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Diffstat (limited to 'audio/filter/af_sub.c')
| -rw-r--r-- | audio/filter/af_sub.c | 148 |
1 files changed, 0 insertions, 148 deletions
diff --git a/audio/filter/af_sub.c b/audio/filter/af_sub.c deleted file mode 100644 index 82aa77f4a4..0000000000 --- a/audio/filter/af_sub.c +++ /dev/null @@ -1,148 +0,0 @@ -/* - * Copyright (C) 2002 Anders Johansson ajh@watri.uwa.edu.au - * - * This file is part of mpv. - * - * mpv is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * mpv 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with mpv. If not, see <http://www.gnu.org/licenses/>. - */ - -/* This filter adds a sub-woofer channels to the audio stream by - averaging the left and right channel and low-pass filter them. The - low-pass filter is implemented as a 4th order IIR Butterworth - filter, with a variable cutoff frequency between 10 and 300 Hz. The - filter gives 24dB/octave attenuation. There are two runtime - controls one for setting which channel to insert the sub-audio into - called AF_CONTROL_SUB_CH and one for setting the cutoff frequency - called AF_CONTROL_SUB_FC. -*/ - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> - -#include "common/common.h" -#include "af.h" -#include "dsp.h" - -// Q value for low-pass filter -#define Q 1.0 - -// Analog domain biquad section -typedef struct{ - float a[3]; // Numerator coefficients - float b[3]; // Denominator coefficients -} biquad_t; - -// S-parameters for designing 4th order Butterworth filter -static const biquad_t sp[2] = {{{1.0,0.0,0.0},{1.0,0.765367,1.0}}, - {{1.0,0.0,0.0},{1.0,1.847759,1.0}}}; - -// Data for specific instances of this filter -typedef struct af_sub_s -{ - float w[2][4]; // Filter taps for low-pass filter - float q[2][2]; // Circular queues - float fc; // Cutoff frequency [Hz] for low-pass filter - float k; // Filter gain; - int ch; // Channel number which to insert the filtered data - -}af_sub_t; - -// Initialization and runtime control -static int control(struct af_instance* af, int cmd, void* arg) -{ - af_sub_t* s = af->priv; - - switch(cmd){ - case AF_CONTROL_REINIT:{ - // Sanity check - if(!arg) return AF_ERROR; - - af->data->rate = ((struct mp_audio*)arg)->rate; - mp_audio_set_channels_old(af->data, MPMAX(s->ch+1,((struct mp_audio*)arg)->nch)); - mp_audio_set_format(af->data, AF_FORMAT_FLOAT); - - // Design low-pass filter - s->k = 1.0; - if((-1 == af_filter_szxform(sp[0].a, sp[0].b, Q, s->fc, - (float)af->data->rate, &s->k, s->w[0])) || - (-1 == af_filter_szxform(sp[1].a, sp[1].b, Q, s->fc, - (float)af->data->rate, &s->k, s->w[1]))) - return AF_ERROR; - return af_test_output(af,(struct mp_audio*)arg); - } - } - return AF_UNKNOWN; -} - -#ifndef IIR -#define IIR(in,w,q,out) { \ - float h0 = (q)[0]; \ - float h1 = (q)[1]; \ - float hn = (in) - h0 * (w)[0] - h1 * (w)[1]; \ - out = hn + h0 * (w)[2] + h1 * (w)[3]; \ - (q)[1] = h0; \ - (q)[0] = hn; \ -} -#endif - -static int filter_frame(struct af_instance *af, struct mp_audio *data) -{ - if (!data) - return 0; - if (af_make_writeable(af, data) < 0) { - talloc_free(data); - return -1; - } - - struct mp_audio* c = data; // Current working data - af_sub_t* s = af->priv; // Setup for this instance - float* a = c->planes[0]; // Audio data - int len = c->samples*c->nch; // Number of samples in current audio block - int nch = c->nch; // Number of channels - int ch = s->ch; // Channel in which to insert the sub audio - register int i; - - // Run filter - for(i=0;i<len;i+=nch){ - // Average left and right - register float x = 0.5 * (a[i] + a[i+1]); - IIR(x * s->k, s->w[0], s->q[0], x); - IIR(x , s->w[1], s->q[1], a[i+ch]); - } - - af_add_output_frame(af, data); - return 0; -} - -// Allocate memory and set function pointers -static int af_open(struct af_instance* af){ - af->control=control; - af->filter_frame = filter_frame; - return AF_OK; -} - -#define OPT_BASE_STRUCT af_sub_t -const struct af_info af_info_sub = { - .info = "Audio filter for adding a sub-base channel", - .name = "sub", - .flags = AF_FLAGS_NOT_REENTRANT, - .open = af_open, - .priv_size = sizeof(af_sub_t), - .options = (const struct m_option[]) { - OPT_FLOATRANGE("fc", fc, 0, 20, 300, OPTDEF_FLOAT(60.0)), - OPT_INTRANGE("ch", ch, 0, 0, AF_NCH - 1, OPTDEF_INT(5)), - {0} - }, -}; |