avfilter: add showspatial multimedia filter

6 files changed, 432 insertions, 2 deletions

diff --git a/Changelog b/Changelog
index e6b209a..1facc1f 100644
--- a/Changelog
+++ b/Changelog
@@ -30,6 +30,7 @@ version <next>:
 - colorhold filter
 - xmedian filter
 - asr filter
+- showspatial multimedia filter
 
 
 version 4.1:
diff --git a/doc/filters.texi b/doc/filters.texi
index 4fdcfe9..60df5bf 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -22248,6 +22248,58 @@ Set minimum amplitude used in @code{log} amplitude scaler.
 
 @end table
 
+@section showspatial
+
+Convert stereo input audio to a video output, representing the spatial relationship
+between two channels.
+
+The filter accepts the following options:
+
+@table @option
+@item size, s
+Specify the video size for the output. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default value is @code{512x512}.
+
+@item win_size
+Set window size. Allowed range is from @var{1024} to @var{65536}. Default size is @var{4096}.
+
+@item win_func
+Set window function.
+
+It accepts the following values:
+@table @samp
+@item rect
+@item bartlett
+@item hann
+@item hanning
+@item hamming
+@item blackman
+@item welch
+@item flattop
+@item bharris
+@item bnuttall
+@item bhann
+@item sine
+@item nuttall
+@item lanczos
+@item gauss
+@item tukey
+@item dolph
+@item cauchy
+@item parzen
+@item poisson
+@item bohman
+@end table
+
+Default value is @code{hann}.
+
+@item overlap
+Set ratio of overlap window. Default value is @code{0.5}.
+When value is @code{1} overlap is set to recommended size for specific
+window function currently used.
+@end table
+
 @anchor{showspectrum}
 @section showspectrum
 
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 9a61c25..a99362b 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -465,6 +465,7 @@ OBJS-$(CONFIG_AVECTORSCOPE_FILTER)           += avf_avectorscope.o
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o
 OBJS-$(CONFIG_SHOWCQT_FILTER)                += avf_showcqt.o lswsutils.o lavfutils.o
 OBJS-$(CONFIG_SHOWFREQS_FILTER)              += avf_showfreqs.o
+OBJS-$(CONFIG_SHOWSPATIAL_FILTER)            += avf_showspatial.o
 OBJS-$(CONFIG_SHOWSPECTRUM_FILTER)           += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWSPECTRUMPIC_FILTER)        += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWVOLUME_FILTER)             += avf_showvolume.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 4053473..858ed1c 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -443,6 +443,7 @@ extern AVFilter ff_avf_avectorscope;
 extern AVFilter ff_avf_concat;
 extern AVFilter ff_avf_showcqt;
 extern AVFilter ff_avf_showfreqs;
+extern AVFilter ff_avf_showspatial;
 extern AVFilter ff_avf_showspectrum;
 extern AVFilter ff_avf_showspectrumpic;
 extern AVFilter ff_avf_showvolume;
diff --git a/libavfilter/avf_showspatial.c b/libavfilter/avf_showspatial.c
new file mode 100644
index 0000000..5a7657f
--- /dev/null
+++ b/libavfilter/avf_showspatial.c
@@ -0,0 +1,375 @@
+/*
+ * Copyright (c) 2019 Paul B Mahol
+ *
+ * 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 <float.h>
+#include <math.h>
+
+#include "libavcodec/avfft.h"
+#include "libavutil/audio_fifo.h"
+#include "libavutil/avassert.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "audio.h"
+#include "video.h"
+#include "avfilter.h"
+#include "filters.h"
+#include "internal.h"
+#include "window_func.h"
+
+typedef struct ShowSpatialContext {
+    const AVClass *class;
+    int w, h;
+    AVRational frame_rate;
+    FFTContext *fft[2];           ///< Fast Fourier Transform context
+    FFTContext *ifft[2];          ///< Inverse Fast Fourier Transform context
+    int fft_bits;                 ///< number of bits (FFT window size = 1<<fft_bits)
+    FFTComplex *fft_data[2];      ///< bins holder for each (displayed) channels
+    float *window_func_lut;       ///< Window function LUT
+    int win_func;
+    int win_size;
+    int buf_size;
+    float overlap;
+    int consumed;
+    int hop_size;
+    AVAudioFifo *fifo;
+    int64_t pts;
+} ShowSpatialContext;
+
+#define OFFSET(x) offsetof(ShowSpatialContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption showspatial_options[] = {
+    { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
+    { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
+    { "win_size", "set window size", OFFSET(win_size), AV_OPT_TYPE_INT, {.i64 = 4096}, 1024, 65536, FLAGS },
+    { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
+        { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, FLAGS, "win_func" },
+        { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },
+        { "hann",     "Hann",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
+        { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
+        { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },
+        { "blackman", "Blackman",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },
+        { "welch",    "Welch",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH},    0, 0, FLAGS, "win_func" },
+        { "flattop",  "Flat-top",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP},  0, 0, FLAGS, "win_func" },
+        { "bharris",  "Blackman-Harris",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS},  0, 0, FLAGS, "win_func" },
+        { "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },
+        { "bhann",    "Bartlett-Hann",    0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN},    0, 0, FLAGS, "win_func" },
+        { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, FLAGS, "win_func" },
+        { "nuttall",  "Nuttall",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL},  0, 0, FLAGS, "win_func" },
+        { "lanczos",  "Lanczos",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_LANCZOS},  0, 0, FLAGS, "win_func" },
+        { "gauss",    "Gauss",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_GAUSS},    0, 0, FLAGS, "win_func" },
+        { "tukey",    "Tukey",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_TUKEY},    0, 0, FLAGS, "win_func" },
+        { "dolph",    "Dolph-Chebyshev",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_DOLPH},    0, 0, FLAGS, "win_func" },
+        { "cauchy",   "Cauchy",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_CAUCHY},   0, 0, FLAGS, "win_func" },
+        { "parzen",   "Parzen",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_PARZEN},   0, 0, FLAGS, "win_func" },
+        { "poisson",  "Poisson",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_POISSON},  0, 0, FLAGS, "win_func" },
+        { "bohman",   "Bohman",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BOHMAN},   0, 0, FLAGS, "win_func" },
+    { "overlap", "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(showspatial);
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    ShowSpatialContext *s = ctx->priv;
+    int i;
+
+    for (i = 0; i < 2; i++)
+        av_fft_end(s->fft[i]);
+    for (i = 0; i < 2; i++)
+        av_fft_end(s->ifft[i]);
+    for (i = 0; i < 2; i++)
+        av_freep(&s->fft_data[i]);
+    av_freep(&s->window_func_lut);
+    av_audio_fifo_free(s->fifo);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats = NULL;
+    AVFilterChannelLayouts *layout = NULL;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
+    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GBRP, AV_PIX_FMT_NONE };
+    int ret;
+
+    formats = ff_make_format_list(sample_fmts);
+    if ((ret = ff_formats_ref         (formats, &inlink->out_formats        )) < 0 ||
+        (ret = ff_add_channel_layout  (&layout, AV_CH_LAYOUT_STEREO         )) < 0 ||
+        (ret = ff_channel_layouts_ref (layout , &inlink->out_channel_layouts)) < 0)
+        return ret;
+
+    formats = ff_all_samplerates();
+    if ((ret = ff_formats_ref(formats, &inlink->out_samplerates)) < 0)
+        return ret;
+
+    formats = ff_make_format_list(pix_fmts);
+    if ((ret = ff_formats_ref(formats, &outlink->in_formats)) < 0)
+        return ret;
+
+    return 0;
+}
+
+static int run_channel_fft(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    ShowSpatialContext *s = ctx->priv;
+    const float *window_func_lut = s->window_func_lut;
+    AVFrame *fin = arg;
+    const int ch = jobnr;
+    const float *p = (float *)fin->extended_data[ch];
+
+    for (int n = 0; n < fin->nb_samples; n++) {
+        s->fft_data[ch][n].re = p[n] * window_func_lut[n];
+        s->fft_data[ch][n].im = 0;
+    }
+
+    av_fft_permute(s->fft[ch], s->fft_data[ch]);
+    av_fft_calc(s->fft[ch], s->fft_data[ch]);
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    AVFilterLink *inlink = ctx->inputs[0];
+    ShowSpatialContext *s = ctx->priv;
+    int i, fft_bits, h, w;
+    float overlap;
+
+    outlink->w = s->w;
+    outlink->h = s->h;
+    outlink->sample_aspect_ratio = (AVRational){1,1};
+
+    h = s->h;
+    w = s->w;
+
+    s->buf_size = 1 << av_log2(s->win_size);
+    s->win_size = s->buf_size;
+    fft_bits = av_log2(s->win_size);
+
+    /* (re-)configuration if the video output changed (or first init) */
+    if (fft_bits != s->fft_bits) {
+        s->fft_bits = fft_bits;
+
+        /* FFT buffers: x2 for each channel buffer.
+         * Note: we use free and malloc instead of a realloc-like function to
+         * make sure the buffer is aligned in memory for the FFT functions. */
+        for (i = 0; i < 2; i++) {
+            av_fft_end(s->fft[i]);
+            av_freep(&s->fft_data[i]);
+        }
+        for (i = 0; i < 2; i++) {
+            s->fft[i] = av_fft_init(fft_bits, 0);
+            if (!s->fft[i]) {
+                av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "
+                       "The window size might be too high.\n");
+                return AVERROR(EINVAL);
+            }
+        }
+
+        for (i = 0; i < 2; i++) {
+            s->fft_data[i] = av_calloc(s->buf_size, sizeof(**s->fft_data));
+            if (!s->fft_data[i])
+                return AVERROR(ENOMEM);
+        }
+
+        /* pre-calc windowing function */
+        s->window_func_lut =
+            av_realloc_f(s->window_func_lut, s->win_size,
+                         sizeof(*s->window_func_lut));
+        if (!s->window_func_lut)
+            return AVERROR(ENOMEM);
+        generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
+        if (s->overlap == 1)
+            s->overlap = overlap;
+
+        s->hop_size = (1.f - s->overlap) * s->win_size;
+        if (s->hop_size < 1) {
+            av_log(ctx, AV_LOG_ERROR, "overlap %f too big\n", s->overlap);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    outlink->time_base = av_inv_q(outlink->frame_rate);
+
+    av_audio_fifo_free(s->fifo);
+    s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->win_size);
+    if (!s->fifo)
+        return AVERROR(ENOMEM);
+    return 0;
+}
+
+#define RE(y, ch) s->fft_data[ch][y].re
+#define IM(y, ch) s->fft_data[ch][y].im
+
+static void draw_dot(uint8_t *dst, int linesize, int value)
+{
+    dst[0] = value;
+    dst[1] = value;
+    dst[-1] = value;
+    dst[linesize] = value;
+    dst[-linesize] = value;
+}
+
+static int draw_spatial(AVFilterLink *inlink, AVFrame *insamples)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    ShowSpatialContext *s = ctx->priv;
+    AVFrame *outpicref;
+    int h = s->h - 2;
+    int w = s->w - 2;
+    int z = s->win_size / 2;
+
+    outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!outpicref)
+        return AVERROR(ENOMEM);
+
+    outpicref->sample_aspect_ratio = (AVRational){1,1};
+    for (int i = 0; i < outlink->h; i++) {
+        memset(outpicref->data[0] + i * outpicref->linesize[0], 0, outlink->w);
+        memset(outpicref->data[1] + i * outpicref->linesize[1], 0, outlink->w);
+        memset(outpicref->data[2] + i * outpicref->linesize[2], 0, outlink->w);
+    }
+
+    for (int j = 0; j < z; j++) {
+        const int idx = z - 1 - j;
+        float l = hypotf(RE(idx, 0), IM(idx, 0));
+        float r = hypotf(RE(idx, 1), IM(idx, 1));
+        float sum = l + r;
+        float lp = atan2f(IM(idx, 0), RE(idx, 0));
+        float rp = atan2f(IM(idx, 1), RE(idx, 1));
+        float diffp = ((rp - lp) / (2.f * M_PI) + 1.f) * 0.5f;
+        float diff = (sum < 0.000001f ? 0.f : (r - l) / sum) * 0.5f + 0.5f;
+        float cr = av_clipf(cbrtf(l / sum), 0, 1) * 255.f;
+        float cb = av_clipf(cbrtf(r / sum), 0, 1) * 255.f;
+        float cg;
+        int x, y;
+
+        cg = diffp * 255.f;
+        x = av_clip(w * diff,  0, w - 2) + 1;
+        y = av_clip(h * diffp, 0, h - 2) + 1;
+
+        draw_dot(outpicref->data[0] + outpicref->linesize[0] * y + x, outpicref->linesize[0], cg);
+        draw_dot(outpicref->data[1] + outpicref->linesize[1] * y + x, outpicref->linesize[1], cb);
+        draw_dot(outpicref->data[2] + outpicref->linesize[2] * y + x, outpicref->linesize[2], cr);
+    }
+
+    outpicref->pts = av_rescale_q(insamples->pts, inlink->time_base, outlink->time_base);
+
+    return ff_filter_frame(outlink, outpicref);
+}
+
+static int spatial_activate(AVFilterContext *ctx)
+{
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+    ShowSpatialContext *s = ctx->priv;
+    int ret;
+
+    FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
+
+    if (av_audio_fifo_size(s->fifo) < s->win_size) {
+        AVFrame *frame = NULL;
+
+        ret = ff_inlink_consume_frame(inlink, &frame);
+        if (ret < 0)
+            return ret;
+        if (ret > 0) {
+            s->pts = frame->pts;
+            s->consumed = 0;
+
+            av_audio_fifo_write(s->fifo, (void **)frame->extended_data, frame->nb_samples);
+            av_frame_free(&frame);
+        }
+    }
+
+    if (av_audio_fifo_size(s->fifo) >= s->win_size) {
+        AVFrame *fin = ff_get_audio_buffer(inlink, s->win_size);
+        if (!fin)
+            return AVERROR(ENOMEM);
+
+        fin->pts = s->pts + s->consumed;
+        s->consumed += s->hop_size;
+        ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data,
+                                 FFMIN(s->win_size, av_audio_fifo_size(s->fifo)));
+        if (ret < 0) {
+            av_frame_free(&fin);
+            return ret;
+        }
+
+        av_assert0(fin->nb_samples == s->win_size);
+
+        ctx->internal->execute(ctx, run_channel_fft, fin, NULL, 2);
+
+        ret = draw_spatial(inlink, fin);
+
+        av_frame_free(&fin);
+        av_audio_fifo_drain(s->fifo, s->hop_size);
+        if (ret <= 0)
+            return ret;
+    }
+
+    FF_FILTER_FORWARD_STATUS(inlink, outlink);
+    if (ff_outlink_frame_wanted(outlink) && av_audio_fifo_size(s->fifo) < s->win_size) {
+        ff_inlink_request_frame(inlink);
+        return 0;
+    }
+
+    if (av_audio_fifo_size(s->fifo) >= s->win_size) {
+        ff_filter_set_ready(ctx, 10);
+        return 0;
+    }
+    return FFERROR_NOT_READY;
+}
+
+static const AVFilterPad showspatial_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+static const AVFilterPad showspatial_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_avf_showspatial = {
+    .name          = "showspatial",
+    .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a spatial video output."),
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(ShowSpatialContext),
+    .inputs        = showspatial_inputs,
+    .outputs       = showspatial_outputs,
+    .activate      = spatial_activate,
+    .priv_class    = &showspatial_class,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 8610381..91a5a16 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  54
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  55
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \