Bit DepthReduction.csd Written by Iain McCurdy -iadc -odac -dm0 sr = 44100 ;SAMPLE RATE ksmps = 1 ;NUMBER OF AUDIO SAMPLES IN EACH CONTROL CYCLE nchnls = 2 ;NUMBER OF CHANNELS (2=STEREO) ;FLTK INTERFACE CODE;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FLcolor 255, 255, 255, 0, 0, 0 ;SETUP BASIC COLOURS ; LABEL | WIDTH | HEIGHT | X | Y FLpanel "Bit Depth Reduction", 500, 170, 0, 0 ;SWITCHES ON | OFF | TYPE | WIDTH | HEIGHT | X | Y | OPCODE | INS | STARTTIM | DUR gkOnOff,ihOnOff FLbutton "On/Off", 1, 0, 22, 100, 25, 5, 5, 0, 1, 0, -1 FLsetColor2 255, 255, 50, ihOnOff ;SET SECONDARY COLOUR TO YELLOW ;VALUE DISPLAY BOXES LABEL | WIDTH | HEIGHT | X | Y idbitdepth FLvalue " ", 70, 20, 5, 95 idgain FLvalue " ", 70, 20, 5, 145 ;SLIDERS MIN | MAX | EXP | TYPE | DISP | WIDTH | HEIGHT | X | Y gkbitdepth, ihbitdepth FLslider "Bit Depth", 1, 16, 0, 23, idbitdepth, 490, 25, 5, 70 gkgain,ihgain FLslider "Output Gain", 0, 2, 0, 23, idgain, 490, 25, 5, 120 ;GENERAL_TEXT_SETTINGS SIZE | FONT | ALIGN | RED | GREEN | BLUE FLlabel 13, 1, 1, 255, 255, 255 ;NUMBERS MADE INVISIBLE ; FLBUTBANK TYPE | NUMX | NUMY | WIDTH | HEIGHT | X | Y | OPCODE gkinput, ihinput FLbutBank 4 , 1, 3, 18, 60, 150, 0, -1 ;GENERAL_TEXT_SETTINGS SIZE | FONT | ALIGN | RED | GREEN | BLUE FLlabel 13, 5, 4, 0, 0, 0 ;LABELS MADE VISIBLE AGAIN ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox "Voice ", 1, 5, 12, 70, 18, 170, 0 ih FLbox "Drums ", 1, 5, 12, 70, 18, 170, 20 ih FLbox "Live Input", 1, 5, 12, 70, 18, 170, 40 ;SET INITIAL VALUES FOR SLIDERS |VALUE | HANDLE FLsetVal_i 16, ihbitdepth FLsetVal_i 1, ihgain FLsetVal_i 1, ihinput FLpanel_end ; END OF PANEL CONTENTS ;INSTRUCTIONS AND INFO PANEL WIDTH | HEIGHT | X | Y FLpanel " ", 515, 140, 512, 0 ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox " Artificial Bit Depth Reduction ", 1, 5, 14, 490, 15, 5, 0 ih FLbox "-------------------------------------------------------------", 1, 5, 14, 490, 15, 5, 20 ih FLbox "This example uses a mathematical quantizing procedure upon an", 1, 5, 14, 490, 15, 5, 40 ih FLbox "audio signal to create the effect of lower bit depth sample ", 1, 5, 14, 490, 15, 5, 60 ih FLbox "storage. The example is designed to work with 16 bit samples ", 1, 5, 14, 490, 15, 5, 80 ih FLbox "but could easily be adapted to work with samples of other ", 1, 5, 14, 490, 15, 5, 100 ih FLbox "depths. ", 1, 5, 14, 490, 15, 5, 120 FLpanel_end FLrun ;RUN THE FLTK WIDGET THREAD ;END OF FLTK INTERFACE CODE;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; instr 1 if gkOnOff=0 then ;IF ON/OFF SWITCH IS OFF... turnoff ;TURN THIS INSTRUMENT OFF endif ;END OF CONDITIONAL BRANCHING if gkinput=0 then ;CHECK STATUS OF gkinput (FLTK BUTTON BANK) asig diskin2 "AndItsAll.wav", 1, 0, 1 ;READ IN SOUND FILE FROM DISK elseif gkinput=1 then ;CHECK STATUS OF gkinput (FLTK BUTTON BANK) asig diskin2 "808loopmono.wav", 1, 0, 1 ;READ IN SOUND FILE FROM DISK elseif gkinput=2 then ;CHECK STATUS OF gkinput (FLTK BUTTON BANK) asig inch 1 ;READ THE COMPUTER'S LIVE AUDIO INPUT endif ;END OF if... BRANCHING kvalues pow 2, gkbitdepth ;RAISES 2 TO THE POWER OF kbitdepth. THE OUTPUT VALUE REPRESENTS THE NUMBER OF POSSIBLE VALUES AT THAT PARTICULAR BIT DEPTH k16bit pow 2, 16 ;RAISES 2 TO THE POWER OF 16 ksig downsamp asig ;CREATE A K-RATE VERSION OF asig ksig = int(ksig * (kvalues/k16bit)) ;QUANTISE ksig- ksig = ksig * (k16bit/kvalues) ;-AND RESCALE IT TO MATCH THE ORIGINAL AMPLITUDE asig interp ksig ;CREATE AN AUDIO-RATE VERSION OF THE QUANTISED SIGNAL outs asig*gkgain, asig*gkgain endin f 0 3600