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Add trellis for DC

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Add option to apply trellis quantization to the DC coefficients ( see
#57 ). May need further refinement to make sure block order during
trellis optimization matches order during coding.
This commit is contained in:
Frank Bossen
2014-07-31 12:11:36 -04:00
parent 0533b31891
commit 049e5c80b9
6 changed files with 107 additions and 7 deletions
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4
cjpeg.c
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@@ -487,6 +487,10 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv,
/* disable trellis quantization */
cinfo->trellis_quant = FALSE;
} else if (keymatch(arg, "trellis-dc", 9)) {
/* enable DC trellis quantization */
cinfo->trellis_quant_dc = TRUE;
} else if (keymatch(arg, "tune-psnr", 6)) {
cinfo->use_flat_quant_tbl = TRUE;
cinfo->lambda_log_scale1 = 9.0;

8
jccoefct.c
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@@ -361,10 +361,13 @@ compress_trellis_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
JBLOCKARRAY buffer_dst;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
c_derived_tbl dctbl_data;
c_derived_tbl *dctbl = &dctbl_data;
c_derived_tbl actbl_data;
c_derived_tbl *actbl = &actbl_data;
compptr = cinfo->cur_comp_info[ci];
jpeg_make_c_derived_tbl(cinfo, TRUE, compptr->dc_tbl_no, &dctbl);
jpeg_make_c_derived_tbl(cinfo, FALSE, compptr->ac_tbl_no, &actbl);
/* Align the virtual buffer for this component. */
@@ -392,12 +395,15 @@ compress_trellis_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
ndummy = (int) (blocks_across % h_samp_factor);
if (ndummy > 0)
ndummy = h_samp_factor - ndummy;
lastDC = 0;
/* Perform DCT for all non-dummy blocks in this iMCU row. Each call
* on forward_DCT processes a complete horizontal row of DCT blocks.
*/
for (block_row = 0; block_row < block_rows; block_row++) {
thisblockrow = buffer[block_row];
quantize_trellis(cinfo, actbl, thisblockrow, buffer_dst[block_row], blocks_across, cinfo->quant_tbl_ptrs[compptr->quant_tbl_no], cinfo->norm_src[compptr->quant_tbl_no], cinfo->norm_coef[compptr->quant_tbl_no]);
quantize_trellis(cinfo, dctbl, actbl, thisblockrow, buffer_dst[block_row], blocks_across, cinfo->quant_tbl_ptrs[compptr->quant_tbl_no], cinfo->norm_src[compptr->quant_tbl_no], cinfo->norm_coef[compptr->quant_tbl_no], &lastDC);
if (ndummy > 0) {
/* Create dummy blocks at the right edge of the image. */

96
jcdctmgr.c
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@@ -615,10 +615,10 @@ static const float jpeg_lambda_weights_csf_luma[64] = {
};
GLOBAL(void)
quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks,
JQUANT_TBL * qtbl, double *norm_src, double *norm_coef)
quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *dctbl, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks,
JQUANT_TBL * qtbl, double *norm_src, double *norm_coef, JCOEF *last_dc_val)
{
int i, j, k;
int i, j, k, l;
float accumulated_zero_dist[DCTSIZE2];
float accumulated_cost[DCTSIZE2];
int run_start[DCTSIZE2];
@@ -628,6 +628,7 @@ quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_bloc
float norm = 0.0;
float lambda_base;
float lambda;
float lambda_dc;
const float *lambda_tbl = (cinfo->use_lambda_weight_tbl) ? jpeg_lambda_weights_csf_luma : jpeg_lambda_weights_flat;
int Ss, Se;
float *accumulated_zero_block_cost = NULL;
@@ -641,6 +642,9 @@ quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_bloc
int zero_run;
int run_bits;
int rate;
float *accumulated_dc_cost[3];
int *dc_cost_backtrack[3];
JCOEF *dc_candidate[3];
Ss = cinfo->Ss;
Se = cinfo->Se;
@@ -657,7 +661,13 @@ quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_bloc
accumulated_block_cost[0] = 0;
requires_eob[0] = 0;
}
if (cinfo->trellis_quant_dc) {
for (i = 0; i < 3; i++) {
accumulated_dc_cost[i] = (float *)malloc(num_blocks * SIZEOF(float));
dc_cost_backtrack[i] = (int *)malloc(num_blocks * SIZEOF(int));
dc_candidate[i] = (JCOEF *)malloc(num_blocks * SIZEOF(JCOEF));
}
}
norm = 0.0;
for (i = 1; i < DCTSIZE2; i++) {
norm += qtbl->quantval[i] * qtbl->quantval[i];
@@ -679,9 +689,65 @@ quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_bloc
else
lambda = pow(2.0, cinfo->lambda_log_scale1-12.0) * lambda_base;
lambda_dc = lambda * lambda_tbl[0];
accumulated_zero_dist[Ss-1] = 0.0;
accumulated_cost[Ss-1] = 0.0;
// Do DC coefficient
if (cinfo->trellis_quant_dc) {
int sign = src[bi][0] >> 31;
int x = abs(src[bi][0]);
int q = 8 * qtbl->quantval[0];
int qval;
float dc_candidate_dist;
qval = (x + q/2) / q; /* quantized value (round nearest) */
for (k = 0; k < 3; k++) {
int delta;
int dc_delta;
int bits;
dc_candidate[k][bi] = qval - 1 + k;
delta = dc_candidate[k][bi] * q - x;
dc_candidate_dist = delta * delta * lambda_dc;
dc_candidate[k][bi] *= 1 + 2*sign;
if (bi == 0) {
dc_delta = dc_candidate[k][bi] - *last_dc_val;
// Derive number of suffix bits
bits = 0;
dc_delta = abs(dc_delta);
while (dc_delta) {
dc_delta >>= 1;
bits++;
}
cost = bits + dctbl->ehufsi[bits] + dc_candidate_dist;
accumulated_dc_cost[k][0] = cost;
dc_cost_backtrack[k][0] = -1;
} else {
for (l = 0; l < 3; l++) {
dc_delta = dc_candidate[k][bi] - dc_candidate[l][bi-1];
// Derive number of suffix bits
bits = 0;
dc_delta = abs(dc_delta);
while (dc_delta) {
dc_delta >>= 1;
bits++;
}
cost = bits + dctbl->ehufsi[bits] + dc_candidate_dist;
if (l == 0 || cost < accumulated_dc_cost[k][bi]) {
accumulated_dc_cost[k][bi] = cost;
dc_cost_backtrack[k][bi] = l;
}
}
}
}
}
// Do AC coefficients
for (i = Ss; i <= Se; i++) {
int z = jpeg_natural_order[i];
@@ -865,6 +931,28 @@ quantize_trellis(j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_bloc
}
}
}
if (cinfo->trellis_quant_dc) {
j = 0;
for (i = 1; i < 3; i++) {
if (accumulated_dc_cost[i][num_blocks-1] < accumulated_dc_cost[j][num_blocks-1])
j = i;
}
for (bi = num_blocks-1; bi >= 0; bi--) {
coef_blocks[bi][0] = dc_candidate[j][bi];
j = dc_cost_backtrack[j][bi];
}
// Save DC predictor
*last_dc_val = coef_blocks[num_blocks-1][0];
for (i = 0; i < 3; i++) {
free(accumulated_dc_cost[i]);
free(dc_cost_backtrack[i]);
free(dc_candidate[i]);
}
}
}
/*

4
jchuff.h
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@@ -49,5 +49,5 @@ EXTERN(void) jpeg_gen_optimal_table
JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[]));
EXTERN(void) quantize_trellis
JPP((j_compress_ptr cinfo, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks,
JQUANT_TBL * qtbl, double *norm_src, double *norm_coef));
JPP((j_compress_ptr cinfo, c_derived_tbl *dctbl, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks,
JQUANT_TBL * qtbl, double *norm_src, double *norm_coef, JCOEF *last_dc_val));

1
jcparam.c
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@@ -444,6 +444,7 @@ jpeg_set_defaults (j_compress_ptr cinfo)
cinfo->trellis_freq_split = 8;
cinfo->trellis_num_loops = 1;
cinfo->trellis_q_opt = FALSE;
cinfo->trellis_quant_dc = FALSE;
}

1
jpeglib.h
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@@ -380,6 +380,7 @@ struct jpeg_compress_struct {
boolean optimize_scans; /* TRUE=optimize progressive coding scans */
boolean one_dc_scan; /* TRUE=use a single DC scan interleaving all components */
boolean trellis_quant; /* TRUE=use trellis quantization */
boolean trellis_quant_dc; /* TRUE=use trellis quant for DC coefficient */
boolean trellis_eob_opt; /* TRUE=optimize for sequences of EOB */
boolean use_flat_quant_tbl; /* TRUE=use flat quantization table */
boolean use_lambda_weight_tbl; /* TRUE=use lambda weighting table */