vocaloid

Vocaloid is a technology for singing voice synthesis developed by Yamaha, and the name of this software application. The software allows users to input melody and lyrics in order to synthesize singing. In other words, with this technology, singing can be produced without a singer.
Singing voice synthesis is produced by using fragments of voices recorded from actual singers, called the Singer Library. By changing this Singer Library, various voices such as Miku Hatsune and Gakupoid are able to be created. There are countless musical pieces that have been uploaded to Nico Video and Youtube that use these products.