+++ /dev/null
-/*
- * jdmerge.c
- *
- * Copyright (C) 1994-1996, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains code for merged upsampling/color conversion.
- *
- * This file combines functions from jdsample.c and jdcolor.c;
- * read those files first to understand what's going on.
- *
- * When the chroma components are to be upsampled by simple replication
- * (ie, box filtering), we can save some work in color conversion by
- * calculating all the output pixels corresponding to a pair of chroma
- * samples at one time. In the conversion equations
- * R = Y + K1 * Cr
- * G = Y + K2 * Cb + K3 * Cr
- * B = Y + K4 * Cb
- * only the Y term varies among the group of pixels corresponding to a pair
- * of chroma samples, so the rest of the terms can be calculated just once.
- * At typical sampling ratios, this eliminates half or three-quarters of the
- * multiplications needed for color conversion.
- *
- * This file currently provides implementations for the following cases:
- * YCbCr => RGB color conversion only.
- * Sampling ratios of 2h1v or 2h2v.
- * No scaling needed at upsample time.
- * Corner-aligned (non-CCIR601) sampling alignment.
- * Other special cases could be added, but in most applications these are
- * the only common cases. (For uncommon cases we fall back on the more
- * general code in jdsample.c and jdcolor.c.)
- */
-
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "jpeglib.h"
-
-#ifdef UPSAMPLE_MERGING_SUPPORTED
-
-
-/* Private subobject */
-
-typedef struct {
- struct jpeg_upsampler pub; /* public fields */
-
- /* Pointer to routine to do actual upsampling/conversion of one row group */
- JMETHOD(void, upmethod, (j_decompress_ptr cinfo,
- JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
- JSAMPARRAY output_buf));
-
- /* Private state for YCC->RGB conversion */
- int * Cr_r_tab; /* => table for Cr to R conversion */
- int * Cb_b_tab; /* => table for Cb to B conversion */
- INT32 * Cr_g_tab; /* => table for Cr to G conversion */
- INT32 * Cb_g_tab; /* => table for Cb to G conversion */
-
- /* For 2:1 vertical sampling, we produce two output rows at a time.
- * We need a "spare" row buffer to hold the second output row if the
- * application provides just a one-row buffer; we also use the spare
- * to discard the dummy last row if the image height is odd.
- */
- JSAMPROW spare_row;
- boolean spare_full; /* T if spare buffer is occupied */
-
- JDIMENSION out_row_width; /* samples per output row */
- JDIMENSION rows_to_go; /* counts rows remaining in image */
-} my_upsampler;
-
-typedef my_upsampler * my_upsample_ptr;
-
-#define SCALEBITS 16 /* speediest right-shift on some machines */
-#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
-#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
-
-
-/*
- * Initialize tables for YCC->RGB colorspace conversion.
- * This is taken directly from jdcolor.c; see that file for more info.
- */
-
-LOCAL(void)
-build_ycc_rgb_table (j_decompress_ptr cinfo)
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
- int i;
- INT32 x;
- SHIFT_TEMPS
-
- upsample->Cr_r_tab = (int *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (MAXJSAMPLE+1) * SIZEOF(int));
- upsample->Cb_b_tab = (int *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (MAXJSAMPLE+1) * SIZEOF(int));
- upsample->Cr_g_tab = (INT32 *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (MAXJSAMPLE+1) * SIZEOF(INT32));
- upsample->Cb_g_tab = (INT32 *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (MAXJSAMPLE+1) * SIZEOF(INT32));
-
- for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
- /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
- /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
- /* Cr=>R value is nearest int to 1.40200 * x */
- upsample->Cr_r_tab[i] = (int)
- RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
- /* Cb=>B value is nearest int to 1.77200 * x */
- upsample->Cb_b_tab[i] = (int)
- RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
- /* Cr=>G value is scaled-up -0.71414 * x */
- upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x;
- /* Cb=>G value is scaled-up -0.34414 * x */
- /* We also add in ONE_HALF so that need not do it in inner loop */
- upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
- }
-}
-
-
-/*
- * Initialize for an upsampling pass.
- */
-
-METHODDEF(void)
-start_pass_merged_upsample (j_decompress_ptr cinfo)
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
-
- /* Mark the spare buffer empty */
- upsample->spare_full = FALSE;
- /* Initialize total-height counter for detecting bottom of image */
- upsample->rows_to_go = cinfo->output_height;
-}
-
-
-/*
- * Control routine to do upsampling (and color conversion).
- *
- * The control routine just handles the row buffering considerations.
- */
-
-METHODDEF(void)
-merged_2v_upsample (j_decompress_ptr cinfo,
- JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
- JDIMENSION in_row_groups_avail,
- JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
- JDIMENSION out_rows_avail)
-/* 2:1 vertical sampling case: may need a spare row. */
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
- JSAMPROW work_ptrs[2];
- JDIMENSION num_rows; /* number of rows returned to caller */
-
- if (upsample->spare_full) {
- /* If we have a spare row saved from a previous cycle, just return it. */
- jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0,
- 1, upsample->out_row_width);
- num_rows = 1;
- upsample->spare_full = FALSE;
- } else {
- /* Figure number of rows to return to caller. */
- num_rows = 2;
- /* Not more than the distance to the end of the image. */
- if (num_rows > upsample->rows_to_go)
- num_rows = upsample->rows_to_go;
- /* And not more than what the client can accept: */
- out_rows_avail -= *out_row_ctr;
- if (num_rows > out_rows_avail)
- num_rows = out_rows_avail;
- /* Create output pointer array for upsampler. */
- work_ptrs[0] = output_buf[*out_row_ctr];
- if (num_rows > 1) {
- work_ptrs[1] = output_buf[*out_row_ctr + 1];
- } else {
- work_ptrs[1] = upsample->spare_row;
- upsample->spare_full = TRUE;
- }
- /* Now do the upsampling. */
- (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs);
- }
-
- /* Adjust counts */
- *out_row_ctr += num_rows;
- upsample->rows_to_go -= num_rows;
- /* When the buffer is emptied, declare this input row group consumed */
- if (! upsample->spare_full)
- (*in_row_group_ctr)++;
-}
-
-
-METHODDEF(void)
-merged_1v_upsample (j_decompress_ptr cinfo,
- JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
- JDIMENSION in_row_groups_avail,
- JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
- JDIMENSION out_rows_avail)
-/* 1:1 vertical sampling case: much easier, never need a spare row. */
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
-
- /* Just do the upsampling. */
- (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr,
- output_buf + *out_row_ctr);
- /* Adjust counts */
- (*out_row_ctr)++;
- (*in_row_group_ctr)++;
-}
-
-
-/*
- * These are the routines invoked by the control routines to do
- * the actual upsampling/conversion. One row group is processed per call.
- *
- * Note: since we may be writing directly into application-supplied buffers,
- * we have to be honest about the output width; we can't assume the buffer
- * has been rounded up to an even width.
- */
-
-
-/*
- * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
- */
-
-METHODDEF(void)
-h2v1_merged_upsample (j_decompress_ptr cinfo,
- JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
- JSAMPARRAY output_buf)
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
- register int y, cred, cgreen, cblue;
- int cb, cr;
- register JSAMPROW outptr;
- JSAMPROW inptr0, inptr1, inptr2;
- JDIMENSION col;
- /* copy these pointers into registers if possible */
- register JSAMPLE * range_limit = cinfo->sample_range_limit;
- int * Crrtab = upsample->Cr_r_tab;
- int * Cbbtab = upsample->Cb_b_tab;
- INT32 * Crgtab = upsample->Cr_g_tab;
- INT32 * Cbgtab = upsample->Cb_g_tab;
- SHIFT_TEMPS
-
- inptr0 = input_buf[0][in_row_group_ctr];
- inptr1 = input_buf[1][in_row_group_ctr];
- inptr2 = input_buf[2][in_row_group_ctr];
- outptr = output_buf[0];
- /* Loop for each pair of output pixels */
- for (col = cinfo->output_width >> 1; col > 0; col--) {
- /* Do the chroma part of the calculation */
- cb = GETJSAMPLE(*inptr1++);
- cr = GETJSAMPLE(*inptr2++);
- cred = Crrtab[cr];
- cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
- cblue = Cbbtab[cb];
- /* Fetch 2 Y values and emit 2 pixels */
- y = GETJSAMPLE(*inptr0++);
- outptr[RGB_RED] = range_limit[y + cred];
- outptr[RGB_GREEN] = range_limit[y + cgreen];
- outptr[RGB_BLUE] = range_limit[y + cblue];
- outptr += RGB_PIXELSIZE;
- y = GETJSAMPLE(*inptr0++);
- outptr[RGB_RED] = range_limit[y + cred];
- outptr[RGB_GREEN] = range_limit[y + cgreen];
- outptr[RGB_BLUE] = range_limit[y + cblue];
- outptr += RGB_PIXELSIZE;
- }
- /* If image width is odd, do the last output column separately */
- if (cinfo->output_width & 1) {
- cb = GETJSAMPLE(*inptr1);
- cr = GETJSAMPLE(*inptr2);
- cred = Crrtab[cr];
- cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
- cblue = Cbbtab[cb];
- y = GETJSAMPLE(*inptr0);
- outptr[RGB_RED] = range_limit[y + cred];
- outptr[RGB_GREEN] = range_limit[y + cgreen];
- outptr[RGB_BLUE] = range_limit[y + cblue];
- }
-}
-
-
-/*
- * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
- */
-
-METHODDEF(void)
-h2v2_merged_upsample (j_decompress_ptr cinfo,
- JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
- JSAMPARRAY output_buf)
-{
- my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
- register int y, cred, cgreen, cblue;
- int cb, cr;
- register JSAMPROW outptr0, outptr1;
- JSAMPROW inptr00, inptr01, inptr1, inptr2;
- JDIMENSION col;
- /* copy these pointers into registers if possible */
- register JSAMPLE * range_limit = cinfo->sample_range_limit;
- int * Crrtab = upsample->Cr_r_tab;
- int * Cbbtab = upsample->Cb_b_tab;
- INT32 * Crgtab = upsample->Cr_g_tab;
- INT32 * Cbgtab = upsample->Cb_g_tab;
- SHIFT_TEMPS
-
- inptr00 = input_buf[0][in_row_group_ctr*2];
- inptr01 = input_buf[0][in_row_group_ctr*2 + 1];
- inptr1 = input_buf[1][in_row_group_ctr];
- inptr2 = input_buf[2][in_row_group_ctr];
- outptr0 = output_buf[0];
- outptr1 = output_buf[1];
- /* Loop for each group of output pixels */
- for (col = cinfo->output_width >> 1; col > 0; col--) {
- /* Do the chroma part of the calculation */
- cb = GETJSAMPLE(*inptr1++);
- cr = GETJSAMPLE(*inptr2++);
- cred = Crrtab[cr];
- cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
- cblue = Cbbtab[cb];
- /* Fetch 4 Y values and emit 4 pixels */
- y = GETJSAMPLE(*inptr00++);
- outptr0[RGB_RED] = range_limit[y + cred];
- outptr0[RGB_GREEN] = range_limit[y + cgreen];
- outptr0[RGB_BLUE] = range_limit[y + cblue];
- outptr0 += RGB_PIXELSIZE;
- y = GETJSAMPLE(*inptr00++);
- outptr0[RGB_RED] = range_limit[y + cred];
- outptr0[RGB_GREEN] = range_limit[y + cgreen];
- outptr0[RGB_BLUE] = range_limit[y + cblue];
- outptr0 += RGB_PIXELSIZE;
- y = GETJSAMPLE(*inptr01++);
- outptr1[RGB_RED] = range_limit[y + cred];
- outptr1[RGB_GREEN] = range_limit[y + cgreen];
- outptr1[RGB_BLUE] = range_limit[y + cblue];
- outptr1 += RGB_PIXELSIZE;
- y = GETJSAMPLE(*inptr01++);
- outptr1[RGB_RED] = range_limit[y + cred];
- outptr1[RGB_GREEN] = range_limit[y + cgreen];
- outptr1[RGB_BLUE] = range_limit[y + cblue];
- outptr1 += RGB_PIXELSIZE;
- }
- /* If image width is odd, do the last output column separately */
- if (cinfo->output_width & 1) {
- cb = GETJSAMPLE(*inptr1);
- cr = GETJSAMPLE(*inptr2);
- cred = Crrtab[cr];
- cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
- cblue = Cbbtab[cb];
- y = GETJSAMPLE(*inptr00);
- outptr0[RGB_RED] = range_limit[y + cred];
- outptr0[RGB_GREEN] = range_limit[y + cgreen];
- outptr0[RGB_BLUE] = range_limit[y + cblue];
- y = GETJSAMPLE(*inptr01);
- outptr1[RGB_RED] = range_limit[y + cred];
- outptr1[RGB_GREEN] = range_limit[y + cgreen];
- outptr1[RGB_BLUE] = range_limit[y + cblue];
- }
-}
-
-
-/*
- * Module initialization routine for merged upsampling/color conversion.
- *
- * NB: this is called under the conditions determined by use_merged_upsample()
- * in jdmaster.c. That routine MUST correspond to the actual capabilities
- * of this module; no safety checks are made here.
- */
-
-GLOBAL(void)
-jinit_merged_upsampler (j_decompress_ptr cinfo)
-{
- my_upsample_ptr upsample;
-
- upsample = (my_upsample_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(my_upsampler));
- cinfo->upsample = (struct jpeg_upsampler *) upsample;
- upsample->pub.start_pass = start_pass_merged_upsample;
- upsample->pub.need_context_rows = FALSE;
-
- upsample->out_row_width = cinfo->output_width * cinfo->out_color_components;
-
- if (cinfo->max_v_samp_factor == 2) {
- upsample->pub.upsample = merged_2v_upsample;
- upsample->upmethod = h2v2_merged_upsample;
- /* Allocate a spare row buffer */
- upsample->spare_row = (JSAMPROW)
- (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (size_t) (upsample->out_row_width * SIZEOF(JSAMPLE)));
- } else {
- upsample->pub.upsample = merged_1v_upsample;
- upsample->upmethod = h2v1_merged_upsample;
- /* No spare row needed */
- upsample->spare_row = NULL;
- }
-
- build_ycc_rgb_table(cinfo);
-}
-
-#endif /* UPSAMPLE_MERGING_SUPPORTED */
projects / opencv / blobdiff