diff options
Diffstat (limited to 'intern/audaspace/FX/AUD_ButterworthReader.cpp')
| -rw-r--r-- | intern/audaspace/FX/AUD_ButterworthReader.cpp | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/intern/audaspace/FX/AUD_ButterworthReader.cpp b/intern/audaspace/FX/AUD_ButterworthReader.cpp new file mode 100644 index 00000000000..adcae87ce9f --- /dev/null +++ b/intern/audaspace/FX/AUD_ButterworthReader.cpp @@ -0,0 +1,120 @@ +/* + * $Id$ + * + * ***** BEGIN LGPL LICENSE BLOCK ***** + * + * Copyright 2009 Jörg Hermann Müller + * + * This file is part of AudaSpace. + * + * AudaSpace is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * AudaSpace is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with AudaSpace. If not, see <http://www.gnu.org/licenses/>. + * + * ***** END LGPL LICENSE BLOCK ***** + */ + +#include "AUD_ButterworthReader.h" +#include "AUD_Buffer.h" + +#include <cstring> +#include <cmath> + +#define BWPB41 0.76536686473 +#define BWPB42 1.84775906502 +#define CC channels + channel + +AUD_ButterworthReader::AUD_ButterworthReader(AUD_IReader* reader, + float frequency) : + AUD_EffectReader(reader) +{ + AUD_Specs specs = reader->getSpecs(); + int samplesize = AUD_SAMPLE_SIZE(specs); + + m_buffer = new AUD_Buffer(); AUD_NEW("buffer") + + m_outvalues = new AUD_Buffer(samplesize * 5); AUD_NEW("buffer") + memset(m_outvalues->getBuffer(), 0, samplesize * 5); + + m_invalues = new AUD_Buffer(samplesize * 5); AUD_NEW("buffer") + memset(m_invalues->getBuffer(), 0, samplesize * 5); + + m_position = 0; + + // calculate coefficients + float omega = 2 * tan(frequency * M_PI / specs.rate); + float o2 = omega * omega; + float o4 = o2 * o2; + float x1 = o2 + 2 * BWPB41 * omega + 4; + float x2 = o2 + 2 * BWPB42 * omega + 4; + float y1 = o2 - 2 * BWPB41 * omega + 4; + float y2 = o2 - 2 * BWPB42 * omega + 4; + float o228 = 2 * o2 - 8; + float norm = x1 * x2; + m_coeff[0][0] = 0; + m_coeff[0][1] = (x1 + x2) * o228 / norm; + m_coeff[0][2] = (x1 * y2 + x2 * y1 + o228 * o228) / norm; + m_coeff[0][3] = (y1 + y2) * o228 / norm; + m_coeff[0][4] = y1 * y2 / norm; + m_coeff[1][4] = m_coeff[1][0] = o4 / norm; + m_coeff[1][3] = m_coeff[1][1] = 4 * o4 / norm; + m_coeff[1][2] = 6 * o4 / norm; +} + +AUD_ButterworthReader::~AUD_ButterworthReader() +{ + delete m_buffer; AUD_DELETE("buffer") + + delete m_outvalues; AUD_DELETE("buffer") + delete m_invalues; AUD_DELETE("buffer"); +} + +void AUD_ButterworthReader::read(int & length, sample_t* & buffer) +{ + sample_t* buf; + sample_t* outvalues; + sample_t* invalues; + + outvalues = m_outvalues->getBuffer(); + invalues = m_invalues->getBuffer(); + + AUD_Specs specs = m_reader->getSpecs(); + + m_reader->read(length, buf); + + if(m_buffer->getSize() < length * AUD_SAMPLE_SIZE(specs)) + m_buffer->resize(length * AUD_SAMPLE_SIZE(specs)); + + buffer = m_buffer->getBuffer(); + int channels = specs.channels; + + for(int channel = 0; channel < channels; channel++) + { + for(int i = 0; i < length; i++) + { + invalues[m_position * CC] = buf[i * CC]; + outvalues[m_position * CC] = 0; + + for(int j = 0; j < 4; j++) + { + outvalues[m_position * CC] += m_coeff[1][j] * + invalues[((m_position + j) % 5) * CC] - + m_coeff[0][j] * + outvalues[((m_position + j) % 5) * CC]; + } + + buffer[i * CC] = outvalues[m_position * CC]; + + m_position = (m_position + 4) % 5; + } + } +} |