mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-21 10:55:51 +02:00
446 lines
14 KiB
C
446 lines
14 KiB
C
/*
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* Copyright (c) 2008-2009 Rob Sykes <robs@users.sourceforge.net>
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* Copyright (c) 2017 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avassert.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/opt.h"
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#include "libavutil/tx.h"
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#include "audio.h"
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#include "avfilter.h"
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#include "filters.h"
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#include "internal.h"
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typedef struct SincContext {
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const AVClass *class;
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int sample_rate, nb_samples;
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float att, beta, phase, Fc0, Fc1, tbw0, tbw1;
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int num_taps[2];
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int round;
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int n, rdft_len;
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float *coeffs;
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int64_t pts;
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AVTXContext *tx, *itx;
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av_tx_fn tx_fn, itx_fn;
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} SincContext;
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static int activate(AVFilterContext *ctx)
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{
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AVFilterLink *outlink = ctx->outputs[0];
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SincContext *s = ctx->priv;
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const float *coeffs = s->coeffs;
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AVFrame *frame = NULL;
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int nb_samples;
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if (!ff_outlink_frame_wanted(outlink))
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return FFERROR_NOT_READY;
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nb_samples = FFMIN(s->nb_samples, s->n - s->pts);
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if (nb_samples <= 0) {
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ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
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return 0;
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}
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if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
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return AVERROR(ENOMEM);
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memcpy(frame->data[0], coeffs + s->pts, nb_samples * sizeof(float));
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frame->pts = s->pts;
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s->pts += nb_samples;
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return ff_filter_frame(outlink, frame);
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}
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static int query_formats(AVFilterContext *ctx)
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{
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SincContext *s = ctx->priv;
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static const AVChannelLayout chlayouts[] = { AV_CHANNEL_LAYOUT_MONO, { 0 } };
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int sample_rates[] = { s->sample_rate, -1 };
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static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLT,
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AV_SAMPLE_FMT_NONE };
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int ret = ff_set_common_formats_from_list(ctx, sample_fmts);
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if (ret < 0)
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return ret;
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ret = ff_set_common_channel_layouts_from_list(ctx, chlayouts);
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if (ret < 0)
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return ret;
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return ff_set_common_samplerates_from_list(ctx, sample_rates);
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}
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static float bessel_I_0(float x)
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{
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float term = 1, sum = 1, last_sum, x2 = x / 2;
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int i = 1;
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do {
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float y = x2 / i++;
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last_sum = sum;
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sum += term *= y * y;
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} while (sum != last_sum);
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return sum;
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}
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static float *make_lpf(int num_taps, float Fc, float beta, float rho,
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float scale, int dc_norm)
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{
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int i, m = num_taps - 1;
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float *h = av_calloc(num_taps, sizeof(*h)), sum = 0;
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float mult = scale / bessel_I_0(beta), mult1 = 1.f / (.5f * m + rho);
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if (!h)
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return NULL;
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av_assert0(Fc >= 0 && Fc <= 1);
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for (i = 0; i <= m / 2; i++) {
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float z = i - .5f * m, x = z * M_PI, y = z * mult1;
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h[i] = x ? sinf(Fc * x) / x : Fc;
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sum += h[i] *= bessel_I_0(beta * sqrtf(1.f - y * y)) * mult;
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if (m - i != i) {
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h[m - i] = h[i];
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sum += h[i];
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}
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}
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for (i = 0; dc_norm && i < num_taps; i++)
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h[i] *= scale / sum;
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return h;
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}
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static float kaiser_beta(float att, float tr_bw)
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{
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if (att >= 60.f) {
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static const float coefs[][4] = {
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{-6.784957e-10, 1.02856e-05, 0.1087556, -0.8988365 + .001},
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{-6.897885e-10, 1.027433e-05, 0.10876, -0.8994658 + .002},
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{-1.000683e-09, 1.030092e-05, 0.1087677, -0.9007898 + .003},
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{-3.654474e-10, 1.040631e-05, 0.1087085, -0.8977766 + .006},
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{8.106988e-09, 6.983091e-06, 0.1091387, -0.9172048 + .015},
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{9.519571e-09, 7.272678e-06, 0.1090068, -0.9140768 + .025},
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{-5.626821e-09, 1.342186e-05, 0.1083999, -0.9065452 + .05},
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{-9.965946e-08, 5.073548e-05, 0.1040967, -0.7672778 + .085},
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{1.604808e-07, -5.856462e-05, 0.1185998, -1.34824 + .1},
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{-1.511964e-07, 6.363034e-05, 0.1064627, -0.9876665 + .18},
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};
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float realm = logf(tr_bw / .0005f) / logf(2.f);
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float const *c0 = coefs[av_clip((int)realm, 0, FF_ARRAY_ELEMS(coefs) - 1)];
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float const *c1 = coefs[av_clip(1 + (int)realm, 0, FF_ARRAY_ELEMS(coefs) - 1)];
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float b0 = ((c0[0] * att + c0[1]) * att + c0[2]) * att + c0[3];
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float b1 = ((c1[0] * att + c1[1]) * att + c1[2]) * att + c1[3];
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return b0 + (b1 - b0) * (realm - (int)realm);
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}
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if (att > 50.f)
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return .1102f * (att - 8.7f);
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if (att > 20.96f)
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return .58417f * powf(att - 20.96f, .4f) + .07886f * (att - 20.96f);
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return 0;
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}
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static void kaiser_params(float att, float Fc, float tr_bw, float *beta, int *num_taps)
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{
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*beta = *beta < 0.f ? kaiser_beta(att, tr_bw * .5f / Fc): *beta;
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att = att < 60.f ? (att - 7.95f) / (2.285f * M_PI * 2.f) :
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((.0007528358f-1.577737e-05 * *beta) * *beta + 0.6248022f) * *beta + .06186902f;
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*num_taps = !*num_taps ? ceilf(att/tr_bw + 1) : *num_taps;
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}
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static float *lpf(float Fn, float Fc, float tbw, int *num_taps, float att, float *beta, int round)
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{
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int n = *num_taps;
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if ((Fc /= Fn) <= 0.f || Fc >= 1.f) {
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*num_taps = 0;
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return NULL;
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}
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att = att ? att : 120.f;
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kaiser_params(att, Fc, (tbw ? tbw / Fn : .05f) * .5f, beta, num_taps);
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if (!n) {
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n = *num_taps;
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*num_taps = av_clip(n, 11, 32767);
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if (round)
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*num_taps = 1 + 2 * (int)((int)((*num_taps / 2) * Fc + .5f) / Fc + .5f);
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}
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return make_lpf(*num_taps |= 1, Fc, *beta, 0.f, 1.f, 0);
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}
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static void invert(float *h, int n)
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{
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for (int i = 0; i < n; i++)
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h[i] = -h[i];
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h[(n - 1) / 2] += 1;
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}
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#define SQR(a) ((a) * (a))
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static float safe_log(float x)
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{
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av_assert0(x >= 0);
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if (x)
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return logf(x);
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return -26;
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}
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static int fir_to_phase(SincContext *s, float **h, int *len, int *post_len, float phase)
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{
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float *pi_wraps, *work, phase1 = (phase > 50.f ? 100.f - phase : phase) / 50.f;
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int i, work_len, begin, end, imp_peak = 0, peak = 0;
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float imp_sum = 0, peak_imp_sum = 0, scale = 1.f;
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float prev_angle2 = 0, cum_2pi = 0, prev_angle1 = 0, cum_1pi = 0;
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for (i = *len, work_len = 2 * 2 * 8; i > 1; work_len <<= 1, i >>= 1);
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/* The first part is for work (+2 for (UN)PACK), the latter for pi_wraps. */
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work = av_calloc((work_len + 2) + (work_len / 2 + 1), sizeof(float));
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if (!work)
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return AVERROR(ENOMEM);
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pi_wraps = &work[work_len + 2];
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memcpy(work, *h, *len * sizeof(*work));
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av_tx_uninit(&s->tx);
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av_tx_uninit(&s->itx);
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av_tx_init(&s->tx, &s->tx_fn, AV_TX_FLOAT_RDFT, 0, work_len, &scale, AV_TX_INPLACE);
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av_tx_init(&s->itx, &s->itx_fn, AV_TX_FLOAT_RDFT, 1, work_len, &scale, AV_TX_INPLACE);
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if (!s->tx || !s->itx) {
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av_free(work);
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return AVERROR(ENOMEM);
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}
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s->tx_fn(s->tx, work, work, sizeof(float)); /* Cepstral: */
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for (i = 0; i <= work_len; i += 2) {
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float angle = atan2f(work[i + 1], work[i]);
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float detect = 2 * M_PI;
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float delta = angle - prev_angle2;
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float adjust = detect * ((delta < -detect * .7f) - (delta > detect * .7f));
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prev_angle2 = angle;
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cum_2pi += adjust;
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angle += cum_2pi;
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detect = M_PI;
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delta = angle - prev_angle1;
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adjust = detect * ((delta < -detect * .7f) - (delta > detect * .7f));
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prev_angle1 = angle;
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cum_1pi += fabsf(adjust); /* fabs for when 2pi and 1pi have combined */
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pi_wraps[i >> 1] = cum_1pi;
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work[i] = safe_log(sqrtf(SQR(work[i]) + SQR(work[i + 1])));
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work[i + 1] = 0;
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}
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s->itx_fn(s->itx, work, work, sizeof(AVComplexFloat));
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for (i = 0; i < work_len; i++)
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work[i] *= 2.f / work_len;
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for (i = 1; i < work_len / 2; i++) { /* Window to reject acausal components */
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work[i] *= 2;
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work[i + work_len / 2] = 0;
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}
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s->tx_fn(s->tx, work, work, sizeof(float));
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for (i = 2; i < work_len; i += 2) /* Interpolate between linear & min phase */
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work[i + 1] = phase1 * i / work_len * pi_wraps[work_len >> 1] + (1 - phase1) * (work[i + 1] + pi_wraps[i >> 1]) - pi_wraps[i >> 1];
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work[0] = exp(work[0]);
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work[1] = exp(work[1]);
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for (i = 2; i < work_len; i += 2) {
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float x = expf(work[i]);
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work[i ] = x * cosf(work[i + 1]);
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work[i + 1] = x * sinf(work[i + 1]);
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}
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s->itx_fn(s->itx, work, work, sizeof(AVComplexFloat));
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for (i = 0; i < work_len; i++)
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work[i] *= 2.f / work_len;
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/* Find peak pos. */
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for (i = 0; i <= (int) (pi_wraps[work_len >> 1] / M_PI + .5f); i++) {
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imp_sum += work[i];
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if (fabs(imp_sum) > fabs(peak_imp_sum)) {
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peak_imp_sum = imp_sum;
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peak = i;
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}
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if (work[i] > work[imp_peak]) /* For debug check only */
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imp_peak = i;
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}
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while (peak && fabsf(work[peak - 1]) > fabsf(work[peak]) && (work[peak - 1] * work[peak] > 0)) {
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peak--;
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}
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if (!phase1) {
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begin = 0;
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} else if (phase1 == 1) {
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begin = peak - *len / 2;
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} else {
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begin = (.997f - (2 - phase1) * .22f) * *len + .5f;
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end = (.997f + (0 - phase1) * .22f) * *len + .5f;
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begin = peak - (begin & ~3);
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end = peak + 1 + ((end + 3) & ~3);
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*len = end - begin;
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*h = av_realloc_f(*h, *len, sizeof(**h));
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if (!*h) {
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av_free(work);
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return AVERROR(ENOMEM);
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}
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}
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for (i = 0; i < *len; i++) {
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(*h)[i] = work[(begin + (phase > 50.f ? *len - 1 - i : i) + work_len) & (work_len - 1)];
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}
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*post_len = phase > 50 ? peak - begin : begin + *len - (peak + 1);
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av_log(s, AV_LOG_DEBUG, "%d nPI=%g peak-sum@%i=%g (val@%i=%g); len=%i post=%i (%g%%)\n",
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work_len, pi_wraps[work_len >> 1] / M_PI, peak, peak_imp_sum, imp_peak,
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work[imp_peak], *len, *post_len, 100.f - 100.f * *post_len / (*len - 1));
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av_free(work);
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return 0;
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}
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static int config_output(AVFilterLink *outlink)
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{
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AVFilterContext *ctx = outlink->src;
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SincContext *s = ctx->priv;
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float Fn = s->sample_rate * .5f;
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float *h[2];
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int i, n, post_peak, longer;
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outlink->sample_rate = s->sample_rate;
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s->pts = 0;
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if (s->Fc0 >= Fn || s->Fc1 >= Fn) {
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av_log(ctx, AV_LOG_ERROR,
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"filter frequency must be less than %d/2.\n", s->sample_rate);
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return AVERROR(EINVAL);
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}
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h[0] = lpf(Fn, s->Fc0, s->tbw0, &s->num_taps[0], s->att, &s->beta, s->round);
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h[1] = lpf(Fn, s->Fc1, s->tbw1, &s->num_taps[1], s->att, &s->beta, s->round);
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if (h[0])
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invert(h[0], s->num_taps[0]);
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longer = s->num_taps[1] > s->num_taps[0];
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n = s->num_taps[longer];
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if (h[0] && h[1]) {
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for (i = 0; i < s->num_taps[!longer]; i++)
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h[longer][i + (n - s->num_taps[!longer]) / 2] += h[!longer][i];
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if (s->Fc0 < s->Fc1)
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invert(h[longer], n);
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av_free(h[!longer]);
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}
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if (s->phase != 50.f) {
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int ret = fir_to_phase(s, &h[longer], &n, &post_peak, s->phase);
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if (ret < 0)
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return ret;
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} else {
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post_peak = n >> 1;
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}
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s->n = 1 << (av_log2(n) + 1);
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s->rdft_len = 1 << av_log2(n);
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s->coeffs = av_calloc(s->n, sizeof(*s->coeffs));
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if (!s->coeffs)
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return AVERROR(ENOMEM);
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for (i = 0; i < n; i++)
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s->coeffs[i] = h[longer][i];
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av_free(h[longer]);
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av_tx_uninit(&s->tx);
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av_tx_uninit(&s->itx);
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return 0;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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SincContext *s = ctx->priv;
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av_freep(&s->coeffs);
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av_tx_uninit(&s->tx);
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av_tx_uninit(&s->itx);
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}
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static const AVFilterPad sinc_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.config_props = config_output,
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},
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};
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#define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
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#define OFFSET(x) offsetof(SincContext, x)
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static const AVOption sinc_options[] = {
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{ "sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
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{ "r", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
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{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
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{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
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{ "hp", "set high-pass filter frequency", OFFSET(Fc0), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, INT_MAX, AF },
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{ "lp", "set low-pass filter frequency", OFFSET(Fc1), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, INT_MAX, AF },
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{ "phase", "set filter phase response", OFFSET(phase), AV_OPT_TYPE_FLOAT, {.dbl=50}, 0, 100, AF },
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{ "beta", "set kaiser window beta", OFFSET(beta), AV_OPT_TYPE_FLOAT, {.dbl=-1}, -1, 256, AF },
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{ "att", "set stop-band attenuation", OFFSET(att), AV_OPT_TYPE_FLOAT, {.dbl=120}, 40, 180, AF },
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{ "round", "enable rounding", OFFSET(round), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, AF },
|
|
{ "hptaps", "set number of taps for high-pass filter", OFFSET(num_taps[0]), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
|
|
{ "lptaps", "set number of taps for low-pass filter", OFFSET(num_taps[1]), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
|
|
{ NULL }
|
|
};
|
|
|
|
AVFILTER_DEFINE_CLASS(sinc);
|
|
|
|
const AVFilter ff_asrc_sinc = {
|
|
.name = "sinc",
|
|
.description = NULL_IF_CONFIG_SMALL("Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients."),
|
|
.priv_size = sizeof(SincContext),
|
|
.priv_class = &sinc_class,
|
|
.uninit = uninit,
|
|
.activate = activate,
|
|
.inputs = NULL,
|
|
FILTER_OUTPUTS(sinc_outputs),
|
|
FILTER_QUERY_FUNC(query_formats),
|
|
};
|