Niraval also known as Neraval or Sahitya Vinyasa is considered to be one of the important features in the extempore improvisation aspect (Manodharma Sangita) of Carnatic music.
Niraval is essentially the extempore construction, elaboration and improvisation of melody for a particular line in the kriti, within the framework of a talam which brings out the Raga bhava effectively. It is usually just one line from the charanam part of the kriti and has to sit within the framework of a tala and highlight every rasa and bhava singularly.
For example : 4-beat niravals for Shyama Sastri's "sarojadala netri himagiri putri" set to Adi talam (double) in the Raga Shankarabharanam can be constructed for the line "sama gana vinodhini guna" (like this : gpmgrs | s,ndpmgrs) in the charanam of the song.
Repetition of the line in different ways within the entire range of the Raga phrases brings out the musician's imagination.
Palghat K. V. Narayanaswamy was known and is remembered today as a master of niraval singing.