You can weave bardic music effects into your spellcasting in such a way that your spellcasting and bardic performance become indistinguishable.
Prerequisites: Bardic performance ability.
Benefit: Whenever you cast a 1st or higher level spell while you are maintaining a bardic performance, you can maintain the bardic performance for that round without expending one of your rounds of performance for the day. In addition, you can switch from one bardic performance to another as a swift action when you cast a spell while maintaining a bardic performance.
Pathfinder Campaign Setting: The Inner Sea World Guide. © 2011, Paizo Publishing, LLC; Authors: Keith Baker, Wolfgang Baur, Clinton J. Boomer, Jason Bulmahn, Joshua J. Frost, Ed Greenwood, Stephen S. Greer, Jeff Grubb, James Jacobs, Michael Kortes, Tito Leati, Mike McArtor, Rob McCreary, Erik Mona, Jason Eric Nelson, Jeff Quick, Sean K Reynolds, F. Wesley Schneider, Leandra Christine Schneider, David Schwartz, Amber E. Scott, Stan!, Owen K.C. Stephens, Todd Stewart, James L. Sutter, Greg A. Vaughan, Jeremy Walker, and JD Wiker.