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101 lines
3.2 KiB
C
101 lines
3.2 KiB
C
/* GStreamer
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* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
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* Library <2002> Ronald Bultje <rbultje@ronald.bitfreak.net>
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* Copyright (C) 2007 David A. Schleef <ds@schleef.org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <string.h>
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#include <stdio.h>
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#include "video.h"
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#include "gstvideometa.h"
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/**
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* SECTION:gstvideo
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* @short_description: Support library for video operations
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*
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* <refsect2>
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* <para>
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* This library contains some helper functions and includes the
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* videosink and videofilter base classes.
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* </para>
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* </refsect2>
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*/
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/**
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* gst_video_calculate_display_ratio:
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* @dar_n: Numerator of the calculated display_ratio
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* @dar_d: Denominator of the calculated display_ratio
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* @video_width: Width of the video frame in pixels
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* @video_height: Height of the video frame in pixels
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* @video_par_n: Numerator of the pixel aspect ratio of the input video.
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* @video_par_d: Denominator of the pixel aspect ratio of the input video.
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* @display_par_n: Numerator of the pixel aspect ratio of the display device
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* @display_par_d: Denominator of the pixel aspect ratio of the display device
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*
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* Given the Pixel Aspect Ratio and size of an input video frame, and the
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* pixel aspect ratio of the intended display device, calculates the actual
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* display ratio the video will be rendered with.
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*
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* Returns: A boolean indicating success and a calculated Display Ratio in the
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* dar_n and dar_d parameters.
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* The return value is FALSE in the case of integer overflow or other error.
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*
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* Since: 0.10.7
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*/
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gboolean
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gst_video_calculate_display_ratio (guint * dar_n, guint * dar_d,
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guint video_width, guint video_height,
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guint video_par_n, guint video_par_d,
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guint display_par_n, guint display_par_d)
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{
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gint num, den;
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gint tmp_n, tmp_d;
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g_return_val_if_fail (dar_n != NULL, FALSE);
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g_return_val_if_fail (dar_d != NULL, FALSE);
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/* Calculate (video_width * video_par_n * display_par_d) /
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* (video_height * video_par_d * display_par_n) */
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if (!gst_util_fraction_multiply (video_width, video_height, video_par_n,
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video_par_d, &tmp_n, &tmp_d))
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goto error_overflow;
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if (!gst_util_fraction_multiply (tmp_n, tmp_d, display_par_d, display_par_n,
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&num, &den))
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goto error_overflow;
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g_return_val_if_fail (num > 0, FALSE);
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g_return_val_if_fail (den > 0, FALSE);
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*dar_n = num;
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*dar_d = den;
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return TRUE;
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/* ERRORS */
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error_overflow:
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{
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GST_WARNING ("overflow in multiply");
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return FALSE;
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}
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}
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