NIAONiao Virtual Singer (袅袅虚拟歌手) (commonly shortened to NIAONiao) is a Chinese voice synthesizer program which is similar to UTAU and VOCALOID.
For more information on NIAONiao, visit the NIAONiao Wiki.
The principle is the same as UTAU and VOCALOID.
The default voicebank is named Yu Niaoniao (余袅袅). Many Chinese fans have begun producing vocal banks for both NIAONiao and UTAU. The voicebank format for NIAONiao is radically different from UTAU, the main difference being that the voice samples are packed in a large file. Due to being made for a Chinese audience, NIAONiao can have final consonants in a voice, also unlike UTAU. NIAONiao is not exclusive to singing in Chinese, just as UTAU is not restricted to Japanese. For example, a NIAONiao voicebank for Nagone Mako can be downloaded from the official NIAONiao website.
The interface is much closer in similarity to VOCALOID than UTAU. Like VOCALOID (and unlike UTAU), there is a panel at the bottom for controlling parameters, pitchbends, and vibrato.
NIAONiao can import MIDI files, VSQX files, and UST files, export tracks as the "Niao" file format (*.nn), and can render vocal tracks directly as WAV, MP3, or MIDI files.