[FFmpeg-devel] [PATCH] lavfi: add showspectrum filter.
Clément Bœsch
ubitux at gmail.com
Fri Aug 10 00:30:27 CEST 2012
TODO: bump
---
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/avf_showspectrum.c | 318 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 320 insertions(+)
create mode 100644 libavfilter/avf_showspectrum.c
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index d50c99d..7ae43f9 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -200,6 +200,7 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/pullup.o
# multimedia filters
OBJS-$(CONFIG_CONCAT_FILTER) += avf_concat.o
+OBJS-$(CONFIG_SHOWSPECTRUM_FILTER) += avf_showspectrum.o
OBJS-$(CONFIG_SHOWWAVES_FILTER) += avf_showwaves.o
# multimedia sources
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 5dc75a6..5207527 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -138,6 +138,7 @@ void avfilter_register_all(void)
/* multimedia filters */
REGISTER_FILTER (CONCAT, concat, avf);
+ REGISTER_FILTER (SHOWSPECTRUM,showspectrum,avf);
REGISTER_FILTER (SHOWWAVES, showwaves, avf);
/* multimedia sources */
diff --git a/libavfilter/avf_showspectrum.c b/libavfilter/avf_showspectrum.c
new file mode 100644
index 0000000..f763646
--- /dev/null
+++ b/libavfilter/avf_showspectrum.c
@@ -0,0 +1,318 @@
+/*
+ * 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
+ * and lavfi/avf_showwaves
+ */
+
+#include <math.h>
+
+#include "libavcodec/avfft.h"
+#include "libavutil/audioconvert.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "audio.h"
+#include "video.h"
+#include "internal.h"
+#include "drawutils.h"
+
+typedef struct {
+ const AVClass *class;
+ int w, h;
+ int xpos;
+ AVFilterBufferRef *outpicref;
+ FFDrawContext draw;
+ int req_fullfilled;
+ 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 *windowing; ///< Window function LUT
+} ShowSpectrumContext;
+
+#define OFFSET(x) offsetof(ShowSpectrumContext, x)
+
+static const AVOption showspectrum_options[] = {
+ { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0 },
+ { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0 },
+ { 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->windowing);
+ 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 */
+ av_free(showspectrum->rdft_data);
+ showspectrum->rdft_data = av_malloc(2 * win_size * sizeof(*showspectrum->rdft_data));
+ if (!showspectrum->rdft_data)
+ return AVERROR(ENOMEM);
+ showspectrum->filled = 0;
+
+ /* pre-calc windowing function (hann here) */
+ av_free(showspectrum->windowing);
+ showspectrum->windowing = av_malloc(win_size * sizeof(*showspectrum->windowing));
+ if (!showspectrum->windowing)
+ return AVERROR(ENOMEM);
+ for (i = 0; i < win_size; i++)
+ showspectrum->windowing[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_REUSE,
+ outlink->w, outlink->h);
+ outpicref->video->w = outlink->w;
+ outpicref->video->h = outlink->h;
+ 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_READ));
+ 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->windowing[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 }
+ },
+};
--
1.7.11.4
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