The invention provides a switching audio power amplifier with de-noise function including a pulse width modulator, a de-noise circuit and a bridge circuit. The test circuit includes a first clock generator, a second clock generator, a test target circuit, a BIST circuit for performing the test, and a tester synchronous circuit. The sheet of translucent material rests within a longitudinal groove formed within the frame. The semantic features identifying likelihoods of semantic concepts being present as content in the frames of the video.