/*
 * Copyright (c) 2003 The FFmpeg Project
 *
 * 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
 */

/*
 * How to use this decoder:
 * SVQ3 data is transported within Apple Quicktime files. Quicktime files
 * have stsd atoms to describe media trak properties. A stsd atom for a
 * video trak contains 1 or more ImageDescription atoms. These atoms begin
 * with the 4-byte length of the atom followed by the codec fourcc. Some
 * decoders need information in this atom to operate correctly. Such
 * is the case with SVQ3. In order to get the best use out of this decoder,
 * the calling app must make the SVQ3 ImageDescription atom available
 * via the AVCodecContext's extradata[_size] field:
 *
 * AVCodecContext.extradata = pointer to ImageDescription, first characters
 * are expected to be 'S', 'V', 'Q', and '3', NOT the 4-byte atom length
 * AVCodecContext.extradata_size = size of ImageDescription atom memory
 * buffer (which will be the same as the ImageDescription atom size field
 * from the QT file, minus 4 bytes since the length is missing)
 *
 * You will know you have these parameters passed correctly when the decoder
 * correctly decodes this file:
 *  http://samples.mplayerhq.hu/V-codecs/SVQ3/Vertical400kbit.sorenson3.mov
 */

#if CONFIG_ZLIB
#include <zlib.h>
#endif

#include "svq1.h"

/**
 * @file libavcodec/svq3.c
 * svq3 decoder.
 */

#define FULLPEL_MODE  1
#define HALFPEL_MODE  2
#define THIRDPEL_MODE 3
#define PREDICT_MODE  4

/* dual scan (from some older h264 draft)
 o-->o-->o   o
         |  /|
 o   o   o / o
 | / |   |/  |
 o   o   o   o
   /
 o-->o-->o-->o
*/
static const uint8_t svq3_scan[16] = {
    0+0*4, 1+0*4, 2+0*4, 2+1*4,
    2+2*4, 3+0*4, 3+1*4, 3+2*4,
    0+1*4, 0+2*4, 1+1*4, 1+2*4,
    0+3*4, 1+3*4, 2+3*4, 3+3*4,
};

static const uint8_t svq3_pred_0[25][2] = {
    { 0, 0 },
    { 1, 0 }, { 0, 1 },
    { 0, 2 }, { 1, 1 }, { 2, 0 },
    { 3, 0 }, { 2, 1 }, { 1, 2 }, { 0, 3 },
    { 0, 4 }, { 1, 3 }, { 2, 2 }, { 3, 1 }, { 4, 0 },
    { 4, 1 }, { 3, 2 }, { 2, 3 }, { 1, 4 },
    { 2, 4 }, { 3, 3 }, { 4, 2 },
    { 4, 3 }, { 3, 4 },
    { 4, 4 }
};

static const int8_t svq3_pred_1[6][6][5] = {
    { { 2,-1,-1,-1,-1 }, { 2, 1,-1,-1,-1 }, { 1, 2,-1,-1,-1 },
      { 2, 1,-1,-1,-1 }, { 1, 2,-1,-1,-1 }, { 1, 2,-1,-1,-1 } },
    { { 0, 2,-1,-1,-1 }, { 0, 2, 1, 4, 3 }, { 0, 1, 2, 4, 3 },
      { 0, 2, 1, 4, 3 }, { 2, 0, 1, 3, 4 }, { 0, 4, 2, 1, 3 } },
    { { 2, 0,-1,-1,-1 }, { 2, 1, 0, 4, 3 }, { 1, 2, 4, 0, 3 },
      { 2, 1, 0, 4, 3 }, { 2, 1, 4, 3, 0 }, { 1, 2, 4, 0, 3 } },
    { { 2, 0,-1,-1,-1 }, { 2, 0, 1, 4, 3 }, { 1, 2, 0, 4, 3 },
      { 2, 1, 0, 4, 3 }, { 2, 1, 3, 4, 0 }, { 2, 4, 1, 0, 3 } },
    { { 0, 2,-1,-1,-1 }, { 0, 2, 1, 3, 4 }, { 1, 2, 3, 0, 4 },
      { 2, 0, 1, 3, 4 }, { 2, 1, 3, 0, 4 }, { 2, 0, 4, 3, 1 } },
    { { 0, 2,-1,-1,-1 }, { 0, 2, 4, 1, 3 }, { 1, 4, 2, 0, 3 },
      { 4, 2, 0, 1, 3 }, { 2, 0, 1, 4, 3 }, { 4, 2, 1, 0, 3 } },
};

static const struct { uint8_t run; uint8_t level; } svq3_dct_tables[2][16] = {
    { { 0, 0 }, { 0, 1 }, { 1, 1 }, { 2, 1 }, { 0, 2 }, { 3, 1 }, { 4, 1 }, { 5, 1 },
      { 0, 3 }, { 1, 2 }, { 2, 2 }, { 6, 1 }, { 7, 1 }, { 8, 1 }, { 9, 1 }, { 0, 4 } },
    { { 0, 0 }, { 0, 1 }, { 1, 1 }, { 0, 2 }, { 2, 1 }, { 0, 3 }, { 0, 4 }, { 0, 5 },
      { 3, 1 }, { 4, 1 }, { 1, 2 }, { 1, 3 }, { 0, 6 }, { 0, 7 }, { 0, 8 }, { 0, 9 } }
};

static const uint32_t svq3_dequant_coeff[32] = {
     3881,  4351,  4890,  5481,  6154,  6914,  7761,  8718,
     9781, 10987, 12339, 13828, 15523, 17435, 19561, 21873,
    24552, 27656, 30847, 34870, 38807, 43747, 49103, 54683,
    61694, 68745, 77615, 89113,100253,109366,126635,141533
};


static void svq3_luma_dc_dequant_idct_c(DCTELEM *block, int qp)
{
    const int qmul = svq3_dequant_coeff[qp];
#define stride 16
    int i;
    int temp[16];
    static const int x_offset[4] = {0, 1*stride, 4* stride,  5*stride};
    static const int y_offset[4] = {0, 2*stride, 8* stride, 10*stride};

    for (i = 0; i < 4; i++){
        const int offset = y_offset[i];
        const int z0 = 13*(block[offset+stride*0] +    block[offset+stride*4]);
        const int z1 = 13*(block[offset+stride*0] -    block[offset+stride*4]);
        const int z2 =  7* block[offset+stride*1] - 17*block[offset+stride*5];
        const int z3 = 17* block[offset+stride*1] +  7*block[offset+stride*5];

        temp[4*i+0] = z0+z3;
        temp[4*i+1] = z1+z2;
        temp[4*i+2] = z1-z2;
        temp[4*i+3] = z0-z3;
    }

    for (i = 0; i < 4; i++){
        const int offset = x_offset[i];
        const int z0 = 13*(temp[4*0+i] +    temp[4*2+i]);
        const int z1 = 13*(temp[4*0+i] -    temp[4*2+i]);
        const int z2 =  7* temp[4*1+i] - 17*temp[4*3+i];
        const int z3 = 17* temp[4*1+i] +  7*temp[4*3+i];

        block[stride*0 +offset] = ((z0 + z3)*qmul + 0x80000) >> 20;
        block[stride*2 +offset] = ((z1 + z2)*qmul + 0x80000) >> 20;
        block[stride*8 +offset] = ((z1 - z2)*qmul + 0x80000) >> 20;
        block[stride*10+offset] = ((z0 - z3)*qmul + 0x80000) >> 20;
    }
}
#undef stride

static void svq3_add_idct_c(uint8_t *dst, DCTELEM *block, int stride, int qp,
                            int dc)
{
    const int qmul = svq3_dequant_coeff[qp];
    int i;
    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

    if (dc) {
        dc = 13*13*((dc == 1) ? 1538*block[0] : ((qmul*(block[0] >> 3)) / 2));
        block[0] = 0;
    }

    for (i = 0; i < 4; i++) {
        const int z0 = 13*(block[0 + 4*i] +    block[2 + 4*i]);
        const int z1 = 13*(block[0 + 4*i] -    block[2 + 4*i]);
        const int z2 =  7* block[1 + 4*i] - 17*block[3 + 4*i];
        const int z3 = 17* block[1 + 4*i] +  7*block[3 + 4*i];

        block[0 + 4*i] = z0 + z3;
        block[1 + 4*i] = z1 + z2;
        block[2 + 4*i] = z1 - z2;
        block[3 + 4*i] = z0 - z3;
    }

    for (i = 0; i < 4; i++) {
        const int z0 = 13*(block[i + 4*0] +    block[i + 4*2]);
        const int z1 = 13*(block[i + 4*0] -    block[i + 4*2]);
        const int z2 =  7* block[i + 4*1] - 17*block[i + 4*3];
        const int z3 = 17* block[i + 4*1] +  7*block[i + 4*3];
        const int rr = (dc + 0x80000);

        dst[i + stride*0] = cm[ dst[i + stride*0] + (((z0 + z3)*qmul + rr) >> 20) ];
        dst[i + stride*1] = cm[ dst[i + stride*1] + (((z1 + z2)*qmul + rr) >> 20) ];
        dst[i + stride*2] = cm[ dst[i + stride*2] + (((z1 - z2)*qmul + rr) >> 20) ];
        dst[i + stride*3] = cm[ dst[i + stride*3] + (((z0 - z3)*qmul + rr) >> 20) ];
    }
}

static inline int svq3_decode_block(GetBitContext *gb, DCTELEM *block,
                                    int index, const int type)
{
    static const uint8_t *const scan_patterns[4] =
    { luma_dc_zigzag_scan, zigzag_scan, svq3_scan, chroma_dc_scan };

    int run, level, sign, vlc, limit;
    const int intra = (3 * type) >> 2;
    const uint8_t *const scan = scan_patterns[type];

    for (limit = (16 >> intra); index < 16; index = limit, limit += 8) {
        for (; (vlc = svq3_get_ue_golomb(gb)) != 0; index++) {

          if (vlc < 0)
              return -1;

          sign = (vlc & 0x1) - 1;
          vlc  = (vlc + 1) >> 1;

          if (type == 3) {
              if (vlc < 3) {
                  run   = 0;
                  level = vlc;
              } else if (vlc < 4) {
                  run   = 1;
                  level = 1;
              } else {
                  run   = (vlc & 0x3);
                  level = ((vlc + 9) >> 2) - run;
              }
          } else {
              if (vlc < 16U) {
                  run   = svq3_dct_tables[intra][vlc].run;
                  level = svq3_dct_tables[intra][vlc].level;
              } else if (intra) {
                  run   = (vlc & 0x7);
                  level = (vlc >> 3) + ((run == 0) ? 8 : ((run < 2) ? 2 : ((run < 5) ? 0 : -1)));
              } else {
                  run   = (vlc & 0xF);
                  level = (vlc >> 4) + ((run == 0) ? 4 : ((run < 3) ? 2 : ((run < 10) ? 1 : 0)));
              }
          }

          if ((index += run) >= limit)
              return -1;

          block[scan[index]] = (level ^ sign) - sign;
        }

        if (type != 2) {
            break;
        }
    }

    return 0;
}

static inline void svq3_mc_dir_part(MpegEncContext *s,
                                    int x, int y, int width, int height,
                                    int mx, int my, int dxy,
                                    int thirdpel, int dir, int avg)
{
    const Picture *pic = (dir == 0) ? &s->last_picture : &s->next_picture;
    uint8_t *src, *dest;
    int i, emu = 0;
    int blocksize = 2 - (width>>3); //16->0, 8->1, 4->2

    mx += x;
    my += y;

    if (mx < 0 || mx >= (s->h_edge_pos - width  - 1) ||
        my < 0 || my >= (s->v_edge_pos - height - 1)) {

        if ((s->flags & CODEC_FLAG_EMU_EDGE)) {
            emu = 1;
        }

        mx = av_clip (mx, -16, (s->h_edge_pos - width  + 15));
        my = av_clip (my, -16, (s->v_edge_pos - height + 15));
    }

    /* form component predictions */
    dest = s->current_picture.data[0] + x + y*s->linesize;
    src  = pic->data[0] + mx + my*s->linesize;

    if (emu) {
        ff_emulated_edge_mc(s->edge_emu_buffer, src, s->linesize, (width + 1), (height + 1),
                            mx, my, s->h_edge_pos, s->v_edge_pos);
        src = s->edge_emu_buffer;
    }
    if (thirdpel)
        (avg ? s->dsp.avg_tpel_pixels_tab : s->dsp.put_tpel_pixels_tab)[dxy](dest, src, s->linesize, width, height);
    else
        (avg ? s->dsp.avg_pixels_tab : s->dsp.put_pixels_tab)[blocksize][dxy](dest, src, s->linesize, height);

    if (!(s->flags & CODEC_FLAG_GRAY)) {
        mx     = (mx + (mx < (int) x)) >> 1;
        my     = (my + (my < (int) y)) >> 1;
        width  = (width  >> 1);
        height = (height >> 1);
        blocksize++;

        for (i = 1; i < 3; i++) {
            dest = s->current_picture.data[i] + (x >> 1) + (y >> 1)*s->uvlinesize;
            src  = pic->data[i] + mx + my*s->uvlinesize;

            if (emu) {
                ff_emulated_edge_mc(s->edge_emu_buffer, src, s->uvlinesize, (width + 1), (height + 1),
                                    mx, my, (s->h_edge_pos >> 1), (s->v_edge_pos >> 1));
                src = s->edge_emu_buffer;
            }
            if (thirdpel)
                (avg ? s->dsp.avg_tpel_pixels_tab : s->dsp.put_tpel_pixels_tab)[dxy](dest, src, s->uvlinesize, width, height);
            else
                (avg ? s->dsp.avg_pixels_tab : s->dsp.put_pixels_tab)[blocksize][dxy](dest, src, s->uvlinesize, height);
        }
    }
}

static inline int svq3_mc_dir(H264Context *h, int size, int mode, int dir,
                              int avg)
{
    int i, j, k, mx, my, dx, dy, x, y;
    MpegEncContext *const s = (MpegEncContext *) h;
    const int part_width  = ((size & 5) == 4) ? 4 : 16 >> (size & 1);
    const int part_height = 16 >> ((unsigned) (size + 1) / 3);
    const int extra_width = (mode == PREDICT_MODE) ? -16*6 : 0;
    const int h_edge_pos  = 6*(s->h_edge_pos - part_width ) - extra_width;
    const int v_edge_pos  = 6*(s->v_edge_pos - part_height) - extra_width;

    for (i = 0; i < 16; i += part_height) {
        for (j = 0; j < 16; j += part_width) {
            const int b_xy = (4*s->mb_x + (j >> 2)) + (4*s->mb_y + (i >> 2))*h->b_stride;
            int dxy;
            x = 16*s->mb_x + j;
            y = 16*s->mb_y + i;
            k = ((j >> 2) & 1) + ((i >> 1) & 2) + ((j >> 1) & 4) + (i & 8);

            if (mode != PREDICT_MODE) {
                pred_motion(h, k, (part_width >> 2), dir, 1, &mx, &my);
            } else {
                mx = s->next_picture.motion_val[0][b_xy][0]<<1;
                my = s->next_picture.motion_val[0][b_xy][1]<<1;

                if (dir == 0) {
                    mx = ((mx * h->frame_num_offset) / h->prev_frame_num_offset + 1) >> 1;
                    my = ((my * h->frame_num_offset) / h->prev_frame_num_offset + 1) >> 1;
                } else {
                    mx = ((mx * (h->frame_num_offset - h->prev_frame_num_offset)) / h->prev_frame_num_offset + 1) >> 1;
                    my = ((my * (h->frame_num_offset - h->prev_frame_num_offset)) / h->prev_frame_num_offset + 1) >> 1;
                }
            }

            /* clip motion vector prediction to frame border */
            mx = av_clip(mx, extra_width - 6*x, h_edge_pos - 6*x);
            my = av_clip(my, extra_width - 6*y, v_edge_pos - 6*y);

            /* get (optional) motion vector differential */
            if (mode == PREDICT_MODE) {
                dx = dy = 0;
            } else {
                dy = svq3_get_se_golomb(&s->gb);
                dx = svq3_get_se_golomb(&s->gb);

                if (dx == INVALID_VLC || dy == INVALID_VLC) {
                    av_log(h->s.avctx, AV_LOG_ERROR, "invalid MV vlc\n");
                    return -1;
                }
            }

            /* compute motion vector */
            if (mode == THIRDPEL_MODE) {
                int fx, fy;
                mx  = ((mx + 1)>>1) + dx;
                my  = ((my + 1)>>1) + dy;
                fx  = ((unsigned)(mx + 0x3000))/3 - 0x1000;
                fy  = ((unsigned)(my + 0x3000))/3 - 0x1000;
                dxy = (mx - 3*fx) + 4*(my - 3*fy);

                svq3_mc_dir_part(s, x, y, part_width, part_height, fx, fy, dxy, 1, dir, avg);
                mx += mx;
                my += my;
            } else if (mode == HALFPEL_MODE || mode == PREDICT_MODE) {
                mx  = ((unsigned)(mx + 1 + 0x3000))/3 + dx - 0x1000;
                my  = ((unsigned)(my + 1 + 0x3000))/3 + dy - 0x1000;
                dxy = (mx&1) + 2*(my&1);

                svq3_mc_dir_part(s, x, y, part_width, part_height, mx>>1, my>>1, dxy, 0, dir, avg);
                mx *= 3;
                my *= 3;
            } else {
                mx = ((unsigned)(mx + 3 + 0x6000))/6 + dx - 0x1000;
                my = ((unsigned)(my + 3 + 0x6000))/6 + dy - 0x1000;

                svq3_mc_dir_part(s, x, y, part_width, part_height, mx, my, 0, 0, dir, avg);
                mx *= 6;
                my *= 6;
            }

            /* update mv_cache */
            if (mode != PREDICT_MODE) {
                int32_t mv = pack16to32(mx,my);

                if (part_height == 8 && i < 8) {
                    *(int32_t *) h->mv_cache[dir][scan8[k] + 1*8] = mv;

                    if (part_width == 8 && j < 8) {
                        *(int32_t *) h->mv_cache[dir][scan8[k] + 1 + 1*8] = mv;
                    }
                }
                if (part_width == 8 && j < 8) {
                    *(int32_t *) h->mv_cache[dir][scan8[k] + 1] = mv;
                }
                if (part_width == 4 || part_height == 4) {
                    *(int32_t *) h->mv_cache[dir][scan8[k]] = mv;
                }
            }

            /* write back motion vectors */
            fill_rectangle(s->current_picture.motion_val[dir][b_xy], part_width>>2, part_height>>2, h->b_stride, pack16to32(mx,my), 4);
        }
    }

    return 0;
}

static int svq3_decode_mb(H264Context *h, unsigned int mb_type)
{
    int i, j, k, m, dir, mode;
    int cbp = 0;
    uint32_t vlc;
    int8_t *top, *left;
    MpegEncContext *const s = (MpegEncContext *) h;
    const int mb_xy = h->mb_xy;
    const int b_xy  = 4*s->mb_x + 4*s->mb_y*h->b_stride;

    h->top_samples_available      = (s->mb_y == 0) ? 0x33FF : 0xFFFF;
    h->left_samples_available     = (s->mb_x == 0) ? 0x5F5F : 0xFFFF;
    h->topright_samples_available = 0xFFFF;

    if (mb_type == 0) {           /* SKIP */
        if (s->pict_type == FF_P_TYPE || s->next_picture.mb_type[mb_xy] == -1) {
            svq3_mc_dir_part(s, 16*s->mb_x, 16*s->mb_y, 16, 16, 0, 0, 0, 0, 0, 0);

            if (s->pict_type == FF_B_TYPE) {
                svq3_mc_dir_part(s, 16*s->mb_x, 16*s->mb_y, 16, 16, 0, 0, 0, 0, 1, 1);
            }

            mb_type = MB_TYPE_SKIP;
        } else {
            mb_type = FFMIN(s->next_picture.mb_type[mb_xy], 6);
            if (svq3_mc_dir(h, mb_type, PREDICT_MODE, 0, 0) < 0)
                return -1;
            if (svq3_mc_dir(h, mb_type, PREDICT_MODE, 1, 1) < 0)
                return -1;

            mb_type = MB_TYPE_16x16;
        }
    } else if (mb_type < 8) {     /* INTER */
        if (h->thirdpel_flag && h->halfpel_flag == !get_bits1 (&s->gb)) {
            mode = THIRDPEL_MODE;
        } else if (h->halfpel_flag && h->thirdpel_flag == !get_bits1 (&s->gb)) {
            mode = HALFPEL_MODE;
        } else {
            mode = FULLPEL_MODE;
        }

        /* fill caches */
        /* note ref_cache should contain here:
            ????????
            ???11111
            N??11111
            N??11111
            N??11111
        */

        for (m = 0; m < 2; m++) {
            if (s->mb_x > 0 && h->intra4x4_pred_mode[mb_xy - 1][0] != -1) {
                for (i = 0; i < 4; i++) {
                    *(uint32_t *) h->mv_cache[m][scan8[0] - 1 + i*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - 1 + i*h->b_stride];
                }
            } else {
                for (i = 0; i < 4; i++) {
                    *(uint32_t *) h->mv_cache[m][scan8[0] - 1 + i*8] = 0;
                }
            }
            if (s->mb_y > 0) {
                memcpy(h->mv_cache[m][scan8[0] - 1*8], s->current_picture.motion_val[m][b_xy - h->b_stride], 4*2*sizeof(int16_t));
                memset(&h->ref_cache[m][scan8[0] - 1*8], (h->intra4x4_pred_mode[mb_xy - s->mb_stride][4] == -1) ? PART_NOT_AVAILABLE : 1, 4);

                if (s->mb_x < (s->mb_width - 1)) {
                    *(uint32_t *) h->mv_cache[m][scan8[0] + 4 - 1*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - h->b_stride + 4];
                    h->ref_cache[m][scan8[0] + 4 - 1*8] =
                        (h->intra4x4_pred_mode[mb_xy - s->mb_stride + 1][0] == -1 ||
                         h->intra4x4_pred_mode[mb_xy - s->mb_stride    ][4] == -1) ? PART_NOT_AVAILABLE : 1;
                }else
                    h->ref_cache[m][scan8[0] + 4 - 1*8] = PART_NOT_AVAILABLE;
                if (s->mb_x > 0) {
                    *(uint32_t *) h->mv_cache[m][scan8[0] - 1 - 1*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - h->b_stride - 1];
                    h->ref_cache[m][scan8[0] - 1 - 1*8] = (h->intra4x4_pred_mode[mb_xy - s->mb_stride - 1][3] == -1) ? PART_NOT_AVAILABLE : 1;
                }else
                    h->ref_cache[m][scan8[0] - 1 - 1*8] = PART_NOT_AVAILABLE;
            }else
                memset(&h->ref_cache[m][scan8[0] - 1*8 - 1], PART_NOT_AVAILABLE, 8);

            if (s->pict_type != FF_B_TYPE)
                break;
        }

        /* decode motion vector(s) and form prediction(s) */
        if (s->pict_type == FF_P_TYPE) {
            if (svq3_mc_dir(h, (mb_type - 1), mode, 0, 0) < 0)
                return -1;
        } else {        /* FF_B_TYPE */
            if (mb_type != 2) {
                if (svq3_mc_dir(h, 0, mode, 0, 0) < 0)
                    return -1;
            } else {
                for (i = 0; i < 4; i++) {
                    memset(s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));
                }
            }
            if (mb_type != 1) {
                if (svq3_mc_dir(h, 0, mode, 1, (mb_type == 3)) < 0)
                    return -1;
            } else {
                for (i = 0; i < 4; i++) {
                    memset(s->current_picture.motion_val[1][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));
                }
            }
        }

        mb_type = MB_TYPE_16x16;
    } else if (mb_type == 8 || mb_type == 33) {   /* INTRA4x4 */
        memset(h->intra4x4_pred_mode_cache, -1, 8*5*sizeof(int8_t));

        if (mb_type == 8) {
            if (s->mb_x > 0) {
                for (i = 0; i < 4; i++) {
                    h->intra4x4_pred_mode_cache[scan8[0] - 1 + i*8] = h->intra4x4_pred_mode[mb_xy - 1][i];
                }
                if (h->intra4x4_pred_mode_cache[scan8[0] - 1] == -1) {
                    h->left_samples_available = 0x5F5F;
                }
            }
            if (s->mb_y > 0) {
                h->intra4x4_pred_mode_cache[4+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][4];
                h->intra4x4_pred_mode_cache[5+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][5];
                h->intra4x4_pred_mode_cache[6+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][6];
                h->intra4x4_pred_mode_cache[7+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][3];

                if (h->intra4x4_pred_mode_cache[4+8*0] == -1) {
                    h->top_samples_available = 0x33FF;
                }
            }

            /* decode prediction codes for luma blocks */
            for (i = 0; i < 16; i+=2) {
                vlc = svq3_get_ue_golomb(&s->gb);

                if (vlc >= 25U){
                    av_log(h->s.avctx, AV_LOG_ERROR, "luma prediction:%d\n", vlc);
                    return -1;
                }

                left    = &h->intra4x4_pred_mode_cache[scan8[i] - 1];
                top     = &h->intra4x4_pred_mode_cache[scan8[i] - 8];

                left[1] = svq3_pred_1[top[0] + 1][left[0] + 1][svq3_pred_0[vlc][0]];
                left[2] = svq3_pred_1[top[1] + 1][left[1] + 1][svq3_pred_0[vlc][1]];

                if (left[1] == -1 || left[2] == -1){
                    av_log(h->s.avctx, AV_LOG_ERROR, "weird prediction\n");
                    return -1;
                }
            }
        } else {    /* mb_type == 33, DC_128_PRED block type */
            for (i = 0; i < 4; i++) {
                memset(&h->intra4x4_pred_mode_cache[scan8[0] + 8*i], DC_PRED, 4);
            }
        }

        write_back_intra_pred_mode(h);

        if (mb_type == 8) {
            check_intra4x4_pred_mode(h);

            h->top_samples_available  = (s->mb_y == 0) ? 0x33FF : 0xFFFF;
            h->left_samples_available = (s->mb_x == 0) ? 0x5F5F : 0xFFFF;
        } else {
            for (i = 0; i < 4; i++) {
                memset(&h->intra4x4_pred_mode_cache[scan8[0] + 8*i], DC_128_PRED, 4);
            }

            h->top_samples_available  = 0x33FF;
            h->left_samples_available = 0x5F5F;
        }

        mb_type = MB_TYPE_INTRA4x4;
    } else {                      /* INTRA16x16 */
        dir = i_mb_type_info[mb_type - 8].pred_mode;
        dir = (dir >> 1) ^ 3*(dir & 1) ^ 1;

        if ((h->intra16x16_pred_mode = check_intra_pred_mode(h, dir)) == -1){
            av_log(h->s.avctx, AV_LOG_ERROR, "check_intra_pred_mode = -1\n");
            return -1;
        }

        cbp = i_mb_type_info[mb_type - 8].cbp;
        mb_type = MB_TYPE_INTRA16x16;
    }

    if (!IS_INTER(mb_type) && s->pict_type != FF_I_TYPE) {
        for (i = 0; i < 4; i++) {
            memset(s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));
        }
        if (s->pict_type == FF_B_TYPE) {
            for (i = 0; i < 4; i++) {
                memset(s->current_picture.motion_val[1][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));
            }
        }
    }
    if (!IS_INTRA4x4(mb_type)) {
        memset(h->intra4x4_pred_mode[mb_xy], DC_PRED, 8);
    }
    if (!IS_SKIP(mb_type) || s->pict_type == FF_B_TYPE) {
        memset(h->non_zero_count_cache + 8, 0, 4*9*sizeof(uint8_t));
        s->dsp.clear_blocks(h->mb);
    }

    if (!IS_INTRA16x16(mb_type) && (!IS_SKIP(mb_type) || s->pict_type == FF_B_TYPE)) {
        if ((vlc = svq3_get_ue_golomb(&s->gb)) >= 48U){
            av_log(h->s.avctx, AV_LOG_ERROR, "cbp_vlc=%d\n", vlc);
            return -1;
        }

        cbp = IS_INTRA(mb_type) ? golomb_to_intra4x4_cbp[vlc] : golomb_to_inter_cbp[vlc];
    }
    if (IS_INTRA16x16(mb_type) || (s->pict_type != FF_I_TYPE && s->adaptive_quant && cbp)) {
        s->qscale += svq3_get_se_golomb(&s->gb);

        if (s->qscale > 31U){
            av_log(h->s.avctx, AV_LOG_ERROR, "qscale:%d\n", s->qscale);
            return -1;
        }
    }
    if (IS_INTRA16x16(mb_type)) {
        if (svq3_decode_block(&s->gb, h->mb, 0, 0)){
            av_log(h->s.avctx, AV_LOG_ERROR, "error while decoding intra luma dc\n");
            return -1;
        }
    }

    if (cbp) {
        const int index = IS_INTRA16x16(mb_type) ? 1 : 0;
        const int type = ((s->qscale < 24 && IS_INTRA4x4(mb_type)) ? 2 : 1);

        for (i = 0; i < 4; i++) {
            if ((cbp & (1 << i))) {
                for (j = 0; j < 4; j++) {
                    k = index ? ((j&1) + 2*(i&1) + 2*(j&2) + 4*(i&2)) : (4*i + j);
                    h->non_zero_count_cache[ scan8[k] ] = 1;

                    if (svq3_decode_block(&s->gb, &h->mb[16*k], index, type)){
                        av_log(h->s.avctx, AV_LOG_ERROR, "error while decoding block\n");
                        return -1;
                    }
                }
            }
        }

        if ((cbp & 0x30)) {
            for (i = 0; i < 2; ++i) {
              if (svq3_decode_block(&s->gb, &h->mb[16*(16 + 4*i)], 0, 3)){
                av_log(h->s.avctx, AV_LOG_ERROR, "error while decoding chroma dc block\n");
                return -1;
              }
            }

            if ((cbp & 0x20)) {
                for (i = 0; i < 8; i++) {
                    h->non_zero_count_cache[ scan8[16+i] ] = 1;

                    if (svq3_decode_block(&s->gb, &h->mb[16*(16 + i)], 1, 1)){
                        av_log(h->s.avctx, AV_LOG_ERROR, "error while decoding chroma ac block\n");
                        return -1;
                    }
                }
            }
        }
    }

    h->cbp= cbp;
    s->current_picture.mb_type[mb_xy] = mb_type;

    if (IS_INTRA(mb_type)) {
        h->chroma_pred_mode = check_intra_pred_mode(h, DC_PRED8x8);
    }

    return 0;
}

static int svq3_decode_slice_header(H264Context *h)
{
    MpegEncContext *const s = (MpegEncContext *) h;
    const int mb_xy = h->mb_xy;
    int i, header;

    header = get_bits(&s->gb, 8);

    if (((header & 0x9F) != 1 && (header & 0x9F) != 2) || (header & 0x60) == 0) {
        /* TODO: what? */
        av_log(h->s.avctx, AV_LOG_ERROR, "unsupported slice header (%02X)\n", header);
        return -1;
    } else {
        int length = (header >> 5) & 3;

        h->next_slice_index = get_bits_count(&s->gb) + 8*show_bits(&s->gb, 8*length) + 8*length;

        if (h->next_slice_index > s->gb.size_in_bits) {
            av_log(h->s.avctx, AV_LOG_ERROR, "slice after bitstream end\n");
            return -1;
    }

        s->gb.size_in_bits = h->next_slice_index - 8*(length - 1);
        skip_bits(&s->gb, 8);

        if (h->svq3_watermark_key) {
            uint32_t header = AV_RL32(&s->gb.buffer[(get_bits_count(&s->gb)>>3)+1]);
            AV_WL32(&s->gb.buffer[(get_bits_count(&s->gb)>>3)+1], header ^ h->svq3_watermark_key);
        }
        if (length > 0) {
            memcpy((uint8_t *) &s->gb.buffer[get_bits_count(&s->gb) >> 3],
                   &s->gb.buffer[s->gb.size_in_bits >> 3], (length - 1));
        }
        skip_bits_long(&s->gb, 0);
    }

    if ((i = svq3_get_ue_golomb(&s->gb)) >= 3U){
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal slice type %d \n", i);
        return -1;
    }

    h->slice_type = golomb_to_pict_type[i];

    if ((header & 0x9F) == 2) {
        i = (s->mb_num < 64) ? 6 : (1 + av_log2 (s->mb_num - 1));
        s->mb_skip_run = get_bits(&s->gb, i) - (s->mb_x + (s->mb_y * s->mb_width));
    } else {
        skip_bits1(&s->gb);
        s->mb_skip_run = 0;
    }

    h->slice_num = get_bits(&s->gb, 8);
    s->qscale = get_bits(&s->gb, 5);
    s->adaptive_quant = get_bits1(&s->gb);

    /* unknown fields */
    skip_bits1(&s->gb);

    if (h->unknown_svq3_flag) {
        skip_bits1(&s->gb);
    }

    skip_bits1(&s->gb);
    skip_bits(&s->gb, 2);

    while (get_bits1(&s->gb)) {
        skip_bits(&s->gb, 8);
    }

    /* reset intra predictors and invalidate motion vector references */
    if (s->mb_x > 0) {
        memset(h->intra4x4_pred_mode[mb_xy - 1], -1, 4*sizeof(int8_t));
        memset(h->intra4x4_pred_mode[mb_xy - s->mb_x], -1, 8*sizeof(int8_t)*s->mb_x);
    }
    if (s->mb_y > 0) {
        memset(h->intra4x4_pred_mode[mb_xy - s->mb_stride], -1, 8*sizeof(int8_t)*(s->mb_width - s->mb_x));

        if (s->mb_x > 0) {
            h->intra4x4_pred_mode[mb_xy - s->mb_stride - 1][3] = -1;
        }
    }

    return 0;
}

static av_cold int svq3_decode_init(AVCodecContext *avctx)
{
    MpegEncContext *const s = avctx->priv_data;
    H264Context *const h = avctx->priv_data;
    int m;
    unsigned char *extradata;
    unsigned int size;

    if (decode_init(avctx) < 0)
        return -1;

    s->flags  = avctx->flags;
    s->flags2 = avctx->flags2;
    s->unrestricted_mv = 1;
    h->is_complex=1;

    if (!s->context_initialized) {
        s->width  = avctx->width;
        s->height = avctx->height;
        h->halfpel_flag      = 1;
        h->thirdpel_flag     = 1;
        h->unknown_svq3_flag = 0;
        h->chroma_qp[0]      = h->chroma_qp[1] = 4;

        if (MPV_common_init(s) < 0)
            return -1;

        h->b_stride = 4*s->mb_width;

        alloc_tables(h);

        /* prowl for the "SEQH" marker in the extradata */
        extradata = (unsigned char *)avctx->extradata;
        for (m = 0; m < avctx->extradata_size; m++) {
            if (!memcmp(extradata, "SEQH", 4))
                break;
            extradata++;
        }

        /* if a match was found, parse the extra data */
        if (extradata && !memcmp(extradata, "SEQH", 4)) {

            GetBitContext gb;

            size = AV_RB32(&extradata[4]);
            init_get_bits(&gb, extradata + 8, size*8);

            /* 'frame size code' and optional 'width, height' */
            if (get_bits(&gb, 3) == 7) {
                skip_bits(&gb, 12);
                skip_bits(&gb, 12);
            }

            h->halfpel_flag  = get_bits1(&gb);
            h->thirdpel_flag = get_bits1(&gb);

            /* unknown fields */
            skip_bits1(&gb);
            skip_bits1(&gb);
            skip_bits1(&gb);
            skip_bits1(&gb);

            s->low_delay = get_bits1(&gb);

            /* unknown field */
            skip_bits1(&gb);

            while (get_bits1(&gb)) {
                skip_bits(&gb, 8);
            }

            h->unknown_svq3_flag = get_bits1(&gb);
            avctx->has_b_frames = !s->low_delay;
            if (h->unknown_svq3_flag) {
#if CONFIG_ZLIB
                unsigned watermark_width  = svq3_get_ue_golomb(&gb);
                unsigned watermark_height = svq3_get_ue_golomb(&gb);
                int u1 = svq3_get_ue_golomb(&gb);
                int u2 = get_bits(&gb, 8);
                int u3 = get_bits(&gb, 2);
                int u4 = svq3_get_ue_golomb(&gb);
                unsigned buf_len = watermark_width*watermark_height*4;
                int offset = (get_bits_count(&gb)+7)>>3;
                uint8_t *buf;

                if ((uint64_t)watermark_width*4 > UINT_MAX/watermark_height)
                    return -1;

                buf = av_malloc(buf_len);
                av_log(avctx, AV_LOG_DEBUG, "watermark size: %dx%d\n", watermark_width, watermark_height);
                av_log(avctx, AV_LOG_DEBUG, "u1: %x u2: %x u3: %x compressed data size: %d offset: %d\n", u1, u2, u3, u4, offset);
                if (uncompress(buf, (uLong*)&buf_len, extradata + 8 + offset, size - offset) != Z_OK) {
                    av_log(avctx, AV_LOG_ERROR, "could not uncompress watermark logo\n");
                    av_free(buf);
                    return -1;
                }
                h->svq3_watermark_key = ff_svq1_packet_checksum(buf, buf_len, 0);
                h->svq3_watermark_key = h->svq3_watermark_key << 16 | h->svq3_watermark_key;
                av_log(avctx, AV_LOG_DEBUG, "watermark key %#x\n", h->svq3_watermark_key);
                av_free(buf);
#else
                av_log(avctx, AV_LOG_ERROR, "this svq3 file contains watermark which need zlib support compiled in\n");
                return -1;
#endif
            }
        }
    }

    return 0;
}

static int svq3_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,
                             const uint8_t *buf, int buf_size)
{
    MpegEncContext *const s = avctx->priv_data;
    H264Context *const h = avctx->priv_data;
    int m, mb_type;

    /* special case for last picture */
    if (buf_size == 0) {
        if (s->next_picture_ptr && !s->low_delay) {
            *(AVFrame *) data = *(AVFrame *) &s->next_picture;
            s->next_picture_ptr = NULL;
            *data_size = sizeof(AVFrame);
        }
        return 0;
    }

    init_get_bits (&s->gb, buf, 8*buf_size);

    s->mb_x = s->mb_y = h->mb_xy = 0;

    if (svq3_decode_slice_header(h))
        return -1;

    s->pict_type = h->slice_type;
    s->picture_number = h->slice_num;

    if (avctx->debug&FF_DEBUG_PICT_INFO){
        av_log(h->s.avctx, AV_LOG_DEBUG, "%c hpel:%d, tpel:%d aqp:%d qp:%d, slice_num:%02X\n",
               av_get_pict_type_char(s->pict_type), h->halfpel_flag, h->thirdpel_flag,
               s->adaptive_quant, s->qscale, h->slice_num);
    }

    /* for hurry_up == 5 */
    s->current_picture.pict_type = s->pict_type;
    s->current_picture.key_frame = (s->pict_type == FF_I_TYPE);

    /* Skip B-frames if we do not have reference frames. */
    if (s->last_picture_ptr == NULL && s->pict_type == FF_B_TYPE)
        return 0;
    /* Skip B-frames if we are in a hurry. */
    if (avctx->hurry_up && s->pict_type == FF_B_TYPE)
        return 0;
    /* Skip everything if we are in a hurry >= 5. */
    if (avctx->hurry_up >= 5)
        return 0;
    if (  (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type == FF_B_TYPE)
        ||(avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type != FF_I_TYPE)
        || avctx->skip_frame >= AVDISCARD_ALL)
        return 0;

    if (s->next_p_frame_damaged) {
        if (s->pict_type == FF_B_TYPE)
            return 0;
        else
            s->next_p_frame_damaged = 0;
    }

    if (frame_start(h) < 0)
        return -1;

    if (s->pict_type == FF_B_TYPE) {
        h->frame_num_offset = (h->slice_num - h->prev_frame_num);

        if (h->frame_num_offset < 0) {
            h->frame_num_offset += 256;
        }
        if (h->frame_num_offset == 0 || h->frame_num_offset >= h->prev_frame_num_offset) {
            av_log(h->s.avctx, AV_LOG_ERROR, "error in B-frame picture id\n");
            return -1;
        }
    } else {
        h->prev_frame_num = h->frame_num;
        h->frame_num = h->slice_num;
        h->prev_frame_num_offset = (h->frame_num - h->prev_frame_num);

        if (h->prev_frame_num_offset < 0) {
            h->prev_frame_num_offset += 256;
        }
    }

    for (m = 0; m < 2; m++){
        int i;
        for (i = 0; i < 4; i++){
            int j;
            for (j = -1; j < 4; j++)
                h->ref_cache[m][scan8[0] + 8*i + j]= 1;
            if (i < 3)
                h->ref_cache[m][scan8[0] + 8*i + j]= PART_NOT_AVAILABLE;
        }
    }

    for (s->mb_y = 0; s->mb_y < s->mb_height; s->mb_y++) {
        for (s->mb_x = 0; s->mb_x < s->mb_width; s->mb_x++) {
            h->mb_xy = s->mb_x + s->mb_y*s->mb_stride;

            if ( (get_bits_count(&s->gb) + 7) >= s->gb.size_in_bits &&
                ((get_bits_count(&s->gb) & 7) == 0 || show_bits(&s->gb, (-get_bits_count(&s->gb) & 7)) == 0)) {

                skip_bits(&s->gb, h->next_slice_index - get_bits_count(&s->gb));
                s->gb.size_in_bits = 8*buf_size;

                if (svq3_decode_slice_header(h))
                    return -1;

                /* TODO: support s->mb_skip_run */
            }

            mb_type = svq3_get_ue_golomb(&s->gb);

            if (s->pict_type == FF_I_TYPE) {
                mb_type += 8;
            } else if (s->pict_type == FF_B_TYPE && mb_type >= 4) {
                mb_type += 4;
            }
            if (mb_type > 33 || svq3_decode_mb(h, mb_type)) {
                av_log(h->s.avctx, AV_LOG_ERROR, "error while decoding MB %d %d\n", s->mb_x, s->mb_y);
                return -1;
            }

            if (mb_type != 0) {
                hl_decode_mb (h);
            }

            if (s->pict_type != FF_B_TYPE && !s->low_delay) {
                s->current_picture.mb_type[s->mb_x + s->mb_y*s->mb_stride] =
                    (s->pict_type == FF_P_TYPE && mb_type < 8) ? (mb_type - 1) : -1;
            }
        }

        ff_draw_horiz_band(s, 16*s->mb_y, 16);
    }

    MPV_frame_end(s);

    if (s->pict_type == FF_B_TYPE || s->low_delay) {
        *(AVFrame *) data = *(AVFrame *) &s->current_picture;
    } else {
        *(AVFrame *) data = *(AVFrame *) &s->last_picture;
    }

    avctx->frame_number = s->picture_number - 1;

    /* Do not output the last pic after seeking. */
    if (s->last_picture_ptr || s->low_delay) {
        *data_size = sizeof(AVFrame);
    }

    return buf_size;
}


AVCodec svq3_decoder = {
    "svq3",
    CODEC_TYPE_VIDEO,
    CODEC_ID_SVQ3,
    sizeof(H264Context),
    svq3_decode_init,
    NULL,
    decode_end,
    svq3_decode_frame,
    CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_DELAY,
    .long_name = NULL_IF_CONFIG_SMALL("Sorenson Vector Quantizer 3"),
    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUVJ420P, PIX_FMT_NONE},
};