mbcoding.c

mpeg4代码,比较具体

/*****************************************************************************
 *
 *  XVID MPEG-4 VIDEO CODEC
 *  - Macro Block coding functions -
 *
 *  Copyright(C) 2002 Michael Militzer <[e-mail]>
 *
 *  This file is part of XviD, a free MPEG-4 video encoder/decoder
 *
 *  XviD is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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
 *
 *  Under section 8 of the GNU General Public License, the copyright
 *  holders of XVID explicitly forbid distribution in the following
 *  countries:
 *
 *    - Japan
 *    - United States of America
 *
 *  Linking XviD statically or dynamically with other modules is making a
 *  combined work based on XviD.  Thus, the terms and conditions of the
 *  GNU General Public License cover the whole combination.
 *
 *  As a special exception, the copyright holders of XviD give you
 *  permission to link XviD with independent modules that communicate with
 *  XviD solely through the VFW1.1 and DShow interfaces, regardless of the
 *  license terms of these independent modules, and to copy and distribute
 *  the resulting combined work under terms of your choice, provided that
 *  every copy of the combined work is accompanied by a complete copy of
 *  the source code of XviD (the version of XviD used to produce the
 *  combined work), being distributed under the terms of the GNU General
 *  Public License plus this exception.  An independent module is a module
 *  which is not derived from or based on XviD.
 *
 *  Note that people who make modified versions of XviD are not obligated
 *  to grant this special exception for their modified versions; it is
 *  their choice whether to do so.  The GNU General Public License gives
 *  permission to release a modified version without this exception; this
 *  exception also makes it possible to release a modified version which
 *  carries forward this exception.
 *
 * $Id: mbcoding.c,v 1.41 2003/02/13 17:31:33 edgomez Exp $
 *
 ****************************************************************************/

#include <stdlib.h>
#include "../portab.h"
#include "bitstream.h"
#include "zigzag.h"
#include "vlc_codes.h"
#include "mbcoding.h"

#include "../utils/mbfunctions.h"

#define ABS(X) (((X)>0)?(X):-(X))
#define CLIP(X,A) (X > A) ? (A) : (X)

/* #define BIGLUT */

#ifdef BIGLUT
#define LEVELOFFSET 2048
#else
#define LEVELOFFSET 32
#endif

/*****************************************************************************
 * Local data
 ****************************************************************************/

static REVERSE_EVENT DCT3D[2][4096];

#ifdef BIGLUT
static VLC coeff_VLC[2][2][4096][64];
static VLC *intra_table, *inter_table; 
#else
static VLC coeff_VLC[2][2][64][64];
#endif

/*****************************************************************************
 * Vector Length Coding Initialization
 ****************************************************************************/

void
init_vlc_tables(void)
{
	uint32_t i, j, intra, last, run,  run_esc, level, level_esc, escape, escape_len, offset;

#ifdef BIGLUT
	intra_table = (VLC*)coeff_VLC[1];
	inter_table = (VLC*)coeff_VLC[0]; 
#endif


	for (intra = 0; intra < 2; intra++)
		for (i = 0; i < 4096; i++)
			DCT3D[intra][i].event.level = 0;

	for (intra = 0; intra < 2; intra++)
		for (last = 0; last < 2; last++)
		{
			for (run = 0; run < 63 + last; run++)
				for (level = 0; level < (uint32_t)(32 << intra); level++)
				{
#ifdef BIGLUT
					offset = LEVELOFFSET;
#else
					offset = !intra * LEVELOFFSET;
#endif
					coeff_VLC[intra][last][level + offset][run].len = 128;
				}
		}

	for (intra = 0; intra < 2; intra++)
		for (i = 0; i < 102; i++)
		{
#ifdef BIGLUT
			offset = LEVELOFFSET;
#else
			offset = !intra * LEVELOFFSET;
#endif
			for (j = 0; j < (uint32_t)(1 << (12 - coeff_tab[intra][i].vlc.len)); j++)
			{
				DCT3D[intra][(coeff_tab[intra][i].vlc.code << (12 - coeff_tab[intra][i].vlc.len)) | j].len	 = coeff_tab[intra][i].vlc.len;
				DCT3D[intra][(coeff_tab[intra][i].vlc.code << (12 - coeff_tab[intra][i].vlc.len)) | j].event = coeff_tab[intra][i].event;
			}

			coeff_VLC[intra][coeff_tab[intra][i].event.last][coeff_tab[intra][i].event.level + offset][coeff_tab[intra][i].event.run].code
				= coeff_tab[intra][i].vlc.code << 1;
			coeff_VLC[intra][coeff_tab[intra][i].event.last][coeff_tab[intra][i].event.level + offset][coeff_tab[intra][i].event.run].len
				= coeff_tab[intra][i].vlc.len + 1;
#ifndef BIGLUT
			if (!intra)
#endif
			{
				coeff_VLC[intra][coeff_tab[intra][i].event.last][offset - coeff_tab[intra][i].event.level][coeff_tab[intra][i].event.run].code
					= (coeff_tab[intra][i].vlc.code << 1) | 1;
				coeff_VLC[intra][coeff_tab[intra][i].event.last][offset - coeff_tab[intra][i].event.level][coeff_tab[intra][i].event.run].len
					= coeff_tab[intra][i].vlc.len + 1;
			}
		}

	for (intra = 0; intra < 2; intra++)
		for (last = 0; last < 2; last++)
			for (run = 0; run < 63 + last; run++)
			{
				for (level = 1; level < (uint32_t)(32 << intra); level++)
				{
					if (level <= max_level[intra][last][run] && run <= max_run[intra][last][level])
					    continue;

#ifdef BIGLUT
					offset = LEVELOFFSET;
#else
					offset = !intra * LEVELOFFSET;
#endif
                    level_esc = level - max_level[intra][last][run];
					run_esc = run - 1 - max_run[intra][last][level];

					if (level_esc <= max_level[intra][last][run] && run <= max_run[intra][last][level_esc])
					{
						escape     = ESCAPE1;
						escape_len = 7 + 1;
						run_esc    = run;
					}
					else
					{
						if (run_esc <= max_run[intra][last][level] && level <= max_level[intra][last][run_esc])
						{
							escape     = ESCAPE2;
							escape_len = 7 + 2;
							level_esc  = level;
						}
						else
						{
#ifndef BIGLUT
							if (!intra)
#endif
							{
								coeff_VLC[intra][last][level + offset][run].code
									= (ESCAPE3 << 21) | (last << 20) | (run << 14) | (1 << 13) | ((level & 0xfff) << 1) | 1;
								coeff_VLC[intra][last][level + offset][run].len = 30;
									coeff_VLC[intra][last][offset - level][run].code
									= (ESCAPE3 << 21) | (last << 20) | (run << 14) | (1 << 13) | ((-level & 0xfff) << 1) | 1;
								coeff_VLC[intra][last][offset - level][run].len = 30;
							}
							continue;
						}
					}

					coeff_VLC[intra][last][level + offset][run].code
						= (escape << coeff_VLC[intra][last][level_esc + offset][run_esc].len)
						|  coeff_VLC[intra][last][level_esc + offset][run_esc].code;
					coeff_VLC[intra][last][level + offset][run].len
						= coeff_VLC[intra][last][level_esc + offset][run_esc].len + escape_len;
#ifndef BIGLUT
					if (!intra)
#endif
					{
						coeff_VLC[intra][last][offset - level][run].code
							= (escape << coeff_VLC[intra][last][level_esc + offset][run_esc].len)
							|  coeff_VLC[intra][last][level_esc + offset][run_esc].code | 1;
						coeff_VLC[intra][last][offset - level][run].len
							= coeff_VLC[intra][last][level_esc + offset][run_esc].len + escape_len;
					}
				}

#ifdef BIGLUT
				for (level = (uint32_t)(32 << intra); level < 2048; level++)
				{
					coeff_VLC[intra][last][level + offset][run].code
						= (ESCAPE3 << 21) | (last << 20) | (run << 14) | (1 << 13) | ((level & 0xfff) << 1) | 1;
					coeff_VLC[intra][last][level + offset][run].len = 30;

					coeff_VLC[intra][last][offset - level][run].code
						= (ESCAPE3 << 21) | (last << 20) | (run << 14) | (1 << 13) | ((-level & 0xfff) << 1) | 1;
					coeff_VLC[intra][last][offset - level][run].len = 30;
				}
#else
				if (!intra)
				{
					coeff_VLC[intra][last][0][run].code
						= (ESCAPE3 << 21) | (last << 20) | (run << 14) | (1 << 13) | ((-32 & 0xfff) << 1) | 1;
					coeff_VLC[intra][last][0][run].len = 30;
				}
#endif
			}

	/* Shut up the compiler -- gcc 3.3 pre release */
	i = dc_threshold[0];

}

/*****************************************************************************
 * Local inlined functions for MB coding
 ****************************************************************************/

static __inline void
CodeVector(Bitstream * bs,
		   int32_t value,
		   int32_t f_code,
		   Statistics * pStat)
{

	const int scale_factor = 1 << (f_code - 1);
	const int cmp = scale_factor << 5;

	if (value < (-1 * cmp))
		value += 64 * scale_factor;

	if (value > (cmp - 1))
		value -= 64 * scale_factor;

	pStat->iMvSum += value * value;
	pStat->iMvCount++;

	if (value == 0) {
		BitstreamPutBits(bs, mb_motion_table[32].code,
						 mb_motion_table[32].len);
	} else {
		uint16_t length, code, mv_res, sign;

		length = 16 << f_code;
		f_code--;

		sign = (value < 0);

		if (value >= length)
			value -= 2 * length;
		else if (value < -length)
			value += 2 * length;

		if (sign)
			value = -value;

		value--;
		mv_res = value & ((1 << f_code) - 1);
		code = ((value - mv_res) >> f_code) + 1;

		if (sign)
			code = -code;

		code += 32;
		BitstreamPutBits(bs, mb_motion_table[code].code,
						 mb_motion_table[code].len);

		if (f_code)
			BitstreamPutBits(bs, mv_res, f_code);
	}

}

#ifdef BIGLUT

static __inline void
CodeCoeff(Bitstream * bs,
		  const int16_t qcoeff[64],
		  VLC * table,
		  const uint16_t * zigzag,
		  uint16_t intra)
{

	uint32_t j, last;
	short v;
	VLC *vlc;

	j = intra;
	last = intra;

	while (j < 64 && (v = qcoeff[zigzag[j]]) == 0)
		j++;

	do {
		vlc = table + 64 * 2048 + (v << 6) + j - last;
		last = ++j;

		/* count zeroes */
		while (j < 64 && (v = qcoeff[zigzag[j]]) == 0)
			j++;

		/* write code */
		if (j != 64) {
			BitstreamPutBits(bs, vlc->code, vlc->len);
		} else {
			vlc += 64 * 4096;
			BitstreamPutBits(bs, vlc->code, vlc->len);
			break;
		}
	} while (1);

}

#else

static __inline void
CodeCoeffInter(Bitstream * bs,
		  const int16_t qcoeff[64],
		  const uint16_t * zigzag)
{
	uint32_t i, run, prev_run, code, len;
	int32_t level, prev_level, level_shifted;

	i	= 0;
	run = 0;

	while (!(level = qcoeff[zigzag[i++]]))
		run++;

	prev_level = level;
	prev_run   = run;
	run = 0;

	while (i < 64)
	{
		if ((level = qcoeff[zigzag[i++]]) != 0)
		{
			level_shifted = prev_level + 32;
			if (!(level_shifted & -64))
			{
				code = coeff_VLC[0][0][level_shifted][prev_run].code;
				len	 = coeff_VLC[0][0][level_shifted][prev_run].len;
			}
			else
			{
				code = (ESCAPE3 << 21) | (prev_run << 14) | (1 << 13) | ((prev_level & 0xfff) << 1) | 1;
				len  = 30;
			}
			BitstreamPutBits(bs, code, len);
			prev_level = level;
			prev_run   = run;
			run = 0;
		}
		else
			run++;
	}

	level_shifted = prev_level + 32;
	if (!(level_shifted & -64))
	{
		code = coeff_VLC[0][1][level_shifted][prev_run].code;
		len	 = coeff_VLC[0][1][level_shifted][prev_run].len;
	}
	else
	{
		code = (ESCAPE3 << 21) | (1 << 20) | (prev_run << 14) | (1 << 13) | ((prev_level & 0xfff) << 1) | 1;
		len  = 30;
	}
	BitstreamPutBits(bs, code, len);
}

static __inline void
CodeCoeffIntra(Bitstream * bs,
		  const int16_t qcoeff[64],
		  const uint16_t * zigzag)
{
	uint32_t i, abs_level, run, prev_run, code, len;
	int32_t level, prev_level;

	i	= 1;
	run = 0;

	while (!(level = qcoeff[zigzag[i++]]))
		run++;

	prev_level = level;
	prev_run   = run;
	run = 0;

	while (i < 64)
	{
		if ((level = qcoeff[zigzag[i++]]) != 0)
		{
			abs_level = ABS(prev_level);
			abs_level = abs_level < 64 ? abs_level : 0;
			code	  = coeff_VLC[1][0][abs_level][prev_run].code;
			len		  = coeff_VLC[1][0][abs_level][prev_run].len;
			if (len != 128)
				code |= (prev_level < 0);
			else
			{
		        code = (ESCAPE3 << 21) | (prev_run << 14) | (1 << 13) | ((prev_level & 0xfff) << 1) | 1;
				len  = 30;
			}
			BitstreamPutBits(bs, code, len);
			prev_level = level;
			prev_run   = run;
			run = 0;
		}
		else
			run++;
	}

	abs_level = ABS(prev_level);
	abs_level = abs_level < 64 ? abs_level : 0;
	code	  = coeff_VLC[1][1][abs_level][prev_run].code;
	len		  = coeff_VLC[1][1][abs_level][prev_run].len;
	if (len != 128)
		code |= (prev_level < 0);
	else
	{
		code = (ESCAPE3 << 21) | (1 << 20) | (prev_run << 14) | (1 << 13) | ((prev_level & 0xfff) << 1) | 1;
		len  = 30;
	}
	BitstreamPutBits(bs, code, len);
}

#endif

/*****************************************************************************
 * Local functions
 ****************************************************************************/

static void
CodeBlockIntra(const FRAMEINFO * frame,
			   const MACROBLOCK * pMB,
			   int16_t qcoeff[6 * 64],
			   Bitstream * bs,
			   Statistics * pStat)
{

	uint32_t i, mcbpc, cbpy, bits;

	cbpy = pMB->cbp >> 2;

	/* write mcbpc */
	if (frame->coding_type == I_VOP) {
		mcbpc = ((pMB->mode >> 1) & 3) | ((pMB->cbp & 3) << 2);
		BitstreamPutBits(bs, mcbpc_intra_tab[mcbpc].code,
						 mcbpc_intra_tab[mcbpc].len);
	} else {
		mcbpc = (pMB->mode & 7) | ((pMB->cbp & 3) << 3);
		BitstreamPutBits(bs, mcbpc_inter_tab[mcbpc].code,
						 mcbpc_inter_tab[mcbpc].len);