/* GStreamer

 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>

 * Library       <2002> Ronald Bultje <rbultje@ronald.bitfreak.net>

 * Copyright (C) 2007 David A. 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., 51 Franklin St, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 */

#ifdef HAVE_CONFIG_H

#  include "config.h"

#endif

#include <string.h>

#include <stdio.h>

#include "video.h"

#include "gstvideometa.h"

/**

 * SECTION:gstvideo

 * @title: GstVideoAlignment

 * @short_description: Support library for video operations

 *

 * This library contains some helper functions and includes the

 * videosink and videofilter base classes.

 *

 */

/**

 * gst_video_calculate_display_ratio:

 * @dar_n: (out): Numerator of the calculated display_ratio

 * @dar_d: (out): Denominator of the calculated display_ratio

 * @video_width: Width of the video frame in pixels

 * @video_height: Height of the video frame in pixels

 * @video_par_n: Numerator of the pixel aspect ratio of the input video.

 * @video_par_d: Denominator of the pixel aspect ratio of the input video.

 * @display_par_n: Numerator of the pixel aspect ratio of the display device

 * @display_par_d: Denominator of the pixel aspect ratio of the display device

 *

 * Given the Pixel Aspect Ratio and size of an input video frame, and the

 * pixel aspect ratio of the intended display device, calculates the actual

 * display ratio the video will be rendered with.

 *

 * Returns: A boolean indicating success and a calculated Display Ratio in the

 * dar_n and dar_d parameters.

 * The return value is FALSE in the case of integer overflow or other error.

 */

gboolean

gst_video_calculate_display_ratio (guint * dar_n, guint * dar_d,

    guint video_width, guint video_height,

    guint video_par_n, guint video_par_d,

    guint display_par_n, guint display_par_d)

{

  gint num, den;

  gint tmp_n, tmp_d;

  g_return_val_if_fail (dar_n != NULL, FALSE);

  g_return_val_if_fail (dar_d != NULL, FALSE);

  /* Calculate (video_width * video_par_n * display_par_d) /

   * (video_height * video_par_d * display_par_n) */

  if (!gst_util_fraction_multiply (video_width, video_height, video_par_n,

          video_par_d, &tmp_n, &tmp_d))

    goto error_overflow;

  if (!gst_util_fraction_multiply (tmp_n, tmp_d, display_par_d, display_par_n,

          &num, &den))

    goto error_overflow;

  g_return_val_if_fail (num > 0, FALSE);

  g_return_val_if_fail (den > 0, FALSE);

  *dar_n = num;

  *dar_d = den;

  return TRUE;

  /* ERRORS */

error_overflow:

  {

    GST_WARNING ("overflow in multiply");

    return FALSE;

  }

}

/**

 * gst_video_guess_framerate:

 * @duration: Nominal duration of one frame

 * @dest_n: (out) (allow-none): Numerator of the calculated framerate

 * @dest_d: (out) (allow-none): Denominator of the calculated framerate

 *

 * Given the nominal duration of one video frame,

 * this function will check some standard framerates for

 * a close match (within 0.1%) and return one if possible,

 *

 * It will calculate an arbitrary framerate if no close

 * match was found, and return %FALSE.

 *

 * It returns %FALSE if a duration of 0 is passed.

 *

 * Returns: %TRUE if a close "standard" framerate was

 * recognised, and %FALSE otherwise.

 *

 * Since: 1.6

 */

gboolean

gst_video_guess_framerate (GstClockTime duration, gint * dest_n, gint * dest_d)

{

  const int common_den[] = { 1, 2, 3, 4, 1001 };

  int best_n, best_d, gcd;

  guint64 best_error = G_MAXUINT64;

  guint64 a;

  int i;

  if (G_UNLIKELY (duration == 0))

    return FALSE;

  /* Use a limited precision conversion by default for more sensible results,

   * unless the frame duration is absurdly small (high speed cameras?) */

  if (duration > 100000) {

    best_n = GST_SECOND / 10000;

    best_d = duration / 10000;

  } else {

    best_n = GST_SECOND;

    best_d = duration;

  }

  for (i = 0; i < G_N_ELEMENTS (common_den); i++) {

    gint d = common_den[i];

    gint n = gst_util_uint64_scale_round (d, GST_SECOND, duration);

    /* For NTSC framerates, round to the nearest 1000 fps */

    if (d == 1001) {

      n += 500;

      n -= (n % 1000);

    }

    if (n > 0) {

      /* See what duration the given framerate should be */

      a = gst_util_uint64_scale_int (GST_SECOND, d, n);

      /* Compute absolute error */

      a = (a < duration) ? (duration - a) : (a - duration);

      if (a < 2) {

        /* Really precise - take this option */

        if (dest_n)

          *dest_n = n;

        if (dest_d)

          *dest_d = d;

        return TRUE;

      }

      /* If within 0.1%, remember this denominator */

      if (a * 1000 < duration && a < best_error) {

        best_error = a;

        best_n = n;

        best_d = d;

      }

    }

  }

  /* set results */

  gcd = gst_util_greatest_common_divisor (best_n, best_d);

  if (gcd) {

    best_n /= gcd;

    best_d /= gcd;

  }

  if (dest_n)

    *dest_n = best_n;

  if (dest_d)

    *dest_d = best_d;

  return (best_error != G_MAXUINT64);

}

/**

 * gst_video_alignment_reset:

 * @align: a #GstVideoAlignment

 *

 * Set @align to its default values with no padding and no alignment.

 */

void

gst_video_alignment_reset (GstVideoAlignment * align)

{

  gint i;

  g_return_if_fail (align != NULL);

  align->padding_top = 0;

  align->padding_bottom = 0;

  align->padding_left = 0;

  align->padding_right = 0;

  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++)

    align->stride_align[i] = 0;

}