huffyuv.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * huffyuv codec for libavcodec
 *
 * Copyright (c) 2002-2003 Michael Niedermayer <[e-mail]>
 *
 * see http://www.pcisys.net/~melanson/codecs/huffyuv.txt for a description of
 * the algorithm used
 *
 * 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 huffyuv.c
 * huffyuv codec for libavcodec.
 */

#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"

#define VLC_BITS 11

#ifdef WORDS_BIGENDIAN
#define B 3
#define G 2
#define R 1
#else
#define B 0
#define G 1
#define R 2
#endif

typedef enum Predictor{
    LEFT= 0,
    PLANE,
    MEDIAN,
} Predictor;

typedef struct HYuvContext{
    AVCodecContext *avctx;
    Predictor predictor;
    GetBitContext gb;
    PutBitContext pb;
    int interlaced;
    int decorrelate;
    int bitstream_bpp;
    int version;
    int yuy2;                               //use yuy2 instead of 422P
    int bgr32;                              //use bgr32 instead of bgr24
    int width, height;
    int flags;
    int context;
    int picture_number;
    int last_slice_end;
    uint8_t *temp[3];
    uint64_t stats[3][256];
    uint8_t len[3][256];
    uint32_t bits[3][256];
    uint32_t pix_bgr_map[1<<VLC_BITS];
    VLC vlc[6];                             //Y,U,V,YY,YU,YV
    AVFrame picture;
    uint8_t *bitstream_buffer;
    unsigned int bitstream_buffer_size;
    DSPContext dsp;
}HYuvContext;

static const unsigned char classic_shift_luma[] = {
  34,36,35,69,135,232,9,16,10,24,11,23,12,16,13,10,14,8,15,8,
  16,8,17,20,16,10,207,206,205,236,11,8,10,21,9,23,8,8,199,70,
  69,68, 0
};

static const unsigned char classic_shift_chroma[] = {
  66,36,37,38,39,40,41,75,76,77,110,239,144,81,82,83,84,85,118,183,
  56,57,88,89,56,89,154,57,58,57,26,141,57,56,58,57,58,57,184,119,
  214,245,116,83,82,49,80,79,78,77,44,75,41,40,39,38,37,36,34, 0
};

static const unsigned char classic_add_luma[256] = {
    3,  9,  5, 12, 10, 35, 32, 29, 27, 50, 48, 45, 44, 41, 39, 37,
   73, 70, 68, 65, 64, 61, 58, 56, 53, 50, 49, 46, 44, 41, 38, 36,
   68, 65, 63, 61, 58, 55, 53, 51, 48, 46, 45, 43, 41, 39, 38, 36,
   35, 33, 32, 30, 29, 27, 26, 25, 48, 47, 46, 44, 43, 41, 40, 39,
   37, 36, 35, 34, 32, 31, 30, 28, 27, 26, 24, 23, 22, 20, 19, 37,
   35, 34, 33, 31, 30, 29, 27, 26, 24, 23, 21, 20, 18, 17, 15, 29,
   27, 26, 24, 22, 21, 19, 17, 16, 14, 26, 25, 23, 21, 19, 18, 16,
   15, 27, 25, 23, 21, 19, 17, 16, 14, 26, 25, 23, 21, 18, 17, 14,
   12, 17, 19, 13,  4,  9,  2, 11,  1,  7,  8,  0, 16,  3, 14,  6,
   12, 10,  5, 15, 18, 11, 10, 13, 15, 16, 19, 20, 22, 24, 27, 15,
   18, 20, 22, 24, 26, 14, 17, 20, 22, 24, 27, 15, 18, 20, 23, 25,
   28, 16, 19, 22, 25, 28, 32, 36, 21, 25, 29, 33, 38, 42, 45, 49,
   28, 31, 34, 37, 40, 42, 44, 47, 49, 50, 52, 54, 56, 57, 59, 60,
   62, 64, 66, 67, 69, 35, 37, 39, 40, 42, 43, 45, 47, 48, 51, 52,
   54, 55, 57, 59, 60, 62, 63, 66, 67, 69, 71, 72, 38, 40, 42, 43,
   46, 47, 49, 51, 26, 28, 30, 31, 33, 34, 18, 19, 11, 13,  7,  8,
};

static const unsigned char classic_add_chroma[256] = {
    3,  1,  2,  2,  2,  2,  3,  3,  7,  5,  7,  5,  8,  6, 11,  9,
    7, 13, 11, 10,  9,  8,  7,  5,  9,  7,  6,  4,  7,  5,  8,  7,
   11,  8, 13, 11, 19, 15, 22, 23, 20, 33, 32, 28, 27, 29, 51, 77,
   43, 45, 76, 81, 46, 82, 75, 55, 56,144, 58, 80, 60, 74,147, 63,
  143, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
   80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 27, 30, 21, 22,
   17, 14,  5,  6,100, 54, 47, 50, 51, 53,106,107,108,109,110,111,
  112,113,114,115,  4,117,118, 92, 94,121,122,  3,124,103,  2,  1,
    0,129,130,131,120,119,126,125,136,137,138,139,140,141,142,134,
  135,132,133,104, 64,101, 62, 57,102, 95, 93, 59, 61, 28, 97, 96,
   52, 49, 48, 29, 32, 25, 24, 46, 23, 98, 45, 44, 43, 20, 42, 41,
   19, 18, 99, 40, 15, 39, 38, 16, 13, 12, 11, 37, 10,  9,  8, 36,
    7,128,127,105,123,116, 35, 34, 33,145, 31, 79, 42,146, 78, 26,
   83, 48, 49, 50, 44, 47, 26, 31, 30, 18, 17, 19, 21, 24, 25, 13,
   14, 16, 17, 18, 20, 21, 12, 14, 15,  9, 10,  6,  9,  6,  5,  8,
    6, 12,  8, 10,  7,  9,  6,  4,  6,  2,  2,  3,  3,  3,  3,  2,
};

static inline int add_left_prediction(uint8_t *dst, uint8_t *src, int w, int acc){
    int i;

    for(i=0; i<w-1; i++){
        acc+= src[i];
        dst[i]= acc;
        i++;
        acc+= src[i];
        dst[i]= acc;
    }

    for(; i<w; i++){
        acc+= src[i];
        dst[i]= acc;
    }

    return acc;
}

static inline void add_median_prediction(uint8_t *dst, uint8_t *src1, uint8_t *diff, int w, int *left, int *left_top){
    int i;
    uint8_t l, lt;

    l= *left;
    lt= *left_top;

    for(i=0; i<w; i++){
        l= mid_pred(l, src1[i], (l + src1[i] - lt)&0xFF) + diff[i];
        lt= src1[i];
        dst[i]= l;
    }

    *left= l;
    *left_top= lt;
}

static inline void add_left_prediction_bgr32(uint8_t *dst, uint8_t *src, int w, int *red, int *green, int *blue){
    int i;
    int r,g,b;
    r= *red;
    g= *green;
    b= *blue;

    for(i=0; i<w; i++){
        b+= src[4*i+B];
        g+= src[4*i+G];
        r+= src[4*i+R];

        dst[4*i+B]= b;
        dst[4*i+G]= g;
        dst[4*i+R]= r;
    }

    *red= r;
    *green= g;
    *blue= b;
}

static inline int sub_left_prediction(HYuvContext *s, uint8_t *dst, uint8_t *src, int w, int left){
    int i;
    if(w<32){
        for(i=0; i<w; i++){
            const int temp= src[i];
            dst[i]= temp - left;
            left= temp;
        }
        return left;
    }else{
        for(i=0; i<16; i++){
            const int temp= src[i];
            dst[i]= temp - left;
            left= temp;
        }
        s->dsp.diff_bytes(dst+16, src+16, src+15, w-16);
        return src[w-1];
    }
}

static inline void sub_left_prediction_bgr32(HYuvContext *s, uint8_t *dst, uint8_t *src, int w, int *red, int *green, int *blue){
    int i;
    int r,g,b;
    r= *red;
    g= *green;
    b= *blue;
    for(i=0; i<FFMIN(w,4); i++){
        const int rt= src[i*4+R];
        const int gt= src[i*4+G];
        const int bt= src[i*4+B];
        dst[i*4+R]= rt - r;
        dst[i*4+G]= gt - g;
        dst[i*4+B]= bt - b;
        r = rt;
        g = gt;
        b = bt;
    }
    s->dsp.diff_bytes(dst+16, src+16, src+12, w*4-16);
    *red=   src[(w-1)*4+R];
    *green= src[(w-1)*4+G];
    *blue=  src[(w-1)*4+B];
}

static void read_len_table(uint8_t *dst, GetBitContext *gb){
    int i, val, repeat;

    for(i=0; i<256;){
        repeat= get_bits(gb, 3);
        val   = get_bits(gb, 5);
        if(repeat==0)
            repeat= get_bits(gb, 8);
//printf("%d %d\n", val, repeat);
        while (repeat--)
            dst[i++] = val;
    }
}

static int generate_bits_table(uint32_t *dst, uint8_t *len_table){
    int len, index;
    uint32_t bits=0;

    for(len=32; len>0; len--){
        for(index=0; index<256; index++){
            if(len_table[index]==len)
                dst[index]= bits++;
        }
        if(bits & 1){
            av_log(NULL, AV_LOG_ERROR, "Error generating huffman table\n");
            return -1;
        }
        bits >>= 1;
    }
    return 0;
}

#ifdef CONFIG_ENCODERS
typedef struct {
    uint64_t val;
    int name;
} heap_elem_t;

static void heap_sift(heap_elem_t *h, int root, int size)
{
    while(root*2+1 < size) {
        int child = root*2+1;
        if(child < size-1 && h[child].val > h[child+1].val)
            child++;
        if(h[root].val > h[child].val) {
            FFSWAP(heap_elem_t, h[root], h[child]);
            root = child;
        } else
            break;
    }
}

static void generate_len_table(uint8_t *dst, uint64_t *stats, int size){
    heap_elem_t h[size];
    int up[2*size];
    int len[2*size];
    int offset, i, next;

    for(offset=1; ; offset<<=1){
        for(i=0; i<size; i++){
            h[i].name = i;
            h[i].val = (stats[i] << 8) + offset;
        }
        for(i=size/2-1; i>=0; i--)
            heap_sift(h, i, size);

        for(next=size; next<size*2-1; next++){
            // merge the two smallest entries, and put it back in the heap
            uint64_t min1v = h[0].val;
            up[h[0].name] = next;
            h[0].val = INT64_MAX;
            heap_sift(h, 0, size);
            up[h[0].name] = next;
            h[0].name = next;
            h[0].val += min1v;
            heap_sift(h, 0, size);
        }

        len[2*size-2] = 0;
        for(i=2*size-3; i>=size; i--)
            len[i] = len[up[i]] + 1;
        for(i=0; i<size; i++) {
            dst[i] = len[up[i]] + 1;
            if(dst[i] >= 32) break;
        }
        if(i==size) break;
    }
}
#endif /* CONFIG_ENCODERS */

static void generate_joint_tables(HYuvContext *s){
    uint16_t symbols[1<<VLC_BITS];
    uint16_t bits[1<<VLC_BITS];
    uint8_t len[1<<VLC_BITS];
    if(s->bitstream_bpp < 24){
        int p, i, y, u;
        for(p=0; p<3; p++){
            for(i=y=0; y<256; y++){
                int len0 = s->len[0][y];
                int limit = VLC_BITS - len0;
                if(limit <= 0)
                    continue;
                for(u=0; u<256; u++){
                    int len1 = s->len[p][u];
                    if(len1 > limit)
                        continue;
                    len[i] = len0 + len1;
                    bits[i] = (s->bits[0][y] << len1) + s->bits[p][u];
                    symbols[i] = (y<<8) + u;
                    if(symbols[i] != 0xffff) // reserved to mean "invalid"
                        i++;
                }
            }
            free_vlc(&s->vlc[3+p]);
            init_vlc_sparse(&s->vlc[3+p], VLC_BITS, i, len, 1, 1, bits, 2, 2, symbols, 2, 2, 0);
        }
    }else{
        uint8_t (*map)[4] = (uint8_t(*)[4])s->pix_bgr_map;
        int i, b, g, r, code;
        int p0 = s->decorrelate;
        int p1 = !s->decorrelate;
        // restrict the range to +/-16 becaues that's pretty much guaranteed to
        // cover all the combinations that fit in 11 bits total, and it doesn't
        // matter if we miss a few rare codes.
        for(i=0, g=-16; g<16; g++){
            int len0 = s->len[p0][g&255];
            int limit0 = VLC_BITS - len0;
            if(limit0 < 2)
                continue;
            for(b=-16; b<16; b++){
                int len1 = s->len[p1][b&255];
                int limit1 = limit0 - len1;
                if(limit1 < 1)
                    continue;
                code = (s->bits[p0][g&255] << len1) + s->bits[p1][b&255];
                for(r=-16; r<16; r++){
                    int len2 = s->len[2][r&255];
                    if(len2 > limit1)
                        continue;
                    len[i] = len0 + len1 + len2;
                    bits[i] = (code << len2) + s->bits[2][r&255];
                    if(s->decorrelate){