The actual musical content of a film score is wholly dependent on the type of film being scored, and the emotions the director wishes the music to convey. A film score can encompass literally thousands of different combinations of instruments, ranging from full symphony orchestral ensembles to single solo instruments to rock bands to jazz combos, along with a multitude of ethnic and world music influences, soloists, vocalists, choirs and electronic textures. The style of the music being written also varies massively from project to project, and can be influenced by the time period in which the film is set, the geographic location of the film's action, and even the musical tastes of the characters. As part of their preparations for writing the score the composer will often research different musical techniques and genres as appropriate for that specific project; as such, it is not uncommon for established film composers to be proficient at writing music in dozens of different styles.