/* Predict.c, motion compensation routines */ /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ /* * Disclaimer of Warranty * * These software programs are available to the user without any license fee or * royalty on an "as is" basis. The MPEG Software Simulation Group disclaims * any and all warranties, whether express, implied, or statuary, including any * implied warranties or merchantability or of fitness for a particular * purpose. In no event shall the copyright-holder be liable for any * incidental, punitive, or consequential damages of any kind whatsoever * arising from the use of these programs. * * This disclaimer of warranty extends to the user of these programs and user's * customers, employees, agents, transferees, successors, and assigns. * * The MPEG Software Simulation Group does not represent or warrant that the * programs furnished hereunder are free of infringement of any third-party * patents. * * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, * are subject to royalty fees to patent holders. Many of these patents are * general enough such that they are unavoidable regardless of implementation * design. * */ #include #include "config.h" #include "global.h" /* private prototypes */ static void form_prediction _ANSI_ARGS_((unsigned char *src[], int sfield, unsigned char *dst[], int dfield, int lx, int lx2, int w, int h, int x, int y, int dx, int dy, int average_flag)); static void form_component_prediction _ANSI_ARGS_( (unsigned char *src, unsigned char *dst, int lx, int lx2, int w, int h, int x, int y, int dx, int dy, int average_flag)); void form_predictions(bx, by, macroblock_type, motion_type, PMV, motion_vertical_field_select, dmvector, stwtype) int bx, by; int macroblock_type; int motion_type; int PMV[2][2][2], motion_vertical_field_select[2][2], dmvector[2]; int stwtype; { int currentfield; unsigned char **predframe; int DMV[2][2]; int stwtop, stwbot; stwtop = stwtype % 3; /* 0:temporal, 1:(spat+temp)/2, 2:spatial */ stwbot = stwtype / 3; if ((macroblock_type & MACROBLOCK_MOTION_FORWARD) || (picture_coding_type == P_TYPE)) { if (picture_structure == FRAME_PICTURE) { if ((motion_type == MC_FRAME) || !(macroblock_type & MACROBLOCK_MOTION_FORWARD)) { /* frame-based prediction (broken into top and bottom halves for spatial scalability prediction purposes) */ if (stwtop < 2) form_prediction(forward_reference_frame, 0, current_frame, 0, Coded_Picture_Width, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][0][0], PMV[0][0][1], stwtop); if (stwbot < 2) form_prediction(forward_reference_frame, 1, current_frame, 1, Coded_Picture_Width, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][0][0], PMV[0][0][1], stwbot); } else if (motion_type == MC_FIELD) { /* field-based prediction */ /* top field prediction */ if (stwtop < 2) form_prediction(forward_reference_frame, motion_vertical_field_select[0][0], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[0][0][0], PMV[0][0][1] >> 1, stwtop); /* bottom field prediction */ if (stwbot < 2) form_prediction(forward_reference_frame, motion_vertical_field_select[1][0], current_frame, 1, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[1][0][0], PMV[1][0][1] >> 1, stwbot); } else if (motion_type == MC_DMV) { /* dual prime prediction */ /* calculate derived motion vectors */ Dual_Prime_Arithmetic(DMV, dmvector, PMV[0][0][0], PMV[0][0][1] >> 1); if (stwtop < 2) { /* predict top field from top field */ form_prediction(forward_reference_frame, 0, current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[0][0][0], PMV[0][0][1] >> 1, 0); /* predict and add to top field from bottom field */ form_prediction(forward_reference_frame, 1, current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, DMV[0][0], DMV[0][1], 1); } if (stwbot < 2) { /* predict bottom field from bottom field */ form_prediction(forward_reference_frame, 1, current_frame, 1, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[0][0][0], PMV[0][0][1] >> 1, 0); /* predict and add to bottom field from top field */ form_prediction(forward_reference_frame, 0, current_frame, 1, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, DMV[1][0], DMV[1][1], 1); } } else /* invalid motion_type */ printf("invalid motion_type\n"); } else { /* TOP_FIELD or BOTTOM_FIELD */ /* field picture */ currentfield = (picture_structure == BOTTOM_FIELD); /* determine which frame to use for prediction */ if ((picture_coding_type == P_TYPE) && Second_Field && (currentfield != motion_vertical_field_select[0][0])) predframe = backward_reference_frame; /* same frame */ else predframe = forward_reference_frame; /* previous frame */ if ((motion_type == MC_FIELD) || !(macroblock_type & MACROBLOCK_MOTION_FORWARD)) { /* field-based prediction */ if (stwtop < 2) form_prediction(predframe, motion_vertical_field_select[0][0], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 16, bx, by, PMV[0][0][0], PMV[0][0][1], stwtop); } else if (motion_type == MC_16X8) { if (stwtop < 2) { form_prediction(predframe, motion_vertical_field_select[0][0], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][0][0], PMV[0][0][1], stwtop); /* determine which frame to use for lower half prediction */ if ((picture_coding_type == P_TYPE) && Second_Field && (currentfield != motion_vertical_field_select[1][0])) predframe = backward_reference_frame; /* same frame */ else predframe = forward_reference_frame; /* previous frame */ form_prediction(predframe, motion_vertical_field_select[1][0], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by + 8, PMV[1][0][0], PMV[1][0][1], stwtop); } } else if (motion_type == MC_DMV) { /* dual prime prediction */ if (Second_Field) predframe = backward_reference_frame; /* same frame */ else predframe = forward_reference_frame; /* previous frame */ /* calculate derived motion vectors */ Dual_Prime_Arithmetic(DMV, dmvector, PMV[0][0][0], PMV[0][0][1]); /* predict from field of same parity */ form_prediction(forward_reference_frame, currentfield, current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 16, bx, by, PMV[0][0][0], PMV[0][0][1], 0); /* predict from field of opposite parity */ form_prediction(predframe, !currentfield, current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 16, bx, by, DMV[0][0], DMV[0][1], 1); } else /* invalid motion_type */ printf("invalid motion_type\n"); } stwtop = stwbot = 1; } if (macroblock_type & MACROBLOCK_MOTION_BACKWARD) { if (picture_structure == FRAME_PICTURE) { if (motion_type == MC_FRAME) { /* frame-based prediction */ if (stwtop < 2) form_prediction(backward_reference_frame, 0, current_frame, 0, Coded_Picture_Width, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][1][0], PMV[0][1][1], stwtop); if (stwbot < 2) form_prediction(backward_reference_frame, 1, current_frame, 1, Coded_Picture_Width, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][1][0], PMV[0][1][1], stwbot); } else { /* field-based prediction */ /* top field prediction */ if (stwtop < 2) form_prediction(backward_reference_frame, motion_vertical_field_select[0][1], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[0][1][0], PMV[0][1][1] >> 1, stwtop); /* bottom field prediction */ if (stwbot < 2) form_prediction(backward_reference_frame, motion_vertical_field_select[1][1], current_frame, 1, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by >> 1, PMV[1][1][0], PMV[1][1][1] >> 1, stwbot); } } else { /* TOP_FIELD or BOTTOM_FIELD */ /* field picture */ if (motion_type == MC_FIELD) { /* field-based prediction */ form_prediction(backward_reference_frame, motion_vertical_field_select[0][1], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 16, bx, by, PMV[0][1][0], PMV[0][1][1], stwtop); } else if (motion_type == MC_16X8) { form_prediction(backward_reference_frame, motion_vertical_field_select[0][1], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by, PMV[0][1][0], PMV[0][1][1], stwtop); form_prediction(backward_reference_frame, motion_vertical_field_select[1][1], current_frame, 0, Coded_Picture_Width << 1, Coded_Picture_Width << 1, 16, 8, bx, by + 8, PMV[1][1][0], PMV[1][1][1], stwtop); } else /* invalid motion_type */ printf("invalid motion_type\n"); } } } static void form_prediction(src, sfield, dst, dfield, lx, lx2, w, h, x, y, dx, dy, average_flag) unsigned char *src[]; /* prediction source buffer */ int sfield; /* prediction source field number (0 or 1) */ unsigned char *dst[]; /* prediction destination buffer */ int dfield; /* prediction destination field number (0 or 1) */ int lx, lx2; /* line strides */ int w, h; /* prediction block/sub-block width, height */ int x, y; /* pixel co-ordinates of top-left sample in current MB */ int dx, dy; /* horizontal, vertical prediction address */ int average_flag; /* add prediction error to prediction ? */ { /* Y */ form_component_prediction(src[0] + (sfield ? lx2 >> 1 : 0), dst[0] + (dfield ? lx2 >> 1 : 0), lx, lx2, w, h, x, y, dx, dy, average_flag); if (chroma_format != CHROMA444) { lx >>= 1; lx2 >>= 1; w >>= 1; x >>= 1; dx /= 2; } if (chroma_format == CHROMA420) { h >>= 1; y >>= 1; dy /= 2; } /* Cb */ form_component_prediction(src[1] + (sfield ? lx2 >> 1 : 0), dst[1] + (dfield ? lx2 >> 1 : 0), lx, lx2, w, h, x, y, dx, dy, average_flag); /* Cr */ form_component_prediction(src[2] + (sfield ? lx2 >> 1 : 0), dst[2] + (dfield ? lx2 >> 1 : 0), lx, lx2, w, h, x, y, dx, dy, average_flag); } /* ISO/IEC 13818-2 section 7.6.4: Forming predictions */ /* NOTE: the arithmetic below produces numerically equivalent results * to 7.6.4, yet is more elegant. It differs in the following ways: * * 1. the vectors (dx, dy) are based on cartesian frame * coordiantes along a half-pel grid (always positive numbers) * In contrast, vector[r][s][t] are differential (with positive and * negative values). As a result, deriving the integer vectors * (int_vec[t]) from dx, dy is accomplished by a simple right shift. * * 2. Half pel flags (xh, yh) are equivalent to the LSB (Least * Significant Bit) of the half-pel coordinates (dx,dy). * * * NOTE: the work of combining predictions (ISO/IEC 13818-2 section 7.6.7) * is distributed among several other stages. This is accomplished by * folding line offsets into the source and destination (src,dst) * addresses (note the call arguments to form_prediction() in Predict()), * line stride variables lx and lx2, the block dimension variables (w,h), * average_flag, and by the very order in which Predict() is called. * This implementation design (implicitly different than the spec) * was chosen for its elegance. */ static void form_component_prediction(src, dst, lx, lx2, w, h, x, y, dx, dy, average_flag) unsigned char *src; unsigned char *dst; int lx; /* raster line increment */ int lx2; int w, h; int x, y; int dx, dy; int average_flag; /* flag that signals bi-directional or Dual-Prime averaging (7.6.7.1 and 7.6.7.4). if average_flag==1, a previously formed prediction has been stored in pel_pred[] */ { int xint; /* horizontal integer sample vector: analogous to int_vec[0] */ int yint; /* vertical integer sample vectors: analogous to int_vec[1] */ int xh; /* horizontal half sample flag: analogous to half_flag[0] */ int yh; /* vertical half sample flag: analogous to half_flag[1] */ int i, j, v; unsigned char *s; /* source pointer: analogous to pel_ref[][] */ unsigned char *d; /* destination pointer: analogous to pel_pred[][] */ /* half pel scaling for integer vectors */ xint = dx >> 1; yint = dy >> 1; /* derive half pel flags */ xh = dx & 1; yh = dy & 1; /* compute the linear address of pel_ref[][] and pel_pred[][] based on cartesian/raster cordinates provided */ s = src + lx * (y + yint) + x + xint; d = dst + lx * y + x; if (!xh && !yh) { /* no horizontal nor vertical half-pel */ if (average_flag) { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { v = d[i] + s[i]; d[i] = (v + (v >= 0 ? 1 : 0)) >> 1; } s += lx2; d += lx2; } } else { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { d[i] = s[i]; } s += lx2; d += lx2; } } } else if (!xh && yh) { /* no horizontal but vertical half-pel */ if (average_flag) { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { v = d[i] + ((unsigned int) (s[i] + s[i + lx] + 1) >> 1); d[i] = (v + (v >= 0 ? 1 : 0)) >> 1; } s += lx2; d += lx2; } } else { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { d[i] = (unsigned int) (s[i] + s[i + lx] + 1) >> 1; } s += lx2; d += lx2; } } } else if (xh && !yh) { /* horizontal but no vertical half-pel */ if (average_flag) { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { v = d[i] + ((unsigned int) (s[i] + s[i + 1] + 1) >> 1); d[i] = (v + (v >= 0 ? 1 : 0)) >> 1; } s += lx2; d += lx2; } } else { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { d[i] = (unsigned int) (s[i] + s[i + 1] + 1) >> 1; } s += lx2; d += lx2; } } } else { /* if (xh && yh) horizontal and vertical half-pel */ if (average_flag) { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { v = d[i] + ((unsigned int) (s[i] + s[i + 1] + s[i + lx] + s[i + lx + 1] + 2) >> 2); d[i] = (v + (v >= 0 ? 1 : 0)) >> 1; } s += lx2; d += lx2; } } else { for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { d[i] = (unsigned int) (s[i] + s[i + 1] + s[i + lx] + s[i + lx + 1] + 2) >> 2; } s += lx2; d += lx2; } } } }