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Diffstat (limited to 'examples/audioresample/resample_chunk.c')
| -rw-r--r-- | examples/audioresample/resample_chunk.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/examples/audioresample/resample_chunk.c b/examples/audioresample/resample_chunk.c new file mode 100644 index 0000000..50c5924 --- /dev/null +++ b/examples/audioresample/resample_chunk.c @@ -0,0 +1,200 @@ +/* + * LIBOIL - Library of Optimized Inner Loops + * Copyright (c) 2001,2006 David A. Schleef <ds@schleef.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + + +#include <string.h> +#include <math.h> +#include <stdio.h> +#include <stdlib.h> +#include <limits.h> +#include <liboil/liboil.h> + +#include <audioresample/resample.h> +#include <audioresample/buffer.h> +#include <audioresample/debug.h> + + +static double +resample_sinc_window (double x, double halfwidth, double scale) +{ + double y; + + if (x == 0) return 1.0; + if (x < -halfwidth || x > halfwidth) return 0.0; + + y = sin(x * M_PI * scale)/(x * M_PI * scale) * scale; + + x /= halfwidth; + y *= (1 - x * x) * (1 - x * x); + + return y; +} + +void +resample_scale_chunk (ResampleState * r) +{ + if (r->need_reinit) { + r->sample_size = r->n_channels * resample_format_size(r->format); + OIL_DEBUG("sample size %d", r->sample_size); + + if (r->buffer) free(r->buffer); + r->buffer_len = r->sample_size * 1000; + r->buffer = malloc(r->buffer_len); + memset (r->buffer, 0, r->buffer_len); + + r->i_inc = r->o_rate / r->i_rate; + r->o_inc = r->i_rate / r->o_rate; + OIL_DEBUG("i_inc %g o_inc %g", r->i_inc, r->o_inc); + + r->i_start = - r->i_inc * r->filter_length; + + r->need_reinit = 0; + +#if 0 + if (r->i_inc < 1.0) { + r->sinc_scale = r->i_inc; + if (r->sinc_scale == 0.5) { + /* strange things happen at integer multiples */ + r->sinc_scale = 1.0; + } + } else { + r->sinc_scale = 1.0; + } +#else + r->sinc_scale = 1.0; +#endif + } + + while(r->o_size > 0) { + double midpoint; + int i; + int j; + + OIL_DEBUG("i_start %g", r->i_start); + midpoint = r->i_start + (r->filter_length - 1)*0.5*r->i_inc; + if (midpoint > 0.5 * r->i_inc) { + OIL_ERROR("inconsistent state"); + } + while (midpoint < -0.5 * r->i_inc) { + AudioresampleBuffer *buffer; + + buffer = audioresample_buffer_queue_pull (r->queue, r->sample_size); + if (buffer == NULL) { + OIL_ERROR("buffer_queue_pull returned NULL"); + return; + } + + r->i_start += r->i_inc; + OIL_DEBUG("pulling (i_start = %g)", r->i_start); + + midpoint += r->i_inc; + memmove (r->buffer, r->buffer + r->sample_size, + r->buffer_len - r->sample_size); + + memcpy (r->buffer + r->buffer_len - r->sample_size, buffer->data, + r->sample_size); + audioresample_buffer_unref (buffer); + } + + switch(r->format) { + case RESAMPLE_FORMAT_S16: + for (i=0;i<r->n_channels;i++) { + double acc = 0; + double offset; + double x; + + for(j=0;j<r->filter_length;j++){ + offset = (r->i_start + j * r->i_inc) * r->o_inc; + x = *(int16_t *)(r->buffer + i * sizeof(int16_t) + j*r->sample_size); + acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x; + } + if(acc<-32768.0)acc=-32768.0; + if(acc>32767.0)acc=32767.0; + + *(int16_t *)(r->o_buf + i * sizeof(int16_t)) = rint(acc); + } + break; + case RESAMPLE_FORMAT_S32: + for (i=0;i<r->n_channels;i++) { + double acc = 0; + double offset; + double x; + + for(j=0;j<r->filter_length;j++){ + offset = (r->i_start + j * r->i_inc) * r->o_inc; + x = *(int32_t *)(r->buffer + i * sizeof(int32_t) + j*r->sample_size); + acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x; + } + if(acc<-2147483648.0)acc=-2147483648.0; + if(acc>2147483647.0)acc=2147483647.0; + + *(int32_t *)(r->o_buf + i * sizeof(int32_t)) = rint(acc); + } + break; + case RESAMPLE_FORMAT_F32: + for (i=0;i<r->n_channels;i++) { + double acc = 0; + double offset; + double x; + + for(j=0;j<r->filter_length;j++){ + offset = (r->i_start + j * r->i_inc) * r->o_inc; + x = *(float *)(r->buffer + i * sizeof(float) + j*r->sample_size); + acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x; + } + + *(float *)(r->o_buf + i * sizeof(float)) = acc; + } + break; + case RESAMPLE_FORMAT_F64: + for (i=0;i<r->n_channels;i++) { + double acc = 0; + double offset; + double x; + + for(j=0;j<r->filter_length;j++){ + offset = (r->i_start + j * r->i_inc) * r->o_inc; + x = *(double *)(r->buffer + i * sizeof(double) + j*r->sample_size); + acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x; + } + + *(double *)(r->o_buf + i * sizeof(double)) = acc; + } + break; + } + + r->i_start -= 1.0; + r->o_buf += r->sample_size; + r->o_size -= r->sample_size; + } + +} + |