mirror of
https://github.com/libretro/RetroArch
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144 lines
4.2 KiB
C
144 lines
4.2 KiB
C
/* Copyright (C) 2010-2017 The RetroArch team
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*
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* ---------------------------------------------------------------------------------------
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* The following license statement only applies to this file (sinc_resampler.c).
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* ---------------------------------------------------------------------------------------
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*
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* Permission is hereby granted, free of charge,
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* to any person obtaining a copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/* Bog-standard windowed SINC implementation. */
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#include <stdint.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#include <retro_inline.h>
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#include <filters.h>
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#include <memalign.h>
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#include <audio/audio_resampler.h>
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#include "sinc_resampler_common.h"
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static void resampler_sinc_process(void *re_, struct resampler_data *data)
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{
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rarch_sinc_resampler_t *re = (rarch_sinc_resampler_t*)re_;
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uint32_t ratio = PHASES / data->ratio;
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const float *input = data->data_in;
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float *output = data->data_out;
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size_t frames = data->input_frames;
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size_t out_frames = 0;
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while (frames)
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{
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while (frames && re->time >= PHASES)
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{
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/* Push in reverse to make filter more obvious. */
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if (!re->ptr)
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re->ptr = re->taps;
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re->ptr--;
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re->buffer_l[re->ptr + re->taps] = re->buffer_l[re->ptr] = *input++;
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re->buffer_r[re->ptr + re->taps] = re->buffer_r[re->ptr] = *input++;
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re->time -= PHASES;
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frames--;
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}
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while (re->time < PHASES)
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{
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process_sinc_func(re, output);
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output += 2;
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out_frames++;
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re->time += ratio;
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}
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}
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data->output_frames = out_frames;
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}
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static void *resampler_sinc_new(const struct resampler_config *config,
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double bandwidth_mod, resampler_simd_mask_t mask)
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{
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double cutoff;
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size_t phase_elems, elems;
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rarch_sinc_resampler_t *re = (rarch_sinc_resampler_t*)
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calloc(1, sizeof(*re));
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if (!re)
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return NULL;
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(void)config;
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re->taps = TAPS;
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cutoff = CUTOFF;
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/* Downsampling, must lower cutoff, and extend number of
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* taps accordingly to keep same stopband attenuation. */
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if (bandwidth_mod < 1.0)
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{
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cutoff *= bandwidth_mod;
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re->taps = (unsigned)ceil(re->taps / bandwidth_mod);
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}
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/* Be SIMD-friendly. */
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#if (defined(__AVX__) && ENABLE_AVX) || (defined(__ARM_NEON__))
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re->taps = (re->taps + 7) & ~7;
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#else
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re->taps = (re->taps + 3) & ~3;
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#endif
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phase_elems = (1 << PHASE_BITS) * re->taps;
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#if SINC_COEFF_LERP
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phase_elems *= 2;
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#endif
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elems = phase_elems + 4 * re->taps;
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re->main_buffer = (float*)memalign_alloc(128, sizeof(float) * elems);
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if (!re->main_buffer)
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goto error;
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re->phase_table = re->main_buffer;
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re->buffer_l = re->main_buffer + phase_elems;
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re->buffer_r = re->buffer_l + 2 * re->taps;
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sinc_init_table(re, cutoff, re->phase_table,
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1 << PHASE_BITS, re->taps, SINC_COEFF_LERP);
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#if defined(__ARM_NEON__)
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process_sinc_func = mask & RESAMPLER_SIMD_NEON
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? process_sinc_neon : process_sinc_C;
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#endif
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return re;
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error:
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sinc_free(re);
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return NULL;
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}
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retro_resampler_t sinc_resampler = {
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resampler_sinc_new,
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resampler_sinc_process,
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sinc_free,
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RESAMPLER_API_VERSION,
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"sinc",
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"sinc"
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};
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