question: public String fadeAudio ( String path , String type , double fadeInLength , double stopTime , double fadeOutLength ) throws IOException { final List < String > curves = Arrays . asList ( new String [ ] { "q" , "h" , "t" , "l" , "p" } ) ; if ( ! curves . contains ( type ) ) { throw new RuntimeException ( "fadeAudio: passed invalid type: " + type ) ; } File file = new File ( path ) ; String outFile = file . getCanonicalPath ( ) + "_faded.wav" ; ArrayList < String > cmd = new ArrayList < String > ( ) ; cmd . add ( soxBin ) ; cmd . add ( path ) ; cmd . add ( outFile ) ; cmd . add ( "fade" ) ; cmd . add ( type ) ; cmd . add ( fadeInLength + "" ) ; if ( stopTime != - 1 ) cmd . add ( stopTime + "" ) ; if ( fadeOutLength != - 1 ) cmd . add ( fadeOutLength + "" ) ; try { int rc = execSox ( cmd , callback ) ; if ( rc != 0 ) { outFile = null ; } } catch ( IOException e ) { e . printStackTrace ( ) ; } catch ( InterruptedException e ) { e . printStackTrace ( ) ; } return outFile ; }
target:  Fade audio file sox <path> outFile fade <type> <fadeInLength> <stopTime> <fadeOutLength>