resize.cpp

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

		psrlw		mm1, 1

		lea			esi, [esi+8]		

		packuswb	mm0, mm1
		movq		[edi], mm0

		lea			edi, [edi+8]		

		dec			ecx
		jnz			pel_loop

		emms
	}
}

#endif

////////////////////////////////////////////////////////
//
//	Performs fast and accurate half horizontal
//		Greg Conklin - 9/05/00
//
////////////////////////////////////////////////////////

static void 
decimate_half_horiz_accurate(
    unsigned char *dest, int dest_width, int dest_height, int dest_pitch,
    unsigned char *src,  int src_width,  int src_height, int src_pitch)
{
	unsigned char *dd;
	unsigned char *ss;
	unsigned char *src_end;
	unsigned char *line_end;
	int dest_skip;
	int src_skip;
	int a,b,c,d;

	dd = dest;
	ss = src;
	dest_skip = dest_pitch - dest_width + 1;
	src_skip = src_pitch - src_width + 2;
	src_end = src + src_width * src_height;

	while (ss < src_end)
	{
		line_end = ss + src_width - 2;

		a = ss[0];
		b = a;
		c = ss[1];
		d = ss[2];

		b += c;
		a += d;
		b *= 9;
		b -= a;
		b += 7;
		b >>= 4;

		dd[0] = CLIP_PEL(b);

		ss += 2;
		dd ++;

		while (ss < line_end)
		{
			a = c;
			b = d;
			c = ss[1];
			d = ss[2];

			b += c;
			a += d;
			b *= 9;
			b -= a;
			b += 7;
			b >>= 4;

			dd[0] = CLIP_PEL(b);

			ss += 2;
			dd ++;
		}

		a = c;
		b = d;
		c = ss[1];
		d = c;

		b += c;
		a += d;
		b *= 9;
		b -= a;
		b += 7;
		b >>= 4;

		dd[0] = CLIP_PEL(b);

		ss += src_skip;
		dd += dest_skip;
	}

}

////////////////////////////////////////////////////////
//
//	Performs accurate decimation
//		Greg Conklin - 9/21/99
//
////////////////////////////////////////////////////////

static void
decimate (
    unsigned char *dest, int dest_width, int dest_height, int dest_pitch,
    unsigned char *src,  int src_width,  int src_height,  int src_pitch, 
	RESIZE_BUFF_TYPE *buff)
{

	unsigned char *sp, *dp;
	RESIZE_BUFF_TYPE *tp;
	int pel;			// destination x position
	int line;			// destination y position
	int tmp;			// temp storage for result pel
	int pos;			// fractional position of source (x or y) location
	int pos_int;		// integer position of source
	int pos_bgn;		// the starting location of pos
	int pos_inc;		// the increment of 'pos' to the next pel
	const int *filt_tab_ptr;	// pointer to the current filter tap
	int filt_tab_inc;	// spacing between tabs in the filter table
	int filt_tap_num;	// number of filter taps
	int	filt_scale;		// filter gain 

#if USE_SOURCE_LEVEL
	int source_level;
#else
#define source_level 0
#endif

	if (dest_height == src_height)
	{
		// no vertical resizing
		for (line = 0; line < src_height; line++)
		{
			tp = buff + line * src_pitch;
			sp = src + line * src_pitch;

			for (pel = 0; pel < src_width - 3; pel += 4)
			{
				tp[0] = sp[0];
				tp[1] = sp[1];
				tp[2] = sp[2];
				tp[3] = sp[3];
				tp += 4;
				sp += 4;
			}
			for (; pel < dest_width; pel++)
			{
				*tp = *sp;
				tp ++;
				sp ++;
			}
		}

	}
	else if (dest_height == (src_height >> 1))
	{
		// decimate vertical by 2

		int src_skip = src_pitch - src_width;
		int a, b, c, d;

		tp = buff;
		sp = src;

		// top line
		for (pel = 0; pel < src_width; pel ++)
		{
			b = *sp;
			c = *(sp + src_pitch);
			d = *(sp + 2 * src_pitch);

			c += b;
			b += d;
			c *= 9;
			c -= b;
			c += 7;
			c >>= 4;

			*tp = CLIP_PEL(c);

			sp++;
			tp++;
		}
		tp += src_skip;
		sp += src_skip + src_pitch;

		// middle lines
		for (line = 2; line < dest_height; line ++)
		{
			for (pel = 0; pel < src_width; pel++)
			{
				a = *(sp - src_pitch);
				b = *sp;
				c = *(sp + src_pitch);
				d = *(sp + 2 * src_pitch);

				b += c;
				a += d;
				b *= 9;
				b -= a;
				b += 7;
				b >>= 4;

				*tp = CLIP_PEL(b);

				sp++;
				tp++;
			}
			tp += src_skip;
			sp += src_skip + src_pitch;
		}

		// bottom line
		for (pel = 0; pel < src_width; pel++)
		{
			a = *(sp - src_pitch);
			b = *sp;
			c = *(sp + src_pitch);

			b += c;
			a += c;
			b *= 9;
			b -= a;
			b += 7;
			b >>= 4;

			*tp = CLIP_PEL(b);

			sp++;
			tp++;
		}
	}
	else
	{
		// arbitrary vertical resize

		pos_inc = ((src_height << POS_SCALE_BITS) + (dest_height >> 1)) / (dest_height);
		pos_bgn = (pos_inc - (1 << POS_SCALE_BITS)) >> 1;
		filt_tab_inc = (FULL_PEL_INC * dest_height + (src_height >> 1)) / (src_height);
		if (filt_tab_inc > FULL_PEL_INC)
			filt_tab_inc = FULL_PEL_INC;
		filt_tap_num = (INT_FILT_SIZE - 1) / (filt_tab_inc << 1);
		filt_scale = ((dest_height << FILT_SCALE_BITS) + (src_height >> 1)) / (src_height);

		for (pel = 0; pel < src_width; pel++)
		{
			tp = buff + pel;
			
			line = 0;
			pos = pos_bgn;
			pos_int = pos >> POS_SCALE_BITS;

			// Top edge pels
			while (pos_int < filt_tap_num)
			{
				sp = src + (pos_int) * src_pitch + pel;
#if USE_SOURCE_LEVEL
				source_level = *sp;
#endif
				sp -= filt_tap_num * src_pitch;

				filt_tab_ptr = int_filt_tab;
				filt_tab_ptr -= (filt_tab_inc * (pos & ((1L << POS_SCALE_BITS) - 1))) >> POS_SCALE_BITS;
				filt_tab_ptr += INT_FILT_CENTER - (filt_tap_num * filt_tab_inc);
				if (filt_tab_ptr < int_filt_tab)
				{
					sp += src_pitch;
					filt_tab_ptr += filt_tab_inc;
				}

				tmp = 0;
				while (filt_tab_ptr < int_filt_tab + INT_FILT_SIZE)
				{
					if (sp < src)
						tmp += (*filt_tab_ptr) * (src[pel] - source_level);
					else
						tmp += (*filt_tab_ptr) * (*sp - source_level);
					sp += src_pitch;;
					filt_tab_ptr += filt_tab_inc;
				}
				tmp *= filt_scale;
				tmp += (source_level << (FILT_COEFF_BITS + FILT_SCALE_BITS));
				tmp += (1U << (FILT_COEFF_BITS + FILT_SCALE_BITS - 1));
				tmp >>= (FILT_COEFF_BITS + FILT_SCALE_BITS);
				*tp = tmp;

				tp += src_pitch;
				pos += pos_inc;
				pos_int = pos >> POS_SCALE_BITS;
				line++;
			}
			// Center pels
			while (pos_int < src_height - filt_tap_num - 1)
			{
				sp = src + (pos_int) * src_pitch + pel;
#if USE_SOURCE_LEVEL
				source_level = *sp;
#endif
				sp -= filt_tap_num * src_pitch;

				filt_tab_ptr = int_filt_tab;
				filt_tab_ptr -= (filt_tab_inc * (pos & ((1L << POS_SCALE_BITS) - 1))) >> POS_SCALE_BITS;
				filt_tab_ptr += INT_FILT_CENTER - (filt_tap_num * filt_tab_inc);
				if (filt_tab_ptr < int_filt_tab)
				{
					sp += src_pitch;
					filt_tab_ptr += filt_tab_inc;
				}

				// There are at least 4 taps...
				tmp = (*filt_tab_ptr) * (*sp - source_level);
				sp += src_pitch;
				filt_tab_ptr += filt_tab_inc;

				tmp += (*filt_tab_ptr) * (*sp - source_level);
				sp += src_pitch;
				filt_tab_ptr += filt_tab_inc;

				tmp += (*filt_tab_ptr) * (*sp - source_level);
				sp += src_pitch;
				filt_tab_ptr += filt_tab_inc;

				tmp += (*filt_tab_ptr) * (*sp - source_level);
				sp += src_pitch;
				filt_tab_ptr += filt_tab_inc;
				
				// Remaining taps...
				while (filt_tab_ptr < int_filt_tab + INT_FILT_SIZE)
				{
					tmp += (*filt_tab_ptr) * (*sp - source_level);
					sp += src_pitch;
					filt_tab_ptr += filt_tab_inc;
				}

				// scale and store result...
				tmp *= filt_scale;
				tmp += (source_level << (FILT_COEFF_BITS + FILT_SCALE_BITS));
				tmp += (1U << (FILT_COEFF_BITS + FILT_SCALE_BITS - 1));
				tmp >>= (FILT_COEFF_BITS + FILT_SCALE_BITS);
				*tp = tmp;

				tp += src_pitch;
				pos += pos_inc;
				pos_int = pos >> POS_SCALE_BITS;
				line++;
			}
			// Bottom edge pels
			while (line < dest_height)
			{
				sp = src + (pos_int) * src_pitch + pel;
#if USE_SOURCE_LEVEL
				source_level = *sp;
#endif
				sp -= filt_tap_num * src_pitch;

				filt_tab_ptr = int_filt_tab;
				filt_tab_ptr -= (filt_tab_inc * (pos & ((1L << POS_SCALE_BITS) - 1))) >> POS_SCALE_BITS;
				filt_tab_ptr += INT_FILT_CENTER - (filt_tap_num * filt_tab_inc);
				if (filt_tab_ptr < int_filt_tab)
				{
					sp += src_pitch;
					filt_tab_ptr += filt_tab_inc;
				}

				tmp = 0;
				while (filt_tab_ptr < int_filt_tab + INT_FILT_SIZE)
				{
					if (sp >= src + src_height*src_pitch)
						tmp += (*filt_tab_ptr) * (src[(src_height - 1) * src_pitch + pel] - source_level);
					else
						tmp += (*filt_tab_ptr) * (*sp - source_level);
					sp += src_pitch;
					filt_tab_ptr += filt_tab_inc;
				}
				tmp *= filt_scale;