diff options
| author | Julien "_FrnchFrgg_" RIVAUD <frnchfrgg@free.fr> | 2016-07-19 16:38:26 +0200 |
|---|---|---|
| committer | Julien "_FrnchFrgg_" RIVAUD <frnchfrgg@free.fr> | 2016-07-19 16:42:27 +0200 |
| commit | 2e933a6414406d9bd069b73ac6094b49c9d2de81 (patch) | |
| tree | 8eca7c915e71100423370e45b754fe0ee98ec7c0 | |
| parent | 55bd8ff4d8b64d0780f7184636f41b9f2d2e2707 (diff) | |
Fix a typo in HiAndLowPass.lua
Instead of mixing two consecutive biquad orders with a linear xfade, the
code used the same weight for both signals to mix, due to a copy-paste
blunder. Brown-bag fix this now. Also change a little the threshold for
using 32-samples chunks to cater for steepness jumping from 0 to 4 (this
doesn't change anything for commonly used rates and is just for
robustness in never-happening cases anyway).
| -rw-r--r-- | scripts/HiAndLowPass.lua | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/scripts/HiAndLowPass.lua b/scripts/HiAndLowPass.lua index 3694ec315b..1c1b0686e5 100644 --- a/scripts/HiAndLowPass.lua +++ b/scripts/HiAndLowPass.lua @@ -70,11 +70,11 @@ function dsp_init (rate) -- For performance reasons, we want to ensure that two consecutive values -- of the interpolated "steepness" are less that 1 apart. By choosing the -- interpolation chunk size to be 64 in most cases, but 32 if the rate is - -- strictly less than 16kHz (there's only 8kHz in standard rates), we can + -- strictly less than 22kHz (there's only 8kHz in standard rates), we can -- ensure that steepness interpolation will never change the parameter by - -- more than ~0.82. + -- more than ~0.86. lpf_chunk = 64 - if rate < 16000 then lpf_chunk = 32 end + if rate < 22000 then lpf_chunk = 32 end -- We apply a discrete version of the standard RC low-pass, with a cutoff -- frequency of 15Hz. For more information about the underlying math, see -- https://en.wikipedia.org/wiki/Low-pass_filter#Discrete-time_realization @@ -198,11 +198,11 @@ function dsp_run (ins, outs, n_samples) if xfade > 0 then ARDOUR.DSP.apply_gain_to_buffer (outs[c]:offset (off), siz, 1 - xfade) hp[c][ho+1]:run (mem:to_float (off), siz) - ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade) + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, xfade) -- also run the next biquad because it needs to have the correct state -- in case it start affecting the next chunck of output. Higher order -- ones are guaranteed not to be needed for the next run because the - -- interpolated order won't increase more than 0.8 in one step thanks + -- interpolated order won't increase more than 0.86 in one step thanks -- to the choice of the value of |lpf|. if ho + 2 <= 4 then hp[c][ho+2]:run (mem:to_float (off), siz) end elseif ho + 1 <= 4 then @@ -227,7 +227,7 @@ function dsp_run (ins, outs, n_samples) if xfade > 0 then ARDOUR.DSP.apply_gain_to_buffer (outs[c]:offset (off), siz, 1 - xfade) lp[c][lo+1]:run (mem:to_float (off), siz) - ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade) + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, xfade) -- also run the next biquad in case it start affecting the next -- chunck of output. if lo + 2 <= 4 then lp[c][lo+2]:run (mem:to_float (off), siz) end |