[FFmpeg-devel] [OPW] OPW Project Proposal

Michael Niedermayer michael at niedermayer.cc
Wed Nov 2 02:32:33 EET 2016


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
> 
> 
> Regards,
> Atana
> 
> On Fri, Oct 28, 2016 at 4:38 AM, Michael Niedermayer <michael at niedermayer.cc
> > wrote:
> 
> > On Thu, Oct 27, 2016 at 11:38:27PM +0530, Pallavi Kumari wrote:
> > > Hi Michael,
> > >
> > > I have attached a patch with the mail.
> > >
> > > With `avcodec_get_frame_defaults (&frame)` in the function readAudio
> > > program was working fine with old version in my system. But this function
> > > is not in the latest git repo so I used `av_frame_unref(&frame)` instead
> > > and the program segfaults. I am not sure why or how to fix this.
> >
> > theres "AVFrame frame;"
> >
> > thats bad, as it depends on sizef(AVFrame) to allocat frame on the
> > stack.
> > you should always allocate/clone/... one if one is not already
> > available, each of these would be setup correctly and not need
> > avcodec_get_frame_defaults()
> >
> >
> > >
> > > Also, I haven't properly understood the input and output flow of
> > > libavfilters (how to write input and output links? and overall flow).
> > Could
> > > you explain it to me?
> >
> > see existing filters, af_*.c
> > maybe libavfilter/af_astats.c has a similar structure to the filter
> > here
> >
> > theres also
> > doc/filter_design.txt
> >
> >
> > >
> > >
> > >
> > > On Thu, Oct 27, 2016 at 3:24 AM, Michael Niedermayer
> > <michael at niedermayer.cc
> > > > wrote:
> > >
> > > > On Thu, Oct 27, 2016 at 12:40:53AM +0530, Pallavi Kumari wrote:
> > > > > I mean deciding a timeline for the opw project. Which is to be
> > mentioned
> > > > in
> > > > > application
> > > >
> > > > its your application, you can choose whatever timeline you feel makes
> > > > sense.
> > > > As far as iam concered whats important is to finish the qualification
> > > > task well before we have to choose the applicant(s) we accept this
> > > > year.
> > > >
> > > > The timeline for the main project in dec-mar can be segmented as you
> > > > like but leave plenty of time toward the end, problems always occur
> > > > and things get delayed.
> > > > Also both for qualification and the main project submit code early
> > > > if you have questions ask early,
> > > > if you dont get satisfactory reply from me on something ask again and
> > > > louder/clearer ... i do sometimes also forget to reply until i then
> > > > remember again days later ...
> > > >
> > > > also i think the architecture wasnt discussed much yet
> > > > do you have some plans about it ?
> > > >
> > > > I mean for example there could be a avfilter that passes audio through
> > > > and adds fingerint(s) as metadata into thf AVFrame
> > > > (as with avpriv_frame_get_metadatap in vf_idet.c) and also print the
> > > > fingerprints via av_log()
> > > >
> > > > a 2nd filter could then look these fingerprints from the metadata
> > > > up in some file/database
> > > >
> > > > a 3rd one could add the fingerprints to the file/database
> > > >
> > > > or these also could all be in one filter of course
> > > >
> > > > this can be extended in the future to for example have a filter
> > > > delay the audio until lookup succeeds and then once identified
> > > > lookup lyrics online and add them or such (this of course would be a
> > > > future thing after outreachy/opw)
> > > >
> > > > but maybe you have a different plan on how the components would
> > > > interact ?
> > > >
> > > > thx
> > > >
> > > > >
> > > > > On Wed, Oct 26, 2016 at 6:01 PM, Michael Niedermayer
> > > > <michael at niedermayer.cc
> > > > > > wrote:
> > > > >
> > > > > > Hi
> > > > > >
> > > > > > On Mon, Oct 17, 2016 at 02:06:26PM +0530, Pallavi Kumari wrote:
> > > > > > > Hi Michael,
> > > > > > >
> > > > > > > I figured out the use of fft. Help me with the time line setting.
> > > > Thanks
> > > > > >
> > > > > > I dont understand the question,
> > > > > > if its about AVFILTER_FLAG_SUPPORT_TIMELINE*, please ignore this
> > for
> > > > > > now, its not needed
> > > > > >
> > > > > > [...]
> > > > > > --
> > > > > > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC7
> > > > 87040B0FAB
> > > > > >
> > > > > > Rewriting code that is poorly written but fully understood is good.
> > > > > > Rewriting code that one doesnt understand is a sign that one is
> > less
> > > > smart
> > > > > > then the original author, trying to rewrite it will not make it
> > better.
> > > > > >
> > > > > _______________________________________________
> > > > > ffmpeg-devel mailing list
> > > > > ffmpeg-devel at ffmpeg.org
> > > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > > >
> > > > --
> > > > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC7
> > 87040B0FAB
> > > >
> > > > He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
> > > >
> > > > _______________________________________________
> > > > ffmpeg-devel mailing list
> > > > ffmpeg-devel at ffmpeg.org
> > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > > >
> > > >
> >
> > >  Makefile        |    1
> > >  af_peakpoints.c |  263 ++++++++++++++++++++++++++++++
> > ++++++++++++++++++++++++++
> > >  allfilters.c    |    1
> > >  version.h       |    2
> > >  4 files changed, 266 insertions(+), 1 deletion(-)
> > > 5cc989fc1ba9466043f833059ee82efcaa3cf898  0001-avfilter-add-peakpoints-
> > filter.patch
> > > From 60429fb7d83d11d6dd733c3477950a940bd0d84a Mon Sep 17 00:00:00 2001
> > > From: Atana <atana at openmailbox.org>
> > > Date: Mon, 24 Oct 2016 17:16:09 +0530
> > > Subject: [PATCH] avfilter: add peakpoints filter
> > >
> > > ---
> > >  libavfilter/Makefile        |   1 +
> > >  libavfilter/af_peakpoints.c | 263 ++++++++++++++++++++++++++++++
> > ++++++++++++++
> > >  libavfilter/allfilters.c    |   1 +
> > >  libavfilter/version.h       |   2 +-
> > >  4 files changed, 266 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..84b51da
> > > --- /dev/null
> > > +++ b/libavfilter/af_peakpoints.c
> > > @@ -0,0 +1,263 @@
> > > +/*
> > > + * Copyright (c) 2016 Pallavi Kumari
> > > + *
> > > + * 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 "libavutil/opt.h"
> > > +
> > > +
> > > +/* Structure to contain peak points context */
> > > +typedef struct {
> > > +    const AVClass *class;
> > > +    double *data;
> > > +    int nsamples;
> > > +    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 endIndex, 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) {
> >
> > % is slow (compared to &)
> > also doing a i++ loop instead of i+= chunkSize-1 is slow too
> > does lots of unneeed operations, which the compiler might or might
> > not optimize out
> >
> >
> > > +            max = getMax(res_arr, startIndex, i);
> > > +             peaks[peakIndex++] = max;
> > > +             startIndex = startIndex + chunkSize;
> > > +         }
> >
> > tabs are also forbidden in ffmpeg git
> >
> >
> > > +        i += 1;
> > > +    }
> > > +}
> > > +
> >
> > > +/* read audio stream from input file */
> > > +static void readAudio (int *sampleRate, PeakPointsContext *ppc) {
> > > +    // Initialize FFmpeg
> > > +    av_register_all ();
> > > +
> > > +    AVFormatContext *formatContext = NULL;
> > > +    AVCodecContext *codecContext = NULL;
> > > +    AVCodec *codec = NULL;
> > > +    AVPacket packet;
> > > +    AVFrame frame;
> > > +
> > > +    ssize_t nSamples = 0;
> > > +
> > > +    // open the file and autodetect the format
> > > +    if (avformat_open_input (&formatContext, ppc->inputFile, NULL,
> > NULL) < 0)
> > > +        printf("Can not open input file %s", ppc->inputFile);
> > > +
> > > +    if (avformat_find_stream_info (formatContext, NULL) < 0)
> > > +        printf("Can not find stream information");
> > > +
> > > +    // find audio stream (between video/audio/subtitles/.. streams)
> > > +        int audioStreamId = av_find_best_stream (formatContext,
> > AVMEDIA_TYPE_AUDIO,
> > > +                                            -1, -1, &codec, 0);
> > > +    if (audioStreamId < 0)
> > > +        printf("Can not find audio stream in the input file");
> > > +
> > > +    codecContext = formatContext->streams[audioStreamId]->codec;
> > > +
> > > +    // init the audio decoder
> > > +    if (avcodec_open2 (codecContext, codec, NULL) < 0)
> > > +        printf("Can not open audio decoder");
> > > +
> > > +    // read all packets
> > > +    int i = 0;
> > > +    while (av_read_frame (formatContext, &packet) == 0)  {
> >
> > A libavfilter would generally analyze its audio input stream instead
> > of opening a audio file on its own
> >
> >
> >
> > > +        if (packet.stream_index == audioStreamId)  {
> > > +            //avcodec_get_frame_defaults (&frame);
> > > +            av_frame_unref (&frame);
> > > +            int gotFrame = 0;
> > > +            if (avcodec_decode_audio4 (codecContext,&frame,&gotFrame,&packet)
> > < 0){
> > > +                printf("Error decoding audio");
> > > +            }
> > > +            if (gotFrame)  {
> > > +                // audio frame has been decoded
> > > +                int size = av_samples_get_buffer_size (NULL,
> > > +
> >  codecContext->channels,
> > > +                                                   frame.nb_samples,
> > > +
> >  codecContext->sample_fmt,
> > > +                                                   1);
> > > +                if (size < 0)  {
> > > +                    printf("av_samples_get_buffer_size invalid value");
> > > +                }
> > > +
> > > +                 // printf("%d\n", *frame.data[0]);
> > > +                ppc->data[i] = (double)*frame.data[0];
> > > +                i += 1;
> > > +                nSamples += frame.nb_samples;
> > > +            }
> > > +        }
> > > +        av_free_packet (&packet);
> > > +    }
> > > +    ppc->nsamples = i;
> > > +
> > > +    if (nSamples < 1)
> > > +        printf("Decoded audio data is empty");
> > > +
> > > +    int sampleSize = av_get_bytes_per_sample (codecContext->sample_fmt);
> > > +    if (sampleSize < 1)
> > > +        printf("Invalid sample format");
> > > +
> > > +    // optional, return value with sample rate
> > > +    if (sampleRate) *sampleRate = codecContext->sample_rate;
> > > +
> > > +    if (codecContext) avcodec_close (codecContext);
> > > +
> > > +    avformat_close_input (&formatContext);
> > > +}
> > > +
> > > +/* Get peaks points from windowed frequency domain data*/
> > > +static void getPeakPoints(PeakPointsContext *ppc) {
> > > +    int i, k, size, chunkSize, chunkSampleSize, resSize, sample_rate;
> > > +    double *fft_res;
> > > +    int m;
> > > +
> > > +    ppc->data = malloc(sizeof(double)*10000);
> > > +    readAudio (&sample_rate, ppc);
> > > +
> > > +    size = ppc->nsamples;
> > > +    m = log2(ppc->windowSize);
> > > +    chunkSize = ppc->windowSize;
> > > +    chunkSampleSize = size/chunkSize;
> > > +    resSize = chunkSize * chunkSampleSize;
> > > +    fft_res = malloc(sizeof(double) * resSize);
> > > +
> > > +    RDFTContext *rdftC = av_rdft_init(m, DFT_R2C);
> > > +    FFTSample *data;
> >
> > > +    data = malloc(sizeof(FFTSample)*chunkSize);
> > > +    // 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];
> >
> > missing malloc failure check
> >
> >
> > > +        }
> > > +        //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);
> > > +
> > > +    int pSize = resSize/chunkSize;
> > > +    ppc->size = pSize;
> > > +    ppc->peaks = malloc(sizeof(double)*pSize);
> > > +    getPeakPointInChunk(chunkSize, fft_res, resSize, ppc->peaks);
> > > +}
> > > +
> > > +
> > > +#define OFFSET(x) offsetof(PeakPointsContext, x)
> > > +
> > > +static const AVOption peakpoints_options[] = {
> > > +    { "input",  "set input audio file", OFFSET(inputFile),
> > AV_OPT_TYPE_STRING, {.str="sample.mp3"}, CHAR_MIN, CHAR_MAX },
> > > +    { "wsize",  "set window size", OFFSET(windowSize),
> > AV_OPT_TYPE_INT,    {.i64=16},    0, INT_MAX},
> > > +    { NULL },
> > > +};
> > > +
> > > +static const char *peakpoints_get_name(void *ctx) {
> > > +    return "peakpoints";
> > > +}
> > > +
> > > +static const AVClass peakpoints_class = {
> > > +    .class_name = "PeakPointsContext",
> > > +    .item_name  = peakpoints_get_name,
> > > +    .option     = peakpoints_options,
> > > +};
> > > +
> > > +
> > > +AVFILTER_DEFINE_CLASS(peakpoints);
> > > +
> > > +static av_cold int init(AVFilterContext *ctx)
> > > +{
> > > +    PeakPointsContext *p = ctx->priv;
> > > +
> > > +    if (!(p->inputFile)) {
> > > +        av_log(ctx, AV_LOG_ERROR, "Input audio file must be passed\n");
> > > +        return AVERROR(EINVAL);
> > > +    }
> > > +
> > > +    if (p->windowSize < 16) {
> > > +          av_log(ctx, AV_LOG_ERROR, "window size must be greater than
> > or equal to 16");
> > > +        return AVERROR(EINVAL);
> > > +    }
> > > +    //printf("Getting peak points..");
> > > +    // get peaks
> > > +    getPeakPoints(p);
> > > +    //printf("Peak points collected.");
> > > +    // print peaks
> > > +    int i;
> > > +    for (i = 0; i < p->size; i++) {
> > > +        av_log(ctx, AV_LOG_DEBUG, "%f", p->peaks[i]);
> > > +    }
> > > +    return 0;
> > > +}
> > > +
> >
> > > +static av_cold void uninit(AVFilterContext *ctx)
> > > +{
> > > +    PeakPointsContext *p = ctx->priv;
> > > +    int i;
> > > +
> >
> > > +    // free memory allocated for audio data
> > > +    for (i = 0; p->nsamples; i++) {
> > > +     free(&p->data[i]);
> > > +    }
> > > +
> > > +    // free memory allocated for peaks
> > > +    for (i = 0; p->size; i++) {
> > > +     free(&p->data[i]);
> > > +    }
> >
> > looks like a double free
> >
> > also please use av_freep() and av_malloc*()
> >
> > [...]
> >
> > --
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > No human being will ever know the Truth, for even if they happen to say it
> > by chance, they would not even known they had done so. -- Xenophanes
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> >

>  af_peakpoints.c |  300 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 300 insertions(+)
> 993ac68b0e42e9c176a8452eff9126ddcd223c4c  0001-avfilter-added-peakpoints-filter.patch
> From 5ef0d52dbf2fa16ce3630f320c06eb72d83b6c2c Mon Sep 17 00:00:00 2001
> From: Atana <atana at openmailbox.org>
> Date: Wed, 2 Nov 2016 04:49:15 +0530
> Subject: [PATCH] avfilter: added peakpoints filter
> 
> ---
>  libavfilter/af_peakpoints.c | 300 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 300 insertions(+)
>  create mode 100644 libavfilter/af_peakpoints.c
> 
> diff --git a/libavfilter/af_peakpoints.c b/libavfilter/af_peakpoints.c
> new file mode 100644
> index 0000000..e5c4494
> --- /dev/null
> +++ b/libavfilter/af_peakpoints.c
> @@ -0,0 +1,300 @@
> +/*
> + * 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 "libavutil/opt.h"
> +
> +
> +/* Structure to contain peak points context */
> +typedef struct {
> +    const AVClass *class;
> +    double *data;
> +    int nsamples;
> +    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 endIndex, 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;
> +    }
> +}
> +
> +/* read audio stream from input file */
> +static void readAudio (int *sampleRate, PeakPointsContext *ppc) {
> +    // Initialize FFmpeg
> +    av_register_all ();
> +
> +    AVFormatContext *formatContext = NULL;
> +    AVCodecContext *codecContext = NULL;
> +    AVCodec *codec = NULL;
> +    AVPacket packet;
> +    AVFrame *frame = av_frame_alloc();
> +    void *avc;
> +    ssize_t nSamples = 0;
> +

> +    // open the file and autodetect the format
> +    if (avformat_open_input (&formatContext, ppc->inputFile, NULL, NULL) < 0)
> +        av_log(avc, AV_LOG_ERROR, "Can not open input file %s", ppc->inputFile);

This still opens the file instead of using the filter input

The way filters work is that they receive their data through
the .filter_frame() callback
not through calling some open_file()

see for example a simple filter like libavfilter/af_volumedetect.c

you need no AVPacket, no av_read_frame(), no avcodec_decode_audio4()
no avformat_open_input()
you get a already decoded AVFrame in your filter_frame() callback


[...]

> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> +    PeakPointsContext *p = ctx->priv;
> +    int i;
> +

> +    if (p->data) {
> +    	av_free(p->data);
> +        p->data = NULL;
> +    }

this should use av_freep() which does the "= NULL" automatically
see existing uses of av_freep() on how its used

[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Old school: Use the lowest level language in which you can solve the problem
            conveniently.
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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