[FFmpeg-devel] [OPW] OPW Project Proposal
Michael Niedermayer
michael at niedermayer.cc
Wed Nov 2 22:30:42 EET 2016
On Thu, Nov 03, 2016 at 01:10:26AM +0530, Pallavi Kumari wrote:
> Necessary changes has been done. PFA.
>
> Usage:
>
> ./ffmpeg -i kpg.mp3 -filter_complex peakpoints=wsize=16 -f null -
>
> On Wed, Nov 2, 2016 at 6:14 AM, Michael Niedermayer <michael at niedermayer.cc>
> wrote:
>
> > On Wed, Nov 02, 2016 at 05:00:09AM +0530, Pallavi Kumari wrote:
> > > Hi Michael,
> > >
> > > I have attached a working patch with the mail. PFA.
> > >
> > > Usage:
> > >
> >
> > > ./ffmpeg -i kpg.mp3 -filter_complex peakpoints=input=kpg.mp3:wsize=16
> >
> > I realize now, theres a mistake in this, you must provide a output
> > as in
> > ./ffmpeg -i kpg.mp3 -af peakpoints -f null -
> >
> > without some output like "-f null -" it wont read the file fully and
> > wont pass it through filter_frame()
> >
> > you could see this failure as in:
> > ./ffmpeg -i ~/videos/matrixbench_mpeg2.mpg -af volumedetect -f null -
> > vs.
> > ./ffmpeg -i ~/videos/matrixbench_mpeg2.mpg -af volumedetect
> >
> > you get the histogram from the volume detect filter in the first case
> > but not the 2nd.
> >
> > [...]
> > --
> > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > Many things microsoft did are stupid, but not doing something just because
> > microsoft did it is even more stupid. If everything ms did were stupid they
> > would be bankrupt already.
> >
> af_peakpoints.c | 226 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 226 insertions(+)
> 206d91b47bc6066dd01db1c3369d4674ac95f04c 0001-avfilter-added-peakpoints-filter.patch
> From e10f73d363d0313774bcb132b3b1f2417fcfba11 Mon Sep 17 00:00:00 2001
> From: Atana <atana at openmailbox.org>
> Date: Thu, 3 Nov 2016 01:05:51 +0530
> Subject: [PATCH] avfilter: added peakpoints filter
>
> ---
> libavfilter/af_peakpoints.c | 226 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 226 insertions(+)
> create mode 100644 libavfilter/af_peakpoints.c
This is missing changes to the Makefile and libavfilter/allfilters*
>
> diff --git a/libavfilter/af_peakpoints.c b/libavfilter/af_peakpoints.c
> new file mode 100644
> index 0000000..9265c47
> --- /dev/null
> +++ b/libavfilter/af_peakpoints.c
> @@ -0,0 +1,226 @@
> +/*
> + * 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"
> +
> +
> +/* Structure to contain peak points context */
> +typedef struct {
> + const AVClass *class;
> + double *data;
> + int nsamples;
> + int index;
> + 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(sizeof(double) * resSize);
> +
> + 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(sizeof(FFTSample)*chunkSize);
see av_malloc_array() (it avoids potential issues with the multiply
overflowing)
> +
> + 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(sizeof(double)*pSize);
> +
> + 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);
> + 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) {
> + av_log(ctx, AV_LOG_ERROR, "window size must be greater than or equal to 16\n");
> + return AVERROR(EINVAL);
> + }
> +
> + p->index = 0;
> + p->size = 0;
> + p->data = av_malloc(sizeof(double)*10000);
nothing gurantees that 10000 or any constant is large enough
indeed it is not guranteed that all the decoded audio would fit in
memory.
What probably makes most sense is executing the
fft from filter_frame() every time there is sufficient new data
and overwriting the old data with new instead of trying to store
all audio data
> +
> + if (!p->data) {
> + av_log(ctx, AV_LOG_ERROR, "Cann't allocate memmory for audio data\n");
> + return AVERROR(EINVAL);
> + }
> +
> + return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *samples)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + PeakPointsContext *p = ctx->priv;
> +
> + // store audio data
> + p->data[p->index] = (double)*samples->data[0];
There are multiple channels and multiple samples
this uses just the first sample of the first channel
samples->nb_samples contains the number of samples (as in time)
and av_frame_get_channels(samples) is the number of channels
you can see in af_volumedetect.c how to access the samples of the
channels.
I guess its ok to use just the first channel for now but all samples
of the frames (timewise) should be used
> + p->index = p->index + 1;
> +
> + return ff_filter_frame(inlink->dst->outputs[0], samples);
> +}
> +
> +static void ppointsStats(AVFilterContext *ctx, PeakPointsContext *p) {
> + int i, ret;
> + ret = getPeakPoints(p);
> +
> + if (ret && p->size) {
> + // print peaks
> + av_log(ctx, AV_LOG_INFO, "######## Peak points are ########\n");
> + for (i = 0; i < p->size; i++) {
> + av_log(ctx, AV_LOG_INFO, "%f\n", p->peaks[i]);
> + }
> + } else if (p->size || !ret) {
> + av_log(ctx, AV_LOG_ERROR, "Peak points not retrieved\n");
> + return;
> + }
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + PeakPointsContext *p = ctx->priv;
> +
> + 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,
without query_formats you cannot be sure that the data you get is
if double type, see volumedetect for an example implementation, you
only need to adapt it so it requests double and not S16 integers
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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