PeerStreamer

/*

 * DV decoder

 * Copyright (c) 2002 Fabrice Bellard.

 * Copyright (c) 2004 Roman Shaposhnik.

 *

 * DV encoder

 * Copyright (c) 2003 Roman Shaposhnik.

 *

 * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth

 * of DV technical info.

 *

 * This library 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 of the License, or (at your option) any later version.

 *

 * This library 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 this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file dv.c

 * DV codec.

 */

#include "avcodec.h"

#include "dsputil.h"

#include "mpegvideo.h"

#include "simple_idct.h"

#include "dvdata.h"

//#undef NDEBUG

//#include <assert.h>

typedef struct DVVideoContext {

    const DVprofile* sys;

    AVFrame picture;

    AVCodecContext *avctx;

    uint8_t *buf;

    uint8_t dv_zigzag[2][64];

    uint8_t dv_idct_shift[2][2][22][64];

    void (*get_pixels)(DCTELEM *block, const uint8_t *pixels, int line_size);

    void (*fdct[2])(DCTELEM *block);

    void (*idct_put[2])(uint8_t *dest, int line_size, DCTELEM *block);

} DVVideoContext;

/* MultiThreading - applies to entire DV codec, not just the avcontext */

uint8_t** dv_anchor;

#define TEX_VLC_BITS 9

#ifdef DV_CODEC_TINY_TARGET

#define DV_VLC_MAP_RUN_SIZE 15

#define DV_VLC_MAP_LEV_SIZE 23

#else

#define DV_VLC_MAP_RUN_SIZE  64

#define DV_VLC_MAP_LEV_SIZE 512 //FIXME sign was removed so this should be /2 but needs check

#endif

/* XXX: also include quantization */

static RL_VLC_ELEM *dv_rl_vlc;

/* VLC encoding lookup table */

static struct dv_vlc_pair {

   uint32_t vlc;

   uint8_t  size;

} (*dv_vlc_map)[DV_VLC_MAP_LEV_SIZE] = NULL;

static void dv_build_unquantize_tables(DVVideoContext *s, uint8_t* perm)

{

    int i, q, j;

    /* NOTE: max left shift is 6 */

    for(q = 0; q < 22; q++) {

        /* 88DCT */

        for(i = 1; i < 64; i++) {

            /* 88 table */

            j = perm[i];

            s->dv_idct_shift[0][0][q][j] =

                dv_quant_shifts[q][dv_88_areas[i]] + 1;

            s->dv_idct_shift[1][0][q][j] = s->dv_idct_shift[0][0][q][j] + 1;

        }

        /* 248DCT */

        for(i = 1; i < 64; i++) {

            /* 248 table */

            s->dv_idct_shift[0][1][q][i] =

                dv_quant_shifts[q][dv_248_areas[i]] + 1;

            s->dv_idct_shift[1][1][q][i] = s->dv_idct_shift[0][1][q][i] + 1;

        }

    }

}

static int dvvideo_init(AVCodecContext *avctx)

{

    DVVideoContext *s = avctx->priv_data;

    DSPContext dsp;

    static int done=0;

    int i, j;

    if (!done) {

        VLC dv_vlc;

        uint16_t new_dv_vlc_bits[NB_DV_VLC*2];

        uint8_t new_dv_vlc_len[NB_DV_VLC*2];

        uint8_t new_dv_vlc_run[NB_DV_VLC*2];

        int16_t new_dv_vlc_level[NB_DV_VLC*2];

        done = 1;

        dv_vlc_map = av_mallocz_static(DV_VLC_MAP_LEV_SIZE*DV_VLC_MAP_RUN_SIZE*sizeof(struct dv_vlc_pair));

        if (!dv_vlc_map)

            return -ENOMEM;

        /* dv_anchor lets each thread know its Id */

        dv_anchor = av_malloc(12*27*sizeof(void*));

        if (!dv_anchor) {

            return -ENOMEM;

        }

        for (i=0; i<12*27; i++)

            dv_anchor[i] = (void*)(size_t)i;

        /* it's faster to include sign bit in a generic VLC parsing scheme */

        for (i=0, j=0; i<NB_DV_VLC; i++, j++) {

            new_dv_vlc_bits[j] = dv_vlc_bits[i];

            new_dv_vlc_len[j] = dv_vlc_len[i];

            new_dv_vlc_run[j] = dv_vlc_run[i];

            new_dv_vlc_level[j] = dv_vlc_level[i];

            if (dv_vlc_level[i]) {

                new_dv_vlc_bits[j] <<= 1;

                new_dv_vlc_len[j]++;

                j++;

                new_dv_vlc_bits[j] = (dv_vlc_bits[i] << 1) | 1;

                new_dv_vlc_len[j] = dv_vlc_len[i] + 1;

                new_dv_vlc_run[j] = dv_vlc_run[i];

                new_dv_vlc_level[j] = -dv_vlc_level[i];

            }

        }

        /* NOTE: as a trick, we use the fact the no codes are unused

           to accelerate the parsing of partial codes */

        init_vlc(&dv_vlc, TEX_VLC_BITS, j,

                 new_dv_vlc_len, 1, 1, new_dv_vlc_bits, 2, 2, 0);

        dv_rl_vlc = av_mallocz_static(dv_vlc.table_size * sizeof(RL_VLC_ELEM));

        if (!dv_rl_vlc)

            return -ENOMEM;

        for(i = 0; i < dv_vlc.table_size; i++){

            int code= dv_vlc.table[i][0];

            int len = dv_vlc.table[i][1];

            int level, run;

            if(len<0){ //more bits needed

                run= 0;

                level= code;

            } else {

                run=   new_dv_vlc_run[code] + 1;

                level= new_dv_vlc_level[code];

            }

            dv_rl_vlc[i].len = len;

            dv_rl_vlc[i].level = level;

            dv_rl_vlc[i].run = run;

        }

        free_vlc(&dv_vlc);

        for (i = 0; i < NB_DV_VLC - 1; i++) {

           if (dv_vlc_run[i] >= DV_VLC_MAP_RUN_SIZE)

               continue;

#ifdef DV_CODEC_TINY_TARGET

           if (dv_vlc_level[i] >= DV_VLC_MAP_LEV_SIZE)

               continue;

#endif

           if (dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].size != 0)

               continue;

           dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].vlc = dv_vlc_bits[i] <<

                                                            (!!dv_vlc_level[i]);

           dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].size = dv_vlc_len[i] +

                                                             (!!dv_vlc_level[i]);

        }

        for (i = 0; i < DV_VLC_MAP_RUN_SIZE; i++) {

#ifdef DV_CODEC_TINY_TARGET

           for (j = 1; j < DV_VLC_MAP_LEV_SIZE; j++) {

              if (dv_vlc_map[i][j].size == 0) {

                  dv_vlc_map[i][j].vlc = dv_vlc_map[0][j].vlc |

                            (dv_vlc_map[i-1][0].vlc << (dv_vlc_map[0][j].size));

                  dv_vlc_map[i][j].size = dv_vlc_map[i-1][0].size +

                                          dv_vlc_map[0][j].size;

              }

           }

#else

           for (j = 1; j < DV_VLC_MAP_LEV_SIZE/2; j++) {

              if (dv_vlc_map[i][j].size == 0) {

                  dv_vlc_map[i][j].vlc = dv_vlc_map[0][j].vlc |

                            (dv_vlc_map[i-1][0].vlc << (dv_vlc_map[0][j].size));

                  dv_vlc_map[i][j].size = dv_vlc_map[i-1][0].size +

                                          dv_vlc_map[0][j].size;

              }

              dv_vlc_map[i][((uint16_t)(-j))&0x1ff].vlc =

                                            dv_vlc_map[i][j].vlc | 1;

              dv_vlc_map[i][((uint16_t)(-j))&0x1ff].size =

                                            dv_vlc_map[i][j].size;

           }

#endif

        }

    }

    /* Generic DSP setup */

    dsputil_init(&dsp, avctx);

    s->get_pixels = dsp.get_pixels;

    /* 88DCT setup */

    s->fdct[0] = dsp.fdct;

    s->idct_put[0] = dsp.idct_put;

    for (i=0; i<64; i++)

       s->dv_zigzag[0][i] = dsp.idct_permutation[ff_zigzag_direct[i]];

    /* 248DCT setup */

    s->fdct[1] = dsp.fdct248;

    s->idct_put[1] = simple_idct248_put;  // FIXME: need to add it to DSP

    if(avctx->lowres){

        for (i=0; i<64; i++){

            int j= ff_zigzag248_direct[i];

            s->dv_zigzag[1][i] = dsp.idct_permutation[(j&7) + (j&8)*4 + (j&48)/2];

        }

    }else

        memcpy(s->dv_zigzag[1], ff_zigzag248_direct, 64);

    /* XXX: do it only for constant case */

    dv_build_unquantize_tables(s, dsp.idct_permutation);

    /* FIXME: I really don't think this should be here */

    if (dv_codec_profile(avctx))

        avctx->pix_fmt = dv_codec_profile(avctx)->pix_fmt;

    avctx->coded_frame = &s->picture;

    s->avctx= avctx;

    return 0;

}

// #define VLC_DEBUG

// #define printf(...) av_log(NULL, AV_LOG_ERROR, __VA_ARGS__)

typedef struct BlockInfo {

    const uint8_t *shift_table;

    const uint8_t *scan_table;

    uint8_t pos; /* position in block */

    uint8_t dct_mode;

    uint8_t partial_bit_count;

    uint16_t partial_bit_buffer;

    int shift_offset;

} BlockInfo;

/* block size in bits */

static const uint16_t block_sizes[6] = {

    112, 112, 112, 112, 80, 80

};

/* bit budget for AC only in 5 MBs */

static const int vs_total_ac_bits = (100 * 4 + 68*2) * 5;

/* see dv_88_areas and dv_248_areas for details */

static const int mb_area_start[5] = { 1, 6, 21, 43, 64 };

#ifndef ALT_BITSTREAM_READER

#warning only works with ALT_BITSTREAM_READER

static int re_index; //Hack to make it compile

#endif

static inline int get_bits_left(GetBitContext *s)

{

    return s->size_in_bits - get_bits_count(s);

}

static inline int get_bits_size(GetBitContext *s)

{

    return s->size_in_bits;

}

static inline int put_bits_left(PutBitContext* s)

{

    return (s->buf_end - s->buf) * 8 - put_bits_count(s);

}

/* decode ac coefs */

static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block)

{

    int last_index = get_bits_size(gb);

    const uint8_t *scan_table = mb->scan_table;

    const uint8_t *shift_table = mb->shift_table;

    int pos = mb->pos;

    int partial_bit_count = mb->partial_bit_count;

    int level, pos1, run, vlc_len, index;

    OPEN_READER(re, gb);

    UPDATE_CACHE(re, gb);

    /* if we must parse a partial vlc, we do it here */

    if (partial_bit_count > 0) {

        re_cache = ((unsigned)re_cache >> partial_bit_count) |

                   (mb->partial_bit_buffer << (sizeof(re_cache)*8 - partial_bit_count));

        re_index -= partial_bit_count;

        mb->partial_bit_count = 0;

    }

    /* get the AC coefficients until last_index is reached */

    for(;;) {

#ifdef VLC_DEBUG

        printf("%2d: bits=%04x index=%d\n", pos, SHOW_UBITS(re, gb, 16), re_index);

#endif

        /* our own optimized GET_RL_VLC */

        index = NEG_USR32(re_cache, TEX_VLC_BITS);

        vlc_len = dv_rl_vlc[index].len;

        if (vlc_len < 0) {

            index = NEG_USR32((unsigned)re_cache << TEX_VLC_BITS, -vlc_len) + dv_rl_vlc[index].level;

            vlc_len = TEX_VLC_BITS - vlc_len;

        }

        level = dv_rl_vlc[index].level;

        run = dv_rl_vlc[index].run;

        /* gotta check if we're still within gb boundaries */

        if (re_index + vlc_len > last_index) {

            /* should be < 16 bits otherwise a codeword could have been parsed */

            mb->partial_bit_count = last_index - re_index;

            mb->partial_bit_buffer = NEG_USR32(re_cache, mb->partial_bit_count);

            re_index = last_index;

            break;

        }

        re_index += vlc_len;

#ifdef VLC_DEBUG

        printf("run=%d level=%d\n", run, level);

#endif

        pos += run;

        if (pos >= 64)

            break;

        assert(level);

        pos1 = scan_table[pos];

        block[pos1] = level << shift_table[pos1];

        UPDATE_CACHE(re, gb);

    }

    CLOSE_READER(re, gb);

    mb->pos = pos;

}

static inline void bit_copy(PutBitContext *pb, GetBitContext *gb)

{

    int bits_left = get_bits_left(gb);

    while (bits_left >= MIN_CACHE_BITS) {

        put_bits(pb, MIN_CACHE_BITS, get_bits(gb, MIN_CACHE_BITS));

        bits_left -= MIN_CACHE_BITS;

    }

    if (bits_left > 0) {

        put_bits(pb, bits_left, get_bits(gb, bits_left));

    }

}

/* mb_x and mb_y are in units of 8 pixels */

static inline void dv_decode_video_segment(DVVideoContext *s,

                                           uint8_t *buf_ptr1,

                                           const uint16_t *mb_pos_ptr)

{

    int quant, dc, dct_mode, class1, j;

    int mb_index, mb_x, mb_y, v, last_index;

    DCTELEM *block, *block1;

    int c_offset;

    uint8_t *y_ptr;

    void (*idct_put)(uint8_t *dest, int line_size, DCTELEM *block);

    uint8_t *buf_ptr;

    PutBitContext pb, vs_pb;

    GetBitContext gb;

    BlockInfo mb_data[5 * 6], *mb, *mb1;

    DCTELEM sblock[5*6][64] __align8;

    uint8_t mb_bit_buffer[80 + 4] __align8; /* allow some slack */

    uint8_t vs_bit_buffer[5 * 80 + 4] __align8; /* allow some slack */

    const int log2_blocksize= 3-s->avctx->lowres;

    assert((((int)mb_bit_buffer)&7)==0);

    assert((((int)vs_bit_buffer)&7)==0);

    memset(sblock, 0, sizeof(sblock));

    /* pass 1 : read DC and AC coefficients in blocks */

    buf_ptr = buf_ptr1;

    block1 = &sblock[0][0];

    mb1 = mb_data;

    init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80);

    for(mb_index = 0; mb_index < 5; mb_index++, mb1 += 6, block1 += 6 * 64) {

        /* skip header */

        quant = buf_ptr[3] & 0x0f;

        buf_ptr += 4;

        init_put_bits(&pb, mb_bit_buffer, 80);

        mb = mb1;

        block = block1;

        for(j = 0;j < 6; j++) {

            last_index = block_sizes[j];

            init_get_bits(&gb, buf_ptr, last_index);

            /* get the dc */

            dc = get_sbits(&gb, 9);

            dct_mode = get_bits1(&gb);

            mb->dct_mode = dct_mode;

            mb->scan_table = s->dv_zigzag[dct_mode];

            class1 = get_bits(&gb, 2);

            mb->shift_table = s->dv_idct_shift[class1 == 3][dct_mode]

                [quant + dv_quant_offset[class1]];

            dc = dc << 2;

            /* convert to unsigned because 128 is not added in the

               standard IDCT */

            dc += 1024;

            block[0] = dc;

            buf_ptr += last_index >> 3;

            mb->pos = 0;

            mb->partial_bit_count = 0;

#ifdef VLC_DEBUG

            printf("MB block: %d, %d ", mb_index, j);

#endif

            dv_decode_ac(&gb, mb, block);

            /* write the remaining bits  in a new buffer only if the

               block is finished */

            if (mb->pos >= 64)

                bit_copy(&pb, &gb);

            block += 64;

            mb++;

        }

        /* pass 2 : we can do it just after */

#ifdef VLC_DEBUG

        printf("***pass 2 size=%d MB#=%d\n", put_bits_count(&pb), mb_index);

#endif

        block = block1;

        mb = mb1;

        init_get_bits(&gb, mb_bit_buffer, put_bits_count(&pb));

        flush_put_bits(&pb);

        for(j = 0;j < 6; j++, block += 64, mb++) {

            if (mb->pos < 64 && get_bits_left(&gb) > 0) {

                dv_decode_ac(&gb, mb, block);

                /* if still not finished, no need to parse other blocks */

                if (mb->pos < 64)

                    break;

            }

        }

        /* all blocks are finished, so the extra bytes can be used at

           the video segment level */

        if (j >= 6)

            bit_copy(&vs_pb, &gb);

    }

    /* we need a pass other the whole video segment */

#ifdef VLC_DEBUG

    printf("***pass 3 size=%d\n", put_bits_count(&vs_pb));

#endif

    block = &sblock[0][0];

    mb = mb_data;

    init_get_bits(&gb, vs_bit_buffer, put_bits_count(&vs_pb));

    flush_put_bits(&vs_pb);

    for(mb_index = 0; mb_index < 5; mb_index++) {

        for(j = 0;j < 6; j++) {

            if (mb->pos < 64) {

#ifdef VLC_DEBUG

                printf("start %d:%d\n", mb_index, j);

#endif

                dv_decode_ac(&gb, mb, block);

            }

            if (mb->pos >= 64 && mb->pos < 127)

                av_log(NULL, AV_LOG_ERROR, "AC EOB marker is absent pos=%d\n", mb->pos);

            block += 64;

            mb++;

        }

    }

    /* compute idct and place blocks */

    block = &sblock[0][0];

    mb = mb_data;

    for(mb_index = 0; mb_index < 5; mb_index++) {

        v = *mb_pos_ptr++;

        mb_x = v & 0xff;

        mb_y = v >> 8;

        y_ptr = s->picture.data[0] + ((mb_y * s->picture.linesize[0] + mb_x)<<log2_blocksize);

        if (s->sys->pix_fmt == PIX_FMT_YUV411P)

            c_offset = ((mb_y * s->picture.linesize[1] + (mb_x >> 2))<<log2_blocksize);

        else

            c_offset = (((mb_y >> 1) * s->picture.linesize[1] + (mb_x >> 1))<<log2_blocksize);

        for(j = 0;j < 6; j++) {

            idct_put = s->idct_put[mb->dct_mode && log2_blocksize==3];

            if (j < 4) {

                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x < (704 / 8)) {

                    /* NOTE: at end of line, the macroblock is handled as 420 */

                    idct_put(y_ptr + (j<<log2_blocksize), s->picture.linesize[0], block);

                } else {

                    idct_put(y_ptr + (((j & 1) + (j >> 1) * s->picture.linesize[0])<<log2_blocksize),

                             s->picture.linesize[0], block);

                }

            } else {

                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x >= (704 / 8)) {

                    uint64_t aligned_pixels[64/8];

                    uint8_t *pixels= (uint8_t*)aligned_pixels;

                    uint8_t *c_ptr, *c_ptr1, *ptr, *ptr1;

                    int x, y, linesize;

                    /* NOTE: at end of line, the macroblock is handled as 420 */

                    idct_put(pixels, 8, block);

                    linesize = s->picture.linesize[6 - j];

                    c_ptr = s->picture.data[6 - j] + c_offset;

                    ptr = pixels;

                    for(y = 0;y < (1<<log2_blocksize); y++) {

                        ptr1= ptr + (1<<(log2_blocksize-1));

                        c_ptr1 = c_ptr + (linesize<<log2_blocksize);

                        for(x=0; x < (1<<(log2_blocksize-1)); x++){

                            c_ptr[x]= ptr[x]; c_ptr1[x]= ptr1[x];

                        }

                        c_ptr += linesize;

                        ptr += 8;

                    }

                } else {

                    /* don't ask me why they inverted Cb and Cr ! */

                    idct_put(s->picture.data[6 - j] + c_offset,

                             s->picture.linesize[6 - j], block);

                }

            }

            block += 64;

            mb++;

        }

    }

}

#ifdef DV_CODEC_TINY_TARGET

/* Converts run and level (where level != 0) pair into vlc, returning bit size */

static always_inline int dv_rl2vlc(int run, int level, int sign, uint32_t* vlc)

{

    int size;

    if (run < DV_VLC_MAP_RUN_SIZE && level < DV_VLC_MAP_LEV_SIZE) {

        *vlc = dv_vlc_map[run][level].vlc | sign;

        size = dv_vlc_map[run][level].size;

    }

    else {

        if (level < DV_VLC_MAP_LEV_SIZE) {

            *vlc = dv_vlc_map[0][level].vlc | sign;

            size = dv_vlc_map[0][level].size;

        } else {

            *vlc = 0xfe00 | (level << 1) | sign;

            size = 16;

        }

        if (run) {

            *vlc |= ((run < 16) ? dv_vlc_map[run-1][0].vlc :

                                  (0x1f80 | (run - 1))) << size;

            size += (run < 16) ? dv_vlc_map[run-1][0].size : 13;

        }

    }

    return size;

}

static always_inline int dv_rl2vlc_size(int run, int level)

{

    int size;

    if (run < DV_VLC_MAP_RUN_SIZE && level < DV_VLC_MAP_LEV_SIZE) {

        size = dv_vlc_map[run][level].size;

    }

    else {

        size = (level < DV_VLC_MAP_LEV_SIZE) ? dv_vlc_map[0][level].size : 16;

        if (run) {

            size += (run < 16) ? dv_vlc_map[run-1][0].size : 13;

        }

    }

    return size;

}

#else

static always_inline int dv_rl2vlc(int run, int l, int sign, uint32_t* vlc)

{

    *vlc = dv_vlc_map[run][l].vlc | sign;

    return dv_vlc_map[run][l].size;

}

static always_inline int dv_rl2vlc_size(int run, int l)

{

    return dv_vlc_map[run][l].size;

}

#endif

typedef struct EncBlockInfo {

    int area_q[4];

    int bit_size[4];

    int prev[5];

    int cur_ac;

    int cno;

    int dct_mode;

    DCTELEM mb[64];

    uint8_t next[64];

    uint8_t sign[64];

    uint8_t partial_bit_count;

    uint32_t partial_bit_buffer; /* we can't use uint16_t here */

} EncBlockInfo;

static always_inline PutBitContext* dv_encode_ac(EncBlockInfo* bi, PutBitContext* pb_pool,

                                       PutBitContext* pb_end)

{

    int prev;

    int bits_left;

    PutBitContext* pb = pb_pool;

    int size = bi->partial_bit_count;

    uint32_t vlc = bi->partial_bit_buffer;

    bi->partial_bit_count = bi->partial_bit_buffer = 0;

    for(;;){

       /* Find suitable storage space */

       for (; size > (bits_left = put_bits_left(pb)); pb++) {

          if (bits_left) {

              size -= bits_left;

              put_bits(pb, bits_left, vlc >> size);

              vlc = vlc & ((1<<size)-1);

          }

          if (pb + 1 >= pb_end) {

              bi->partial_bit_count = size;

              bi->partial_bit_buffer = vlc;

              return pb;

          }

       }

       /* Store VLC */

       put_bits(pb, size, vlc);

       if(bi->cur_ac>=64)

           break;

       /* Construct the next VLC */

       prev= bi->cur_ac;

       bi->cur_ac = bi->next[prev];

       if(bi->cur_ac < 64){

           size = dv_rl2vlc(bi->cur_ac - prev - 1, bi->mb[bi->cur_ac], bi->sign[bi->cur_ac], &vlc);

       } else {

           size = 4; vlc = 6; /* End Of Block stamp */

       }

    }

    return pb;

}

static always_inline void dv_set_class_number(DCTELEM* blk, EncBlockInfo* bi,

                                              const uint8_t* zigzag_scan, int bias)

{

    int i, area;

    static const int classes[] = {12, 24, 36, 0xffff};

    int max=12;

    int prev=0;

    bi->mb[0] = blk[0];

    for (area = 0; area < 4; area++) {

       bi->prev[area] = prev;

       bi->bit_size[area] = 1; // 4 areas 4 bits for EOB :)

       for (i=mb_area_start[area]; i<mb_area_start[area+1]; i++) {

          int level = blk[zigzag_scan[i]];

          if (level+15 > 30U) {

              bi->sign[i] = (level>>31)&1;

              bi->mb[i] = level= ABS(level)>>4;

              if(level>max) max= level;

              bi->bit_size[area] += dv_rl2vlc_size(i - prev  - 1, level);

              bi->next[prev]= i;

              prev= i;

          }

       }

    }

    bi->next[prev]= i;

    for(bi->cno = 0; max > classes[bi->cno]; bi->cno++);

    bi->cno += bias;

    if (bi->cno >= 3) {

        bi->cno = 3;

        prev=0;

        i= bi->next[prev];

        for (area = 0; area < 4; area++) {

            bi->prev[area] = prev;

            bi->bit_size[area] = 1; // 4 areas 4 bits for EOB :)

            for (; i<mb_area_start[area+1]; i= bi->next[i]) {

                bi->mb[i] >>=1;

                if (bi->mb[i]) {

                    bi->bit_size[area] += dv_rl2vlc_size(i - prev - 1, bi->mb[i]);

                    bi->next[prev]= i;

                    prev= i;

                }

            }

        }

        bi->next[prev]= i;

    }

}

//FIXME replace this by dsputil

#define SC(x, y) ((s[x] - s[y]) ^ ((s[x] - s[y]) >> 7))

static always_inline int dv_guess_dct_mode(DCTELEM *blk) {

    DCTELEM *s;

    int score88 = 0;

    int score248 = 0;

    int i;

    /* Compute 8-8 score (small values give a better chance for 8-8 DCT) */

    s = blk;

    for(i=0; i<7; i++) {

        score88 += SC(0,  8) + SC(1, 9) + SC(2, 10) + SC(3, 11) +

                   SC(4, 12) + SC(5,13) + SC(6, 14) + SC(7, 15);

        s += 8;

    }

    /* Compute 2-4-8 score (small values give a better chance for 2-4-8 DCT) */

    s = blk;

    for(i=0; i<6; i++) {

        score248 += SC(0, 16) + SC(1,17) + SC(2, 18) + SC(3, 19) +

                    SC(4, 20) + SC(5,21) + SC(6, 22) + SC(7, 23);

        s += 8;

    }

    return (score88 - score248 > -10);

}

static inline void dv_guess_qnos(EncBlockInfo* blks, int* qnos)

{

    int size[5];

    int i, j, k, a, prev;

    EncBlockInfo* b;

    do {

       b = blks;

       for (i=0; i<5; i++) {

          if (!qnos[i])

              continue;

          qnos[i]--;

          size[i] = 0;

          for (j=0; j<6; j++, b++) {

             for (a=0; a<4; a++) {

                if (b->area_q[a] != dv_quant_shifts[qnos[i] + dv_quant_offset[b->cno]][a]) {

                    b->bit_size[a] = 1; // 4 areas 4 bits for EOB :)

                    b->area_q[a]++;

                    prev= b->prev[a];

                    for (k= b->next[prev] ; k<mb_area_start[a+1]; k= b->next[k]) {

                       b->mb[k] >>= 1;

                       if (b->mb[k]) {

                           b->bit_size[a] += dv_rl2vlc_size(k - prev - 1, b->mb[k]);

                           prev= k;

                       } else {

                           b->next[prev] = b->next[k];

                       }

                    }

                    b->prev[a+1]= prev;

                }

                size[i] += b->bit_size[a];

             }

          }

       }

    } while ((vs_total_ac_bits < size[0] + size[1] + size[2] + size[3] + size[4]) &&

             (qnos[0]|qnos[1]|qnos[2]|qnos[3]|qnos[4]));

}

/*

 * This is a very rough initial implementaion. The performance is

 * horrible and the weighting is missing. But it's missing from the

 * decoding step also -- so at least we're on the same page with decoder ;-)

 */

static inline void dv_encode_video_segment(DVVideoContext *s,

                                           uint8_t *dif,

                                           const uint16_t *mb_pos_ptr)

{

    int mb_index, i, j, v;

    int mb_x, mb_y, c_offset, linesize;

    uint8_t*  y_ptr;

    uint8_t*  data;

    uint8_t*  ptr;

    int       do_edge_wrap;

    DCTELEM   block[64] __align8;

    EncBlockInfo  enc_blks[5*6];

    PutBitContext pbs[5*6];

    PutBitContext* pb;

    EncBlockInfo* enc_blk;

    int       vs_bit_size = 0;

    int       qnos[5];

    assert((((int)block) & 7) == 0);

    enc_blk = &enc_blks[0];

    pb = &pbs[0];

    for(mb_index = 0; mb_index < 5; mb_index++) {

        v = *mb_pos_ptr++;

        mb_x = v & 0xff;

        mb_y = v >> 8;

        y_ptr = s->picture.data[0] + (mb_y * s->picture.linesize[0] * 8) + (mb_x * 8);

        c_offset = (s->sys->pix_fmt == PIX_FMT_YUV411P) ?

                   ((mb_y * s->picture.linesize[1] * 8) + ((mb_x >> 2) * 8)) :

                   (((mb_y >> 1) * s->picture.linesize[1] * 8) + ((mb_x >> 1) * 8));

        do_edge_wrap = 0;

        qnos[mb_index] = 15; /* No quantization */

        ptr = dif + mb_index*80 + 4;

        for(j = 0;j < 6; j++) {

            if (j < 4) {  /* Four Y blocks */

                /* NOTE: at end of line, the macroblock is handled as 420 */

                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x < (704 / 8)) {

                    data = y_ptr + (j * 8);

                } else {

                    data = y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->picture.linesize[0]);

                }

                linesize = s->picture.linesize[0];

            } else {      /* Cr and Cb blocks */

                /* don't ask Fabrice why they inverted Cb and Cr ! */

                data = s->picture.data[6 - j] + c_offset;

                linesize = s->picture.linesize[6 - j];

                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x >= (704 / 8))

                    do_edge_wrap = 1;

            }

            /* Everything is set up -- now just copy data -> DCT block */

            if (do_edge_wrap) {  /* Edge wrap copy: 4x16 -> 8x8 */

                uint8_t* d;

                DCTELEM *b = block;

                for (i=0;i<8;i++) {

                   d = data + 8 * linesize;

                   b[0] = data[0]; b[1] = data[1]; b[2] = data[2]; b[3] = data[3];

                   b[4] =    d[0]; b[5] =    d[1]; b[6] =    d[2]; b[7] =    d[3];

                   data += linesize;

                   b += 8;

                }

            } else {             /* Simple copy: 8x8 -> 8x8 */

                s->get_pixels(block, data, linesize);

            }

            if(s->avctx->flags & CODEC_FLAG_INTERLACED_DCT)

                enc_blk->dct_mode = dv_guess_dct_mode(block);

            else

                enc_blk->dct_mode = 0;

            enc_blk->area_q[0] = enc_blk->area_q[1] = enc_blk->area_q[2] = enc_blk->area_q[3] = 0;

            enc_blk->partial_bit_count = 0;

            enc_blk->partial_bit_buffer = 0;

            enc_blk->cur_ac = 0;

            s->fdct[enc_blk->dct_mode](block);

            dv_set_class_number(block, enc_blk,

                                enc_blk->dct_mode ? ff_zigzag248_direct : ff_zigzag_direct, j/4);

            init_put_bits(pb, ptr, block_sizes[j]/8);

            put_bits(pb, 9, (uint16_t)(((enc_blk->mb[0] >> 3) - 1024 + 2) >> 2));

            put_bits(pb, 1, enc_blk->dct_mode);

            put_bits(pb, 2, enc_blk->cno);

            vs_bit_size += enc_blk->bit_size[0] + enc_blk->bit_size[1] +

                           enc_blk->bit_size[2] + enc_blk->bit_size[3];

            ++enc_blk;

            ++pb;

            ptr += block_sizes[j]/8;

        }

    }

    if (vs_total_ac_bits < vs_bit_size)

        dv_guess_qnos(&enc_blks[0], &qnos[0]);

    for (i=0; i<5; i++) {

       dif[i*80 + 3] = qnos[i];

    }

    /* First pass over individual cells only */

    for (j=0; j<5*6; j++)

       dv_encode_ac(&enc_blks[j], &pbs[j], &pbs[j+1]);

    /* Second pass over each MB space */

    for (j=0; j<5*6; j+=6) {

        pb= &pbs[j];

        for (i=0; i<6; i++) {

            if (enc_blks[i+j].partial_bit_count)

                pb=dv_encode_ac(&enc_blks[i+j], pb, &pbs[j+6]);

        }

    }

    /* Third and final pass over the whole vides segment space */

    pb= &pbs[0];

    for (j=0; j<5*6; j++) {

       if (enc_blks[j].partial_bit_count)

           pb=dv_encode_ac(&enc_blks[j], pb, &pbs[6*5]);

    }

    for (j=0; j<5*6; j++)

       flush_put_bits(&pbs[j]);

}

static int dv_decode_mt(AVCodecContext *avctx, void* sl)

{

    DVVideoContext *s = avctx->priv_data;

    int slice = (size_t)sl;

    dv_decode_video_segment(s, &s->buf[((slice/27)*6+(slice/3)+slice*5+7)*80],

                            &s->sys->video_place[slice*5]);

    return 0;

}

static int dv_encode_mt(AVCodecContext *avctx, void* sl)

{

    DVVideoContext *s = avctx->priv_data;

    int slice = (size_t)sl;

    dv_encode_video_segment(s, &s->buf[((slice/27)*6+(slice/3)+slice*5+7)*80],

                            &s->sys->video_place[slice*5]);

    return 0;

}

/* NOTE: exactly one frame must be given (120000 bytes for NTSC,

   144000 bytes for PAL) */

static int dvvideo_decode_frame(AVCodecContext *avctx,

                                 void *data, int *data_size,

                                 uint8_t *buf, int buf_size)

{

    DVVideoContext *s = avctx->priv_data;

    s->sys = dv_frame_profile(buf);

    if (!s->sys || buf_size < s->sys->frame_size)