ardour { ["type"] = "dsp", name = "Inline Scope", license = "GPLv2", author = "Robin Gareus", email = "robin@gareus.org", site = "http://gareus.org", description = [[An Example DSP Plugin to display the waveform on the mixer strip]] } -- return possible i/o configurations function dsp_ioconfig () -- -1, -1 = any number of channels as long as input and output count matches return { [1] = { audio_in = -1, audio_out = -1}, } end function dsp_params () return { { ["type"] = "input", name = "Timescale", min = .1, max = 5, default = 2, unit="sec", logarithmic = true }, { ["type"] = "input", name = "Logscale", min = 0, max = 1, default = 0, toggled = true }, { ["type"] = "input", name = "Height", min = 0, max = 3, default = 1, unit="dB", enum = true, scalepoints = { ["Min"] = 0, ["16:10"] = 1, ["1:1"] = 2, ["Max"] = 3 } }, } end function dsp_init (rate) -- global variables (DSP part only) samplerate = rate bufsiz = 6 * rate dpy_hz = rate / 25 dpy_wr = 0 end function dsp_configure (ins, outs) -- store configuration in global variable audio_ins = ins:n_audio () local audio_outs = outs:n_audio () assert (audio_ins == audio_outs) -- allocate shared memory area -- this is used to speed up DSP computaton (using a C array) -- and to share data with the GUI self:shmem ():allocate (4 + bufsiz * audio_ins) self:shmem ():clear () self:shmem ():atomic_set_int (0, 0) local cfg = self:shmem ():to_int (1):array () cfg[1] = samplerate cfg[2] = bufsiz cfg[3] = audio_ins end function dsp_runmap (bufs, in_map, out_map, n_samples, offset) local shmem = self:shmem () local write_ptr = shmem:atomic_get_int (0) for c = 1,audio_ins do -- Note: lua starts counting at 1, ardour's ChanMapping::get() at 0 local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1); -- get id of mapped input buffer for given cannel assert (ib ~= ARDOUR.ChanMapping.Invalid) local chn_off = 4 + bufsiz * (c - 1) if (write_ptr + n_samples < bufsiz) then ARDOUR.DSP.copy_vector (shmem:to_float (write_ptr + chn_off), bufs:get_audio (ib):data (offset), n_samples) else local w0 = bufsiz - write_ptr; ARDOUR.DSP.copy_vector (shmem:to_float (write_ptr + chn_off), bufs:get_audio (ib):data (offset), w0) ARDOUR.DSP.copy_vector (shmem:to_float (chn_off) , bufs:get_audio (ib):data (offset), n_samples - w0) end end write_ptr = (write_ptr + n_samples) % bufsiz shmem:atomic_set_int (0, write_ptr) -- emit QueueDraw every FPS dpy_wr = dpy_wr + n_samples if (dpy_wr > dpy_hz) then dpy_wr = dpy_wr % dpy_hz; self:queue_draw () end end -- helper function for drawing symmetric grid function gridline (ctx, x, xr, h, val) ctx:move_to (math.floor (.5 + x + val * xr) -.5, 1) ctx:line_to (math.floor (.5 + x + val * xr) -.5, h - 1) ctx:stroke () ctx:move_to (math.floor (.5 + x - val * xr) -.5, 1) ctx:line_to (math.floor (.5 + x - val * xr) -.5, h - 1) ctx:stroke () end function render_inline (ctx, w, max_h) local ctrl = CtrlPorts:array () -- get control port array (read/write) local shmem = self:shmem () -- get shared memory region local cfg = shmem:to_int (1):array () -- "cast" into lua-table local rate = cfg[1] local buf_size = cfg[2] local n_chn = cfg[3] -- get settings local timescale = ctrl[1] or 1.0 -- display size in seconds local logscale = ctrl[2] or 0; logscale = logscale > 0 -- logscale local hmode = ctrl[3] or 1 -- height mode -- calc height if hmode == 0 then h = math.ceil (w * 10 / 16) if (h > 44) then h = 44 end elseif (hmode == 2) then h = w elseif (hmode == 3) then h = max_h else h = math.ceil (w * 10 / 16) end if (h > max_h) then h = max_h end -- display settings local spp = math.floor (timescale * rate / (h - 2)) -- samples per pixel local spl = spp * (h - 1) -- total number of audio samples to read local read_ptr = (shmem:atomic_get_int (0) + buf_size - spl - 1) % buf_size -- read pointer local xr = math.ceil ((w - 2) * (0.47 / n_chn)) -- x-axis range (per channel) -- clear background ctx:rectangle (0, 0, w, h) ctx:set_source_rgba (.2, .2, .2, 1.0) ctx:fill () -- prepare drawing ctx:set_line_width (1.0) local dash3 = C.DoubleVector () dash3:add ({1, 3}) local dash4 = C.DoubleVector () dash4:add ({1, 4}) -- plot every channel for c = 1,n_chn do local x = math.floor ((w - 2) * (c - .5) / n_chn) + 1.5 -- x-axis center for given channel -- draw grid -- ctx:set_source_rgba (.5, .5, .5, 1.0) ctx:move_to (x, 1) ctx:line_to (x, h - 1) ctx:stroke () ctx:set_dash (dash4, 2) ctx:set_source_rgba (.4, .4, .4, 1.0) if (logscale) then gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-18)) gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-6)) ctx:set_dash (dash3, 2) ctx:set_source_rgba (.5, .1, .1, 1.0) gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-3)) else gridline (ctx, x, xr, h, .1258) gridline (ctx, x, xr, h, .5) ctx:set_dash (dash3, 2) ctx:set_source_rgba (.5, .1, .1, 1.0) gridline (ctx, x, xr, h, .7079) end ctx:unset_dash () ctx:set_source_rgba (.5, .1, .1, 0.7) gridline (ctx, x, xr, h, 1) -- prepare waveform display drawing ctx:set_source_rgba (.8, .8, .8, .7) ctx:save () ctx:rectangle (math.floor (x - xr), 0, math.ceil (2 * xr), h) ctx:clip () local chn_off = 4 + buf_size * (c - 1) local buf_off = read_ptr; -- iterate over every y-axis pixel for y = 1, h - 1 do local s_min = 0 local s_max = 0 -- calc min/max values for given range if (buf_off + spp < buf_size) then _, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off + buf_off), s_min, s_max, spp)) else local r0 = buf_size - buf_off; _, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off + buf_off), s_min, s_max, r0)) _, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off) , s_min, s_max, spp - r0)) end buf_off = (buf_off + spp) % buf_size; if (logscale) then s_max = ARDOUR.DSP.log_meter_coeff (s_max) s_min = - ARDOUR.DSP.log_meter_coeff (-s_min) end ctx:move_to (x + s_min * xr, h - y + .5) ctx:line_to (x + s_max * xr, h - y + .5) end ctx:stroke () ctx:restore () end return {w, h} end