diff options
Diffstat (limited to 'scripts/spectrogram.lua')
| -rw-r--r-- | scripts/spectrogram.lua | 85 |
1 files changed, 59 insertions, 26 deletions
diff --git a/scripts/spectrogram.lua b/scripts/spectrogram.lua index 4f55a654a7..86419682b4 100644 --- a/scripts/spectrogram.lua +++ b/scripts/spectrogram.lua @@ -40,6 +40,11 @@ function dsp_params () } end +-- symbolic names for shmem offsets +local SHMEM_RATE = 0 +local SHMEM_WRITEPTR = 1 +local SHMEM_AUDIO = 2 + -- a C memory area. -- It needs to be in global scope. -- When the variable is set to nil, the allocated memory is free()ed. @@ -53,36 +58,34 @@ function dsp_init (rate) dpy_hz = rate / 25 dpy_wr = 0 - -- create a ringbuffer to hold (float) audio-data - -- http://manual.ardour.org/lua-scripting/class_reference/#PBD:RingBufferF - rb = PBD.RingBufferF (2 * rate) + -- create a shared memory area to hold the sample rate, the write_pointer, + -- and (float) audio-data. Make it big enough to store 2s of audio which + -- should be enough. If not, the DSP will overwrite the oldest data anyway. + self:shmem ():allocate(2 + 2 * rate) + self:shmem ():clear() + self:shmem ():atomic_set_int (SHMEM_RATE, rate) + self:shmem ():atomic_set_int (SHMEM_WRITEPTR, 0) -- allocate memory, local mix buffer cmem = ARDOUR.DSP.DspShm (8192) - - -- create a table of objects to share with the GUI - local tbl = {} - tbl['rb'] = rb; - tbl['samplerate'] = rate - - -- "self" is a special DSP variable referring - -- to the plugin instance itself. - -- - -- "table()" is-a http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR.LuaTableRef - -- which allows to store/retrieve lua-tables to share them other interpreters - self:table ():set (tbl); end -- "dsp_runmap" uses Ardour's internal processor API, eqivalent to -- 'connect_and_run()". There is no overhead (mapping, translating buffers). -- The lua implementation is responsible to map all the buffers directly. function dsp_runmap (bufs, in_map, out_map, n_samples, offset) - -- here we sum all audio input channels channels and then copy the data to a ringbuffer - -- for the GUI to process later + -- here we sum all audio input channels and then copy the data to a + -- custom-made circular table for the GUIs to process later local audio_ins = in_map:count (): n_audio () -- number of audio input buffers local ccnt = 0 -- processed channel count local mem = cmem:to_float(0) -- a "FloatArray", float* for direct C API usage from the previously allocated buffer + local rate = self:shmem ():atomic_get_int (SHMEM_RATE) + local write_ptr = self:shmem ():atomic_get_int (SHMEM_WRITEPTR) + + local ringsize = 2 * rate + local ptr_wrap = math.floor(2^50 / ringsize) * ringsize + for c = 1,audio_ins do -- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:ChanMapping -- Note: lua starts counting at 1, ardour's ChanMapping::get() at 0 @@ -131,9 +134,15 @@ function dsp_runmap (bufs, in_map, out_map, n_samples, offset) ARDOUR.DSP.memset (mem, 0, n_samples) end - -- write data to the ringbuffer - -- http://manual.ardour.org/lua-scripting/class_reference/#PBD:RingBufferF - rb:write (mem, n_samples) + -- write data to the circular table + if (write_ptr % ringsize + n_samples < ringsize) then + ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO + write_ptr % ringsize), mem, n_samples) + else + local chunk = ringsize - write_ptr % ringsize + ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO + write_ptr % ringsize), mem, chunk) + ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO), cmem:to_float (chunk), n_samples - chunk) + end + self:shmem ():atomic_set_int (SHMEM_WRITEPTR, (write_ptr + n_samples) % ptr_wrap) -- emit QueueDraw every FPS -- TODO: call every FFT window-size worth of samples, at most every FPS @@ -154,10 +163,10 @@ local img = nil local fft_size = 0 local last_log = false + function render_inline (ctx, w, max_h) local ctrl = CtrlPorts:array () -- get control port array (read/write) - local tbl = self:table ():get () -- get shared memory table - local rate = tbl['samplerate'] + local rate = self:shmem ():atomic_get_int (SHMEM_RATE) if not cmem then cmem = ARDOUR.DSP.DspShm (0) end @@ -231,12 +240,36 @@ function render_inline (ctx, w, max_h) local f_b = w / math.log (fft_size / 2) -- inverse log-scale base local f_l = math.log (fft_size / rate) * f_b -- inverse logscale lower-bound - local rb = tbl['rb']; local mem = cmem:to_float (0) - while (rb:read_space() >= fft_size) do - -- process one line / buffer - rb:read (mem, fft_size) + local ringsize = 2 * rate + local ptr_wrap = math.floor(2^50 / ringsize) * ringsize + + local write_ptr + function read_space() + write_ptr = self:shmem ():atomic_get_int (SHMEM_WRITEPTR) + local space = (write_ptr - read_ptr + ptr_wrap) % ptr_wrap + if space > ringsize then + -- the GUI lagged too much and unread data was overwritten + -- jump to the oldest audio still present in the ringtable + read_ptr = write_ptr - ringsize + space = ringsize + end + return space + end + + while (read_space() >= fft_size) do + -- read one window from the circular table + if (read_ptr % ringsize + fft_size < ringsize) then + ARDOUR.DSP.copy_vector (mem, self:shmem ():to_float (SHMEM_AUDIO + read_ptr % ringsize), fft_size) + else + local chunk = ringsize - read_ptr % ringsize + ARDOUR.DSP.copy_vector (mem, self:shmem ():to_float (SHMEM_AUDIO + read_ptr % ringsize), chunk) + ARDOUR.DSP.copy_vector (cmem:to_float(chunk), self:shmem ():to_float (SHMEM_AUDIO), fft_size - chunk) + end + read_ptr = (read_ptr + fft_size) % ptr_wrap + + -- process one line fft:set_data_hann (mem, fft_size, 0) fft:execute () |