
/*
 *  mpegconsts.c:  Video format constants for MPEG and utilities for display
 *                 and conversion to format used for yuv4mpeg
 *
 *  Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
 *  Copyright (C) 2001 Matthew Marjanovic <maddog@mir.com>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of version 2 of the GNU General Public License
 *  as published by the Free Software Foundation.
 *
 *  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.
 */

#include <config.h>
#include "mpegconsts.h"
#include "yuv4mpeg.h"
#include "yuv4mpeg_intern.h"

static y4m_ratio_t
mpeg_framerates[] = {
  Y4M_FPS_UNKNOWN,
  Y4M_FPS_NTSC_FILM,
  Y4M_FPS_FILM,
  Y4M_FPS_PAL,
  Y4M_FPS_NTSC,
  Y4M_FPS_30,
  Y4M_FPS_PAL_FIELD,
  Y4M_FPS_NTSC_FIELD,
  Y4M_FPS_60
};


#define MPEG_NUM_RATES (sizeof(mpeg_framerates)/sizeof(mpeg_framerates[0]))
static const mpeg_framerate_code_t mpeg_num_framerates = MPEG_NUM_RATES;

static const char *
framerate_definitions[MPEG_NUM_RATES] =
{
   "illegal", 
  "24000.0/1001.0 (NTSC 3:2 pulldown converted FILM)",
  "24.0 (NATIVE FILM)",
  "25.0 (PAL/SECAM VIDEO / converted FILM)",
  "30000.0/1001.0 (NTSC VIDEO)",
  "30.0",
  "50.0 (PAL FIELD RATE)",
  "60000.0/1001.0 (NTSC FIELD RATE)",
  "60.0"
};


static const char *mpeg1_aspect_ratio_definitions[] =
{
    "illegal",
	"1:1 (square pixels)",
	"1:0.6735",
	"1:0.7031 (16:9 Anamorphic PAL/SECAM for 720x578/352x288 images)",
	"1:0.7615",
	"1:0.8055",
	"1:0.8437 (16:9 Anamorphic NTSC for 720x480/352x240 images)",
	"1:0.8935",
	"1:0.9375 (4:3 PAL/SECAM for 720x578/352x288 images)",
	"1:0.9815",
	"1:1.0255",
	"1:1:0695",
	"1:1.1250 (4:3 NTSC for 720x480/352x240 images)",
	"1:1.1575",
	"1:1.2015"
};

static const y4m_ratio_t mpeg1_aspect_ratios[] =
{
    Y4M_SAR_UNKNOWN,
	Y4M_SAR_MPEG1_1,
	Y4M_SAR_MPEG1_2,
	Y4M_SAR_MPEG1_3, /* Anamorphic 16:9 PAL */
	Y4M_SAR_MPEG1_4,
	Y4M_SAR_MPEG1_5,
	Y4M_SAR_MPEG1_6, /* Anamorphic 16:9 NTSC */
	Y4M_SAR_MPEG1_7,
	Y4M_SAR_MPEG1_8, /* PAL/SECAM 4:3 */
	Y4M_SAR_MPEG1_9,
	Y4M_SAR_MPEG1_10,
	Y4M_SAR_MPEG1_11,
	Y4M_SAR_MPEG1_12, /* NTSC 4:3 */
	Y4M_SAR_MPEG1_13,
	Y4M_SAR_MPEG1_14,
};

static const char *mpeg2_aspect_ratio_definitions[] = 
{
    "illegal",
	"1:1 pixels",
	"4:3 display",
	"16:9 display",
	"2.21:1 display"
};


static const y4m_ratio_t mpeg2_aspect_ratios[] =
{
    Y4M_DAR_UNKNOWN,
	Y4M_DAR_MPEG2_1,
	Y4M_DAR_MPEG2_2,
 	Y4M_DAR_MPEG2_3,
	Y4M_DAR_MPEG2_4
};

static const char **aspect_ratio_definitions[2] = 
{
	mpeg1_aspect_ratio_definitions,
	mpeg2_aspect_ratio_definitions
};

static const y4m_ratio_t *mpeg_aspect_ratios[2] = 
{
	mpeg1_aspect_ratios,
	mpeg2_aspect_ratios
};

static const mpeg_aspect_code_t mpeg_num_aspect_ratios[2] = 
{
  sizeof(mpeg1_aspect_ratios)/sizeof(mpeg1_aspect_ratios[0]),
  sizeof(mpeg2_aspect_ratios)/sizeof(mpeg2_aspect_ratios[0])
};


/*
 * Is code a valid MPEG framerate code?
 */

int
mpeg_valid_framerate_code( mpeg_framerate_code_t code )
{
    return ((code > 0) && (code < mpeg_num_framerates)) ? 1 : 0;
}


/*
 * Convert MPEG frame-rate code to corresponding frame-rate
 */

// y4m_ratio_t
// mpeg_framerate( mpeg_framerate_code_t code )
// {
//     if ((code > 0) && (code < mpeg_num_framerates))
// 		return mpeg_framerates[code];
//     else
// 		return y4m_fps_UNKNOWN;
// }

/*
 * Look-up MPEG frame rate code for a (exact) frame rate.
 */


// mpeg_framerate_code_t 
// mpeg_framerate_code( y4m_ratio_t framerate )
// {
// 	mpeg_framerate_code_t i;
//   
// 	y4m_ratio_reduce(&framerate);
//     /* start at '1', because 0 is unknown/illegal */
// 	for (i = 1; i < mpeg_num_framerates; ++i) {
// 		if (Y4M_RATIO_EQL(framerate, mpeg_framerates[i]))
// 			return i;
// 	}
// 	return 0;
// }


/* small enough to distinguish 1/1000 from 1/1001 */
#define MPEG_FPS_TOLERANCE 0.0001



  

/*
 * Is code a valid MPEG aspect-ratio code?
 */

int
mpeg_valid_aspect_code( int version, mpeg_framerate_code_t c )
{
	if ((version == 1) || (version == 2))
        return ((c > 0) && (c < mpeg_num_aspect_ratios[version-1])) ? 1 : 0;
    else
        return 0;
}


/*
 * Convert MPEG aspect-ratio code to corresponding aspect-ratio
 */

// y4m_ratio_t 
// mpeg_aspect_ratio( int mpeg_version,  mpeg_aspect_code_t code )
// {
// 	y4m_ratio_t ratio;
//     if ((mpeg_version >= 1) && (mpeg_version <= 2) &&
//         (code > 0) && (code < mpeg_num_aspect_ratios[mpeg_version-1]))
// 	{
// 		ratio = mpeg_aspect_ratios[mpeg_version-1][code];
// 		y4m_ratio_reduce(&ratio);
// 		return ratio;
// 	}
//     else
// 		return y4m_sar_UNKNOWN;
// }
// 
// 

/*
 * Look-up corresponding MPEG aspect ratio code given an exact aspect ratio.
 *
 * WARNING: The semantics of aspect ratio coding *changed* between
 * MPEG1 and MPEG2.  In MPEG1 it is the *pixel* aspect ratio. In
 * MPEG2 it is the (far more sensible) aspect ratio of the eventual
 * display.
 *
 */
// 
// mpeg_aspect_code_t 
// mpeg_frame_aspect_code( int mpeg_version, y4m_ratio_t aspect_ratio )
// {
// 	mpeg_aspect_code_t i;
// 	y4m_ratio_t red_ratio = aspect_ratio;
// 	y4m_ratio_reduce( &red_ratio );
// 	if( mpeg_version < 1 || mpeg_version > 2 )
// 		return 0;
//     /* (start at '1', because 0 is unknown/illegal) */
// 	for( i = 1; i < mpeg_num_aspect_ratios[mpeg_version-1]; ++i )
// 	{
// 		y4m_ratio_t red_entry =  mpeg_aspect_ratios[mpeg_version-1][i];
// 		y4m_ratio_reduce( &red_entry );
// 		if(  Y4M_RATIO_EQL( red_entry, red_ratio) )
// 			return i;
// 	}
// 
// 	return 0;
// 			
// }



/*
 * Guess the correct MPEG aspect ratio code,
 *  given the true sample aspect ratio and frame size of a video stream
 *  (and the MPEG version, 1 or 2).
 *
 * Returns 0 if it has no good guess.
 *
 */


/* this is big enough to accommodate the difference between 720 and 704 */
#define GUESS_ASPECT_TOLERANCE 0.03

// mpeg_aspect_code_t 
// mpeg_guess_mpeg_aspect_code(int mpeg_version, y4m_ratio_t sampleaspect,
// 							int frame_width, int frame_height)
// {
// 	if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_UNKNOWN))
//     {
// 		return 0;
//     }
// 	switch (mpeg_version) {
// 	case 1:
// 		if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_SQUARE))
// 		{
// 			return 1;
// 		} 
// 		else if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_NTSC_CCIR601))
// 		{
// 			return 12;
// 		} 
// 		else if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_NTSC_16_9))
// 		{
// 			return 6;
// 		} 
// 		else if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_PAL_CCIR601))
// 		{
// 			return 8;
// 		} 
// 		else if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_PAL_16_9))
// 		{
// 			return 3;
// 		} 
// 		return 0;
// 		break;
// 	case 2:
// 		if (Y4M_RATIO_EQL(sampleaspect, y4m_sar_SQUARE))
// 		{
// 			return 1;  /* '1' means square *pixels* in MPEG-2; go figure. */
// 		}
// 		else
// 		{
// 			int i;
// 			double true_far;  /* true frame aspect ratio */
// 			true_far = 
// 				(double)(sampleaspect.n * frame_width) /
// 				(double)(sampleaspect.d * frame_height);
// 			/* start at '2'... */
// 			for (i = 2; i < (int)(mpeg_num_aspect_ratios[mpeg_version-1]); i++) 
// 			{
// 				double ratio = 
// 					true_far / Y4M_RATIO_DBL(mpeg_aspect_ratios[mpeg_version-1][i]);
// 				if ( (ratio > (1.0 - GUESS_ASPECT_TOLERANCE)) &&
// 					 (ratio < (1.0 + GUESS_ASPECT_TOLERANCE)) )
// 					return i;
// 			}
// 			return 0;
// 		}
// 		break;
// 	default:
// 		return 0;
// 		break;
// 	}
// }
// 
// 
// 
// 
// /*
//  * Guess the true sample aspect ratio of a video stream,
//  *  given the MPEG aspect ratio code and the actual frame size
//  *  (and the MPEG version, 1 or 2).
//  *
//  * Returns y4m_sar_UNKNOWN if it has no good guess.
//  *
//  */
// y4m_ratio_t 
// mpeg_guess_sample_aspect_ratio(int mpeg_version,
// 							   mpeg_aspect_code_t code,
// 							   int frame_width, int frame_height)
// {
// 	switch (mpeg_version) 
// 	{
// 	case 1:
// 		/* MPEG-1 codes turn into SAR's, just not quite the right ones.
// 		   For the common/known values, we provide the ratio used in practice,
// 		   otherwise say we don't know.*/
// 		switch (code)
// 		{
// 		case 1:  return y4m_sar_SQUARE;        break;
// 		case 3:  return y4m_sar_PAL_16_9;      break;
// 		case 6:  return y4m_sar_NTSC_16_9;     break;
// 		case 8:  return y4m_sar_PAL_CCIR601;   break;
// 		case 12: return y4m_sar_NTSC_CCIR601;  break;
// 		default:
// 			return y4m_sar_UNKNOWN;       break;
// 		}
// 		break;
// 	case 2:
// 		/* MPEG-2 codes turn into Display Aspect Ratios, though not exactly the
// 		   DAR's used in practice.  For common/standard frame sizes, we provide
// 		   the original SAR; otherwise, we say we don't know. */
// 		if (code == 1) 
// 		{
// 			return y4m_sar_SQUARE; /* '1' means square *pixels* in MPEG-2 */
// 		}
// 		else if ((code >= 2) && (code <= 4))
// 		{
//             return y4m_guess_sar(frame_width, frame_height,
//                                  mpeg2_aspect_ratios[code]);
// 		} 
// 		else
// 		{
// 			return y4m_sar_UNKNOWN;
// 		}
// 		break;
// 	default:
// 		return y4m_sar_UNKNOWN;
// 		break;
// 	}
// }
// 
// 
// 
// 
// 
// /*
//  * Look-up MPEG explanatory definition string for frame rate code
//  *
//  */
// 
// 
// const char *
// mpeg_framerate_code_definition(   mpeg_framerate_code_t code  )
// {
// 	if( code == 0 || code >=  mpeg_num_framerates )
// 		return "UNDEFINED: illegal/reserved frame-rate ratio code";
// 
// 	return framerate_definitions[code];
// }
// 
// /*
//  * Look-up MPEG explanatory definition string aspect ratio code for an
//  * aspect ratio code
//  *
//  */
// 
// const char *
// mpeg_aspect_code_definition( int mpeg_version,  mpeg_aspect_code_t code  )
// {
// 	if( mpeg_version < 1 || mpeg_version > 2 )
// 		return "UNDEFINED: illegal MPEG version";
// 	
// 	if( code < 1 || code >=  mpeg_num_aspect_ratios[mpeg_version-1] )
// 		return "UNDEFINED: illegal aspect ratio code";
// 
// 	return aspect_ratio_definitions[mpeg_version-1][code];
// }
// 
// 
// /*
//  * Look-up explanatory definition of interlace field order code
//  *
//  */
// 
// const char *
// mpeg_interlace_code_definition( int yuv4m_interlace_code )
// {
// 	const char *def;
// 	switch( yuv4m_interlace_code )
// 	{
// 	case Y4M_UNKNOWN :
// 		def = "unknown";
// 		break;
// 	case Y4M_ILACE_NONE :
// 		def = "none/progressive";
// 		break;
// 	case Y4M_ILACE_TOP_FIRST :
// 		def = "top-field-first";
// 		break;
// 	case Y4M_ILACE_BOTTOM_FIRST :
// 		def = "bottom-field-first";
// 		break;
// 	default :
// 		def = "UNDEFINED: illegal video interlacing type-code!";
// 		break;
// 	}
// 	return def;
// }
// 
// 
/* 
 * Local variables:
 *  c-file-style: "stroustrup"
 *  tab-width: 4
 *  indent-tabs-mode: nil
 * End:
 */
