From 5b7efa32b1e3970d6accbb23fee02331278b118b Mon Sep 17 00:00:00 2001
From: Atana <atana@openmailbox.org>
Date: Fri, 4 Nov 2016 07:43:29 +0530
Subject: [PATCH] avfilter: added peakpoints filter

---
 libavfilter/Makefile        |   1 +
 libavfilter/af_peakpoints.c | 267 ++++++++++++++++++++++++++++++++++++++++++++
 libavfilter/allfilters.c    |   1 +
 libavfilter/version.h       |   2 +-
 4 files changed, 270 insertions(+), 1 deletion(-)
 create mode 100644 libavfilter/af_peakpoints.c

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 7ed4696..1a18902 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -96,6 +96,7 @@ OBJS-$(CONFIG_LADSPA_FILTER)                 += af_ladspa.o
 OBJS-$(CONFIG_LOUDNORM_FILTER)               += af_loudnorm.o
 OBJS-$(CONFIG_LOWPASS_FILTER)                += af_biquads.o
 OBJS-$(CONFIG_PAN_FILTER)                    += af_pan.o
+OBJS-$(CONFIG_PEAKPOINTS_FILTER)             += af_peakpoints.o
 OBJS-$(CONFIG_REPLAYGAIN_FILTER)             += af_replaygain.o
 OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o
 OBJS-$(CONFIG_RUBBERBAND_FILTER)             += af_rubberband.o
diff --git a/libavfilter/af_peakpoints.c b/libavfilter/af_peakpoints.c
new file mode 100644
index 0000000..cb64b82
--- /dev/null
+++ b/libavfilter/af_peakpoints.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (c) 2016 Atana
+ *
+ * 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 "libavcodec/avcodec.h"
+#include "libavcodec/avfft.h"
+#include "libavformat/avformat.h"
+#include "libswscale/swscale.h"
+#include "avfilter.h"
+#include "audio.h"
+#include "libavutil/opt.h"
+
+#define SIZECHECK 4096
+
+/* Structure to contain peak points context */
+typedef struct {
+    const AVClass *class;
+    double *data;
+    int nsamples;
+    int index;
+    int isOnce;
+    int buffFlag;
+    double *peaks;
+    int size; // number of peaks
+    int windowSize;
+    //char *inputFile;
+} PeakPointsContext;
+
+/* returns maximum value from an array conditioned on start and end index */
+static double getMax(double *res_arr, int startIndex, int endIndex) {
+    int i;
+    double max = res_arr[startIndex];
+    for (i = startIndex; i <= endIndex; i++) {
+	    if (res_arr[i] > max) {
+	        max = res_arr[i];
+	    }
+    }
+    return max;
+}
+
+/* Stores peak frequency for each window(of chunkSize) in peaks array */
+static void getPeakPointInChunk(int chunkSize, double *res_arr, int size, double *peaks) {
+    int i = 0, peakIndex = 0;
+    int startIndex = 0;
+    double max;
+    // get a chunk and find max value in it
+    while (i < size) {
+	    if (i % chunkSize-1 == 0) {
+            max = getMax(res_arr, startIndex, i);
+            peaks[peakIndex++] = max;
+            startIndex = startIndex + chunkSize;
+       }
+       i += 1;
+    }
+}
+
+/* Get peaks points from windowed frequency domain data*/
+static int getPeakPoints(PeakPointsContext *ppc) {
+    int i, m, k, size, chunkSize, pSize, chunkSampleSize, resSize;
+    double *fft_res;
+    void *avc;
+    RDFTContext *rdftC;
+    FFTSample *data;
+
+    size = ppc->index;
+    m = log2(ppc->windowSize);
+    chunkSize = ppc->windowSize;
+    chunkSampleSize = size/chunkSize;
+    resSize = chunkSize * chunkSampleSize;
+
+    fft_res = av_malloc_array(resSize, sizeof(double));
+
+    if (!fft_res) {
+        av_log(avc, AV_LOG_ERROR, "Cann't allocate memmory for storing fft data\n");
+        return 0;
+    }
+
+
+    rdftC = av_rdft_init(m, DFT_R2C);
+    data = av_malloc_array(chunkSize, sizeof(FFTSample));
+
+    if (!data) {
+        av_log(avc, AV_LOG_ERROR, "Cann't allocate memmory for chunk fft data\n");
+        return 0;
+    }
+    // FFT transform for windowed time domain data
+    // window is of size chunkSize
+    k = 0;
+    while (k < resSize) {
+        //copy data
+        for (i = 0; i < chunkSize; i++) {
+            data[i] = ppc->data[i+k];
+        }
+        //calculate FFT
+        av_rdft_calc(rdftC, data);
+        for (i = 0; i < chunkSize; i++) {
+            fft_res[i+k] = data[i];
+        }
+        k = k + chunkSize;
+    }
+
+    av_rdft_end(rdftC);
+    pSize = resSize/chunkSize;
+    ppc->size = pSize;
+    ppc->peaks = av_malloc_array(pSize, sizeof(double));
+
+    if (!ppc->peaks) {
+        av_log(avc, AV_LOG_ERROR, "Cann't allocate memory for peak storage\n");
+        return 0;
+    }
+
+    getPeakPointInChunk(chunkSize, fft_res, resSize, ppc->peaks);
+    av_freep(&data);
+    av_freep(&fft_res);
+    return 1;
+}
+
+
+#define OFFSET(x) offsetof(PeakPointsContext, x)
+
+static const AVOption peakpoints_options[] = {
+    { "wsize",  "set window size", OFFSET(windowSize),  AV_OPT_TYPE_INT,    {.i64=16},    0, INT_MAX},
+    { NULL },
+};
+
+AVFILTER_DEFINE_CLASS(peakpoints);
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    PeakPointsContext *p = ctx->priv;
+
+    if (p->windowSize < 16 || p->windowSize > SIZECHECK) {
+        av_log(ctx, AV_LOG_ERROR, "window size must be in range 16 to %d\n", SIZECHECK);
+        return AVERROR(EINVAL);
+    }
+
+    p->index = 0;
+    p->size = 0;
+    p->isOnce = 1;
+    p->data = av_malloc_array(SIZECHECK, sizeof(double));
+
+    if (!p->data) {
+        av_log(ctx, AV_LOG_ERROR, "Cann't allocate memmory for audio data\n");
+        return AVERROR(EINVAL);
+    }
+
+    return 0;
+}
+
+static void ppointsStats(AVFilterContext *ctx, PeakPointsContext *p) {
+    int i, ret;
+    ret = getPeakPoints(p);
+
+    if (ret && p->size) {
+    	// print peaks
+        if (p->isOnce) {
+            av_log(ctx, AV_LOG_INFO, "######## Peak points are ########\n");
+            p->isOnce = 0;
+        }
+        for (i = 0; i < p->size; i++) {
+            av_log(ctx, AV_LOG_INFO, "%f\n", p->peaks[i]);
+        }
+        // free peaks and set size to zero
+        av_freep(&p->peaks);
+        p->size = 0;
+    } else if (p->size || !ret) {
+        av_log(ctx, AV_LOG_ERROR, "Peak points not retrieved\n");
+        return;
+    }
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVSampleFormat sample_fmts[] = {
+        AV_SAMPLE_FMT_DBL,
+        AV_SAMPLE_FMT_DBLP,
+        AV_SAMPLE_FMT_NONE
+    };
+    AVFilterFormats *formats;
+
+    if (!(formats = ff_make_format_list(sample_fmts)))
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, formats);
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *samples)
+{
+    AVFilterContext *ctx = inlink->dst;
+    PeakPointsContext *p = ctx->priv;
+    int i, nb_samples = samples->nb_samples;
+
+    // store audio data
+    for (i = 0; i < nb_samples; i++) {
+        p->data[p->index] = ((double*)(samples->data[0]))[i];
+        p->buffFlag = 1;
+        p->index = p->index + 1;
+
+        // size check
+        if (p->index == SIZECHECK) {
+            // get peak points stats
+            ppointsStats(ctx, p);
+            p->index = 0;
+            p->buffFlag = 1;
+        }
+    }
+
+    return ff_filter_frame(inlink->dst->outputs[0], samples);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    PeakPointsContext *p = ctx->priv;
+
+    // if audio data in buffer get peak points
+    if (p->buffFlag) {
+        ppointsStats(ctx, p);
+    }
+
+    // free allocated memories
+    av_freep(&p->data);
+    av_freep(&p->peaks);
+}
+
+static const AVFilterPad peakpoints_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad peakpoints_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_peakpoints = {
+    .name          = "peakpoints",
+    .description   = NULL_IF_CONFIG_SMALL("peak points from frequency domain windowed data."),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(PeakPointsContext),
+    .inputs        = peakpoints_inputs,
+    .outputs       = peakpoints_outputs,
+    .priv_class    = &peakpoints_class,
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 82a65ee..b3b0330 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -114,6 +114,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(LOUDNORM,       loudnorm,       af);
     REGISTER_FILTER(LOWPASS,        lowpass,        af);
     REGISTER_FILTER(PAN,            pan,            af);
+    REGISTER_FILTER(PEAKPOINTS,     peakpoints,     af);
     REGISTER_FILTER(REPLAYGAIN,     replaygain,     af);
     REGISTER_FILTER(RESAMPLE,       resample,       af);
     REGISTER_FILTER(RUBBERBAND,     rubberband,     af);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 82a5f63..b8c9b81 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  66
+#define LIBAVFILTER_VERSION_MINOR  67
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
-- 
1.9.1

