WebSVN - shark - Blame - Rev 3 - /shark/trunk/ports/mpeg/motionvector.c

Rev	Author	Line No.	Line
2	pj	1	/*
		2	* motionvector.c --
		3	*
		4	* Procedures to compute motion vectors.
		5	*
		6	*/
		7
		8	/*
		9	* Copyright (c) 1995 The Regents of the University of California.
		10	* All rights reserved.
		11	*
		12	* Permission to use, copy, modify, and distribute this software and its
		13	* documentation for any purpose, without fee, and without written agreement is
		14	* hereby granted, provided that the above copyright notice and the following
		15	* two paragraphs appear in all copies of this software.
		16	*
		17	* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
		18	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
		19	* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
		20	* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		21	*
		22	* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
		23	* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
		24	* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
		25	* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
		26	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
		27	*/
		28
		29	/*
		30	* Portions of this software Copyright (c) 1995 Brown University.
		31	* All rights reserved.
		32	*
		33	* Permission to use, copy, modify, and distribute this software and its
		34	* documentation for any purpose, without fee, and without written agreement
		35	* is hereby granted, provided that the above copyright notice and the
		36	* following two paragraphs appear in all copies of this software.
		37	*
		38	* IN NO EVENT SHALL BROWN UNIVERSITY BE LIABLE TO ANY PARTY FOR
		39	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
		40	* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF BROWN
		41	* UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		42	*
		43	* BROWN UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
		44	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
		45	* PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
		46	* BASIS, AND BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
		47	* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
		48	*/
		49
		50	#include "video.h"
		51	#include "proto.h"
		52	#include "util.h"
		53
		54	/*
		55	Changes to make the code reentrant:
		56	deglobalize curVidStream
		57	Additional changes:
		58	none
		59	-lsh@cs.brown.edu (Loring Holden)
		60	*/
		61
		62
		63	/*
		64	*--------------------------------------------------------------
		65	*
		66	* ComputeVector --
		67	*
		68	* Computes motion vector given parameters previously parsed
		69	* and reconstructed.
		70	*
		71	* Results:
		72	* Reconstructed motion vector info is put into recon_* parameters
		73	* passed to this function. Also updated previous motion vector
		74	* information.
		75	*
		76	* Side effects:
		77	* None.
		78	*
		79	*--------------------------------------------------------------
		80	*/
		81
		82	#define ComputeVector(recon_right_ptr, recon_down_ptr, recon_right_prev, recon_down_prev, f, full_pel_vector, motion_h_code, motion_v_code, motion_h_r, motion_v_r) \
		83	\
		84	{ \
		85	int comp_h_r, comp_v_r; \
		86	int right_little, right_big, down_little, down_big; \
		87	int max, min, new_vector; \
		88	\
		89	/* The following procedure for the reconstruction of motion vectors \
		90	is a direct and simple implementation of the instructions given \
		91	in the mpeg December 1991 standard draft. \
		92	*/ \
		93	\
		94	if (f == 1 \|\| motion_h_code == 0) \
		95	comp_h_r = 0; \
		96	else \
		97	comp_h_r = f - 1 - motion_h_r; \
		98	\
		99	if (f == 1 \|\| motion_v_code == 0) \
		100	comp_v_r = 0; \
		101	else \
		102	comp_v_r = f - 1 - motion_v_r; \
		103	\
		104	right_little = motion_h_code * f; \
		105	if (right_little == 0) \
		106	right_big = 0; \
		107	else { \
		108	if (right_little > 0) { \
		109	right_little = right_little - comp_h_r; \
		110	right_big = right_little - 32 * f; \
		111	} \
		112	else { \
		113	right_little = right_little + comp_h_r; \
		114	right_big = right_little + 32 * f; \
		115	} \
		116	} \
		117	\
		118	down_little = motion_v_code * f; \
		119	if (down_little == 0) \
		120	down_big = 0; \
		121	else { \
		122	if (down_little > 0) { \
		123	down_little = down_little - comp_v_r; \
		124	down_big = down_little - 32 * f; \
		125	} \
		126	else { \
		127	down_little = down_little + comp_v_r; \
		128	down_big = down_little + 32 * f; \
		129	} \
		130	} \
		131	\
		132	max = 16 * f - 1; \
		133	min = -16 * f; \
		134	\
		135	new_vector = recon_right_prev + right_little; \
		136	\
		137	if (new_vector <= max && new_vector >= min) \
		138	*recon_right_ptr = recon_right_prev + right_little; \
		139	/* just new_vector */ \
		140	else \
		141	*recon_right_ptr = recon_right_prev + right_big; \
		142	recon_right_prev = *recon_right_ptr; \
		143	if (full_pel_vector) \
		144	recon_right_ptr = recon_right_ptr << 1; \
		145	\
		146	new_vector = recon_down_prev + down_little; \
		147	if (new_vector <= max && new_vector >= min) \
		148	*recon_down_ptr = recon_down_prev + down_little; \
		149	/* just new_vector */ \
		150	else \
		151	*recon_down_ptr = recon_down_prev + down_big; \
		152	recon_down_prev = *recon_down_ptr; \
		153	if (full_pel_vector) \
		154	recon_down_ptr = recon_down_ptr << 1; \
		155	}
		156
		157
		158	/*
		159	*--------------------------------------------------------------
		160	*
		161	* ComputeForwVector --
		162	*
		163	* Computes forward motion vector by calling ComputeVector
		164	* with appropriate parameters.
		165	*
		166	* Results:
		167	* Reconstructed motion vector placed in recon_right_for_ptr and
		168	* recon_down_for_ptr.
		169	*
		170	* Side effects:
		171	* None.
		172	*
		173	*--------------------------------------------------------------
		174	*/
		175
		176	void
		177	ComputeForwVector(recon_right_for_ptr, recon_down_for_ptr, the_stream)
		178	int *recon_right_for_ptr;
		179	int *recon_down_for_ptr;
		180	VidStream *the_stream;
		181	{
		182
		183	Pict *picture;
		184	Macroblock *mblock;
		185
		186	picture = &(the_stream->picture);
		187	mblock = &(the_stream->mblock);
		188
		189	ComputeVector(recon_right_for_ptr, recon_down_for_ptr,
		190	mblock->recon_right_for_prev,
		191	mblock->recon_down_for_prev,
		192	(int) picture->forw_f,
		193	picture->full_pel_forw_vector,
		194	mblock->motion_h_forw_code, mblock->motion_v_forw_code,
		195	mblock->motion_h_forw_r, mblock->motion_v_forw_r);
		196	}
		197
		198
		199	/*
		200	*--------------------------------------------------------------
		201	*
		202	* ComputeBackVector --
		203	*
		204	* Computes backward motion vector by calling ComputeVector
		205	* with appropriate parameters.
		206	*
		207	* Results:
		208	* Reconstructed motion vector placed in recon_right_back_ptr and
		209	* recon_down_back_ptr.
		210	*
		211	* Side effects:
		212	* None.
		213	*
		214	*--------------------------------------------------------------
		215	*/
		216
		217	void
		218	ComputeBackVector(recon_right_back_ptr, recon_down_back_ptr, the_stream)
		219	int *recon_right_back_ptr;
		220	int *recon_down_back_ptr;
		221	VidStream *the_stream;
		222	{
		223	Pict *picture;
		224	Macroblock *mblock;
		225
		226	picture = &(the_stream->picture);
		227	mblock = &(the_stream->mblock);
		228
		229	ComputeVector(recon_right_back_ptr, recon_down_back_ptr,
		230	mblock->recon_right_back_prev,
		231	mblock->recon_down_back_prev,
		232	(int) picture->back_f,
		233	picture->full_pel_back_vector,
		234	mblock->motion_h_back_code, mblock->motion_v_back_code,
		235	mblock->motion_h_back_r, mblock->motion_v_back_r);
		236
		237	}

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(root)/shark/trunk/ports/mpeg/motionvector.c @ 517 - Rev 3