

This paper describes a broad course in computing that the author developed with the goal of attracting and engaging students with a limited Computer Science background but with an interest in compu...

Information Hiding in Standard MIDI Files Based on Velocity Reference Values

This paper proposed a novel method to embed information in SMFs (Standard MIDI Files) by slightly adjusting the velocity values of notes. First, this method uses the velocity values of the first note of strong beat, the first of weak beat, and the first second-strong beat with non-zero velocity value in a measure as the referencing values for velocity of other notes in the same measure. Then, the data are embedded in the velocity values of notes excluding the notes with the referencing values. The method uses the difference between the velocity value of each note and its corresponding reference value to decide the number of bits which can be used for embedding data in each note. The proposed method limits the changes of the velocity value of each note to its original value and its corresponding reference value during the data embedding. It can avoid the differences from the original music being heard due to the velocity values excessive change. In addition, the proposed method can also embed data with- out changing the file sizes of the SMFs. It can also avoid attracting attention. The experimental results show the feasibility of the proposed method.

Reversible data hiding in Standard MIDI Files by adjusting delta time values

In this paper, an effective method of hiding information in Standard MIDI Files (SMF) is presented. The method simultaneously shifts the binary representations of both the division value and non-zero delta time values in a MIDI file left in order to hide information, and embeds secret information in the bits of the non-zero delta time values produced by the left shifting. The number of left shift bits is in accordance with both the tolerance of beat-changing and the size of the secret information to be embedded. Experimental results show that the proposed method is not only able to embed secret information in Standard MIDI Files without influencing their playing quality, but is also able to recover the original MIDI files without distortion after the hidden data have been extracted.

Topology of musical data

The musical realm is a promising area in which to expect to find nontrivial topological structures. This paper describes several kinds of metrics on musical data, and explores the implications of these metrics in two ways: via techniques of classical topology where the metric space of all-possible musical data can be described explicitly, and via modern data-driven ideas of persistent homology which calculates the Betti-number barcodes of individual musical works. Both analyses are able to recover three well-known topological structures in music: the circularity of octave-reduced musical scales, the circle of fifths, and the rhythmic repetition of timelines. Applications to a variety of musical works (for example, folk music in the form of standard MIDI files) are presented, and the barcodes show many interesting features. Examples show that individual pieces may span the complete space (in which case the classical and the data-driven analyses agree), or they may span only part of the space.

2P1-Q06 自動演奏ロボットの合奏を可能にするシステム : サクソフォン自動演奏ロボットの協調テンポ制御(アミューズメント・エンタティナーロボット)

The purpose of this research is to make a system for controlling acoustic wind instruments by a robot. The system can play wind instruments by using Standard MIDI File as an interface between a human player and the automatic music performance robots already developed. It can control various articulations, for example, changing tone velocity, pitch bending and tone vibration as freely as MIDI data can control synthesizers. Furthermore, by improving and using the system in real time, it may perform any kind of music performance with human players as a band member. A new system that can perform music cooperating with human band members automatically is also considered. For that purpose, a method to analyze a performance and find playing tempo of other players in real time is proposed.

A musical system for emotional expression

The automatic control of emotional expression in music is a challenge that is far from being solved. This paper describes research conducted with the aim of developing a system with such capabilities. The system works with standard MIDI files and develops in two stages: the first offline, the second online. In the first stage, MIDI files are partitioned in segments with uniform emotional content. These are subjected to a process of features extraction, then classified according to emotional values of valence and arousal and stored in a music base. In the second stage, segments are selected and transformed according to the desired emotion and then arranged in song-like structures. The system is using a knowledge base, grounded on empirical results of works of Music Psychology that was refined with data obtained with questionnaires; we also plan to use data obtained with other methods of emotional recognition in a near future. For the experimental setups, we prepared web-based questionnaires with musical segments of different emotional content. Each subject classified each segment after listening to it, with values for valence and arousal. The modularity, adaptability and flexibility of our system’s architecture make it applicable in various contexts like video-games, theater, films and healthcare contexts.

An Approach to Automatic Motion Synthesis Harmonized with Music for Multiple Objects.

This paper proposed a research approach to automatic choreography synthesis based on SMF(Standard Midi File) for multiple animated figures. Based on the K.Hevner’s theory, 8 types of emotion in each beat can be extracted from music structure elements, such as tempo, key, rythm, melody, harmony, pitch, which can be computed from SMF. The time of one beat is limited to transmit the emotion to human. By the analysis of emotion, a music can be integrated to several time intervals, every which includes several continuous beats. The top value of synthetic emotion vector represents the emotion type of the interval. Based on the experiment result of C.Matsumoto, 14 motion factors can be mapped from the emotion of interval. According to the 14 motion factors, the macro-motions at the terminals of every interval, and the micromotions between every interval can be generated by mapping rules. We made a prototype system and did a subjective evaluation experiment. The result is fairly good at the congruity between generated motions and given emotion music. A successful research to solve these issues should lead to aid the designation of 3DCG animation.

Iterated Functions Systems Music

As a new technique of computer-assisted composition, measures of attractors of iterated functions systems codes (Barnsley 1989) can be interpreted as musical scores. The technique is called here music. In some important respects, it appears to be more general and more powerful than previous methods for generating musical scores from fractals, such as Koch curves (Dodge and Bahn 1986), 1/If distributions (Voss and Clarke 1978; Bolognese 1983; Dodge 1988), and nonlinear dynamical systems of the general type z # z2 + c. (Pressing 1988) Unlike these earlier methods, iterated functions systems can produce either connected or disconnected fractals, self-similar or non-self-similar fractals, and fractals which appear to contain nonfractal elements. There is theoretical and experimental reason, discussed below, to believe that IFS music can produce, in principle, any arbitrary score specifying pitch and time. The technique brings computer-assisted composition several steps towards what increasingly appears to be a fundamental goal-a universal compositional algorithm with a coherent parametric map. I have written a small-scale IFS music program, IFSMUSIC, in GFA BASIC version 2.0 for the Atari 520ST computer. The program generates standard MIDI file sequences to be used either as selfcontained compositions or as raw material for manipulation and combination with commercial sequencers. This article introduces the mathematics underlying iterated functions systems, outlines the algorithm for approximating the measure of an IFS attractor and interpreting the measure as music, illustrates some basic geometric techniques for generating and manipulating scores, and concludes with a brief discussion of coherent parametric maps of compositionally universal algorithms. For proofs of the theorems used here about iterated functions systems, see (Barnsley 1989). Mathematics of Iterated Functions Systems