jpeg_enc.c

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/* Straightforward (to be) optimized JPEG encoder for the YUV422 format 
 * based on mjpeg code from ffmpeg. 
 *
 * Copyright (c) 2002, Rik Snel
 * Parts from ffmpeg Copyright (c) 2000-2002 Fabrice Bellard
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * For an excellent introduction to the JPEG format, see:
 * http://www.ece.purdue.edu/~bouman/grad-labs/lab8/pdf/lab.pdf
 */



#include <sys/types.h>
#include <mplaylib.h>
#include <mplaylib.h>
#include "config.h"
#include "mp_msg.h"
/* We need this #define because we need ../libavcodec/common.h to #define 
 * be2me_32, otherwise the linker will complain that it doesn't exist */
#define HAVE_AV_CONFIG_H
#include "libavcodec/avcodec.h"
#include "libavcodec/dsputil.h"
#include "libavcodec/mpegvideo.h"

#include "jpeg_enc.h"

extern int avcodec_inited;

/* zr_mjpeg_encode_mb needs access to these tables for the black & white 
 * option */
typedef struct MJpegContext {
    uint8_t huff_size_dc_luminance[12];
    uint16_t huff_code_dc_luminance[12];
    uint8_t huff_size_dc_chrominance[12];
    uint16_t huff_code_dc_chrominance[12];

    uint8_t huff_size_ac_luminance[256];
    uint16_t huff_code_ac_luminance[256];
    uint8_t huff_size_ac_chrominance[256];
    uint16_t huff_code_ac_chrominance[256];
} MJpegContext;


/* Begin excessive code duplication ************************************/
/* Code coming from mpegvideo.c and mjpeg.c in ../libavcodec ***********/

static const unsigned short aanscales[64] = {
    /* precomputed values scaled up by 14 bits */
    16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
    22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
    21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
    19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
    16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
    12873, 17855, 16819, 15137, 12873, 10114,  6967,  3552,
    8867, 12299, 11585, 10426,  8867,  6967,  4799,  2446,
    4520,  6270,  5906,  5315,  4520,  3552,  2446,  1247
};

static void convert_matrix(MpegEncContext *s, int (*qmat)[64], 
		uint16_t (*qmat16)[2][64], const uint16_t *quant_matrix,
		int bias, int qmin, int qmax)
{
    int qscale;

    for(qscale=qmin; qscale<=qmax; qscale++){
        int i;
	if (s->dsp.fdct == ff_jpeg_fdct_islow) {
		for (i = 0; i < 64; i++) {
			const int j = s->dsp.idct_permutation[i];
			/* 16    <= qscale * quant_matrix[i] <= 7905 
			 * 19952 <= aanscales[i] *  \
			 * 	        qscale * quant_matrix[i]     <= 205026 
			 * (1<<36)/19952 >= (1<<36)/(aanscales[i] * \
			 * 	qscale * quant_matrix[i]) >= (1<<36)/249205025
			 * 3444240       >= (1<<36)/(aanscales[i] *
			 *      qscale * quant_matrix[i]) >= 275              */
			qmat[qscale][i] = (int)((UINT64_C(1) << (QMAT_SHIFT-3))/
					(qscale * quant_matrix[j]));
		}
	} else if (s->dsp.fdct == fdct_ifast) {
            for(i=0;i<64;i++) {
                const int j = s->dsp.idct_permutation[i];
                /* 16 <= qscale * quant_matrix[i] <= 7905 */
                /* 19952         <= aanscales[i] * qscale * quant_matrix[i]           <= 249205026 */
                /* (1<<36)/19952 >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= (1<<36)/249205026 */
                /* 3444240       >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= 275 */
                
                qmat[qscale][i] = (int)((UINT64_C(1) << (QMAT_SHIFT + 11)) / 
                                (aanscales[i] * qscale * quant_matrix[j]));
            }
        } else {
            for(i=0;i<64;i++) {
		const int j = s->dsp.idct_permutation[i];
                /* We can safely suppose that 16 <= quant_matrix[i] <= 255
                   So 16           <= qscale * quant_matrix[i]             <= 7905
                   so (1<<19) / 16 >= (1<<19) / (qscale * quant_matrix[i]) >= (1<<19) / 7905
                   so 32768        >= (1<<19) / (qscale * quant_matrix[i]) >= 67
                */
                qmat  [qscale][i] = (int)((UINT64_C(1) << QMAT_SHIFT_MMX) / (qscale * quant_matrix[j]));
                qmat16[qscale][0][i] = (1 << QMAT_SHIFT_MMX) / (qscale * quant_matrix[j]);

                if(qmat16[qscale][0][i]==0 || qmat16[qscale][0][i]==128*256) qmat16[qscale][0][i]=128*256-1;
                qmat16[qscale][1][i]= ROUNDED_DIV(bias<<(16-QUANT_BIAS_SHIFT), qmat16[qscale][0][i]);
            }
        }
    }
}

static inline void encode_dc(MpegEncContext *s, int val, 
                             uint8_t *huff_size, uint16_t *huff_code)
{
    int mant, nbits;

    if (val == 0) {
        put_bits(&s->pb, huff_size[0], huff_code[0]);
    } else {
        mant = val;
        if (val < 0) {
            val = -val;
            mant--;
        }
        
        /* compute the log (XXX: optimize) */
        nbits = 0;
        while (val != 0) {
            val = val >> 1;
            nbits++;
        }
            
        put_bits(&s->pb, huff_size[nbits], huff_code[nbits]);
        
        put_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));
    }
}

static void encode_block(MpegEncContext *s, DCTELEM *block, int n)
{
    int mant, nbits, code, i, j;
    int component, dc, run, last_index, val;
    MJpegContext *m = s->mjpeg_ctx;
    uint8_t *huff_size_ac;
    uint16_t *huff_code_ac;
    
    /* DC coef */
    component = (n <= 3 ? 0 : n - 4 + 1);
    dc = block[0]; /* overflow is impossible */
    val = dc - s->last_dc[component];
    if (n < 4) {
        encode_dc(s, val, m->huff_size_dc_luminance, m->huff_code_dc_luminance);
        huff_size_ac = m->huff_size_ac_luminance;
        huff_code_ac = m->huff_code_ac_luminance;
    } else {
        encode_dc(s, val, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);
        huff_size_ac = m->huff_size_ac_chrominance;
        huff_code_ac = m->huff_code_ac_chrominance;
    }
    s->last_dc[component] = dc;
    
    /* AC coefs */
    
    run = 0;
    last_index = s->block_last_index[n];
    for(i=1;i<=last_index;i++) {
        j = s->intra_scantable.permutated[i];
        val = block[j];
        if (val == 0) {
            run++;
        } else {
            while (run >= 16) {
                put_bits(&s->pb, huff_size_ac[0xf0], huff_code_ac[0xf0]);
                run -= 16;
            }
            mant = val;
            if (val < 0) {
                val = -val;
                mant--;
            }
            
            /* compute the log (XXX: optimize) */
            nbits = 0;
            while (val != 0) {
                val = val >> 1;
                nbits++;
            }
            code = (run << 4) | nbits;

            put_bits(&s->pb, huff_size_ac[code], huff_code_ac[code]);
        
            put_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));
            run = 0;
        }
    }

    /* output EOB only if not already 64 values */
    if (last_index < 63 || run != 0)
        put_bits(&s->pb, huff_size_ac[0], huff_code_ac[0]);
}

static inline void clip_coeffs(MpegEncContext *s, DCTELEM *block, int last_index)
{
    int i;
    const int maxlevel= s->max_qcoeff;
    const int minlevel= s->min_qcoeff;

    for(i=0; i<=last_index; i++){
        const int j = s->intra_scantable.permutated[i];
        int level = block[j];
       
        if     (level>maxlevel) level=maxlevel;
        else if(level<minlevel) level=minlevel;
        block[j]= level;
    }
}

/* End excessive code duplication **************************************/

/* this function is a reproduction of the one in mjpeg, it includes two
 * changes, it allows for black&white encoding (it skips the U and V
 * macroblocks and it outputs the huffman code for 'no change' (dc) and
 * 'all zero' (ac)) and it takes 4 macroblocks (422) instead of 6 (420) */
static void zr_mjpeg_encode_mb(jpeg_enc_t *j) {

	MJpegContext *m = j->s->mjpeg_ctx;

	encode_block(j->s, j->s->block[0], 0);
	encode_block(j->s, j->s->block[1], 1);
	if (j->bw) {
		/* U */
		put_bits(&j->s->pb, m->huff_size_dc_chrominance[0],
				m->huff_code_dc_chrominance[0]);
		put_bits(&j->s->pb, m->huff_size_ac_chrominance[0],
				m->huff_code_ac_chrominance[0]);
		/* V */
		put_bits(&j->s->pb, m->huff_size_dc_chrominance[0],
				m->huff_code_dc_chrominance[0]);
		put_bits(&j->s->pb, m->huff_size_ac_chrominance[0],
				m->huff_code_ac_chrominance[0]);
    	} else {
		/* we trick encode_block here so that it uses
		 * chrominance huffman tables instead of luminance ones 
		 * (see the effect of second argument of encode_block) */
		encode_block(j->s, j->s->block[2], 4); 
		encode_block(j->s, j->s->block[3], 5);
    	}
}

/* this function can take all kinds of YUV colorspaces
 * YV12, YVYU, UYVY. The necesary parameters must be set up by the caller
 * y_ps means "y pixel size", y_rs means "y row size".
 * For YUYV, for example, is u_buf = y_buf + 1, v_buf = y_buf + 3, 
 * y_ps = 2, u_ps = 4, v_ps = 4, y_rs = u_rs = v_rs.