gstreamer/gst/scopes/gstspectrascope.c

/* GStreamer
 * Copyright (C) <2011> Stefan Kost <ensonic@users.sf.net>
 *
 * gstspectrascope.c: simple oscilloscope
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
/**
 * SECTION:element-spectrascope
 * @see_also: goom
 *
 * Wavescope is a simple audio visualisation element. It renders the waveforms
 * like on an oscilloscope.
 *
 * <refsect2>
 * <title>Example launch line</title>
 * |[
 * gst-launch 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,
    GST_STATIC_CAPS (GST_VIDEO_CAPS_xRGB_HOST_ENDIAN)
    );

static GstStaticPadTemplate gst_spectra_scope_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS (GST_AUDIO_INT_STANDARD_PAD_TEMPLATE_CAPS)
    );


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 (GstBaseScope * scope);
static gboolean gst_spectra_scope_render (GstBaseScope * scope,
    GstBuffer * audio, GstBuffer * video);


GST_BOILERPLATE (GstSpectraScope, gst_spectra_scope, GstBaseScope,
    GST_TYPE_BASE_SCOPE);

static void
gst_spectra_scope_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details_simple (element_class, "Waveform oscilloscope",
      "Visualization",
      "Simple waveform oscilloscope", "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));
}

static void
gst_spectra_scope_class_init (GstSpectraScopeClass * g_class)
{
  GObjectClass *gobject_class = (GObjectClass *) g_class;
  GstBaseScopeClass *scope_class = (GstBaseScopeClass *) g_class;

  gobject_class->finalize = gst_spectra_scope_finalize;

  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, GstSpectraScopeClass * g_class)
{
  /* 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 (parent_class)->finalize (object);
}

static gboolean
gst_spectra_scope_setup (GstBaseScope * bscope)
{
  GstSpectraScope *scope = GST_SPECTRA_SCOPE (bscope);

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

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

  return TRUE;
}

static gboolean
gst_spectra_scope_render (GstBaseScope * bscope, GstBuffer * audio,
    GstBuffer * video)
{
  GstSpectraScope *scope = GST_SPECTRA_SCOPE (bscope);
  guint8 *vdata = GST_BUFFER_DATA (video);
  gint16 *adata = (gint16 *) GST_BUFFER_DATA (audio);
  GstFFTS16Complex *fdata = scope->freq_data;
  guint x, y, off;
  guint l, h = bscope->height - 1;
  gfloat fr, fi;
  guint bpp = gst_video_format_get_pixel_stride (bscope->video_format, 0);
  guint bpl = bpp * bscope->width;

  if (bscope->channels > 1) {
    gint ch = bscope->channels;
    gint num_samples = GST_BUFFER_SIZE (audio) / (ch * sizeof (gint16));
    gint 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 += adata[s++];
      }
      adata[i] = v / ch;
    }
  }

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

  /* draw lines */
  for (x = 0; x < bscope->width; x++) {
    /* figure out the range so that we don't need to clip,
     * or even better do a log mapping? */
    fr = (gfloat) fdata[x].r / 2048.0;
    fi = (gfloat) fdata[x].i / 2048.0;
    y = (guint) (h * fabs (fr * fr + fi * fi));
    if (y > h)
      y = h;
    y = h - y;
    off = (y * bpl) + (x * bpp);
    vdata[off + 0] = 0xFF;
    vdata[off + 1] = 0xFF;
    vdata[off + 2] = 0xFF;
    for (l = y + 1; l <= h; l++) {
      off += bpl;
      vdata[off + 0] = 0x7F;
      vdata[off + 1] = 0x7F;
      vdata[off + 2] = 0x7F;
    }
  }
  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);
}