mirror of
https://github.com/mpv-player/mpv
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5194d8791e
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@3787 b3059339-0415-0410-9bf9-f77b7e298cf2
114 lines
3.4 KiB
C
114 lines
3.4 KiB
C
/*
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* yuv4mpeg_ratio.c: Functions for dealing with y4m_ratio_t datatype.
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*
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* Copyright (C) 2001 Matthew J. Marjanovic <maddog@mir.com>
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*
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* This file is part of the lavtools packaged (mjpeg.sourceforge.net)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#include "config.h"
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#include <string.h>
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#include "yuv4mpeg.h"
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#include "yuv4mpeg_intern.h"
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/* useful list of standard framerates */
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const y4m_ratio_t y4m_fps_UNKNOWN = Y4M_FPS_UNKNOWN;
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const y4m_ratio_t y4m_fps_NTSC_FILM = Y4M_FPS_NTSC_FILM;
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const y4m_ratio_t y4m_fps_FILM = Y4M_FPS_FILM;
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const y4m_ratio_t y4m_fps_PAL = Y4M_FPS_PAL;
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const y4m_ratio_t y4m_fps_NTSC = Y4M_FPS_NTSC;
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const y4m_ratio_t y4m_fps_30 = Y4M_FPS_30;
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const y4m_ratio_t y4m_fps_PAL_FIELD = Y4M_FPS_PAL_FIELD;
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const y4m_ratio_t y4m_fps_NTSC_FIELD = Y4M_FPS_NTSC_FIELD;
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const y4m_ratio_t y4m_fps_60 = Y4M_FPS_60;
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/* useful list of standard pixel aspect ratios */
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const y4m_ratio_t y4m_sar_UNKNOWN = Y4M_SAR_UNKNOWN;
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const y4m_ratio_t y4m_sar_SQUARE = Y4M_SAR_SQUARE;
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const y4m_ratio_t y4m_sar_NTSC_CCIR601 = Y4M_SAR_NTSC_CCIR601;
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const y4m_ratio_t y4m_sar_NTSC_16_9 = Y4M_SAR_NTSC_16_9;
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const y4m_ratio_t y4m_sar_NTSC_SVCD_4_3 = Y4M_SAR_NTSC_SVCD_4_3;
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const y4m_ratio_t y4m_sar_NTSC_SVCD_16_9 = Y4M_SAR_NTSC_SVCD_16_9;
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const y4m_ratio_t y4m_sar_PAL_CCIR601 = Y4M_SAR_PAL_CCIR601;
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const y4m_ratio_t y4m_sar_PAL_16_9 = Y4M_SAR_PAL_16_9;
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const y4m_ratio_t y4m_sar_PAL_SVCD_4_3 = Y4M_SAR_PAL_SVCD_4_3;
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const y4m_ratio_t y4m_sar_PAL_SVCD_16_9 = Y4M_SAR_PAL_SVCD_16_9;
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/*
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* Euler's algorithm for greatest common divisor
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*/
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static int gcd(int a, int b)
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{
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a = (a >= 0) ? a : -a;
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b = (b >= 0) ? b : -b;
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while (b > 0) {
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int x = b;
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b = a % b;
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a = x;
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}
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return a;
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}
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/*************************************************************************
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*
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* Remove common factors from a ratio
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*
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*************************************************************************/
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void y4m_ratio_reduce(y4m_ratio_t *r)
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{
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int d;
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if ((r->n == 0) && (r->d == 0)) return; /* "unknown" */
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d = gcd(r->n, r->d);
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r->n /= d;
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r->d /= d;
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}
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/*************************************************************************
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*
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* Parse "nnn:ddd" into a ratio
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*
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* returns: Y4M_OK - success
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* Y4M_ERR_RANGE - range error
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*
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*************************************************************************/
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int y4m_parse_ratio(y4m_ratio_t *r, const char *s)
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{
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char *t = strchr(s, ':');
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if (t == NULL) return Y4M_ERR_RANGE;
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r->n = atoi(s);
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r->d = atoi(t+1);
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if (r->d < 0) return Y4M_ERR_RANGE;
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/* 0:0 == unknown, so that is ok, otherwise zero denominator is bad */
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if ((r->d == 0) && (r->n != 0)) return Y4M_ERR_RANGE;
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y4m_ratio_reduce(r);
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return Y4M_OK;
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}
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