WebSVN - shark - Rev 3 - /shark/trunk/ports/mpeg/parseblock.c

/*
* parseblock.c --
*
* Procedures to read in the values of a block and store them
* in a place where the player can use them.
*
*/

/*
* Copyright (c) 1995 The Regents of the University of California.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/

/*
* Portions of this software Copyright (c) 1995 Brown University.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement
* is hereby granted, provided that the above copyright notice and the
* following two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL BROWN UNIVERSITY BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF BROWN
* UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* BROWN UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
* BASIS, AND BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/

#define NO_SANITY_CHECKS
#include <assert.h>
#include "video.h"
#include "proto.h"
#include "decoders.h"

/*
Changes to make the code reentrant:
deglobalized: curBits, bitOffset, bitLength, bitBuffer, curVidStream,
zigzag_direct now a const int variable initialized once
-lsh@cs.brown.edu (Loring Holden)
*/

/* External declarations. */
extern const int zigzag_direct[];
#ifdef DCPREC
extern int dcprec;
#endif

/* Macro for returning 1 if num is positive, -1 if negative, 0 if 0. */

#define Sign(num) ((num > 0) ? 1 : ((num == 0) ? 0 : -1))

/*
*--------------------------------------------------------------
*
* ParseReconBlock --
*
* Parse values for block structure from bitstream.
* n is an indication of the position of the block within
* the macroblock (i.e. 0-5) and indicates the type of
* block (i.e. luminance or chrominance). Reconstructs
* coefficients from values parsed and puts in
* block.dct_recon array in vid stream structure.
* sparseFlag is set when the block contains only one
* coeffictient and is used by the IDCT.
*
* Results:
*
*
* Side effects:
* Bit stream irreversibly parsed.
*
*--------------------------------------------------------------
*/

#define DCT_recon blockPtr->dct_recon
#define DCT_dc_y_past blockPtr->dct_dc_y_past
#define DCT_dc_cr_past blockPtr->dct_dc_cr_past
#define DCT_dc_cb_past blockPtr->dct_dc_cb_past

#define DECODE_DCT_COEFF_FIRST DecodeDCTCoeffFirst
#define DECODE_DCT_COEFF_NEXT DecodeDCTCoeffNext

void
ParseReconBlock(n, vid_stream)
int n;
VidStream *vid_stream;
{
#ifdef RISC
unsigned int temp_curBits;
int temp_bitOffset;
int temp_bufLength;
unsigned int *temp_bitBuffer;
#endif

Block *blockPtr = &vid_stream->block;
int coeffCount=0;

if (vid_stream->buf_length < 100)
correct_underflow(vid_stream);

#ifdef RISC
temp_curBits = vid_stream->curBits;
temp_bitOffset = vid_stream->buf_offset;
temp_bufLength = vid_stream->buf_length;
temp_bitBuffer = bitBuffer;
#endif

{
/*
* Copy the VidStream fields curBits, bitOffset, and bitBuffer
* into local variables with the same names, so the macros use the
* local variables instead. This allows register allocation and
* can provide 1-2 fps speedup. On machines with not so many registers,
* don't do this.
*/
#ifdef RISC
register unsigned int curBits = temp_curBits;
register int bitOffset = temp_bitOffset;
register int bufLength = temp_bufLength;
register unsigned int *bitBuffer = temp_bitBuffer;
#endif

int diff;
int size, level=0, i, run, pos, coeff;
short int *reconptr;
unsigned char *iqmatrixptr, *niqmatrixptr;
int qscale;

reconptr = DCT_recon[0];

/*
* Hand coded version of memset that's a little faster...
* Old call:
* memset((char *) DCT_recon, 0, 64*sizeof(short int));
*/
{
INT32 *p;
p = (INT32 *) reconptr;

p[0] = p[1] = p[2] = p[3] = p[4] = p[5] = p[6] = p[7] = p[8] = p[9] =
p[10] = p[11] = p[12] = p[13] = p[14] = p[15] = p[16] = p[17] = p[18] =
p[19] = p[20] = p[21] = p[22] = p[23] = p[24] = p[25] = p[26] = p[27] =
p[28] = p[29] = p[30] = p[31] = 0;

}

if (vid_stream->mblock.mb_intra) {

if (n < 4) {

/*
* Get the luminance bits. This code has been hand optimized to
* get by the normal bit parsing routines. We get some speedup
* by grabbing the next 16 bits and parsing things locally.
* Thus, calls are translated as:
*
* show_bitsX <--> next16bits >> (16-X)
* get_bitsX <--> val = next16bits >> (16-flushed-X);
* flushed += X;
* next16bits &= bitMask[flushed];
* flush_bitsX <--> flushed += X;
* next16bits &= bitMask[flushed];
*
* I've streamlined the code a lot, so that we don't have to mask
* out the low order bits and a few of the extra adds are removed.
* bsmith
*/
unsigned int next16bits, index, flushed;

show_bits16(next16bits);
index = next16bits >> (16-5);
if (index < 31) {
size = dct_dc_size_luminance[index].value;
flushed = dct_dc_size_luminance[index].num_bits;
} else {
index = next16bits >> (16-9);
index -= 0x1f0;
size = dct_dc_size_luminance1[index].value;
flushed = dct_dc_size_luminance1[index].num_bits;
}
next16bits &= bitMask[16+flushed];

if (size != 0) {
flushed += size;
diff = next16bits >> (16-flushed);
if (!(diff & bitTest[32-size])) {
diff = rBitMask[size] | (diff + 1);
}
} else {
diff = 0;
}
flush_bits(flushed);

if (n == 0) {
coeff = diff << 3;
if (vid_stream->mblock.mb_address -
vid_stream->mblock.past_intra_addr > 1) {
coeff += 1024;
} else {
coeff += DCT_dc_y_past;
}
DCT_dc_y_past = coeff;
} else {
coeff = DCT_dc_y_past + (diff << 3);
DCT_dc_y_past = coeff;
}

} else { /* n = 4 or 5 */

/*
* Get the chrominance bits. This code has been hand optimized to
* as described above
*/

unsigned int next16bits, index, flushed;

show_bits16(next16bits);
index = next16bits >> (16-5);
if (index < 31) {
size = dct_dc_size_chrominance[index].value;
flushed = dct_dc_size_chrominance[index].num_bits;
} else {
index = next16bits >> (16-10);
index -= 0x3e0;
size = dct_dc_size_chrominance1[index].value;
flushed = dct_dc_size_chrominance1[index].num_bits;
}
next16bits &= bitMask[16+flushed];

if (size != 0) {
flushed += size;
diff = next16bits >> (16-flushed);
if (!(diff & bitTest[32-size])) {
diff = rBitMask[size] | (diff + 1);
}
} else {
diff = 0;
}
flush_bits(flushed);

/* We test 5 first; a result of the mixup of Cr and Cb */
if (n == 5) {
coeff = diff << 3;

if (vid_stream->mblock.mb_address -
vid_stream->mblock.past_intra_addr > 1) {
coeff += 1024;
} else {
coeff += DCT_dc_cr_past;
}
DCT_dc_cr_past = coeff;
} else {
coeff = diff << 3;
if (vid_stream->mblock.mb_address -
vid_stream->mblock.past_intra_addr > 1) {
coeff += 1024;
} else {
coeff += DCT_dc_cb_past;
}
DCT_dc_cb_past = coeff;
}
}

*reconptr = coeff;
i = 0;
pos = 0;
coeffCount = (coeff != 0);

if (vid_stream->picture.code_type != 4) {

qscale = vid_stream->slice.quant_scale;
iqmatrixptr = vid_stream->intra_quant_matrix[0];

while(1) {

DECODE_DCT_COEFF_NEXT(run, level);

if (run >= END_OF_BLOCK) break;

i = i + run + 1;
pos = zigzag_direct[i];

/* quantizes and oddifies each coefficient */
if (level < 0) {
coeff = ((level<<1) * qscale *
((int) (iqmatrixptr[pos]))) / 16;
coeff += (1 - (coeff & 1));
} else {
coeff = ((level<<1) * qscale *
((int) (*(iqmatrixptr+pos)))) >> 4;
coeff -= (1 - (coeff & 1));
}
#ifdef QUANT_CHECK
printf ("coeff: %d\n", coeff);
#endif

reconptr[pos] = coeff;
coeffCount++;

}

#ifdef QUANT_CHECK
printf ("\n");
#endif

#ifdef ANALYSIS
{
extern unsigned int *mbCoeffPtr;
mbCoeffPtr[pos]++;
}
#endif

flush_bits(2);
goto end;
}
} else { /* non-intra-coded macroblock */

niqmatrixptr = vid_stream->non_intra_quant_matrix[0];
qscale = vid_stream->slice.quant_scale;

DECODE_DCT_COEFF_FIRST(run, level);
i = run;

pos = zigzag_direct[i];

/* quantizes and oddifies each coefficient */
if (level < 0) {
coeff = (((level<<1) - 1) * qscale *
((int) (niqmatrixptr[pos]))) / 16;
if ((coeff & 1) == 0) {coeff = coeff + 1;}
} else {
coeff = (((level<<1) + 1) * qscale *
((int) (*(niqmatrixptr+pos)))) >> 4;
coeff = (coeff-1) | 1; /* equivalent to: if ((coeff&1)==0) coeff = coeff - 1; */
}

reconptr[pos] = coeff;
if (coeff) {
coeffCount = 1;
}

if (vid_stream->picture.code_type != 4) {

while(1) {

DECODE_DCT_COEFF_NEXT(run, level);

if (run >= END_OF_BLOCK) {
break;
}

i = i+run+1;
pos = zigzag_direct[i];
if (level < 0) {
coeff = (((level<<1) - 1) * qscale *
((int) (niqmatrixptr[pos]))) / 16;
if ((coeff & 1) == 0) {coeff = coeff + 1;}
} else {
coeff = (((level<<1) + 1) * qscale *
((int) (*(niqmatrixptr+pos)))) >> 4;
coeff = (coeff-1) | 1; /* equivalent to: if ((coeff&1)==0) coeff = coeff - 1; */
}
reconptr[pos] = coeff;
coeffCount++;
} /* end while */

#ifdef ANALYSIS
{
extern unsigned int *mbCoeffPtr;
mbCoeffPtr[pos]++;
}
#endif

flush_bits(2);

goto end;
} /* end if (vid_stream->picture.code_type != 4) */
}

end:

if (coeffCount == 1) {
j_rev_dct_sparse (reconptr, pos);
}
else {
#ifdef FLOATDCT
if (qualityFlag) {
float_idct(reconptr);
} else {
#endif
j_rev_dct(reconptr);
#ifdef FLOATDCT
}
#endif
}

#ifdef RISC
temp_curBits = vid_stream->curBits;
temp_bitOffset = vid_stream->bit_offset;
temp_bufLength = vid_stream->buf_length;
temp_bitBuffer = bitBuffer;
#endif

}

#ifdef RISC
vid_stream->curBits = temp_curBits;
vid_stream->bitOffset = temp_bitOffset;
vid_stream->buf_length = temp_bufLength;
bitBuffer = temp_bitBuffer;
#endif
}

#undef DCT_recon
#undef DCT_dc_y_past
#undef DCT_dc_cr_past
#undef DCT_dc_cb_past

/*
*--------------------------------------------------------------
*
* ParseAwayBlock --
*
* Parses off block values, throwing them away.
* Used with grayscale dithering.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/

void
ParseAwayBlock(n, vid_stream)
int n;
VidStream *vid_stream;
{
unsigned int diff;
unsigned int size, run;
int level;

if (vid_stream->buf_length < 100)
correct_underflow(vid_stream);

if (vid_stream->mblock.mb_intra) {

/* If the block is a luminance block... */

if (n < 4) {

/* Parse and decode size of first coefficient. */

DecodeDCTDCSizeLum(size);

/* Parse first coefficient. */

if (size != 0) {
get_bitsn(size, diff);
}
}

/* Otherwise, block is chrominance block... */

else {

/* Parse and decode size of first coefficient. */

DecodeDCTDCSizeChrom(size);

/* Parse first coefficient. */

if (size != 0) {
get_bitsn(size, diff);
}
}
}

/* Otherwise, block is not intracoded... */

else {

/* Decode and set first coefficient. */

DECODE_DCT_COEFF_FIRST(run, level);
}

/* If picture is not D type (i.e. I, P, or B)... */

if (vid_stream->picture.code_type != 4) {

/* While end of macroblock has not been reached... */

while (1) {

/* Get the dct_coeff_next */

DECODE_DCT_COEFF_NEXT(run, level);

if (run >= END_OF_BLOCK) break;
}

/* End_of_block */

flush_bits(2);
}
}

Subversion Repositories shark

(root)/shark/trunk/ports/mpeg/parseblock.c @ 859 - Rev 3