mjpeg.h

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/*
 * MJPEG encoder and decoder
 * Copyright (c) 2000, 2001 Fabrice Bellard
 * Copyright (c) 2003 Alex Beregszaszi
 * Copyright (c) 2003-2004 Michael Niedermayer
 *
 * Support for external huffman table, various fixes (AVID workaround),
 * aspecting, new decode_frame mechanism and apple mjpeg-b support
 *                                  by Alex Beregszaszi
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * MJPEG encoder and decoder.
 */

#ifndef AVCODEC_MJPEG_H
#define AVCODEC_MJPEG_H

/* JPEG marker codes */
enum JpegMarker {
    /* start of frame */
    SOF0  = 0xc0,       /* baseline */
    SOF1  = 0xc1,       /* extended sequential, huffman */
    SOF2  = 0xc2,       /* progressive, huffman */
    SOF3  = 0xc3,       /* lossless, huffman */

    SOF5  = 0xc5,       /* differential sequential, huffman */
    SOF6  = 0xc6,       /* differential progressive, huffman */
    SOF7  = 0xc7,       /* differential lossless, huffman */
    JPG   = 0xc8,       /* reserved for JPEG extension */
    SOF9  = 0xc9,       /* extended sequential, arithmetic */
    SOF10 = 0xca,       /* progressive, arithmetic */
    SOF11 = 0xcb,       /* lossless, arithmetic */

    SOF13 = 0xcd,       /* differential sequential, arithmetic */
    SOF14 = 0xce,       /* differential progressive, arithmetic */
    SOF15 = 0xcf,       /* differential lossless, arithmetic */

    DHT   = 0xc4,       /* define huffman tables */

    DAC   = 0xcc,       /* define arithmetic-coding conditioning */

    /* restart with modulo 8 count "m" */
    RST0  = 0xd0,
    RST1  = 0xd1,
    RST2  = 0xd2,
    RST3  = 0xd3,
    RST4  = 0xd4,
    RST5  = 0xd5,
    RST6  = 0xd6,
    RST7  = 0xd7,

    SOI   = 0xd8,       /* start of image */
    EOI   = 0xd9,       /* end of image */
    SOS   = 0xda,       /* start of scan */
    DQT   = 0xdb,       /* define quantization tables */
    DNL   = 0xdc,       /* define number of lines */
    DRI   = 0xdd,       /* define restart interval */
    DHP   = 0xde,       /* define hierarchical progression */
    EXP   = 0xdf,       /* expand reference components */

    APP0  = 0xe0,
    APP1  = 0xe1,
    APP2  = 0xe2,
    APP3  = 0xe3,
    APP4  = 0xe4,
    APP5  = 0xe5,
    APP6  = 0xe6,
    APP7  = 0xe7,
    APP8  = 0xe8,
    APP9  = 0xe9,
    APP10 = 0xea,
    APP11 = 0xeb,
    APP12 = 0xec,
    APP13 = 0xed,
    APP14 = 0xee,
    APP15 = 0xef,

    JPG0  = 0xf0,
    JPG1  = 0xf1,
    JPG2  = 0xf2,
    JPG3  = 0xf3,
    JPG4  = 0xf4,
    JPG5  = 0xf5,
    JPG6  = 0xf6,
    SOF48 = 0xf7,       ///< JPEG-LS
    LSE   = 0xf8,       ///< JPEG-LS extension parameters
    JPG9  = 0xf9,
    JPG10 = 0xfa,
    JPG11 = 0xfb,
    JPG12 = 0xfc,
    JPG13 = 0xfd,

    COM   = 0xfe,       /* comment */

    TEM   = 0x01,       /* temporary private use for arithmetic coding */

    /* 0x02 -> 0xbf reserved */
};

#define PREDICT(ret, topleft, top, left, predictor)\
    switch(predictor){\
        case 0: ret= 0; break;\
        case 1: ret= left; break;\
        case 2: ret= top; break;\
        case 3: ret= topleft; break;\
        case 4: ret= left   +   top - topleft; break;\
        case 5: ret= left   + ((top - topleft)>>1); break;\
        case 6: ret= top + ((left   - topleft)>>1); break;\
        default:\
        case 7: ret= (left + top)>>1; break;\
    }

#endif /* AVCODEC_MJPEG_H */