ardour { ["type"] = "dsp", name = "a-Amplifier", category = "Amplifier", license = "MIT", author = "Ardour Team", description = [[Versatile +/- 20dB multichannel amplifier]] } function dsp_ioconfig () return { -- -1, -1 = any number of channels as long as input and output count matches { audio_in = -1, audio_out = -1}, } end function dsp_params () return { { ["type"] = "input", name = "Gain", min = -20, max = 20, default = 0, unit="dB"}, } end local sr = 48000 local cur_gain = 1 function dsp_init (rate) sr = rate end function dsp_configure (ins, outs) n_out = outs n_audio = outs:n_audio () assert (outs:n_midi () == 0) end -- the DSP callback function function dsp_runmap (bufs, in_map, out_map, n_samples, offset) -- apply I/O map ARDOUR.DSP.process_map (bufs, n_out, in_map, out_map, n_samples, offset) local ctrl = CtrlPorts:array() -- get control port array local target_gain = ARDOUR.DSP.dB_to_coefficient (ctrl[1]) -- 10 ^ (0.05 * ctrl[1]) local current_gain = cur_gain -- start with the same for all channels cur_gain = target_gain -- use target gain if no channel is mapped. for c = 1, n_audio do local ob = out_map:get (ARDOUR.DataType ("audio"), c - 1); -- get id of mapped output buffer for given cannel if (ob ~= ARDOUR.ChanMapping.Invalid) then cur_gain = ARDOUR.Amp.apply_gain (bufs:get_audio(ob), sr, n_samples, current_gain, target_gain, offset) end end --[[ if current_gain ~= cur_gain then self:queue_draw () -- notify display end --]] end ------------------------------------------------------------------------------- --- inline display + text example --[[ local txt = nil -- cache pango context globally function render_inline (ctx, w, max_h) local ctrl = CtrlPorts:array () -- get control ports if not txt then -- allocate PangoLayout and set font --http://manual.ardour.org/lua-scripting/class_reference/#Cairo:PangoLayout txt = Cairo.PangoLayout (ctx, "Mono 8px") end txt:set_text (string.format ("%+.2f dB", ctrl[1])); tw, th = txt:get_pixel_size () local h = th + 4 -- use text-height with 4px padding if (h > max_h) then h = max_h end -- but at most max-height -- clear background ctx:rectangle (0, 0, w, h) ctx:set_source_rgba (.2, .2, .2, 1.0) ctx:fill () -- center text ctx:set_source_rgba (.8, .8, .8, 1.0) ctx:move_to (.5 * (w - tw), .5 * (h - th)) txt:show_in_cairo_context (ctx) return {w, h} end --]]