gstreamer/gst/audiovisualizers/gstspectrascope.c

/* GStreamer
 * Copyright (C) <2011> Stefan Kost <ensonic@users.sf.net>
 *
 * gstspectrascope.c: frequency spectrum scope
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.

 */
/**
 * SECTION:element-spectrascope
 * @see_also: goom
 *
 * Spectrascope is a simple spectrum visualisation element. It renders the
 * frequency spectrum as a series of bars.
 *
 * <refsect2>
 * <title>Example launch line</title>
 * |[
 * gst-launch-1.0 audiotestsrc ! audioconvert ! spectrascope ! ximagesink
 * ]|
 * </refsect2>
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>

#include "gstspectrascope.h"

static GstStaticPadTemplate gst_spectra_scope_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
#if G_BYTE_ORDER == G_BIG_ENDIAN
    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("xRGB"))
#else
    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("BGRx"))
#endif
    );

static GstStaticPadTemplate gst_spectra_scope_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-raw, "
        "format = (string) " GST_AUDIO_NE (S16) ", "
        "layout = (string) interleaved, "
        "rate = (int) [ 8000, 96000 ], "
        "channels = (int) 2, " "channel-mask = (bitmask) 0x3")
    );


GST_DEBUG_CATEGORY_STATIC (spectra_scope_debug);
#define GST_CAT_DEFAULT spectra_scope_debug

static void gst_spectra_scope_finalize (GObject * object);

static gboolean gst_spectra_scope_setup (GstAudioVisualizer * scope);
static gboolean gst_spectra_scope_render (GstAudioVisualizer * scope,
    GstBuffer * audio, GstVideoFrame * video);


G_DEFINE_TYPE (GstSpectraScope, gst_spectra_scope, GST_TYPE_AUDIO_VISUALIZER);

static void
gst_spectra_scope_class_init (GstSpectraScopeClass * g_class)
{
  GObjectClass *gobject_class = (GObjectClass *) g_class;
  GstElementClass *element_class = (GstElementClass *) g_class;
  GstAudioVisualizerClass *scope_class = (GstAudioVisualizerClass *) g_class;

  gobject_class->finalize = gst_spectra_scope_finalize;

  gst_element_class_set_static_metadata (element_class,
      "Frequency spectrum scope", "Visualization",
      "Simple frequency spectrum scope", "Stefan Kost <ensonic@users.sf.net>");

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_spectra_scope_src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_spectra_scope_sink_template));

  scope_class->setup = GST_DEBUG_FUNCPTR (gst_spectra_scope_setup);
  scope_class->render = GST_DEBUG_FUNCPTR (gst_spectra_scope_render);
}

static void
gst_spectra_scope_init (GstSpectraScope * scope)
{
  /* do nothing */
}

static void
gst_spectra_scope_finalize (GObject * object)
{
  GstSpectraScope *scope = GST_SPECTRA_SCOPE (object);

  if (scope->fft_ctx) {
    gst_fft_s16_free (scope->fft_ctx);
    scope->fft_ctx = NULL;
  }
  if (scope->freq_data) {
    g_free (scope->freq_data);
    scope->freq_data = NULL;
  }

  G_OBJECT_CLASS (gst_spectra_scope_parent_class)->finalize (object);
}

static gboolean
gst_spectra_scope_setup (GstAudioVisualizer * bscope)
{
  GstSpectraScope *scope = GST_SPECTRA_SCOPE (bscope);
  guint num_freq = GST_VIDEO_INFO_WIDTH (&bscope->vinfo) + 1;

  if (scope->fft_ctx)
    gst_fft_s16_free (scope->fft_ctx);
  g_free (scope->freq_data);

  /* we'd need this amount of samples per render() call */
  bscope->req_spf = num_freq * 2 - 2;
  scope->fft_ctx = gst_fft_s16_new (bscope->req_spf, FALSE);
  scope->freq_data = g_new (GstFFTS16Complex, num_freq);

  return TRUE;
}

static inline void
add_pixel (guint32 * _p, guint32 _c)
{
  guint8 *p = (guint8 *) _p;
  guint8 *c = (guint8 *) & _c;

  if (p[0] < 255 - c[0])
    p[0] += c[0];
  else
    p[0] = 255;
  if (p[1] < 255 - c[1])
    p[1] += c[1];
  else
    p[1] = 255;
  if (p[2] < 255 - c[2])
    p[2] += c[2];
  else
    p[2] = 255;
  if (p[3] < 255 - c[3])
    p[3] += c[3];
  else
    p[3] = 255;
}

static gboolean
gst_spectra_scope_render (GstAudioVisualizer * bscope, GstBuffer * audio,
    GstVideoFrame * video)
{
  GstSpectraScope *scope = GST_SPECTRA_SCOPE (bscope);
  gint16 *mono_adata;
  GstFFTS16Complex *fdata = scope->freq_data;
  guint x, y, off, l;
  guint w = GST_VIDEO_INFO_WIDTH (&bscope->vinfo);
  guint h = GST_VIDEO_INFO_HEIGHT (&bscope->vinfo) - 1;
  gfloat fr, fi;
  GstMapInfo amap;
  guint32 *vdata;
  gint channels;

  gst_buffer_map (audio, &amap, GST_MAP_READ);
  vdata = (guint32 *) GST_VIDEO_FRAME_PLANE_DATA (video, 0);

  channels = GST_AUDIO_INFO_CHANNELS (&bscope->ainfo);

  mono_adata = (gint16 *) g_memdup (amap.data, amap.size);

  if (channels > 1) {
    guint ch = channels;
    guint num_samples = amap.size / (ch * sizeof (gint16));
    guint i, c, v, s = 0;

    /* deinterleave and mixdown adata */
    for (i = 0; i < num_samples; i++) {
      v = 0;
      for (c = 0; c < ch; c++) {
        v += mono_adata[s++];
      }
      mono_adata[i] = v / ch;
    }
  }

  /* run fft */
  gst_fft_s16_window (scope->fft_ctx, mono_adata, GST_FFT_WINDOW_HAMMING);
  gst_fft_s16_fft (scope->fft_ctx, mono_adata, fdata);
  g_free (mono_adata);

  /* draw lines */
  for (x = 0; x < w; x++) {
    /* figure out the range so that we don't need to clip,
     * or even better do a log mapping? */
    fr = (gfloat) fdata[1 + x].r / 512.0;
    fi = (gfloat) fdata[1 + x].i / 512.0;
    y = (guint) (h * sqrt (fr * fr + fi * fi));
    if (y > h)
      y = h;
    y = h - y;
    off = (y * w) + x;
    vdata[off] = 0x00FFFFFF;
    for (l = y; l < h; l++) {
      off += w;
      add_pixel (&vdata[off], 0x007F7F7F);
    }
    /* ensure bottom line is full bright (especially in move-up mode) */
    add_pixel (&vdata[off], 0x007F7F7F);
  }
  gst_buffer_unmap (audio, &amap);
  return TRUE;
}

gboolean
gst_spectra_scope_plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (spectra_scope_debug, "spectrascope", 0,
      "spectrascope");

  return gst_element_register (plugin, "spectrascope", GST_RANK_NONE,
      GST_TYPE_SPECTRA_SCOPE);
}