mp4_predict.c

VC++视频开发实例集锦(包括“远程视频监控”"语音识别系统"等13个经典例子)

#include <math.h>

#include "mp4_vars.h"

#include "mp4_predict.h"

/**
 *
**/

static void rescue_predict();



void dc_recon(int block_num, short * dc_value)
{
	if (mp4_state->hdr.prediction_type == P_VOP) {
		rescue_predict();
	}

	if (block_num < 4)
	{
		int b_xpos = (mp4_state->hdr.mb_xpos << 1) + (block_num & 1);
		int b_ypos = (mp4_state->hdr.mb_ypos << 1) + ((block_num & 2) >> 1);
		int dc_pred;


		if (abs(mp4_state->coeff_pred.dc_store_lum[b_ypos+1-1][b_xpos+1-1] -
			mp4_state->coeff_pred.dc_store_lum[b_ypos+1][b_xpos+1-1]) < // Fa - Fb
			abs(mp4_state->coeff_pred.dc_store_lum[b_ypos+1-1][b_xpos+1-1] -
			mp4_state->coeff_pred.dc_store_lum[b_ypos+1-1][b_xpos+1])) // Fb - Fc
			{
				mp4_state->coeff_pred.predict_dir = TOP;
				dc_pred = mp4_state->coeff_pred.dc_store_lum[b_ypos+1-1][b_xpos+1];
			}
		else
			{
				mp4_state->coeff_pred.predict_dir = LEFT;
				dc_pred = mp4_state->coeff_pred.dc_store_lum[b_ypos+1][b_xpos+1-1];
			}

		(* dc_value) += _div_div(dc_pred, mp4_state->hdr.dc_scaler);
		(* dc_value) *= mp4_state->hdr.dc_scaler;


		mp4_state->coeff_pred.dc_store_lum[b_ypos+1][b_xpos+1] = (* dc_value);
	}
	else 
	{
		int b_xpos = mp4_state->hdr.mb_xpos;
		int b_ypos = mp4_state->hdr.mb_ypos;
		int chr_num = block_num - 4;
		int dc_pred;


		if (abs(mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1-1][b_xpos+1-1] -
			mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1][b_xpos+1-1]) < // Fa - Fb
			abs(mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1-1][b_xpos+1-1] -
			mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1-1][b_xpos+1])) // Fb - Fc
			{
				mp4_state->coeff_pred.predict_dir = TOP;
				dc_pred = mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1-1][b_xpos+1];
			}
		else
			{
				mp4_state->coeff_pred.predict_dir = LEFT;
				dc_pred = mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1][b_xpos+1-1];
			}

		(* dc_value) += _div_div(dc_pred, mp4_state->hdr.dc_scaler);
		(* dc_value) *= mp4_state->hdr.dc_scaler;


		mp4_state->coeff_pred.dc_store_chr[chr_num][b_ypos+1][b_xpos+1] = (* dc_value);
	}
}

/***/

static int saiAcLeftIndex[8] = 
{
	0, 8,16,24,32,40,48,56
};

void ac_recon(int block_num, short * psBlock)
{
	int b_xpos, b_ypos;
	int i;

	if (block_num < 4) {
		b_xpos = (mp4_state->hdr.mb_xpos << 1) + (block_num & 1);
		b_ypos = (mp4_state->hdr.mb_ypos << 1) + ((block_num & 2) >> 1);
	}
	else {
		b_xpos = mp4_state->hdr.mb_xpos;
		b_ypos = mp4_state->hdr.mb_ypos;
	}


	if (mp4_state->hdr.ac_pred_flag) 
	{
		if (block_num < 4) 
		{
			if (mp4_state->coeff_pred.predict_dir == TOP)
			{
				for (i = 1; i < 8; i++) 
					psBlock[i] += mp4_state->coeff_pred.ac_top_lum[b_ypos+1-1][b_xpos+1][i-1];
			}
			else 
			{
				for (i = 1; i < 8; i++)
					psBlock[mp4_tables->saiAcLeftIndex[i]] += mp4_state->coeff_pred.ac_left_lum[b_ypos+1][b_xpos+1-1][i-1];
			}
		}
		else
		{
			int chr_num = block_num - 4;

			if (mp4_state->coeff_pred.predict_dir == TOP)
			{
				for (i = 1; i < 8; i++)
					psBlock[i] += mp4_state->coeff_pred.ac_top_chr[chr_num][b_ypos+1-1][b_xpos+1][i-1];
			}
			else 
			{
				for (i = 1; i < 8; i++)
					psBlock[mp4_tables->saiAcLeftIndex[i]] += mp4_state->coeff_pred.ac_left_chr[chr_num][b_ypos+1][b_xpos+1-1][i-1];
			}
		}
	}
}

/***/

void ac_store(int block_num, short * psBlock)
{
	int b_xpos, b_ypos;
	int i;

	if (block_num < 4) { 
		b_xpos = (mp4_state->hdr.mb_xpos << 1) + (block_num & 1);
		b_ypos = (mp4_state->hdr.mb_ypos << 1) + ((block_num & 2) >> 1);
	}
	else {
		b_xpos = mp4_state->hdr.mb_xpos;
		b_ypos = mp4_state->hdr.mb_ypos;
	}

	if (block_num < 4)
	{
		for (i = 1; i < 8; i++) {
			mp4_state->coeff_pred.ac_top_lum[b_ypos+1][b_xpos+1][i-1] = psBlock[i];
			mp4_state->coeff_pred.ac_left_lum[b_ypos+1][b_xpos+1][i-1] = psBlock[mp4_tables->saiAcLeftIndex[i]];
		}
	}
	else 
	{
		int chr_num = block_num - 4;

		for (i = 1; i < 8; i++) {
			mp4_state->coeff_pred.ac_top_chr[chr_num][b_ypos+1][b_xpos+1][i-1] = psBlock[i];
			mp4_state->coeff_pred.ac_left_chr[chr_num][b_ypos+1][b_xpos+1][i-1] = psBlock[mp4_tables->saiAcLeftIndex[i]];
		}
	}
}


/***/

#define _rescale(predict_quant, current_quant, coeff)	(coeff != 0) ?	\
_div_div((coeff) * (predict_quant), (current_quant))	: 0

int ac_rescaling(int block_num, short * psBlock)
{
	int mb_xpos = mp4_state->hdr.mb_xpos;
	int mb_ypos = mp4_state->hdr.mb_ypos;
	int current_quant = mp4_state->hdr.quantizer;
	int predict_quant = (mp4_state->coeff_pred.predict_dir == TOP) ?
		mp4_state->quant_store[mb_ypos][mb_xpos+1] : mp4_state->quant_store[mb_ypos+1][mb_xpos];
	int b_xpos, b_ypos; 
	int i;

	if ((! mp4_state->hdr.ac_pred_flag) || (current_quant == predict_quant) || (block_num == 3))
		return 0;

	if ((mb_ypos == 0) && (mp4_state->coeff_pred.predict_dir == TOP))
		return 0;
	if ((mb_xpos == 0) && (mp4_state->coeff_pred.predict_dir == LEFT))
		return 0;
	if ((mb_xpos == 0) && (mb_ypos == 0))
		return 0;

	if (block_num < 4) {
		b_xpos = (mp4_state->hdr.mb_xpos << 1) + (block_num & 1);
		b_ypos = (mp4_state->hdr.mb_ypos << 1) + ((block_num & 2) >> 1);
	}
	else {
		b_xpos = mp4_state->hdr.mb_xpos;
		b_ypos = mp4_state->hdr.mb_ypos;
	}

	if (mp4_state->coeff_pred.predict_dir == TOP) 
		switch (block_num)
		{
		case 0: case 1:
			for (i = 1; i < 8; i++)
				psBlock[i] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_top_lum[b_ypos][b_xpos+1][i-1]);
			return 1;
			break;
		case 4:
			for (i = 1; i < 8; i++)
				psBlock[i] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_top_chr[0][b_ypos][b_xpos+1][i-1]);
			return 1;
			break;
		case 5:
			for (i = 1; i < 8; i++)
				psBlock[i] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_top_chr[1][b_ypos][b_xpos+1][i-1]);
			return 1;
			break;
		}
	else 
	{
		switch (block_num)
		{
		case 0: case 2:
			for (i = 1; i < 8; i++)
				psBlock[mp4_tables->saiAcLeftIndex[i]] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_left_lum[b_ypos+1][b_xpos][i-1]);
			return 1;
			break;
		case 4:
			for (i = 1; i < 8; i++)
				psBlock[mp4_tables->saiAcLeftIndex[i]] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_left_chr[0][b_ypos+1][b_xpos][i-1]);
			return 1;
			break;
		case 5:
			for (i = 1; i < 8; i++)
				psBlock[mp4_tables->saiAcLeftIndex[i]] += _rescale(predict_quant, current_quant, mp4_state->coeff_pred.ac_left_chr[1][b_ypos+1][b_xpos][i-1]);
			return 1;
			break;
		}
	}

	return 0;
}

/***/

#define _IsIntra(mb_y, mb_x) ((mp4_state->modemap[(mb_y)+1][(mb_x)+1] == INTRA) || \
	(mp4_state->modemap[(mb_y)+1][(mb_x)+1] == INTRA_Q))

static void rescue_predict() 
{
	int mb_xpos = mp4_state->hdr.mb_xpos;
	int mb_ypos = mp4_state->hdr.mb_ypos;
	int i;

	if (! _IsIntra(mb_ypos-1, mb_xpos-1)) {
	
		mp4_state->coeff_pred.dc_store_lum[2*mb_ypos+1-1][2*mb_xpos+1-1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[0][mb_ypos+1-1][mb_xpos+1-1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[1][mb_ypos+1-1][mb_xpos+1-1] = 1024;
	}
	
	if (! _IsIntra(mb_ypos, mb_xpos-1)) {
	
		mp4_state->coeff_pred.dc_store_lum[2*mb_ypos+1][2*mb_xpos+1-1] = 1024;
		mp4_state->coeff_pred.dc_store_lum[2*mb_ypos+1+1][2*mb_xpos+1-1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[0][mb_ypos+1][mb_xpos+1-1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[1][mb_ypos+1][mb_xpos+1-1] = 1024;

		for(i = 0; i < 7; i++) {
			mp4_state->coeff_pred.ac_left_lum[2*mb_ypos+1][2*mb_xpos+1-1][i] = 0;
			mp4_state->coeff_pred.ac_left_lum[2*mb_ypos+1+1][2*mb_xpos+1-1][i] = 0;
			mp4_state->coeff_pred.ac_left_chr[0][mb_ypos+1][mb_xpos+1-1][i] = 0;
			mp4_state->coeff_pred.ac_left_chr[1][mb_ypos+1][mb_xpos+1-1][i] = 0;
		}
	}

	if (! _IsIntra(mb_ypos-1, mb_xpos)) {

		mp4_state->coeff_pred.dc_store_lum[2*mb_ypos+1-1][2*mb_xpos+1] = 1024;
		mp4_state->coeff_pred.dc_store_lum[2*mb_ypos+1-1][2*mb_xpos+1+1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[0][mb_ypos+1-1][mb_xpos+1] = 1024;
		mp4_state->coeff_pred.dc_store_chr[1][mb_ypos+1-1][mb_xpos+1] = 1024;

		for(i = 0; i < 7; i++) {
			mp4_state->coeff_pred.ac_top_lum[2*mb_ypos+1-1][2*mb_xpos+1][i] = 0;
			mp4_state->coeff_pred.ac_top_lum[2*mb_ypos+1-1][2*mb_xpos+1+1][i] = 0;
			mp4_state->coeff_pred.ac_top_chr[0][mb_ypos+1-1][mb_xpos+1][i] = 0;
			mp4_state->coeff_pred.ac_top_chr[1][mb_ypos+1-1][mb_xpos+1][i] = 0;
		}
	}
}