/* * Copyright (c) 2018 Paul B Mahol * * This file is part of FFmpeg. * * FFmpeg 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 2.1 of the License, or (at your option) any later version. * * FFmpeg 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 FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <float.h> #include "libavutil/ffmath.h"#include "libavutil/mem.h"#include "libavutil/opt.h"#include "audio.h"#include "avfilter.h"#include "filters.h" #define BINS 32768 typedef struct ChannelStats {    uint64_t nb_samples;    uint64_t blknum;    float peak;    float sum;    uint32_t peaks[BINS+1];    uint32_t rms[BINS+1];} ChannelStats; typedef struct DRMeterContext {    const AVClass *class;    ChannelStats *chstats;    int nb_channels;    int64_t tc_samples;    double time_constant;} DRMeterContext; #define OFFSET(x) offsetof(DRMeterContext, x)#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM static const AVOption drmeter_options[] = {    { "length", "set the window length", OFFSET(time_constant), AV_OPT_TYPE_DOUBLE, {.dbl=3}, .01, 10, FLAGS },    { NULL }}; AVFILTER_DEFINE_CLASS(drmeter); static int config_output(AVFilterLink *outlink){    DRMeterContext *s = outlink->src->priv;     s->chstats = av_calloc(outlink->ch_layout.nb_channels, sizeof(*s->chstats));    if (!s->chstats)        return AVERROR(ENOMEM);    s->nb_channels = outlink->ch_layout.nb_channels;    s->tc_samples = lrint(s->time_constant * outlink->sample_rate);     return 0;} static void finish_block(ChannelStats *p){    int peak_bin, rms_bin;    float peak, rms;     rms = sqrtf(2.f * p->sum / p->nb_samples);    peak = p->peak;    rms_bin = av_clip(lrintf(rms * BINS), 0, BINS);    peak_bin = av_clip(lrintf(peak * BINS), 0, BINS);    p->rms[rms_bin]++;    p->peaks[peak_bin]++;     p->peak = 0;    p->sum = 0;    p->nb_samples = 0;    p->blknum++;} static void update_stat(DRMeterContext *s, ChannelStats *p, float sample){    p->peak = fmaxf(fabsf(sample), p->peak);    p->sum += sample * sample;    p->nb_samples++;    if (p->nb_samples >= s->tc_samples)        finish_block(p);} static int filter_frame(AVFilterLink *inlink, AVFrame *buf){    DRMeterContext *s = inlink->dst->priv;    const int channels = s->nb_channels;     switch (inlink->format) {    case AV_SAMPLE_FMT_FLTP:        for (int c = 0; c < channels; c++) {            ChannelStats *p = &s->chstats[c];            const float *src = (const float *)buf->extended_data[c];             for (int i = 0; i < buf->nb_samples; i++, src++)                update_stat(s, p, *src);        }        break;    case AV_SAMPLE_FMT_FLT: {        const float *src = (const float *)buf->extended_data[0];         for (int i = 0; i < buf->nb_samples; i++) {            for (int c = 0; c < channels; c++, src++)                update_stat(s, &s->chstats[c], *src);        }}        break;    }     return ff_filter_frame(inlink->dst->outputs[0], buf);} #define SQR(a) ((a)*(a)) static void print_stats(AVFilterContext *ctx){    DRMeterContext *s = ctx->priv;    float dr = 0.f;     for (int ch = 0; ch < s->nb_channels; ch++) {        ChannelStats *p = &s->chstats[ch];        float chdr, secondpeak, rmssum = 0.f;        int first = 0, last = lrintf(0.2f * p->blknum);        int peak_bin = BINS;         if (!p->nb_samples) {            av_log(ctx, AV_LOG_INFO, "No data, dynamic range not meassurable\n");            return;        }         if (p->nb_samples)            finish_block(p);         for (int i = BINS; i >= 0; i--) {            if (p->peaks[i]) {                if (first || p->peaks[i] > 1) {                    peak_bin = i;                    break;                }                first = 1;            }        }         secondpeak = peak_bin / (float)BINS;         for (int64_t i = BINS, j = 0; i >= 0 && j < last; i--) {            if (p->rms[i]) {                rmssum += SQR(i / (float)BINS) * p->rms[i];                j += p->rms[i];            }        }         chdr = 20.f * log10f(secondpeak / sqrtf(rmssum / (float)last));        dr += chdr;        av_log(ctx, AV_LOG_INFO, "Channel %d: DR: %g\n", ch + 1, chdr);    }     av_log(ctx, AV_LOG_INFO, "Overall DR: %g\n", dr / s->nb_channels);} static av_cold void uninit(AVFilterContext *ctx){    DRMeterContext *s = ctx->priv;     if (s->nb_channels)        print_stats(ctx);    av_freep(&s->chstats);} static const AVFilterPad drmeter_inputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_AUDIO,        .filter_frame = filter_frame,    },}; static const AVFilterPad drmeter_outputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_AUDIO,        .config_props = config_output,    },}; const FFFilter ff_af_drmeter = {    .p.name        = "drmeter",    .p.description = NULL_IF_CONFIG_SMALL("Measure audio dynamic range."),    .p.priv_class  = &drmeter_class,    .p.flags       = AVFILTER_FLAG_METADATA_ONLY,    .priv_size     = sizeof(DRMeterContext),    .uninit        = uninit,    FILTER_INPUTS(drmeter_inputs),    FILTER_OUTPUTS(drmeter_outputs),    FILTER_SAMPLEFMTS(AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_FLT),};