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/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
*/
/**
* @file
* audio to spectrum (video) transmedia filter, based on ffplay rdft showmode
* (by Michael Niedermayer) and lavfi/avf_showwaves (by Stefano Sabatini).
*/
#include <math.h>
#include "libavcodec/avfft.h"
#include "libavutil/audioconvert.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
typedef struct {
const AVClass *class;
int w, h;
AVFilterBufferRef *outpicref;
int req_fullfilled;
int xpos; ///< x position (current column)
RDFTContext *rdft; ///< Real Discrete Fourier Transform context
int rdft_bits; ///< number of bits (RDFT window size = 1<<rdft_bits)
FFTSample *rdft_data; ///< bins holder for each (displayed) channels
int filled; ///< number of samples (per channel) filled in current rdft_buffer
int consumed; ///< number of samples (per channel) consumed from the input frame
float *window_func_lut; ///< Window function LUT
} ShowSpectrumContext;
#define OFFSET(x) offsetof(ShowSpectrumContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption showspectrum_options[] = {
{ "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, FLAGS },
{ "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, FLAGS },
{ NULL },
};
AVFILTER_DEFINE_CLASS(showspectrum);
static av_cold int init(AVFilterContext *ctx, const char *args)
{
ShowSpectrumContext *showspectrum = ctx->priv;
int err;
showspectrum->class = &showspectrum_class;
av_opt_set_defaults(showspectrum);
if ((err = av_set_options_string(showspectrum, args, "=", ":")) < 0)
return err;
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
ShowSpectrumContext *showspectrum = ctx->priv;
av_rdft_end(showspectrum->rdft);
av_freep(&showspectrum->rdft_data);
av_freep(&showspectrum->window_func_lut);
avfilter_unref_bufferp(&showspectrum->outpicref);
}
static int query_formats(AVFilterContext *ctx)
{
AVFilterFormats *formats = NULL;
AVFilterChannelLayouts *layouts = NULL;
AVFilterLink *inlink = ctx->inputs[0];
AVFilterLink *outlink = ctx->outputs[0];
static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16P, -1 };
static const enum PixelFormat pix_fmts[] = { PIX_FMT_RGB24, -1 };
/* set input audio formats */
formats = ff_make_format_list(sample_fmts);
if (!formats)
return AVERROR(ENOMEM);
ff_formats_ref(formats, &inlink->out_formats);
layouts = ff_all_channel_layouts();
if (!layouts)
return AVERROR(ENOMEM);
ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
formats = ff_all_samplerates();
if (!formats)
return AVERROR(ENOMEM);
ff_formats_ref(formats, &inlink->out_samplerates);
/* set output video format */
formats = ff_make_format_list(pix_fmts);
if (!formats)
return AVERROR(ENOMEM);
ff_formats_ref(formats, &outlink->in_formats);
return 0;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
ShowSpectrumContext *showspectrum = ctx->priv;
int i, rdft_bits, win_size;
outlink->w = showspectrum->w;
outlink->h = showspectrum->h;
/* RDFT window size (precision) according to the requested output frame height */
for (rdft_bits = 1; 1<<rdft_bits < 2*outlink->h; rdft_bits++);
win_size = 1 << rdft_bits;
/* (re-)configuration if the video output changed (or first init) */
if (rdft_bits != showspectrum->rdft_bits) {
AVFilterBufferRef *outpicref;
av_rdft_end(showspectrum->rdft);
showspectrum->rdft = av_rdft_init(rdft_bits, DFT_R2C);
showspectrum->rdft_bits = rdft_bits;
/* RDFT buffers: x2 for each (display) channel buffer */
showspectrum->rdft_data =
av_realloc_f(showspectrum->rdft_data, 2 * win_size,
sizeof(*showspectrum->rdft_data));
if (!showspectrum->rdft_data)
return AVERROR(ENOMEM);
showspectrum->filled = 0;
/* pre-calc windowing function (hann here) */
showspectrum->window_func_lut =
av_realloc_f(showspectrum->window_func_lut, win_size,
sizeof(*showspectrum->window_func_lut));
if (!showspectrum->window_func_lut)
return AVERROR(ENOMEM);
for (i = 0; i < win_size; i++)
showspectrum->window_func_lut[i] = .5f * (1 - cos(2*M_PI*i / (win_size-1)));
/* prepare the initial picref buffer (black frame) */
avfilter_unref_bufferp(&showspectrum->outpicref);
showspectrum->outpicref = outpicref =
ff_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_PRESERVE|AV_PERM_REUSE2,
outlink->w, outlink->h);
if (!outpicref)
return AVERROR(ENOMEM);
outlink->sample_aspect_ratio = (AVRational){1,1};
memset(outpicref->data[0], 0, outlink->h * outpicref->linesize[0]);
}
if (showspectrum->xpos >= outlink->w)
showspectrum->xpos = 0;
av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d RDFT window size:%d\n",
showspectrum->w, showspectrum->h, win_size);
return 0;
}
inline static void push_frame(AVFilterLink *outlink)
{
ShowSpectrumContext *showspectrum = outlink->src->priv;
showspectrum->xpos++;
if (showspectrum->xpos >= outlink->w)
showspectrum->xpos = 0;
showspectrum->filled = 0;
showspectrum->req_fullfilled = 1;
ff_start_frame(outlink, avfilter_ref_buffer(showspectrum->outpicref, ~AV_PERM_WRITE));
ff_draw_slice(outlink, 0, outlink->h, 1);
ff_end_frame(outlink);
}
static int request_frame(AVFilterLink *outlink)
{
ShowSpectrumContext *showspectrum = outlink->src->priv;
AVFilterLink *inlink = outlink->src->inputs[0];
int ret;
showspectrum->req_fullfilled = 0;
do {
ret = ff_request_frame(inlink);
} while (!showspectrum->req_fullfilled && ret >= 0);
if (ret == AVERROR_EOF && showspectrum->outpicref)
push_frame(outlink);
return ret;
}
static int plot_spectrum_column(AVFilterLink *inlink, AVFilterBufferRef *insamples, int nb_samples)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
ShowSpectrumContext *showspectrum = ctx->priv;
AVFilterBufferRef *outpicref = showspectrum->outpicref;
const int nb_channels = av_get_channel_layout_nb_channels(insamples->audio->channel_layout);
/* nb_freq contains the power of two superior or equal to the output image
* height (or half the RDFT window size) */
const int nb_freq = 1 << (showspectrum->rdft_bits - 1);
const int win_size = nb_freq << 1;
int ch, n, y;
FFTSample *data[2];
const int nb_display_channels = FFMIN(nb_channels, 2);
const int start = showspectrum->filled;
const int add_samples = FFMIN(win_size - start, nb_samples);
/* fill RDFT input with the number of samples available */
for (ch = 0; ch < nb_display_channels; ch++) {
const int16_t *p = (int16_t *)insamples->extended_data[ch];
p += showspectrum->consumed;
data[ch] = showspectrum->rdft_data + win_size * ch; // select channel buffer
for (n = 0; n < add_samples; n++)
data[ch][start + n] = p[n] * showspectrum->window_func_lut[start + n];
}
showspectrum->filled += add_samples;
/* complete RDFT window size? */
if (showspectrum->filled == win_size) {
/* run RDFT on each samples set */
for (ch = 0; ch < nb_display_channels; ch++)
av_rdft_calc(showspectrum->rdft, data[ch]);
/* fill a new spectrum column */
#define RE(ch) data[ch][2*y + 0]
#define IM(ch) data[ch][2*y + 1]
#define MAGNITUDE(re, im) sqrt((re)*(re) + (im)*(im))
for (y = 0; y < outlink->h; y++) {
// FIXME: bin[0] contains first and last bins
const int pos = showspectrum->xpos * 3 + (outlink->h - y - 1) * outpicref->linesize[0];
const double w = 1. / sqrt(nb_freq);
int a = sqrt(w * MAGNITUDE(RE(0), IM(0)));
int b = nb_display_channels > 1 ? sqrt(w * MAGNITUDE(RE(1), IM(1))) : a;
a = FFMIN(a, 255);
b = FFMIN(b, 255);
outpicref->data[0][pos] = a;
outpicref->data[0][pos+1] = b;
outpicref->data[0][pos+2] = (a + b) / 2;
}
outpicref->pts = insamples->pts +
av_rescale_q(showspectrum->consumed,
(AVRational){ 1, inlink->sample_rate },
outlink->time_base);
push_frame(outlink);
}
return add_samples;
}
static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
{
AVFilterContext *ctx = inlink->dst;
ShowSpectrumContext *showspectrum = ctx->priv;
int left_samples = insamples->audio->nb_samples;
showspectrum->consumed = 0;
while (left_samples) {
const int added_samples = plot_spectrum_column(inlink, insamples, left_samples);
showspectrum->consumed += added_samples;
left_samples -= added_samples;
}
avfilter_unref_buffer(insamples);
return 0;
}
AVFilter avfilter_avf_showspectrum = {
.name = "showspectrum",
.description = NULL_IF_CONFIG_SMALL("Convert input audio to a spectrum video output."),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.priv_size = sizeof(ShowSpectrumContext),
.inputs = (const AVFilterPad[]) {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_samples = filter_samples,
.min_perms = AV_PERM_READ,
},
{ .name = NULL }
},
.outputs = (const AVFilterPad[]) {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
.request_frame = request_frame,
},
{ .name = NULL }
},
.priv_class = &showspectrum_class,
};
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