gstreamer/gst/videoscale/gstvideoscale.c

/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 * Copyright (C) 2005 David Schleef <ds@schleef.org>
 *
 * 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/**
 * SECTION:element-videoscale
 * @see_also: videorate, ffmpegcolorspace
 *
 * This element resizes video frames. By default the element will try to
 * negotiate to the same size on the source and sinkpad so that no scaling
 * is needed. It is therefore safe to insert this element in a pipeline to
 * get more robust behaviour without any cost if no scaling is needed.
 *
 * This element supports a wide range of color spaces including various YUV and
 * RGB formats and is therefore generally able to operate anywhere in a
 * pipeline.
 *
 * <refsect2>
 * <title>Example pipelines</title>
 * |[
 * gst-launch -v filesrc location=videotestsrc.ogg ! oggdemux ! theoradec ! ffmpegcolorspace ! videoscale ! ximagesink
 * ]| Decode an Ogg/Theora and display the video using ximagesink. Since
 * ximagesink cannot perform scaling, the video scaling will be performed by
 * videoscale when you resize the video window.
 * To create the test Ogg/Theora file refer to the documentation of theoraenc.
 * |[
 * gst-launch -v filesrc location=videotestsrc.ogg ! oggdemux ! theoradec ! videoscale ! video/x-raw-yuv, width=50 ! xvimagesink
 * ]| Decode an Ogg/Theora and display the video using xvimagesink with a width
 * of 50.
 * </refsect2>
 *
 * Last reviewed on 2006-03-02 (0.10.4)
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>

#include <math.h>

#include <gst/video/video.h>

#include "gstvideoscale.h"
#include "vs_image.h"
#include "vs_4tap.h"


/* debug variable definition */
GST_DEBUG_CATEGORY (video_scale_debug);

#define DEFAULT_PROP_METHOD	GST_VIDEO_SCALE_BILINEAR

enum
{
  PROP_0,
  PROP_METHOD
      /* FILL ME */
};

#undef GST_VIDEO_SIZE_RANGE
#define GST_VIDEO_SIZE_RANGE "(int) [ 1, 32767]"

static GstStaticCaps gst_video_scale_format_caps[] = {
  GST_STATIC_CAPS (GST_VIDEO_CAPS_RGBA),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_ARGB),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_BGRA),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_ABGR),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_RGBx),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_xRGB),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_BGRx),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_xBGR),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y444")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("v308")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_BGR),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y42B")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("YUY2")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("YVYU")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("UYVY")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("I420")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("YV12")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y41B")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB_16),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB_15),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY16 ("BYTE_ORDER")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y16 ")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY8),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y800")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("Y8  ")),
  GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("GREY"))
};

#define GST_TYPE_VIDEO_SCALE_METHOD (gst_video_scale_method_get_type())
static GType
gst_video_scale_method_get_type (void)
{
  static GType video_scale_method_type = 0;

  static const GEnumValue video_scale_methods[] = {
    {GST_VIDEO_SCALE_NEAREST, "Nearest Neighbour", "nearest-neighbour"},
    {GST_VIDEO_SCALE_BILINEAR, "Bilinear", "bilinear"},
    {GST_VIDEO_SCALE_4TAP, "4-tap", "4-tap"},
    {0, NULL, NULL},
  };

  if (!video_scale_method_type) {
    video_scale_method_type =
        g_enum_register_static ("GstVideoScaleMethod", video_scale_methods);
  }
  return video_scale_method_type;
}

static GstCaps *
gst_video_scale_get_capslist (void)
{
  static GstCaps *caps = NULL;
  static volatile gsize inited = 0;

  if (g_once_init_enter (&inited)) {
    gint i;

    g_assert (caps == NULL);

    caps = gst_caps_new_empty ();
    for (i = 0; i < G_N_ELEMENTS (gst_video_scale_format_caps); i++)
      gst_caps_append (caps,
          gst_caps_make_writable
          (gst_static_caps_get (&gst_video_scale_format_caps[i])));
    g_once_init_leave (&inited, 1);
  }

  return caps;
}

static GstPadTemplate *
gst_video_scale_src_template_factory (void)
{
  return gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
      gst_caps_ref (gst_video_scale_get_capslist ()));
}

static GstPadTemplate *
gst_video_scale_sink_template_factory (void)
{
  return gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
      gst_caps_ref (gst_video_scale_get_capslist ()));
}


static void gst_video_scale_finalize (GstVideoScale * videoscale);
static gboolean gst_video_scale_src_event (GstBaseTransform * trans,
    GstEvent * event);

/* base transform vmethods */
static GstCaps *gst_video_scale_transform_caps (GstBaseTransform * trans,
    GstPadDirection direction, GstCaps * caps);
static gboolean gst_video_scale_set_caps (GstBaseTransform * trans,
    GstCaps * in, GstCaps * out);
static gboolean gst_video_scale_get_unit_size (GstBaseTransform * trans,
    GstCaps * caps, guint * size);
static GstFlowReturn gst_video_scale_transform (GstBaseTransform * trans,
    GstBuffer * in, GstBuffer * out);
static void gst_video_scale_fixate_caps (GstBaseTransform * base,
    GstPadDirection direction, GstCaps * caps, GstCaps * othercaps);

static void gst_video_scale_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_video_scale_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

GST_BOILERPLATE (GstVideoScale, gst_video_scale, GstVideoFilter,
    GST_TYPE_VIDEO_FILTER);

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

  gst_element_class_set_details_simple (element_class,
      "Video scaler", "Filter/Effect/Video",
      "Resizes video", "Wim Taymans <wim.taymans@chello.be>");

  gst_element_class_add_pad_template (element_class,
      gst_video_scale_sink_template_factory ());
  gst_element_class_add_pad_template (element_class,
      gst_video_scale_src_template_factory ());
}

static void
gst_video_scale_class_init (GstVideoScaleClass * klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;
  GstBaseTransformClass *trans_class = (GstBaseTransformClass *) klass;

  gobject_class->finalize = (GObjectFinalizeFunc) gst_video_scale_finalize;
  gobject_class->set_property = gst_video_scale_set_property;
  gobject_class->get_property = gst_video_scale_get_property;

  g_object_class_install_property (gobject_class, PROP_METHOD,
      g_param_spec_enum ("method", "method", "method",
          GST_TYPE_VIDEO_SCALE_METHOD, DEFAULT_PROP_METHOD,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  trans_class->transform_caps =
      GST_DEBUG_FUNCPTR (gst_video_scale_transform_caps);
  trans_class->set_caps = GST_DEBUG_FUNCPTR (gst_video_scale_set_caps);
  trans_class->get_unit_size =
      GST_DEBUG_FUNCPTR (gst_video_scale_get_unit_size);
  trans_class->transform = GST_DEBUG_FUNCPTR (gst_video_scale_transform);
  trans_class->fixate_caps = GST_DEBUG_FUNCPTR (gst_video_scale_fixate_caps);
  trans_class->src_event = GST_DEBUG_FUNCPTR (gst_video_scale_src_event);
}

static void
gst_video_scale_init (GstVideoScale * videoscale, GstVideoScaleClass * klass)
{
  videoscale->tmp_buf = NULL;
  videoscale->method = DEFAULT_PROP_METHOD;
}

static void
gst_video_scale_finalize (GstVideoScale * videoscale)
{
  if (videoscale->tmp_buf)
    g_free (videoscale->tmp_buf);

  G_OBJECT_CLASS (parent_class)->finalize (G_OBJECT (videoscale));
}

static void
gst_video_scale_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstVideoScale *vscale = GST_VIDEO_SCALE (object);

  switch (prop_id) {
    case PROP_METHOD:
      GST_OBJECT_LOCK (vscale);
      vscale->method = g_value_get_enum (value);
      GST_OBJECT_UNLOCK (vscale);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_video_scale_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstVideoScale *vscale = GST_VIDEO_SCALE (object);

  switch (prop_id) {
    case PROP_METHOD:
      GST_OBJECT_LOCK (vscale);
      g_value_set_enum (value, vscale->method);
      GST_OBJECT_UNLOCK (vscale);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstCaps *
gst_video_scale_transform_caps (GstBaseTransform * trans,
    GstPadDirection direction, GstCaps * caps)
{
  GstCaps *ret;
  GstStructure *structure;

  /* this function is always called with a simple caps */
  g_return_val_if_fail (GST_CAPS_IS_SIMPLE (caps), NULL);

  ret = gst_caps_copy (caps);
  structure = gst_structure_copy (gst_caps_get_structure (ret, 0));

  gst_structure_set (structure,
      "width", GST_TYPE_INT_RANGE, 1, G_MAXINT,
      "height", GST_TYPE_INT_RANGE, 1, G_MAXINT, NULL);

  /* if pixel aspect ratio, make a range of it */
  if (gst_structure_has_field (structure, "pixel-aspect-ratio")) {
    gst_structure_set (structure,
        "pixel-aspect-ratio", GST_TYPE_FRACTION_RANGE, 1, G_MAXINT, G_MAXINT, 1,
        NULL);
  }
  gst_caps_merge_structure (ret, gst_structure_copy (structure));
  gst_structure_free (structure);

  GST_DEBUG_OBJECT (trans, "returning caps: %" GST_PTR_FORMAT, ret);

  return ret;
}

static gboolean
gst_video_scale_set_caps (GstBaseTransform * trans, GstCaps * in, GstCaps * out)
{
  GstVideoScale *videoscale = GST_VIDEO_SCALE (trans);
  gboolean ret;
  gint from_dar_n, from_dar_d, to_dar_n, to_dar_d;
  gint from_par_n, from_par_d, to_par_n, to_par_d;

  ret =
      gst_video_format_parse_caps (in, &videoscale->format,
      &videoscale->from_width, &videoscale->from_height);
  ret &=
      gst_video_format_parse_caps (out, NULL, &videoscale->to_width,
      &videoscale->to_height);
  ret &= gst_video_format_parse_caps_interlaced (in, &videoscale->interlaced);
  if (!ret)
    goto done;


  videoscale->src_size = gst_video_format_get_size (videoscale->format,
      videoscale->from_width, videoscale->from_height);
  videoscale->dest_size = gst_video_format_get_size (videoscale->format,
      videoscale->to_width, videoscale->to_height);

  videoscale->src.width =
      gst_video_format_get_component_width (videoscale->format, 0,
      videoscale->from_width);
  videoscale->src.height =
      gst_video_format_get_component_height (videoscale->format, 0,
      videoscale->from_height);
  videoscale->src.stride =
      gst_video_format_get_row_stride (videoscale->format, 0,
      videoscale->from_width);

  videoscale->dest.width =
      gst_video_format_get_component_width (videoscale->format, 0,
      videoscale->to_width);
  videoscale->dest.height =
      gst_video_format_get_component_height (videoscale->format, 0,
      videoscale->to_height);
  videoscale->dest.stride =
      gst_video_format_get_row_stride (videoscale->format, 0,
      videoscale->to_width);

  if (videoscale->tmp_buf)
    g_free (videoscale->tmp_buf);

  videoscale->tmp_buf =
      g_malloc (videoscale->dest.stride * 4 * (videoscale->interlaced ? 2 : 1));

  if (!gst_video_parse_caps_pixel_aspect_ratio (in, &from_par_n, &from_par_d))
    from_par_n = from_par_d = 1;
  if (!gst_video_parse_caps_pixel_aspect_ratio (out, &to_par_n, &to_par_d))
    to_par_n = to_par_d = 1;

  if (!gst_util_fraction_multiply (videoscale->from_width,
          videoscale->from_height, from_par_n, from_par_d, &from_dar_n,
          &from_dar_d)) {
    from_dar_n = from_dar_d = -1;
  }

  if (!gst_util_fraction_multiply (videoscale->to_width, videoscale->to_height,
          to_par_n, to_par_d, &to_dar_n, &to_dar_d)) {
    to_dar_n = to_dar_d = -1;
  }

  if (to_dar_n != from_dar_n || to_dar_d != from_dar_d)
    GST_WARNING_OBJECT (videoscale, "Can't keep DAR!");

  gst_base_transform_set_passthrough (trans,
      (videoscale->from_width == videoscale->to_width
          && videoscale->from_height == videoscale->to_height));

  GST_DEBUG_OBJECT (videoscale, "from=%dx%d (par=%d/%d dar=%d/%d), size %d "
      "-> to=%dx%d (par=%d/%d dar=%d/%d), size %d",
      videoscale->from_width, videoscale->from_height, from_par_n, from_par_d,
      from_dar_n, from_dar_d, videoscale->src_size, videoscale->to_width,
      videoscale->to_height, to_par_n, to_par_d, to_dar_n, to_dar_d,
      videoscale->dest_size);

done:
  return ret;
}

static gboolean
gst_video_scale_get_unit_size (GstBaseTransform * trans, GstCaps * caps,
    guint * size)
{
  GstVideoFormat format;
  gint width, height;

  if (!gst_video_format_parse_caps (caps, &format, &width, &height))
    return FALSE;

  *size = gst_video_format_get_size (format, width, height);

  return TRUE;
}

static void
gst_video_scale_fixate_caps (GstBaseTransform * base, GstPadDirection direction,
    GstCaps * caps, GstCaps * othercaps)
{
  GstStructure *ins, *outs;
  const GValue *from_par, *to_par;
  GValue fpar = { 0, }, tpar = {
  0,};

  g_return_if_fail (gst_caps_is_fixed (caps));

  GST_DEBUG_OBJECT (base, "trying to fixate othercaps %" GST_PTR_FORMAT
      " based on caps %" GST_PTR_FORMAT, othercaps, caps);

  ins = gst_caps_get_structure (caps, 0);
  outs = gst_caps_get_structure (othercaps, 0);

  from_par = gst_structure_get_value (ins, "pixel-aspect-ratio");
  to_par = gst_structure_get_value (outs, "pixel-aspect-ratio");

  /* If we're fixating from the sinkpad we always set the PAR and
   * assume that missing PAR on the sinkpad means 1/1 and
   * missing PAR on the srcpad means undefined
   */
  if (direction == GST_PAD_SINK) {
    if (!from_par) {
      g_value_init (&fpar, GST_TYPE_FRACTION);
      gst_value_set_fraction (&fpar, 1, 1);
      from_par = &fpar;
    }
    if (!to_par) {
      g_value_init (&tpar, GST_TYPE_FRACTION_RANGE);
      gst_value_set_fraction_range_full (&tpar, 1, G_MAXINT, G_MAXINT, 1);
      to_par = &tpar;

      gst_structure_set (outs, "pixel-aspect-ratio", GST_TYPE_FRACTION_RANGE, 1,
          G_MAXINT, G_MAXINT, 1, NULL);
    }
  } else {
    if (!to_par) {
      g_value_init (&tpar, GST_TYPE_FRACTION);
      gst_value_set_fraction (&tpar, 1, 1);
      to_par = &tpar;

      gst_structure_set (outs, "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
          NULL);
    }
    if (!from_par) {
      g_value_init (&fpar, GST_TYPE_FRACTION_RANGE);
      gst_value_set_fraction_range_full (&fpar, 1, G_MAXINT, G_MAXINT, 1);
      from_par = &fpar;
    }
  }

  /* we have both PAR but they might not be fixated */
  {
    gint from_w, from_h, from_par_n, from_par_d, to_par_n, to_par_d;
    gint w = 0, h = 0;
    gint from_dar_n, from_dar_d;
    gint num, den;

    /* from_par should be fixed */
    g_return_if_fail (gst_value_is_fixed (from_par));

    from_par_n = gst_value_get_fraction_numerator (from_par);
    from_par_d = gst_value_get_fraction_denominator (from_par);

    gst_structure_get_int (ins, "width", &from_w);
    gst_structure_get_int (ins, "height", &from_h);

    /* if both width and height are already fixed, we can't do anything
     * about it anymore */
    if (gst_structure_get_int (outs, "width", &w)
        && gst_structure_get_int (outs, "height", &h)) {
      guint n, d;

      GST_DEBUG_OBJECT (base, "dimensions already set to %dx%d, not fixating",
          w, h);
      if (!gst_value_is_fixed (to_par)) {
        if (gst_video_calculate_display_ratio (&n, &d, from_w, from_h,
                from_par_n, from_par_d, w, h)) {
          GST_DEBUG_OBJECT (base, "fixating to_par to %dx%d", n, d);
          if (gst_structure_has_field (outs, "pixel-aspect-ratio"))
            gst_structure_fixate_field_nearest_fraction (outs,
                "pixel-aspect-ratio", n, d);
          else
            gst_structure_set (outs, "pixel-aspect-ratio", GST_TYPE_FRACTION,
                n, d, NULL);
        }
      }
      goto done;
    }

    /* Calculate input DAR */
    if (!gst_util_fraction_multiply (from_w, from_h, from_par_n, from_par_d,
            &from_dar_n, &from_dar_d)) {
      GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
          ("Error calculating the output scaled size - integer overflow"));
      goto done;
    }

    GST_DEBUG_OBJECT (base, "Input DAR is %d/%d", from_dar_n, from_dar_d);

    /* If either width or height are fixed there's not much we
     * can do either except choosing a height or width and PAR
     * that matches the DAR as good as possible
     */
    if (h) {
      GstStructure *tmp;
      gint set_w, set_par_n, set_par_d;

      GST_DEBUG_OBJECT (base, "height is fixed (%d)", h);

      /* If the PAR is fixed too, there's not much to do
       * except choosing the width that is nearest to the
       * width with the same DAR */
      if (gst_value_is_fixed (to_par)) {
        to_par_n = gst_value_get_fraction_numerator (to_par);
        to_par_d = gst_value_get_fraction_denominator (to_par);

        GST_DEBUG_OBJECT (base, "PAR is fixed %d/%d", to_par_n, to_par_d);

        if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, to_par_d,
                to_par_n, &num, &den)) {
          GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
              ("Error calculating the output scaled size - integer overflow"));
          goto done;
        }

        w = (guint) gst_util_uint64_scale_int (h, num, den);
        gst_structure_fixate_field_nearest_int (outs, "width", w);

        goto done;
      }

      /* The PAR is not fixed and it's quite likely that we can set
       * an arbitrary PAR. */

      /* Check if we can keep the input width */
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "width", from_w);
      gst_structure_get_int (tmp, "width", &set_w);

      /* Might have failed but try to keep the DAR nonetheless by
       * adjusting the PAR */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, h, set_w,
              &to_par_n, &to_par_d)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        gst_structure_free (tmp);
        goto done;
      }
      gst_structure_fixate_field_nearest_fraction (tmp, "pixel-aspect-ratio",
          to_par_n, to_par_d);
      gst_structure_get_fraction (tmp, "pixel-aspect-ratio", &set_par_n,
          &set_par_d);
      gst_structure_free (tmp);

      /* Check if the adjusted PAR is accepted */
      if (set_par_n == to_par_n && set_par_d == to_par_d) {
        gst_structure_set (outs, "width", G_TYPE_INT, set_w,
            "pixel-aspect-ratio", GST_TYPE_FRACTION, set_par_n, set_par_d,
            NULL);
        goto done;
      }

      /* Otherwise scale the width to the new PAR and check if the
       * adjusted with is accepted. If all that fails we can't keep
       * the DAR */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, set_par_d,
              set_par_n, &num, &den)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        goto done;
      }

      w = (guint) gst_util_uint64_scale_int (h, num, den);
      gst_structure_fixate_field_nearest_int (outs, "width", w);
      gst_structure_set (outs, "pixel-aspect-ratio", GST_TYPE_FRACTION,
          set_par_n, set_par_d, NULL);

      goto done;
    } else if (w) {
      GstStructure *tmp;
      gint set_h, set_par_n, set_par_d;

      GST_DEBUG_OBJECT (base, "width is fixed (%d)", w);

      /* If the PAR is fixed too, there's not much to do
       * except choosing the height that is nearest to the
       * height with the same DAR */
      if (gst_value_is_fixed (to_par)) {
        to_par_n = gst_value_get_fraction_numerator (to_par);
        to_par_d = gst_value_get_fraction_denominator (to_par);

        GST_DEBUG_OBJECT (base, "PAR is fixed %d/%d", to_par_n, to_par_d);

        if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, to_par_d,
                to_par_n, &num, &den)) {
          GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
              ("Error calculating the output scaled size - integer overflow"));
          goto done;
        }

        h = (guint) gst_util_uint64_scale_int (w, den, num);
        gst_structure_fixate_field_nearest_int (outs, "height", h);

        goto done;
      }

      /* The PAR is not fixed and it's quite likely that we can set
       * an arbitrary PAR. */

      /* Check if we can keep the input height */
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "height", from_h);
      gst_structure_get_int (tmp, "height", &set_h);

      /* Might have failed but try to keep the DAR nonetheless by
       * adjusting the PAR */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, set_h, w,
              &to_par_n, &to_par_d)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        gst_structure_free (tmp);
        goto done;
      }
      gst_structure_fixate_field_nearest_fraction (tmp, "pixel-aspect-ratio",
          to_par_n, to_par_d);
      gst_structure_get_fraction (tmp, "pixel-aspect-ratio", &set_par_n,
          &set_par_d);
      gst_structure_free (tmp);

      /* Check if the adjusted PAR is accepted */
      if (set_par_n == to_par_n && set_par_d == to_par_d) {
        gst_structure_set (outs, "height", G_TYPE_INT, set_h,
            "pixel-aspect-ratio", GST_TYPE_FRACTION, set_par_n, set_par_d,
            NULL);
        goto done;
      }

      /* Otherwise scale the height to the new PAR and check if the
       * adjusted with is accepted. If all that fails we can't keep
       * the DAR */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, set_par_d,
              set_par_n, &num, &den)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        goto done;
      }

      h = (guint) gst_util_uint64_scale_int (w, den, num);
      gst_structure_fixate_field_nearest_int (outs, "height", h);
      gst_structure_set (outs, "pixel-aspect-ratio", GST_TYPE_FRACTION,
          set_par_n, set_par_d, NULL);

      goto done;
    } else if (gst_value_is_fixed (to_par)) {
      GstStructure *tmp;
      gint set_h, set_w, f_h, f_w;

      to_par_n = gst_value_get_fraction_numerator (to_par);
      to_par_d = gst_value_get_fraction_denominator (to_par);

      /* Calculate scale factor for the PAR change */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, to_par_n,
              to_par_d, &num, &den)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        goto done;
      }

      /* Try to keep the input height (because of interlacing) */
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "height", from_h);
      gst_structure_get_int (tmp, "height", &set_h);

      /* This might have failed but try to scale the width
       * to keep the DAR nonetheless */
      w = (guint) gst_util_uint64_scale_int (set_h, num, den);
      gst_structure_fixate_field_nearest_int (tmp, "width", w);
      gst_structure_get_int (tmp, "width", &set_w);
      gst_structure_free (tmp);

      /* We kept the DAR and the height is nearest to the original height */
      if (set_w == w) {
        gst_structure_set (outs, "width", G_TYPE_INT, set_w, "height",
            G_TYPE_INT, set_h, NULL);
        goto done;
      }

      f_h = set_h;
      f_w = set_w;

      /* If the former failed, try to keep the input width at least */
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "width", from_w);
      gst_structure_get_int (tmp, "width", &set_w);

      /* This might have failed but try to scale the width
       * to keep the DAR nonetheless */
      h = (guint) gst_util_uint64_scale_int (set_w, den, num);
      gst_structure_fixate_field_nearest_int (tmp, "height", h);
      gst_structure_get_int (tmp, "height", &set_h);
      gst_structure_free (tmp);

      /* We kept the DAR and the width is nearest to the original width */
      if (set_h == h) {
        gst_structure_set (outs, "width", G_TYPE_INT, set_w, "height",
            G_TYPE_INT, set_h, NULL);
        goto done;
      }

      /* If all this failed, keep the height that was nearest to the orignal
       * height and the nearest possible width. This changes the DAR but
       * there's not much else to do here.
       */
      gst_structure_set (outs, "width", G_TYPE_INT, f_w, "height", G_TYPE_INT,
          f_h, NULL);
      goto done;
    } else {
      GstStructure *tmp;
      gint set_h, set_w, set_par_n, set_par_d, tmp2;

      /* width, height and PAR are not fixed but passthrough is not possible */

      /* First try to keep the height and width as good as possible
       * and scale PAR */
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "height", from_h);
      gst_structure_get_int (tmp, "height", &set_h);
      gst_structure_fixate_field_nearest_int (tmp, "width", from_w);
      gst_structure_get_int (tmp, "width", &set_w);

      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, set_h, set_w,
              &to_par_n, &to_par_d)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        goto done;
      }

      gst_structure_fixate_field_nearest_fraction (tmp, "pixel-aspect-ratio",
          to_par_n, to_par_d);
      gst_structure_get_fraction (tmp, "pixel-aspect-ratio", &set_par_n,
          &set_par_d);
      gst_structure_free (tmp);

      if (set_par_n == to_par_n && set_par_d == to_par_d) {
        gst_structure_set (outs, "width", G_TYPE_INT, set_w, "height",
            G_TYPE_INT, set_h, "pixel-aspect-ratio", GST_TYPE_FRACTION,
            set_par_n, set_par_d, NULL);
        goto done;
      }

      /* Otherwise try to scale width to keep the DAR with the set
       * PAR and height */
      if (!gst_util_fraction_multiply (from_dar_n, from_dar_d, set_par_d,
              set_par_n, &num, &den)) {
        GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
            ("Error calculating the output scaled size - integer overflow"));
        goto done;
      }

      w = (guint) gst_util_uint64_scale_int (set_h, num, den);
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "width", w);
      gst_structure_get_int (tmp, "width", &tmp2);
      gst_structure_free (tmp);

      if (tmp2 == w) {
        gst_structure_set (outs, "width", G_TYPE_INT, tmp2, "height",
            G_TYPE_INT, set_h, "pixel-aspect-ratio", GST_TYPE_FRACTION,
            set_par_n, set_par_d, NULL);
        goto done;
      }

      /* ... or try the same with the height */
      h = (guint) gst_util_uint64_scale_int (set_w, den, num);
      tmp = gst_structure_copy (outs);
      gst_structure_fixate_field_nearest_int (tmp, "height", h);
      gst_structure_get_int (tmp, "height", &tmp2);
      gst_structure_free (tmp);

      if (tmp2 == h) {
        gst_structure_set (outs, "width", G_TYPE_INT, set_w, "height",
            G_TYPE_INT, tmp2, "pixel-aspect-ratio", GST_TYPE_FRACTION,
            set_par_n, set_par_d, NULL);
        goto done;
      }

      /* If all fails we can't keep the DAR and take the nearest values
       * for everything from the first try */
      gst_structure_set (outs, "width", G_TYPE_INT, set_w, "height",
          G_TYPE_INT, set_h, "pixel-aspect-ratio", GST_TYPE_FRACTION,
          set_par_n, set_par_d, NULL);
    }
  }

done:
  GST_DEBUG_OBJECT (base, "fixated othercaps to %" GST_PTR_FORMAT, othercaps);

  if (from_par == &fpar)
    g_value_unset (&fpar);
  if (to_par == &tpar)
    g_value_unset (&tpar);
}

static gboolean
gst_video_scale_prepare_image (gint format, GstBuffer * buf,
    VSImage * img, VSImage * img_u, VSImage * img_v, gint step,
    gboolean interlaced)
{
  gboolean res = TRUE;

  switch (format) {
    case GST_VIDEO_FORMAT_I420:
    case GST_VIDEO_FORMAT_YV12:
    case GST_VIDEO_FORMAT_Y444:
    case GST_VIDEO_FORMAT_Y42B:
    case GST_VIDEO_FORMAT_Y41B:
      img_u->pixels =
          GST_BUFFER_DATA (buf) + gst_video_format_get_component_offset (format,
          1, img->width, img->height);
      img_v->pixels =
          GST_BUFFER_DATA (buf) + gst_video_format_get_component_offset (format,
          2, img->width, img->height);
      img_u->height =
          gst_video_format_get_component_height (format, 1, img->height);
      img_v->height =
          gst_video_format_get_component_height (format, 2, img->height);
      img_u->width =
          gst_video_format_get_component_width (format, 1, img->width);
      img_v->width =
          gst_video_format_get_component_width (format, 2, img->width);
      img_u->stride = gst_video_format_get_row_stride (format, 1, img->width);
      img_v->stride = gst_video_format_get_row_stride (format, 2, img->width);

      if (interlaced && step == 1) {
        img_v->pixels += img_v->stride;
        img_u->pixels += img_u->stride;
      }

      if (interlaced) {
        img_u->height = (img_u->height / 2) + ((step == 0
                && img_u->height % 2 == 1) ? 1 : 0);
        img_u->stride *= 2;
        img_v->height = (img_v->height / 2) + ((step == 0
                && img_v->height % 2 == 1) ? 1 : 0);
        img_v->stride *= 2;
      }

      break;
      img_u->pixels =
          GST_BUFFER_DATA (buf) + GST_ROUND_UP_4 (img->width) * img->height;
      img_u->height = img->height;
      img_u->width = GST_ROUND_UP_2 (img->width) / 2;
      img_u->stride = GST_ROUND_UP_8 (img->width) / 2;
      memcpy (img_v, img_u, sizeof (*img_v));
      img_v->pixels =
          GST_BUFFER_DATA (buf) + (GST_ROUND_UP_4 (img->width) +
          (GST_ROUND_UP_8 (img->width) / 2)) * img->height;

      if (interlaced && step == 1) {
        img_v->pixels += img_v->stride;
        img_u->pixels += img_u->stride;
      }

      if (interlaced) {
        img_u->height = (img_u->height / 2) + ((step == 0
                && img_u->height % 2 == 1) ? 1 : 0);
        img_u->stride *= 2;
        img_v->height = (img_v->height / 2) + ((step == 0
                && img_v->height % 2 == 1) ? 1 : 0);
        img_v->stride *= 2;
      }
      break;
    default:
      break;
  }
  return res;
}

static GstFlowReturn
gst_video_scale_transform (GstBaseTransform * trans, GstBuffer * in,
    GstBuffer * out)
{
  GstVideoScale *videoscale = GST_VIDEO_SCALE (trans);
  GstFlowReturn ret = GST_FLOW_OK;
  VSImage dest = videoscale->dest;
  VSImage src = videoscale->src;
  VSImage dest_u = { NULL, };
  VSImage dest_v = { NULL, };
  VSImage src_u = { NULL, };
  VSImage src_v = { NULL, };
  gint method;
  gint step;
  gboolean interlaced = videoscale->interlaced;

  GST_OBJECT_LOCK (videoscale);
  method = videoscale->method;
  GST_OBJECT_UNLOCK (videoscale);

  src.pixels = GST_BUFFER_DATA (in);
  dest.pixels = GST_BUFFER_DATA (out);

  /* For interlaced content we have to run two times with half height
   * and doubled stride */
  if (interlaced) {
    dest.height /= 2;
    src.height /= 2;
    dest.stride *= 2;
    src.stride *= 2;
  }

  if (src.height < 4 && method == GST_VIDEO_SCALE_4TAP)
    method = GST_VIDEO_SCALE_BILINEAR;

  for (step = 0; step < (interlaced ? 2 : 1); step++) {
    gst_video_scale_prepare_image (videoscale->format, in, &videoscale->src,
        &src_u, &src_v, step, interlaced);
    gst_video_scale_prepare_image (videoscale->format, out, &videoscale->dest,
        &dest_u, &dest_v, step, interlaced);

    if (step == 0 && interlaced) {
      if (videoscale->from_height % 2 == 1) {
        src.height += 1;
      }

      if (videoscale->to_height % 2 == 1) {
        dest.height += 1;
      }
    } else if (step == 1 && interlaced) {
      if (videoscale->from_height % 2 == 1) {
        src.height -= 1;
      }

      if (videoscale->to_height % 2 == 1) {
        dest.height -= 1;
      }
      src.pixels += (src.stride / 2);
      dest.pixels += (dest.stride / 2);
    }

    switch (method) {
      case GST_VIDEO_SCALE_NEAREST:
        GST_LOG_OBJECT (videoscale, "doing nearest scaling");
        switch (videoscale->format) {
          case GST_VIDEO_FORMAT_RGBx:
          case GST_VIDEO_FORMAT_xRGB:
          case GST_VIDEO_FORMAT_BGRx:
          case GST_VIDEO_FORMAT_xBGR:
          case GST_VIDEO_FORMAT_RGBA:
          case GST_VIDEO_FORMAT_ARGB:
          case GST_VIDEO_FORMAT_BGRA:
          case GST_VIDEO_FORMAT_ABGR:
          case GST_VIDEO_FORMAT_AYUV:
            vs_image_scale_nearest_RGBA (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB:
          case GST_VIDEO_FORMAT_BGR:
          case GST_VIDEO_FORMAT_v308:
            vs_image_scale_nearest_RGB (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_YUY2:
          case GST_VIDEO_FORMAT_YVYU:
            vs_image_scale_nearest_YUYV (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_UYVY:
            vs_image_scale_nearest_UYVY (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_Y800:
          case GST_VIDEO_FORMAT_GRAY8:
            vs_image_scale_nearest_Y (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_GRAY16_LE:
          case GST_VIDEO_FORMAT_GRAY16_BE:
          case GST_VIDEO_FORMAT_Y16:
            vs_image_scale_nearest_Y16 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_I420:
          case GST_VIDEO_FORMAT_YV12:
          case GST_VIDEO_FORMAT_Y444:
          case GST_VIDEO_FORMAT_Y42B:
          case GST_VIDEO_FORMAT_Y41B:
            vs_image_scale_nearest_Y (&dest, &src, videoscale->tmp_buf);
            vs_image_scale_nearest_Y (&dest_u, &src_u, videoscale->tmp_buf);
            vs_image_scale_nearest_Y (&dest_v, &src_v, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB16:
            vs_image_scale_nearest_RGB565 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB15:
            vs_image_scale_nearest_RGB555 (&dest, &src, videoscale->tmp_buf);
            break;
          default:
            goto unsupported;
        }
        break;
      case GST_VIDEO_SCALE_BILINEAR:
        GST_LOG_OBJECT (videoscale, "doing bilinear scaling");
        switch (videoscale->format) {
          case GST_VIDEO_FORMAT_RGBx:
          case GST_VIDEO_FORMAT_xRGB:
          case GST_VIDEO_FORMAT_BGRx:
          case GST_VIDEO_FORMAT_xBGR:
          case GST_VIDEO_FORMAT_RGBA:
          case GST_VIDEO_FORMAT_ARGB:
          case GST_VIDEO_FORMAT_BGRA:
          case GST_VIDEO_FORMAT_ABGR:
          case GST_VIDEO_FORMAT_AYUV:
            vs_image_scale_linear_RGBA (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB:
          case GST_VIDEO_FORMAT_BGR:
          case GST_VIDEO_FORMAT_v308:
            vs_image_scale_linear_RGB (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_YUY2:
          case GST_VIDEO_FORMAT_YVYU:
            vs_image_scale_linear_YUYV (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_UYVY:
            vs_image_scale_linear_UYVY (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_Y800:
          case GST_VIDEO_FORMAT_GRAY8:
            vs_image_scale_linear_Y (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_GRAY16_LE:
          case GST_VIDEO_FORMAT_GRAY16_BE:
            vs_image_scale_linear_Y16 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_I420:
          case GST_VIDEO_FORMAT_YV12:
          case GST_VIDEO_FORMAT_Y444:
          case GST_VIDEO_FORMAT_Y42B:
          case GST_VIDEO_FORMAT_Y41B:
            vs_image_scale_linear_Y (&dest, &src, videoscale->tmp_buf);
            vs_image_scale_linear_Y (&dest_u, &src_u, videoscale->tmp_buf);
            vs_image_scale_linear_Y (&dest_v, &src_v, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB16:
            vs_image_scale_linear_RGB565 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB15:
            vs_image_scale_linear_RGB555 (&dest, &src, videoscale->tmp_buf);
            break;
          default:
            goto unsupported;
        }
        break;
      case GST_VIDEO_SCALE_4TAP:
        GST_LOG_OBJECT (videoscale, "doing 4tap scaling");

        switch (videoscale->format) {
          case GST_VIDEO_FORMAT_RGBx:
          case GST_VIDEO_FORMAT_xRGB:
          case GST_VIDEO_FORMAT_BGRx:
          case GST_VIDEO_FORMAT_xBGR:
          case GST_VIDEO_FORMAT_RGBA:
          case GST_VIDEO_FORMAT_ARGB:
          case GST_VIDEO_FORMAT_BGRA:
          case GST_VIDEO_FORMAT_ABGR:
          case GST_VIDEO_FORMAT_AYUV:
            vs_image_scale_4tap_RGBA (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB:
          case GST_VIDEO_FORMAT_BGR:
          case GST_VIDEO_FORMAT_v308:
            vs_image_scale_4tap_RGB (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_YUY2:
          case GST_VIDEO_FORMAT_YVYU:
            vs_image_scale_4tap_YUYV (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_UYVY:
            vs_image_scale_4tap_UYVY (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_Y800:
          case GST_VIDEO_FORMAT_GRAY8:
            vs_image_scale_4tap_Y (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_GRAY16_LE:
          case GST_VIDEO_FORMAT_GRAY16_BE:
            vs_image_scale_4tap_Y16 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_I420:
          case GST_VIDEO_FORMAT_YV12:
          case GST_VIDEO_FORMAT_Y444:
          case GST_VIDEO_FORMAT_Y42B:
          case GST_VIDEO_FORMAT_Y41B:
            vs_image_scale_4tap_Y (&dest, &src, videoscale->tmp_buf);
            vs_image_scale_4tap_Y (&dest_u, &src_u, videoscale->tmp_buf);
            vs_image_scale_4tap_Y (&dest_v, &src_v, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB16:
            vs_image_scale_4tap_RGB565 (&dest, &src, videoscale->tmp_buf);
            break;
          case GST_VIDEO_FORMAT_RGB15:
            vs_image_scale_4tap_RGB555 (&dest, &src, videoscale->tmp_buf);
            break;
          default:
            goto unsupported;
        }
        break;
      default:
        goto unknown_mode;
    }

  }

  GST_LOG_OBJECT (videoscale, "pushing buffer of %d bytes",
      GST_BUFFER_SIZE (out));

  return ret;

  /* ERRORS */
unsupported:
  {
    GST_ELEMENT_ERROR (videoscale, STREAM, NOT_IMPLEMENTED, (NULL),
        ("Unsupported format %d for scaling method %d",
            videoscale->format, method));
    return GST_FLOW_ERROR;
  }
unknown_mode:
  {
    GST_ELEMENT_ERROR (videoscale, STREAM, NOT_IMPLEMENTED, (NULL),
        ("Unknown scaling method %d", videoscale->method));
    return GST_FLOW_ERROR;
  }
}

static gboolean
gst_video_scale_src_event (GstBaseTransform * trans, GstEvent * event)
{
  GstVideoScale *videoscale = GST_VIDEO_SCALE (trans);
  gboolean ret;
  gdouble a;
  GstStructure *structure;

  GST_DEBUG_OBJECT (videoscale, "handling %s event",
      GST_EVENT_TYPE_NAME (event));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_NAVIGATION:
      event =
          GST_EVENT (gst_mini_object_make_writable (GST_MINI_OBJECT (event)));

      structure = (GstStructure *) gst_event_get_structure (event);
      if (gst_structure_get_double (structure, "pointer_x", &a)) {
        gst_structure_set (structure, "pointer_x", G_TYPE_DOUBLE,
            a * videoscale->from_width / videoscale->to_width, NULL);
      }
      if (gst_structure_get_double (structure, "pointer_y", &a)) {
        gst_structure_set (structure, "pointer_y", G_TYPE_DOUBLE,
            a * videoscale->from_height / videoscale->to_height, NULL);
      }
      break;
    default:
      break;
  }

  ret = GST_BASE_TRANSFORM_CLASS (parent_class)->src_event (trans, event);

  return ret;
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  if (!gst_element_register (plugin, "videoscale", GST_RANK_NONE,
          GST_TYPE_VIDEO_SCALE))
    return FALSE;

  GST_DEBUG_CATEGORY_INIT (video_scale_debug, "videoscale", 0,
      "videoscale element");

  vs_4tap_init ();

  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "videoscale",
    "Resizes video", plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME,
    GST_PACKAGE_ORIGIN)