FFmpeg/libavcodec/ljpegenc.c

/*
 * lossless JPEG encoder
 * 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
 * lossless JPEG encoder.
 */

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "mjpeg.h"
#include "mjpegenc.h"


static int encode_picture_lossless(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
    MpegEncContext * const s = avctx->priv_data;
    MJpegContext * const m = s->mjpeg_ctx;
    AVFrame *pict = data;
    const int width= s->width;
    const int height= s->height;
    AVFrame * const p= (AVFrame*)&s->current_picture;
    const int predictor= avctx->prediction_method+1;

    init_put_bits(&s->pb, buf, buf_size);

    *p = *pict;
    p->pict_type= AV_PICTURE_TYPE_I;
    p->key_frame= 1;

    ff_mjpeg_encode_picture_header(s);

    s->header_bits= put_bits_count(&s->pb);

    if(avctx->pix_fmt == PIX_FMT_BGRA){
        int x, y, i;
        const int linesize= p->linesize[0];
        uint16_t (*buffer)[4]= (void *) s->rd_scratchpad;
        int left[3], top[3], topleft[3];

        for(i=0; i<3; i++){
            buffer[0][i]= 1 << (9 - 1);
        }

        for(y = 0; y < height; y++) {
            const int modified_predictor= y ? predictor : 1;
            uint8_t *ptr = p->data[0] + (linesize * y);

            if(s->pb.buf_end - s->pb.buf - (put_bits_count(&s->pb)>>3) < width*3*4){
                av_log(s->avctx, AV_LOG_ERROR, "encoded frame too large\n");
                return -1;
            }

            for(i=0; i<3; i++){
                top[i]= left[i]= topleft[i]= buffer[0][i];
            }
            for(x = 0; x < width; x++) {
                buffer[x][1] = ptr[4*x+0] - ptr[4*x+1] + 0x100;
                buffer[x][2] = ptr[4*x+2] - ptr[4*x+1] + 0x100;
                buffer[x][0] = (ptr[4*x+0] + 2*ptr[4*x+1] + ptr[4*x+2])>>2;

                for(i=0;i<3;i++) {
                    int pred, diff;

                    PREDICT(pred, topleft[i], top[i], left[i], modified_predictor);

                    topleft[i]= top[i];
                    top[i]= buffer[x+1][i];

                    left[i]= buffer[x][i];

                    diff= ((left[i] - pred + 0x100)&0x1FF) - 0x100;

                    if(i==0)
                        ff_mjpeg_encode_dc(s, diff, m->huff_size_dc_luminance, m->huff_code_dc_luminance); //FIXME ugly
                    else
                        ff_mjpeg_encode_dc(s, diff, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);
                }
            }
        }
    }else{
        int mb_x, mb_y, i;
        const int mb_width  = (width  + s->mjpeg_hsample[0] - 1) / s->mjpeg_hsample[0];
        const int mb_height = (height + s->mjpeg_vsample[0] - 1) / s->mjpeg_vsample[0];

        for(mb_y = 0; mb_y < mb_height; mb_y++) {
            if(s->pb.buf_end - s->pb.buf - (put_bits_count(&s->pb)>>3) < mb_width * 4 * 3 * s->mjpeg_hsample[0] * s->mjpeg_vsample[0]){
                av_log(s->avctx, AV_LOG_ERROR, "encoded frame too large\n");
                return -1;
            }
            for(mb_x = 0; mb_x < mb_width; mb_x++) {
                if(mb_x==0 || mb_y==0){
                    for(i=0;i<3;i++) {
                        uint8_t *ptr;
                        int x, y, h, v, linesize;
                        h = s->mjpeg_hsample[i];
                        v = s->mjpeg_vsample[i];
                        linesize= p->linesize[i];

                        for(y=0; y<v; y++){
                            for(x=0; x<h; x++){
                                int pred;

                                ptr = p->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
                                if(y==0 && mb_y==0){
                                    if(x==0 && mb_x==0){
                                        pred= 128;
                                    }else{
                                        pred= ptr[-1];
                                    }
                                }else{
                                    if(x==0 && mb_x==0){
                                        pred= ptr[-linesize];
                                    }else{
                                        PREDICT(pred, ptr[-linesize-1], ptr[-linesize], ptr[-1], predictor);
                                    }
                                }

                                if(i==0)
                                    ff_mjpeg_encode_dc(s, *ptr - pred, m->huff_size_dc_luminance, m->huff_code_dc_luminance); //FIXME ugly
                                else
                                    ff_mjpeg_encode_dc(s, *ptr - pred, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);
                            }
                        }
                    }
                }else{
                    for(i=0;i<3;i++) {
                        uint8_t *ptr;
                        int x, y, h, v, linesize;
                        h = s->mjpeg_hsample[i];
                        v = s->mjpeg_vsample[i];
                        linesize= p->linesize[i];

                        for(y=0; y<v; y++){
                            for(x=0; x<h; x++){
                                int pred;

                                ptr = p->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
//printf("%d %d %d %d %8X\n", mb_x, mb_y, x, y, ptr);
                                PREDICT(pred, ptr[-linesize-1], ptr[-linesize], ptr[-1], predictor);

                                if(i==0)
                                    ff_mjpeg_encode_dc(s, *ptr - pred, m->huff_size_dc_luminance, m->huff_code_dc_luminance); //FIXME ugly
                                else
                                    ff_mjpeg_encode_dc(s, *ptr - pred, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);
                            }
                        }
                    }
                }
            }
        }
    }

    emms_c();

    ff_mjpeg_encode_picture_trailer(s);
    s->picture_number++;

    flush_put_bits(&s->pb);
    return put_bits_ptr(&s->pb) - s->pb.buf;
//    return (put_bits_count(&f->pb)+7)/8;
}


AVCodec ff_ljpeg_encoder = { //FIXME avoid MPV_* lossless JPEG should not need them
    "ljpeg",
    AVMEDIA_TYPE_VIDEO,
    CODEC_ID_LJPEG,
    sizeof(MpegEncContext),
    MPV_encode_init,
    encode_picture_lossless,
    MPV_encode_end,
    .long_name = NULL_IF_CONFIG_SMALL("Lossless JPEG"),
};