lavfi: avectorscope filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -39,6 +39,7 @@ version <next>:
   transcoding audio
 - Matroska muxer can now put the index at the beginning of the file.
 - extractplanes filter
+- avectorscope filter
 
 
 version 1.2:

doc/filters.texi

@@ -7324,6 +7324,68 @@ tools.
 
 Below is a description of the currently available multimedia filters.
 
+@section avectorscope
+
+Convert input audio to a video output, representing the audio vector
+scope.
+
+The filter is used to measure the difference between channels of stereo
+audio stream. A monoaural signal, consisting of identical left and right
+signal, results in straight vertical line. Any stereo separation is visible
+as a deviation from this line, creating a Lissajous figure.
+If the straight (or deviation from it) but horizontal line appears this
+indicates that the left and right channels are out of phase.
+
+The filter accepts the following options:
+
+@table @option
+@item mode, m
+Set the vectorscope mode.
+
+Available values are:
+@table @samp
+@item lissajous
+Lissajous rotated by 45 degrees.
+
+@item lissajous_xy
+Same as above but not rotated.
+@end table
+
+Default value is @samp{lissajous}.
+
+@item size, s
+Set the video size for the output. Default value is @code{400x400}.
+
+@item rate, r
+Set the output frame rate. Default value is @code{25}.
+
+@item rc
+@item gc
+@item bc
+Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
+Allowed range is @code{[0, 255]}.
+
+@item rf
+@item gf
+@item bf
+Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
+Allowed range is @code{[0, 255]}.
+
+@item zoom
+Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Complete example using @command{ffplay}:
+@example
+ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
+             [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
+@end example
+@end itemize
+
 @section concat
 
 Concatenate audio and video streams, joining them together one after the

libavfilter/Makefile

@@ -223,6 +223,7 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/vf_uspp.o
 OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/pullup.o
 
 # multimedia filters
+OBJS-$(CONFIG_AVECTORSCOPE_FILTER)           += avf_avectorscope.o
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o
 OBJS-$(CONFIG_SHOWSPECTRUM_FILTER)           += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWWAVES_FILTER)              += avf_showwaves.o

libavfilter/allfilters.c

@@ -199,6 +199,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(NULLSINK,       nullsink,       vsink);
 
     /* multimedia filters */
+    REGISTER_FILTER(AVECTORSCOPE,   avectorscope,   avf);
     REGISTER_FILTER(CONCAT,         concat,         avf);
     REGISTER_FILTER(SHOWSPECTRUM,   showspectrum,   avf);
     REGISTER_FILTER(SHOWWAVES,      showwaves,      avf);

libavfilter/avf_avectorscope.c

@@ -0,0 +1,273 @@
+/*
+ * Copyright (c) 2013 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
+ */
+
+/**
+ * @file
+ * audio to video multimedia vector scope filter
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "audio.h"
+#include "video.h"
+#include "internal.h"
+
+enum VectorScopeMode {
+    LISSAJOUS,
+    LISSAJOUS_XY,
+    MODE_NB,
+};
+
+typedef struct AudioVectorScopeContext {
+    const AVClass *class;
+    AVFrame *outpicref;
+    int w, h;
+    int hw, hh;
+    enum VectorScopeMode mode;
+    int contrast[3];
+    int fade[3];
+    double zoom;
+    AVRational frame_rate;
+} AudioVectorScopeContext;
+
+#define OFFSET(x) offsetof(AudioVectorScopeContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption avectorscope_options[] = {
+    { "mode", "set mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=LISSAJOUS}, 0, MODE_NB-1, FLAGS, "mode" },
+    { "m",    "set mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=LISSAJOUS}, 0, MODE_NB-1, FLAGS, "mode" },
+    { "lissajous",    "", 0, AV_OPT_TYPE_CONST, {.i64=LISSAJOUS},    0, 0, FLAGS, "mode" },
+    { "lissajous_xy", "", 0, AV_OPT_TYPE_CONST, {.i64=LISSAJOUS_XY}, 0, 0, FLAGS, "mode" },
+    { "rate", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, 0, FLAGS },
+    { "r",    "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, 0, FLAGS },
+    { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="400x400"}, 0, 0, FLAGS },
+    { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="400x400"}, 0, 0, FLAGS },
+    { "rc", "set red contrast",   OFFSET(contrast[0]), AV_OPT_TYPE_INT, {.i64=40}, 0, 255, FLAGS },
+    { "gc", "set green contrast", OFFSET(contrast[1]), AV_OPT_TYPE_INT, {.i64=160}, 0, 255, FLAGS },
+    { "bc", "set blue contrast",  OFFSET(contrast[2]), AV_OPT_TYPE_INT, {.i64=80}, 0, 255, FLAGS },
+    { "rf", "set red fade",       OFFSET(fade[0]), AV_OPT_TYPE_INT, {.i64=15}, 0, 255, FLAGS },
+    { "gf", "set green fade",     OFFSET(fade[1]), AV_OPT_TYPE_INT, {.i64=10}, 0, 255, FLAGS },
+    { "bf", "set blue fade",      OFFSET(fade[2]), AV_OPT_TYPE_INT, {.i64=5}, 0, 255, FLAGS },
+    { "zoom", "set zoom factor",  OFFSET(zoom), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 1, 10, FLAGS },
+    {NULL},
+};
+
+AVFILTER_DEFINE_CLASS(avectorscope);
+
+static void draw_dot(AudioVectorScopeContext *p, unsigned x, unsigned y)
+{
+    const int linesize = p->outpicref->linesize[0];
+    uint8_t *dst;
+
+    if (p->zoom > 1) {
+        if (y >= p->h || x >= p->w)
+            return;
+    } else {
+        y = FFMIN(y, p->h - 1);
+        x = FFMIN(x, p->w - 1);
+    }
+
+    dst = &p->outpicref->data[0][y * linesize + x * 4];
+    dst[0] = FFMIN(dst[0] + p->contrast[0], 255);
+    dst[1] = FFMIN(dst[1] + p->contrast[1], 255);
+    dst[2] = FFMIN(dst[2] + p->contrast[2], 255);
+}
+
+static void fade(AudioVectorScopeContext *p)
+{
+    const int linesize = p->outpicref->linesize[0];
+    int i, j;
+
+    if (p->fade[0] || p->fade[1] || p->fade[2]) {
+        uint8_t *d = p->outpicref->data[0];
+        for (i = 0; i < p->h; i++) {
+            for (j = 0; j < p->w*4; j+=4) {
+                d[j+0] = FFMAX(d[j+0] - p->fade[0], 0);
+                d[j+1] = FFMAX(d[j+1] - p->fade[1], 0);
+                d[j+2] = FFMAX(d[j+2] - p->fade[2], 0);
+            }
+            d += linesize;
+        }
+    }
+}
+
+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_S16, AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_NONE };
+    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGBA, AV_PIX_FMT_NONE };
+
+    formats = ff_make_format_list(sample_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_formats);
+
+    ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO);
+    ff_channel_layouts_ref(layout, &inlink->out_channel_layouts);
+
+    formats = ff_all_samplerates();
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_samplerates);
+
+    formats = ff_make_format_list(pix_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &outlink->in_formats);
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AudioVectorScopeContext *p = ctx->priv;
+    int nb_samples;
+
+    nb_samples = FFMAX(1024, ((double)inlink->sample_rate / av_q2d(p->frame_rate)) + 0.5);
+    inlink->partial_buf_size =
+    inlink->min_samples =
+    inlink->max_samples = nb_samples;
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AudioVectorScopeContext *p = outlink->src->priv;
+
+    outlink->w = p->w;
+    outlink->h = p->h;
+    outlink->sample_aspect_ratio = (AVRational){1,1};
+    outlink->frame_rate = p->frame_rate;
+
+    p->hw = p->w / 2;
+    p->hh = p->h / 2;
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AudioVectorScopeContext *p = ctx->priv;
+    const int hw = p->hw;
+    const int hh = p->hh;
+    unsigned x, y;
+    const double zoom = p->zoom;
+    int i;
+
+    if (!p->outpicref || p->outpicref->width  != outlink->w ||
+                         p->outpicref->height != outlink->h) {
+        av_frame_free(&p->outpicref);
+        p->outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+        if (!p->outpicref)
+            av_frame_free(&insamples);
+            return AVERROR(ENOMEM);
+
+        for (i = 0; i < outlink->h; i++)
+            memset(p->outpicref->data[0] + i * p->outpicref->linesize[0], 0, outlink->w * 4);
+    }
+    p->outpicref->pts = insamples->pts;
+
+    fade(p);
+
+    switch (insamples->format) {
+    case AV_SAMPLE_FMT_S16:
+        for (i = 0; i < insamples->nb_samples; i++) {
+            int16_t *src = (int16_t *)insamples->data[0] + i * 2;
+
+            if (p->mode == LISSAJOUS) {
+                x = ((src[1] - src[0]) * zoom / (float)(UINT16_MAX) + 1) * hw;
+                y = (1.0 - (src[0] + src[1]) * zoom / (float)UINT16_MAX) * hh;
+            } else {
+                x = (src[1] * zoom / (float)INT16_MAX + 1) * hw;
+                y = (src[0] * zoom / (float)INT16_MAX + 1) * hh;
+            }
+
+            draw_dot(p, x, y);
+        }
+        break;
+    case AV_SAMPLE_FMT_FLT:
+        for (i = 0; i < insamples->nb_samples; i++) {
+            float *src = (float *)insamples->data[0] + i * 2;
+
+            if (p->mode == LISSAJOUS) {
+                x = ((src[1] - src[0]) * zoom / 2 + 1) * hw;
+                y = (1.0 - (src[0] + src[1]) * zoom / 2) * hh;
+            } else {
+                x = (src[1] * zoom + 1) * hw;
+                y = (src[0] * zoom + 1) * hh;
+            }
+
+            draw_dot(p, x, y);
+        }
+        break;
+    }
+
+    av_frame_free(&insamples);
+
+    return ff_filter_frame(outlink, av_frame_clone(p->outpicref));
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    AudioVectorScopeContext *p = ctx->priv;
+
+    av_frame_free(&p->outpicref);
+}
+
+static const AVFilterPad audiovectorscope_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .config_props = config_input,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad audiovectorscope_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_avf_avectorscope = {
+    .name          = "avectorscope",
+    .description   = NULL_IF_CONFIG_SMALL("Display audio vector scope."),
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(AudioVectorScopeContext),
+    .inputs        = audiovectorscope_inputs,
+    .outputs       = audiovectorscope_outputs,
+    .priv_class    = &avectorscope_class,
+};

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  63
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  64
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \