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Add support for scan optimisation of monochrome pictures

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This commit is contained in:
fbossen
2014-02-14 18:12:51 -05:00
parent fa9569fcec
commit a4137a6c14
3 changed files with 137 additions and 133 deletions
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103
jcparam.c
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@@ -612,12 +612,15 @@ fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al)
* cinfo->num_components and cinfo->jpeg_color_space must be correct.
*/
LOCAL(void)
LOCAL(boolean)
jpeg_search_progression (j_compress_ptr cinfo)
{
int ncomps = cinfo->num_components;
int nscans;
jpeg_scan_info * scanptr;
int Al;
int frequency_split[] = { 2, 8, 5, 12, 18 };
int i;
/* Safety check to ensure start_compress not called yet. */
if (cinfo->global_state != CSTATE_START)
@@ -627,19 +630,11 @@ jpeg_search_progression (j_compress_ptr cinfo)
if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
/* Custom script for YCbCr color images. */
nscans = 64;
} else if (ncomps == 1) {
nscans = 23;
} else {
/* All-purpose script for other color spaces. */
if (cinfo->use_moz_defaults) {
if (ncomps > MAX_COMPS_IN_SCAN)
nscans = 5 * ncomps; /* 2 DC + 4 AC scans per component */
else
nscans = 1 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
} else {
if (ncomps > MAX_COMPS_IN_SCAN)
nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */
else
nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
}
cinfo->num_scans_luma = 0;
return FALSE;
}
/* Allocate space for script.
@@ -650,7 +645,7 @@ jpeg_search_progression (j_compress_ptr cinfo)
* enough space to handle YCbCr even if initially asked for grayscale.
*/
if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) {
cinfo->script_space_size = MAX(nscans, 10);
cinfo->script_space_size = MAX(nscans, 64);
cinfo->script_space = (jpeg_scan_info *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
cinfo->script_space_size * SIZEOF(jpeg_scan_info));
@@ -659,44 +654,43 @@ jpeg_search_progression (j_compress_ptr cinfo)
cinfo->scan_info = scanptr;
cinfo->num_scans = nscans;
if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
int Al;
int frequency_split[] = { 2, 8, 5, 12, 18 };
int i;
cinfo->Al_max_luma = 3;
cinfo->Al_max_luma = 3;
cinfo->num_scans_luma_dc = 1;
cinfo->num_frequency_splits = 5;
cinfo->num_scans_luma = cinfo->num_scans_luma_dc + (3 * cinfo->Al_max_luma + 2) + (2 * cinfo->num_frequency_splits + 1);
/* 23 scans for luma */
/* 1 scan for DC */
/* 11 scans to determine successive approximation */
/* 11 scans to determine frequency approximation */
/* after 12 scans need to update following 11 */
/* after 23 scans need to determine which to keep */
/* last 4 done conditionally */
/* luma DC by itself */
scanptr = fill_dc_scans(scanptr, 1, 0, 0);
for (Al = 0; Al <= cinfo->Al_max_luma; Al++) {
scanptr = fill_a_scan(scanptr, 0, 1, 8, 0, Al);
scanptr = fill_a_scan(scanptr, 0, 9, 63, 0, Al);
}
for (Al = 0; Al < cinfo->Al_max_luma; Al++)
scanptr = fill_a_scan(scanptr, 0, 1, 63, Al+1, Al);
scanptr = fill_a_scan(scanptr, 0, 1, 63, 0, 0);
for (i = 0; i < cinfo->num_frequency_splits; i++) {
scanptr = fill_a_scan(scanptr, 0, 1, frequency_split[i], 0, 0);
scanptr = fill_a_scan(scanptr, 0, frequency_split[i]+1, 63, 0, 0);
}
if (ncomps == 1) {
cinfo->Al_max_chroma = 0;
cinfo->num_scans_chroma_dc = 0;
} else {
cinfo->Al_max_chroma = 2;
cinfo->num_scans_luma_dc = 1;
cinfo->num_scans_chroma_dc = 3;
cinfo->num_frequency_splits = 5;
cinfo->num_scans_luma = cinfo->num_scans_luma_dc + (3 * cinfo->Al_max_luma + 2) + (2 * cinfo->num_frequency_splits + 1);
/* 23 scans for luma */
/* 1 scan for DC */
/* 11 scans to determine successive approximation */
/* 11 scans to determine frequency approximation */
/* after 12 scans need to update following 11 */
/* after 23 scans need to determine which to keep */
/* last 4 done conditionally */
/* luma DC by itself */
scanptr = fill_dc_scans(scanptr, 1, 0, 0);
for (Al = 0; Al <= cinfo->Al_max_luma; Al++) {
scanptr = fill_a_scan(scanptr, 0, 1, 8, 0, Al);
scanptr = fill_a_scan(scanptr, 0, 9, 63, 0, Al);
}
for (Al = 0; Al < cinfo->Al_max_luma; Al++)
scanptr = fill_a_scan(scanptr, 0, 1, 63, Al+1, Al);
scanptr = fill_a_scan(scanptr, 0, 1, 63, 0, 0);
for (i = 0; i < cinfo->num_frequency_splits; i++) {
scanptr = fill_a_scan(scanptr, 0, 1, frequency_split[i], 0, 0);
scanptr = fill_a_scan(scanptr, 0, frequency_split[i]+1, 63, 0, 0);
}
/* 41 scans for chroma */
/* chroma DC combined */
@@ -726,9 +720,9 @@ jpeg_search_progression (j_compress_ptr cinfo)
scanptr = fill_a_scan(scanptr, 2, 1, frequency_split[i], 0, 0);
scanptr = fill_a_scan(scanptr, 2, frequency_split[i]+1, 63, 0, 0);
}
} else {
/* TODO */
}
return TRUE;
}
/*
@@ -740,9 +734,10 @@ GLOBAL(void)
jpeg_simple_progression (j_compress_ptr cinfo)
{
if (cinfo->optimize_scans) {
jpeg_search_progression(cinfo);
return;
if (jpeg_search_progression(cinfo) == TRUE)
return;
}
int ncomps = cinfo->num_components;
int nscans;
jpeg_scan_info * scanptr;