A Study On The Composing Style Imitation And Quality Evaluation Methods Of Song Melody

Automatic composition is an important branch of the field of artificial intelligence,is a research which trying to use a formal model to imitate the composer's music creation behavior.As the creative style of music works is different,the study of automatic composition technology is to explore different composer's creative style calculation model essentially.Based on the theoretical research of the field of automatic composing and combined with the diversity of song style,a melody creative calculation model is designed.This model involves two stages:training and creation.In the training phase,by collecting and training a series of different styles of model songs,using melodic phrase as the basic unit of creation,extracting attribute characteristics like emotion,mode,melodic phrase(which related to a single-stage or multi-stage multi-melodic-phrase structure consisting of the logical relationship between adjacent melodic phrases or interval melodic phrases in a model song)and topic information and so on to create melodic phrase and song template database.In the creation phase,by selecting the song template in the song template database to create the creative goal(which related to the determining of the lyrics' form of poetry,expressing emotions and beat information),finding the melodic phrase in the melodic phrase database which matches the relationship between the corresponding melodic phrases in the multi-melodic-phrase structure of the specified song template,replacing the melodic phrase's scale degree in the multi-melodic-phrase structure,after splicing and arranging the melodic phrase and generating a song of similar style.It mainly relates to the following research:1.An improved multi-melodic-phrase structure recognition algorithm is proposed,which can identify numbers of relationship between the adjacent or interval melodic phrases and study the relationship between melodic phrases from template song fully.2.The idea of seeking melodic phrase based on the music structure is proposed.According to the music form of template song,finding the suitable melodic phrase by the previous or interval melodic phrase information and the corresponding relationship until all the corresponding melodic phrases are found.3.The method of scale degree replacement is proposed,which means transfer the different existed songs' melodic phrases,converting each note pitch in the melodic phrase into scale degree under the same mode,and replacing the i-th note'scale degree of this melodic phrase with another i-th note scale degree of melodic phrase which contains the same numbers of non-stop notes and non-decorative notes and forms a new melodic phrase.4.Adjusting the information of melodic phrase.When splicing the melodic phrases into a complete song,need to merge,split or add notes and so on to ensure the the correctness of melody and consistent of style.In addition,how to assess the quality of the music produced by the automatic composing system is another unavoidable problem in the field of automatic composing.An objective estimation model for evaluating the quality of songs is proposed in this paper,which includes the introduction of the related concepts and calculation formula of the evaluation model to calculate the melody innovation and beauty degree.The subjective evaluation and objective evaluation of the existing songs' melody and the machine songs generated by algorithms are carried out,and the results are compared and discussed.On the basis of the above research,this paper constructs a song creation system based on style imitation.It can be proved by experiment and evaluation that the system can imitate the song style of the specified song and generate a complete song of similar style,it has high application value.