diff options
author | Hans Baier <hansfbaier@googlemail.com> | 2009-07-22 08:42:33 +0000 |
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committer | Hans Baier <hansfbaier@googlemail.com> | 2009-07-22 08:42:33 +0000 |
commit | b0bb5342dd0fddf867208ea1e4c4a87a32a7b214 (patch) | |
tree | e51bed9ecdb42e9a2c5582977a12fdecd1b60bef /libs/ardour/interpolation.cc | |
parent | 272cad6241ababb0e2033f27e0511596b3e32b15 (diff) |
interpolation.cc/.h: Spline-Bugfixes: Crash bug at tempos close to 0, wrong calculation of M, unbounded precalculated L/U Matrices
git-svn-id: svn://localhost/ardour2/branches/3.0@5410 d708f5d6-7413-0410-9779-e7cbd77b26cf
Diffstat (limited to 'libs/ardour/interpolation.cc')
-rw-r--r-- | libs/ardour/interpolation.cc | 49 |
1 files changed, 28 insertions, 21 deletions
diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index 8b4bb862ed..716ebd4139 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -120,10 +120,12 @@ SplineInterpolation::SplineInterpolation() { // precompute LU-factorization of matrix A // see "Teubner Taschenbuch der Mathematik", p. 1105 - m[0] = 4.0; - for (int i = 0; i <= MAX_PERIOD_SIZE - 2; i++) { - l[i] = 1.0 / m[i]; - m[i+1] = 4.0 - l[i]; + // We only need to calculate up to 20, because they + // won't change any more above that + _m[0] = 4.0; + for (int i = 0; i <= 20 - 2; i++) { + _l[i] = 1.0 / _m[i]; + _m[i+1] = 4.0 - _l[i]; } } @@ -131,9 +133,12 @@ nframes_t SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output) { // How many input samples we need - nframes_t n = ceil (double(nframes) * _speed) + 2; - // |------------------------------------------^ - // this won't be here in the debugged version. + nframes_t n = ceil (double(nframes) * _speed + phase[channel]) + 1; + //printf("n = %d\n", n); + + if (n <= 3) { + return 0; + } double M[n], t[n-2]; @@ -142,20 +147,19 @@ SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, M[n - 1] = 0.0; // solve L * t = d - // see "Teubner Taschenbuch der Mathematik", p. 1105 t[0] = 6.0 * (input[0] - 2*input[1] + input[2]); for (nframes_t i = 1; i <= n - 3; i++) { t[i] = 6.0 * (input[i] - 2*input[i+1] + input[i+2]) - - l[i-1] * t[i-1]; + - l(i-1) * t[i-1]; } - // solve R * M = t - // see "Teubner Taschenbuch der Mathematik", p. 1105 - M[n-2] = -t[n-3] / m[n-3]; + // solve U * M = t + M[n-2] = t[n-3] / m(n-3); for (nframes_t i = n-4;; i--) { - M[i+1] = -(t[i] + M[i+2]) / m[i]; + M[i+1] = (t[i]-M[i+2])/m(i); if ( i == 0 ) break; } + assert (M[0] == 0.0 && M[n-1] == 0.0); // now interpolate // index in the input buffers @@ -174,29 +178,32 @@ SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, for (nframes_t outsample = 0; outsample < nframes; outsample++) { i = floor(distance); - Sample x = distance - i; + Sample x = double(distance) - double(i); - /* this would break the assertion below + // if distance is something like 0.999999999999 + // it will get rounded to 1 in the conversion to float above if (x >= 1.0) { - x -= 1.0; + x = 0.0; i++; } - */ + + assert(x >= 0.0 && x < 1.0); if (input && output) { assert (i <= n-1); - double a0 = input[i]; - double a1 = input[i+1] - input[i] - M[i+1]/6.0 - M[i]/3.0; - double a2 = M[i] / 2.0; double a3 = (M[i+1] - M[i]) / 6.0; + double a2 = M[i] / 2.0; + double a1 = input[i+1] - input[i] - (M[i+1] + 2.0*M[i])/6.0; + double a0 = input[i]; // interpolate into the output buffer - output[outsample] = ((a3*x +a2)*x +a1)*x + a0; + output[outsample] = ((a3*x + a2)*x + a1)*x + a0; } distance += _speed + acceleration; } i = floor(distance); phase[channel] = distance - floor(distance); + assert (phase[channel] >= 0.0 && phase[channel] < 1.0); return i; } |