289 lines
6.6 KiB
C
289 lines
6.6 KiB
C
/*
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* Small jpeg decoder library
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*
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* Copyright (c) 2006, Luc Saillard <luc@saillard.org>
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* All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* - Neither the name of the author nor the names of its contributors may be
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* used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/*
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* yuv420p.c
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdint.h>
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#include "tinyjpeg.h"
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#include "tinyjpeg-internal.h"
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/*******************************************************************************
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*
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* Colorspace conversion routine
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*
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*
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* Note:
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* YCbCr is defined per CCIR 601-1, except that Cb and Cr are
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* normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
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* The conversion equations to be implemented are therefore
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* R = Y + 1.40200 * Cr
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* G = Y - 0.34414 * Cb - 0.71414 * Cr
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* B = Y + 1.77200 * Cb
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*
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******************************************************************************/
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/**
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* YCrCb -> YUV420P (1x1)
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* .---.
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* | 1 |
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* `---'
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*/
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static void YCrCB_to_YUV420P_1x1(struct jdec_private *priv, int sx, int sy)
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{
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const unsigned char *s, *y;
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unsigned char *p;
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int i,j;
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p = priv->plane[0];
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y = priv->Y;
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for (i = sy; i > 0; i--)
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{
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memcpy(p, y, sx);
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p += priv->bytes_per_row[0];
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y += 8;
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}
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p = priv->plane[1];
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s = priv->Cb;
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for (i = sy; i > 0; i--)
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{
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for (j = sx; j >= 0; j -= 2) {
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*p++ = *s;
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s += 2;
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}
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s += 8; /* Skip one line */
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p += priv->bytes_per_row[1] - 4;
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}
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p = priv->plane[2];
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s = priv->Cr;
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for (i=0; i<8; i+=2)
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{
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for (j = sx; j >= 0; j -= 2) {
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*p++ = *s;
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s += 2;
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}
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s += 8; /* Skip one line */
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p += priv->bytes_per_row[2] - 4;
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}
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}
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/**
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* YCrCb -> YUV420P (2x1)
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* .-------.
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* | 1 | 2 |
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* `-------'
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*/
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static void YCrCB_to_YUV420P_2x1(struct jdec_private *priv, int sx, int sy)
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{
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unsigned char *p;
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const unsigned char *s, *y1;
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unsigned int i;
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p = priv->plane[0];
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y1 = priv->Y;
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for (i = sy; i > 0; i--)
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{
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memcpy(p, y1, sx);
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p += priv->bytes_per_row[0];
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y1 += 16;
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}
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sx = (sx+1) >> 1;
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p = priv->plane[1];
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s = priv->Cb;
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for (i = sy; i > 0; i -= 2)
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{
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memcpy(p, s, sx);
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s += 16; /* Skip one line */
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p += priv->bytes_per_row[1];
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}
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p = priv->plane[2];
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s = priv->Cr;
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for (i = sy; i > 0; i -= 2)
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{
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memcpy(p, s, sx);
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s += 16; /* Skip one line */
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p += priv->bytes_per_row[2];
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}
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}
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/**
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* YCrCb -> YUV420P (1x2)
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* .---.
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* | 1 |
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* |---|
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* | 2 |
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* `---'
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*/
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static void YCrCB_to_YUV420P_1x2(struct jdec_private *priv, int sx, int sy)
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{
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const unsigned char *s, *y;
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unsigned char *p, *pr;
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int i,j;
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p = priv->plane[0];
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y = priv->Y;
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for (i = sy; i > 0; i++)
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{
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memcpy(p, y, sx);
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p+=priv->bytes_per_row[0];
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y+=8;
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}
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pr = priv->plane[1];
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s = priv->Cb;
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for (i = sy; i > 0; i -= 2)
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{
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p = pr;
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for (j = sx; j > 0; j -= 2) {
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*p++ = *s;
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s += 2;
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}
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pr += priv->bytes_per_row[1];
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}
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pr = priv->plane[2];
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s = priv->Cr;
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for (i=0; i<8; i++)
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{
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p = pr;
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for (j = sx; j > 0; j -= 2) {
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*p++ = *s;
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s += 2;
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}
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pr += priv->bytes_per_row[2] - 4;
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}
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}
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/**
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* YCrCb -> YUV420P (2x2)
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* .-------.
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* | 1 | 2 |
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* |---+---|
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* | 3 | 4 |
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* `-------'
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*/
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static void YCrCB_to_YUV420P_2x2(struct jdec_private *priv, int sx, int sy)
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{
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unsigned char *p;
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const unsigned char *s, *y1;
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unsigned int i;
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p = priv->plane[0];
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y1 = priv->Y;
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for (i = sy; i > 0; i--)
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{
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memcpy(p, y1, sx);
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p += priv->bytes_per_row[0];
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y1 += 16;
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}
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sx = (sx+1) >> 1;
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p = priv->plane[1];
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s = priv->Cb;
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for (i = sy; i > 0; i -= 2)
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{
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memcpy(p, s, sx);
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s += 8;
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p += priv->bytes_per_row[1];
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}
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p = priv->plane[2];
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s = priv->Cr;
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for (i = sy; i > 0; i -= 2)
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{
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memcpy(p, s, sx);
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s += 8;
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p += priv->bytes_per_row[2];
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}
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}
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static int initialize_yuv420p(struct jdec_private *priv,
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unsigned int *bytes_per_blocklines,
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unsigned int *bytes_per_mcu)
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{
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int half_height = (priv->height + 1) >> 2;
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int half_width = (priv->width + 1) >> 2;
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if (!priv->bytes_per_row[0])
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priv->bytes_per_row[0] = priv->width;
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if (!priv->components[0])
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priv->components[0] = malloc(priv->height * priv->bytes_per_row[0]);
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if (!priv->bytes_per_row[1])
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priv->bytes_per_row[1] = half_width;
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if (!priv->components[1])
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priv->components[1] = malloc(half_height * priv->bytes_per_row[1]);
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if (!priv->bytes_per_row[2])
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priv->bytes_per_row[2] = half_width;
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if (!priv->components[2])
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priv->components[2] = malloc(half_height * priv->bytes_per_row[2]);
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bytes_per_mcu[0] = 8;
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bytes_per_mcu[1] = 4;
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bytes_per_mcu[2] = 4;
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bytes_per_blocklines[0] = priv->width << 3;
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bytes_per_blocklines[1] = half_width << 2;
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bytes_per_blocklines[2] = half_width << 2;
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/* Return nonzero on failure */
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return !priv->components[0] || !priv->components[1] || !priv->components[2];
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}
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static const struct tinyjpeg_colorspace format_yuv420p =
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{
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{
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YCrCB_to_YUV420P_1x1,
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YCrCB_to_YUV420P_1x2,
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YCrCB_to_YUV420P_2x1,
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YCrCB_to_YUV420P_2x2,
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},
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tinyjpeg_decode_mcu_3comp_table,
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initialize_yuv420p
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};
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const tinyjpeg_colorspace_t TINYJPEG_FMT_YUV420P = &format_yuv420p;
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