ffmpeg/libavcodec/msmpeg4.c

/*
 * MSMPEG4 backend for encoder and decoder
 * Copyright (c) 2001 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * msmpeg4v1 & v2 stuff by Michael Niedermayer <michaelni@gmx.at>
 *
 * 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
 * MSMPEG4 backend for encoder and decoder
 */

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "msmpeg4.h"
#include "libavutil/x86/asm.h"
#include "h263.h"
#include "mpeg4video.h"
#include "msmpeg4data.h"
#include "vc1data.h"

/*
 * You can also call this codec : MPEG4 with a twist !
 *
 * TODO:
 *        - (encoding) select best mv table (two choices)
 *        - (encoding) select best vlc/dc table
 */
//#define DEBUG

#define DC_VLC_BITS 9
#define V2_INTRA_CBPC_VLC_BITS 3
#define V2_MB_TYPE_VLC_BITS 7
#define MV_VLC_BITS 9
#define V2_MV_VLC_BITS 9
#define TEX_VLC_BITS 9

#define DEFAULT_INTER_INDEX 3

/* This table is practically identical to the one from h263
 * except that it is inverted. */
static av_cold void init_h263_dc_for_msmpeg4(void)
{
        int level, uni_code, uni_len;

        if(ff_v2_dc_chroma_table[255 + 256][1])
            return;

        for(level=-256; level<256; level++){
            int size, v, l;
            /* find number of bits */
            size = 0;
            v = abs(level);
            while (v) {
                v >>= 1;
                    size++;
            }

            if (level < 0)
                l= (-level) ^ ((1 << size) - 1);
            else
                l= level;

            /* luminance h263 */
            uni_code= ff_mpeg4_DCtab_lum[size][0];
            uni_len = ff_mpeg4_DCtab_lum[size][1];
            uni_code ^= (1<<uni_len)-1; //M$ does not like compatibility

            if (size > 0) {
                uni_code<<=size; uni_code|=l;
                uni_len+=size;
                if (size > 8){
                    uni_code<<=1; uni_code|=1;
                    uni_len++;
                }
            }
            ff_v2_dc_lum_table[level + 256][0] = uni_code;
            ff_v2_dc_lum_table[level + 256][1] = uni_len;

            /* chrominance h263 */
            uni_code= ff_mpeg4_DCtab_chrom[size][0];
            uni_len = ff_mpeg4_DCtab_chrom[size][1];
            uni_code ^= (1<<uni_len)-1; //M$ does not like compatibility

            if (size > 0) {
                uni_code<<=size; uni_code|=l;
                uni_len+=size;
                if (size > 8){
                    uni_code<<=1; uni_code|=1;
                    uni_len++;
                }
            }
            ff_v2_dc_chroma_table[level + 256][0] = uni_code;
            ff_v2_dc_chroma_table[level + 256][1] = uni_len;

        }
}

av_cold void ff_msmpeg4_common_init(MpegEncContext *s)
{
    switch(s->msmpeg4_version){
    case 1:
    case 2:
        s->y_dc_scale_table=
        s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
        break;
    case 3:
        if(s->workaround_bugs){
            s->y_dc_scale_table= ff_old_ff_y_dc_scale_table;
            s->c_dc_scale_table= ff_wmv1_c_dc_scale_table;
        } else{
            s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table;
            s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
        }
        break;
    case 4:
    case 5:
        s->y_dc_scale_table= ff_wmv1_y_dc_scale_table;
        s->c_dc_scale_table= ff_wmv1_c_dc_scale_table;
        break;
#if CONFIG_VC1_DECODER
    case 6:
        s->y_dc_scale_table= ff_wmv3_dc_scale_table;
        s->c_dc_scale_table= ff_wmv3_dc_scale_table;
        break;
#endif

    }


    if(s->msmpeg4_version>=4){
        ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_wmv1_scantable[1]);
        ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_wmv1_scantable[2]);
        ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_wmv1_scantable[3]);
        ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_wmv1_scantable[0]);
    }
    //Note the default tables are set in common_init in mpegvideo.c

    init_h263_dc_for_msmpeg4();
}

/* predict coded block */
int ff_msmpeg4_coded_block_pred(MpegEncContext * s, int n, uint8_t **coded_block_ptr)
{
    int xy, wrap, pred, a, b, c;

    xy = s->block_index[n];
    wrap = s->b8_stride;

    /* B C
     * A X
     */
    a = s->coded_block[xy - 1       ];
    b = s->coded_block[xy - 1 - wrap];
    c = s->coded_block[xy     - wrap];

    if (b == c) {
        pred = a;
    } else {
        pred = c;
    }

    /* store value */
    *coded_block_ptr = &s->coded_block[xy];

    return pred;
}

static inline int msmpeg4v1_pred_dc(MpegEncContext * s, int n,
                                    int32_t **dc_val_ptr)
{
    int i;

    if (n < 4) {
        i= 0;
    } else {
        i= n-3;
    }

    *dc_val_ptr= &s->last_dc[i];
    return s->last_dc[i];
}

static int get_dc(uint8_t *src, int stride, int scale)
{
    int y;
    int sum=0;
    for(y=0; y<8; y++){
        int x;
        for(x=0; x<8; x++){
            sum+=src[x + y*stride];
        }
    }
    return FASTDIV((sum + (scale>>1)), scale);
}

/* dir = 0: left, dir = 1: top prediction */
int ff_msmpeg4_pred_dc(MpegEncContext *s, int n,
                       int16_t **dc_val_ptr, int *dir_ptr)
{
    int a, b, c, wrap, pred, scale;
    int16_t *dc_val;

    /* find prediction */
    if (n < 4) {
        scale = s->y_dc_scale;
    } else {
        scale = s->c_dc_scale;
    }

    wrap = s->block_wrap[n];
    dc_val= s->dc_val[0] + s->block_index[n];

    /* B C
     * A X
     */
    a = dc_val[ - 1];
    b = dc_val[ - 1 - wrap];
    c = dc_val[ - wrap];

    if(s->first_slice_line && (n&2)==0 && s->msmpeg4_version<4){
        b=c=1024;
    }

    /* XXX: the following solution consumes divisions, but it does not
       necessitate to modify mpegvideo.c. The problem comes from the
       fact they decided to store the quantized DC (which would lead
       to problems if Q could vary !) */
#if ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE
    __asm__ volatile(
        "movl %3, %%eax         \n\t"
        "shrl $1, %%eax         \n\t"
        "addl %%eax, %2         \n\t"
        "addl %%eax, %1         \n\t"
        "addl %0, %%eax         \n\t"
        "mull %4                \n\t"
        "movl %%edx, %0         \n\t"
        "movl %1, %%eax         \n\t"
        "mull %4                \n\t"
        "movl %%edx, %1         \n\t"
        "movl %2, %%eax         \n\t"
        "mull %4                \n\t"
        "movl %%edx, %2         \n\t"
        : "+b" (a), "+c" (b), "+D" (c)
        : "g" (scale), "S" (ff_inverse[scale])
        : "%eax", "%edx"
    );
#else
    /* #elif ARCH_ALPHA */
    /* Divisions are extremely costly on Alpha; optimize the most
       common case. But they are costly everywhere...
     */
    if (scale == 8) {
        a = (a + (8 >> 1)) / 8;
        b = (b + (8 >> 1)) / 8;
        c = (c + (8 >> 1)) / 8;
    } else {
        a = FASTDIV((a + (scale >> 1)), scale);
        b = FASTDIV((b + (scale >> 1)), scale);
        c = FASTDIV((c + (scale >> 1)), scale);
    }
#endif
    /* XXX: WARNING: they did not choose the same test as MPEG4. This
       is very important ! */
    if(s->msmpeg4_version>3){
        if(s->inter_intra_pred){
            uint8_t *dest;
            int wrap;

            if(n==1){
                pred=a;
                *dir_ptr = 0;
            }else if(n==2){
                pred=c;
                *dir_ptr = 1;
            }else if(n==3){
                if (abs(a - b) < abs(b - c)) {
                    pred = c;
                    *dir_ptr = 1;
                } else {
                    pred = a;
                    *dir_ptr = 0;
                }
            }else{
                if(n<4){
                    wrap= s->linesize;
                    dest= s->current_picture.f.data[0] + (((n >> 1) + 2*s->mb_y) * 8*  wrap ) + ((n & 1) + 2*s->mb_x) * 8;
                }else{
                    wrap= s->uvlinesize;
                    dest= s->current_picture.f.data[n - 3] + (s->mb_y * 8 * wrap) + s->mb_x * 8;
                }
                if(s->mb_x==0) a= (1024 + (scale>>1))/scale;
                else           a= get_dc(dest-8, wrap, scale*8);
                if(s->mb_y==0) c= (1024 + (scale>>1))/scale;
                else           c= get_dc(dest-8*wrap, wrap, scale*8);

                if (s->h263_aic_dir==0) {
                    pred= a;
                    *dir_ptr = 0;
                }else if (s->h263_aic_dir==1) {
                    if(n==0){
                        pred= c;
                        *dir_ptr = 1;
                    }else{
                        pred= a;
                        *dir_ptr = 0;
                    }
                }else if (s->h263_aic_dir==2) {
                    if(n==0){
                        pred= a;
                        *dir_ptr = 0;
                    }else{
                        pred= c;
                        *dir_ptr = 1;
                    }
                } else {
                    pred= c;
                    *dir_ptr = 1;
                }
            }
        }else{
            if (abs(a - b) < abs(b - c)) {
                pred = c;
                *dir_ptr = 1;
            } else {
                pred = a;
                *dir_ptr = 0;
            }
        }
    }else{
        if (abs(a - b) <= abs(b - c)) {
            pred = c;
            *dir_ptr = 1;
        } else {
            pred = a;
            *dir_ptr = 0;
        }
    }

    /* update predictor */
    *dc_val_ptr = &dc_val[0];
    return pred;
}

/****************************************/
/* decoding stuff */

VLC ff_mb_non_intra_vlc[4];
static VLC v2_dc_lum_vlc;
static VLC v2_dc_chroma_vlc;
static VLC v2_intra_cbpc_vlc;
static VLC v2_mb_type_vlc;
static VLC v2_mv_vlc;
VLC ff_inter_intra_vlc;

/* This is identical to h263 except that its range is multiplied by 2. */
static int msmpeg4v2_decode_motion(MpegEncContext * s, int pred, int f_code)
{
    int code, val, sign, shift;

    code = get_vlc2(&s->gb, v2_mv_vlc.table, V2_MV_VLC_BITS, 2);
    av_dlog(s, "MV code %d at %d %d pred: %d\n", code, s->mb_x,s->mb_y, pred);
    if (code < 0)
        return 0xffff;

    if (code == 0)
        return pred;
    sign = get_bits1(&s->gb);
    shift = f_code - 1;
    val = code;
    if (shift) {
        val = (val - 1) << shift;
        val |= get_bits(&s->gb, shift);
        val++;
    }
    if (sign)
        val = -val;

    val += pred;
    if (val <= -64)
        val += 64;
    else if (val >= 64)
        val -= 64;

    return val;
}

static int msmpeg4v12_decode_mb(MpegEncContext *s, DCTELEM block[6][64])
{
    int cbp, code, i;
    uint32_t * const mb_type_ptr = &s->current_picture.f.mb_type[s->mb_x + s->mb_y*s->mb_stride];

    if (s->pict_type == AV_PICTURE_TYPE_P) {
        if (s->use_skip_mb_code) {
            if (get_bits1(&s->gb)) {
                /* skip mb */
                s->mb_intra = 0;
                for(i=0;i<6;i++)
                    s->block_last_index[i] = -1;
                s->mv_dir = MV_DIR_FORWARD;
                s->mv_type = MV_TYPE_16X16;
                s->mv[0][0][0] = 0;
                s->mv[0][0][1] = 0;
                s->mb_skipped = 1;
                *mb_type_ptr = MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
                return 0;
            }
        }

        if(s->msmpeg4_version==2)
            code = get_vlc2(&s->gb, v2_mb_type_vlc.table, V2_MB_TYPE_VLC_BITS, 1);
        else
            code = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
        if(code<0 || code>7){
            av_log(s->avctx, AV_LOG_ERROR, "cbpc %d invalid at %d %d\n", code, s->mb_x, s->mb_y);
            return -1;
        }

        s->mb_intra = code >>2;

        cbp = code & 0x3;
    } else {
        s->mb_intra = 1;
        if(s->msmpeg4_version==2)
            cbp= get_vlc2(&s->gb, v2_intra_cbpc_vlc.table, V2_INTRA_CBPC_VLC_BITS, 1);
        else
            cbp= get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 1);
        if(cbp<0 || cbp>3){
            av_log(s->avctx, AV_LOG_ERROR, "cbpc %d invalid at %d %d\n", cbp, s->mb_x, s->mb_y);
            return -1;
        }
    }

    if (!s->mb_intra) {
        int mx, my, cbpy;

        cbpy= get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
        if(cbpy<0){
            av_log(s->avctx, AV_LOG_ERROR, "cbpy %d invalid at %d %d\n", cbp, s->mb_x, s->mb_y);
            return -1;
        }

        cbp|= cbpy<<2;
        if(s->msmpeg4_version==1 || (cbp&3) != 3) cbp^= 0x3C;

        ff_h263_pred_motion(s, 0, 0, &mx, &my);
        mx= msmpeg4v2_decode_motion(s, mx, 1);
        my= msmpeg4v2_decode_motion(s, my, 1);

        s->mv_dir = MV_DIR_FORWARD;
        s->mv_type = MV_TYPE_16X16;
        s->mv[0][0][0] = mx;
        s->mv[0][0][1] = my;
        *mb_type_ptr = MB_TYPE_L0 | MB_TYPE_16x16;
    } else {
        if(s->msmpeg4_version==2){
            s->ac_pred = get_bits1(&s->gb);
            cbp|= get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1)<<2; //FIXME check errors
        } else{
            s->ac_pred = 0;
            cbp|= get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1)<<2; //FIXME check errors
            if(s->pict_type==AV_PICTURE_TYPE_P) cbp^=0x3C;
        }
        *mb_type_ptr = MB_TYPE_INTRA;
    }

    s->dsp.clear_blocks(s->block[0]);
    for (i = 0; i < 6; i++) {
        if (ff_msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1, NULL) < 0)
        {
             av_log(s->avctx, AV_LOG_ERROR, "\nerror while decoding block: %d x %d (%d)\n", s->mb_x, s->mb_y, i);
             return -1;
        }
    }
    return 0;
}

static int msmpeg4v34_decode_mb(MpegEncContext *s, DCTELEM block[6][64])
{
    int cbp, code, i;
    uint8_t *coded_val;
    uint32_t * const mb_type_ptr = &s->current_picture.f.mb_type[s->mb_x + s->mb_y*s->mb_stride];

    if (s->pict_type == AV_PICTURE_TYPE_P) {
        if (s->use_skip_mb_code) {
            if (get_bits1(&s->gb)) {
                /* skip mb */
                s->mb_intra = 0;
                for(i=0;i<6;i++)
                    s->block_last_index[i] = -1;
                s->mv_dir = MV_DIR_FORWARD;
                s->mv_type = MV_TYPE_16X16;
                s->mv[0][0][0] = 0;
                s->mv[0][0][1] = 0;
                s->mb_skipped = 1;
                *mb_type_ptr = MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;

                return 0;
            }
        }

        code = get_vlc2(&s->gb, ff_mb_non_intra_vlc[DEFAULT_INTER_INDEX].table, MB_NON_INTRA_VLC_BITS, 3);
        if (code < 0)
            return -1;
        //s->mb_intra = (code & 0x40) ? 0 : 1;
        s->mb_intra = (~code & 0x40) >> 6;

        cbp = code & 0x3f;
    } else {
        s->mb_intra = 1;
        code = get_vlc2(&s->gb, ff_msmp4_mb_i_vlc.table, MB_INTRA_VLC_BITS, 2);
        if (code < 0)
            return -1;
        /* predict coded block pattern */
        cbp = 0;
        for(i=0;i<6;i++) {
            int val = ((code >> (5 - i)) & 1);
            if (i < 4) {
                int pred = ff_msmpeg4_coded_block_pred(s, i, &coded_val);
                val = val ^ pred;
                *coded_val = val;
            }
            cbp |= val << (5 - i);
        }
    }

    if (!s->mb_intra) {
        int mx, my;
        if(s->per_mb_rl_table && cbp){
            s->rl_table_index = decode012(&s->gb);
            s->rl_chroma_table_index = s->rl_table_index;
        }
        ff_h263_pred_motion(s, 0, 0, &mx, &my);
        if (ff_msmpeg4_decode_motion(s, &mx, &my) < 0)
            return -1;
        s->mv_dir = MV_DIR_FORWARD;
        s->mv_type = MV_TYPE_16X16;
        s->mv[0][0][0] = mx;
        s->mv[0][0][1] = my;
        *mb_type_ptr = MB_TYPE_L0 | MB_TYPE_16x16;
    } else {
        av_dlog(s, "I at %d %d %d %06X\n", s->mb_x, s->mb_y,
                ((cbp & 3) ? 1 : 0) +((cbp & 0x3C)? 2 : 0),
                show_bits(&s->gb, 24));
        s->ac_pred = get_bits1(&s->gb);
        *mb_type_ptr = MB_TYPE_INTRA;
        if(s->inter_intra_pred){
            s->h263_aic_dir= get_vlc2(&s->gb, ff_inter_intra_vlc.table, INTER_INTRA_VLC_BITS, 1);
            av_dlog(s, "%d%d %d %d/",
                    s->ac_pred, s->h263_aic_dir, s->mb_x, s->mb_y);
        }
        if(s->per_mb_rl_table && cbp){
            s->rl_table_index = decode012(&s->gb);
            s->rl_chroma_table_index = s->rl_table_index;
        }
    }

    s->dsp.clear_blocks(s->block[0]);
    for (i = 0; i < 6; i++) {
        if (ff_msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1, NULL) < 0)
        {
            av_log(s->avctx, AV_LOG_ERROR, "\nerror while decoding block: %d x %d (%d)\n", s->mb_x, s->mb_y, i);
            return -1;
        }
    }

    return 0;
}

/* init all vlc decoding tables */
av_cold int ff_msmpeg4_decode_init(AVCodecContext *avctx)
{
    MpegEncContext *s = avctx->priv_data;
    static volatile int done = 0;
    int i;
    MVTable *mv;

    if (ff_h263_decode_init(avctx) < 0)
        return -1;

    ff_msmpeg4_common_init(s);

    if (!done) {
        for(i=0;i<NB_RL_TABLES;i++) {
            ff_init_rl(&ff_rl_table[i], ff_static_rl_table_store[i]);
        }
        INIT_VLC_RL(ff_rl_table[0], 642);
        INIT_VLC_RL(ff_rl_table[1], 1104);
        INIT_VLC_RL(ff_rl_table[2], 554);
        INIT_VLC_RL(ff_rl_table[3], 940);
        INIT_VLC_RL(ff_rl_table[4], 962);
        INIT_VLC_RL(ff_rl_table[5], 554);

        mv = &ff_mv_tables[0];
        INIT_VLC_STATIC(&mv->vlc, MV_VLC_BITS, mv->n + 1,
                    mv->table_mv_bits, 1, 1,
                    mv->table_mv_code, 2, 2, 3714);
        mv = &ff_mv_tables[1];
        INIT_VLC_STATIC(&mv->vlc, MV_VLC_BITS, mv->n + 1,
                    mv->table_mv_bits, 1, 1,
                    mv->table_mv_code, 2, 2, 2694);

        INIT_VLC_STATIC(&ff_msmp4_dc_luma_vlc[0], DC_VLC_BITS, 120,
                 &ff_table0_dc_lum[0][1], 8, 4,
                 &ff_table0_dc_lum[0][0], 8, 4, 1158);
        INIT_VLC_STATIC(&ff_msmp4_dc_chroma_vlc[0], DC_VLC_BITS, 120,
                 &ff_table0_dc_chroma[0][1], 8, 4,
                 &ff_table0_dc_chroma[0][0], 8, 4, 1118);
        INIT_VLC_STATIC(&ff_msmp4_dc_luma_vlc[1], DC_VLC_BITS, 120,
                 &ff_table1_dc_lum[0][1], 8, 4,
                 &ff_table1_dc_lum[0][0], 8, 4, 1476);
        INIT_VLC_STATIC(&ff_msmp4_dc_chroma_vlc[1], DC_VLC_BITS, 120,
                 &ff_table1_dc_chroma[0][1], 8, 4,
                 &ff_table1_dc_chroma[0][0], 8, 4, 1216);

        INIT_VLC_STATIC(&v2_dc_lum_vlc, DC_VLC_BITS, 512,
                 &ff_v2_dc_lum_table[0][1], 8, 4,
                 &ff_v2_dc_lum_table[0][0], 8, 4, 1472);
        INIT_VLC_STATIC(&v2_dc_chroma_vlc, DC_VLC_BITS, 512,
                 &ff_v2_dc_chroma_table[0][1], 8, 4,
                 &ff_v2_dc_chroma_table[0][0], 8, 4, 1506);

        INIT_VLC_STATIC(&v2_intra_cbpc_vlc, V2_INTRA_CBPC_VLC_BITS, 4,
                 &ff_v2_intra_cbpc[0][1], 2, 1,
                 &ff_v2_intra_cbpc[0][0], 2, 1, 8);
        INIT_VLC_STATIC(&v2_mb_type_vlc, V2_MB_TYPE_VLC_BITS, 8,
                 &ff_v2_mb_type[0][1], 2, 1,
                 &ff_v2_mb_type[0][0], 2, 1, 128);
        INIT_VLC_STATIC(&v2_mv_vlc, V2_MV_VLC_BITS, 33,
                 &ff_mvtab[0][1], 2, 1,
                 &ff_mvtab[0][0], 2, 1, 538);

        INIT_VLC_STATIC(&ff_mb_non_intra_vlc[0], MB_NON_INTRA_VLC_BITS, 128,
                     &ff_wmv2_inter_table[0][0][1], 8, 4,
                     &ff_wmv2_inter_table[0][0][0], 8, 4, 1636);
        INIT_VLC_STATIC(&ff_mb_non_intra_vlc[1], MB_NON_INTRA_VLC_BITS, 128,
                     &ff_wmv2_inter_table[1][0][1], 8, 4,
                     &ff_wmv2_inter_table[1][0][0], 8, 4, 2648);
        INIT_VLC_STATIC(&ff_mb_non_intra_vlc[2], MB_NON_INTRA_VLC_BITS, 128,
                     &ff_wmv2_inter_table[2][0][1], 8, 4,
                     &ff_wmv2_inter_table[2][0][0], 8, 4, 1532);
        INIT_VLC_STATIC(&ff_mb_non_intra_vlc[3], MB_NON_INTRA_VLC_BITS, 128,
                     &ff_wmv2_inter_table[3][0][1], 8, 4,
                     &ff_wmv2_inter_table[3][0][0], 8, 4, 2488);

        INIT_VLC_STATIC(&ff_msmp4_mb_i_vlc, MB_INTRA_VLC_BITS, 64,
                 &ff_msmp4_mb_i_table[0][1], 4, 2,
                 &ff_msmp4_mb_i_table[0][0], 4, 2, 536);

        INIT_VLC_STATIC(&ff_inter_intra_vlc, INTER_INTRA_VLC_BITS, 4,
                 &ff_table_inter_intra[0][1], 2, 1,
                 &ff_table_inter_intra[0][0], 2, 1, 8);
        done = 1;
    }

    switch(s->msmpeg4_version){
    case 1:
    case 2:
        s->decode_mb= msmpeg4v12_decode_mb;
        break;
    case 3:
    case 4:
        s->decode_mb= msmpeg4v34_decode_mb;
        break;
    case 5:
        if (CONFIG_WMV2_DECODER)
            s->decode_mb= ff_wmv2_decode_mb;
    case 6:
        //FIXME + TODO VC1 decode mb
        break;
    }

    s->slice_height= s->mb_height; //to avoid 1/0 if the first frame is not a keyframe

    return 0;
}

int ff_msmpeg4_decode_picture_header(MpegEncContext * s)
{
    int code;

    if(s->msmpeg4_version==1){
        int start_code = get_bits_long(&s->gb, 32);
        if(start_code!=0x00000100){
            av_log(s->avctx, AV_LOG_ERROR, "invalid startcode\n");
            return -1;
        }

        skip_bits(&s->gb, 5); // frame number */
    }

    s->pict_type = get_bits(&s->gb, 2) + 1;
    if (s->pict_type != AV_PICTURE_TYPE_I &&
        s->pict_type != AV_PICTURE_TYPE_P){
        av_log(s->avctx, AV_LOG_ERROR, "invalid picture type\n");
        return -1;
    }
#if 0
{
    static int had_i=0;
    if(s->pict_type == AV_PICTURE_TYPE_I) had_i=1;
    if(!had_i) return -1;
}
#endif
    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
    if(s->qscale==0){
        av_log(s->avctx, AV_LOG_ERROR, "invalid qscale\n");
        return -1;
    }

    if (s->pict_type == AV_PICTURE_TYPE_I) {
        code = get_bits(&s->gb, 5);
        if(s->msmpeg4_version==1){
            if(code==0 || code>s->mb_height){
                av_log(s->avctx, AV_LOG_ERROR, "invalid slice height %d\n", code);
                return -1;
            }

            s->slice_height = code;
        }else{
            /* 0x17: one slice, 0x18: two slices, ... */
            if (code < 0x17){
                av_log(s->avctx, AV_LOG_ERROR, "error, slice code was %X\n", code);
                return -1;
            }

            s->slice_height = s->mb_height / (code - 0x16);
        }

        switch(s->msmpeg4_version){
        case 1:
        case 2:
            s->rl_chroma_table_index = 2;
            s->rl_table_index = 2;

            s->dc_table_index = 0; //not used
            break;
        case 3:
            s->rl_chroma_table_index = decode012(&s->gb);
            s->rl_table_index = decode012(&s->gb);

            s->dc_table_index = get_bits1(&s->gb);
            break;
        case 4:
            ff_msmpeg4_decode_ext_header(s, (2+5+5+17+7)/8);

            if(s->bit_rate > MBAC_BITRATE) s->per_mb_rl_table= get_bits1(&s->gb);
            else                           s->per_mb_rl_table= 0;

            if(!s->per_mb_rl_table){
                s->rl_chroma_table_index = decode012(&s->gb);
                s->rl_table_index = decode012(&s->gb);
            }

            s->dc_table_index = get_bits1(&s->gb);
            s->inter_intra_pred= 0;
            break;
        }
        s->no_rounding = 1;
        if(s->avctx->debug&FF_DEBUG_PICT_INFO)
            av_log(s->avctx, AV_LOG_DEBUG, "qscale:%d rlc:%d rl:%d dc:%d mbrl:%d slice:%d   \n",
                s->qscale,
                s->rl_chroma_table_index,
                s->rl_table_index,
                s->dc_table_index,
                s->per_mb_rl_table,
                s->slice_height);
    } else {
        switch(s->msmpeg4_version){
        case 1:
        case 2:
            if(s->msmpeg4_version==1)
                s->use_skip_mb_code = 1;
            else
                s->use_skip_mb_code = get_bits1(&s->gb);
            s->rl_table_index = 2;
            s->rl_chroma_table_index = s->rl_table_index;
            s->dc_table_index = 0; //not used
            s->mv_table_index = 0;
            break;
        case 3:
            s->use_skip_mb_code = get_bits1(&s->gb);
            s->rl_table_index = decode012(&s->gb);
            s->rl_chroma_table_index = s->rl_table_index;

            s->dc_table_index = get_bits1(&s->gb);

            s->mv_table_index = get_bits1(&s->gb);
            break;
        case 4:
            s->use_skip_mb_code = get_bits1(&s->gb);

            if(s->bit_rate > MBAC_BITRATE) s->per_mb_rl_table= get_bits1(&s->gb);
            else                           s->per_mb_rl_table= 0;

            if(!s->per_mb_rl_table){
                s->rl_table_index = decode012(&s->gb);
                s->rl_chroma_table_index = s->rl_table_index;
            }

            s->dc_table_index = get_bits1(&s->gb);

            s->mv_table_index = get_bits1(&s->gb);
            s->inter_intra_pred= (s->width*s->height < 320*240 && s->bit_rate<=II_BITRATE);
            break;
        }

        if(s->avctx->debug&FF_DEBUG_PICT_INFO)
            av_log(s->avctx, AV_LOG_DEBUG, "skip:%d rl:%d rlc:%d dc:%d mv:%d mbrl:%d qp:%d   \n",
                s->use_skip_mb_code,
                s->rl_table_index,
                s->rl_chroma_table_index,
                s->dc_table_index,
                s->mv_table_index,
                s->per_mb_rl_table,
                s->qscale);

        if(s->flipflop_rounding){
            s->no_rounding ^= 1;
        }else{
            s->no_rounding = 0;
        }
    }
    av_dlog(s->avctx, "%d %d %d %d %d\n", s->pict_type, s->bit_rate,
            s->inter_intra_pred, s->width, s->height);

    s->esc3_level_length= 0;
    s->esc3_run_length= 0;

    return 0;
}

int ff_msmpeg4_decode_ext_header(MpegEncContext * s, int buf_size)
{
    int left= buf_size*8 - get_bits_count(&s->gb);
    int length= s->msmpeg4_version>=3 ? 17 : 16;
    /* the alt_bitstream reader could read over the end so we need to check it */
    if(left>=length && left<length+8)
    {
        skip_bits(&s->gb, 5); /* fps */
        s->bit_rate= get_bits(&s->gb, 11)*1024;
        if(s->msmpeg4_version>=3)
            s->flipflop_rounding= get_bits1(&s->gb);
        else
            s->flipflop_rounding= 0;
    }
    else if(left<length+8)
    {
        s->flipflop_rounding= 0;
        if(s->msmpeg4_version != 2)
            av_log(s->avctx, AV_LOG_ERROR, "ext header missing, %d left\n", left);
    }
    else
    {
        av_log(s->avctx, AV_LOG_ERROR, "I frame too long, ignoring ext header\n");
    }

    return 0;
}

static int msmpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
{
    int level, pred;

    if(s->msmpeg4_version<=2){
        if (n < 4) {
            level = get_vlc2(&s->gb, v2_dc_lum_vlc.table, DC_VLC_BITS, 3);
        } else {
            level = get_vlc2(&s->gb, v2_dc_chroma_vlc.table, DC_VLC_BITS, 3);
        }
        if (level < 0)
            return -1;
        level-=256;
    }else{  //FIXME optimize use unified tables & index
        if (n < 4) {
            level = get_vlc2(&s->gb, ff_msmp4_dc_luma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);
        } else {
            level = get_vlc2(&s->gb, ff_msmp4_dc_chroma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);
        }
        if (level < 0){
            av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
            return -1;
        }

        if (level == DC_MAX) {
            level = get_bits(&s->gb, 8);
            if (get_bits1(&s->gb))
                level = -level;
        } else if (level != 0) {
            if (get_bits1(&s->gb))
                level = -level;
        }
    }

    if(s->msmpeg4_version==1){
        int32_t *dc_val;
        pred = msmpeg4v1_pred_dc(s, n, &dc_val);
        level += pred;

        /* update predictor */
        *dc_val= level;
    }else{
        int16_t *dc_val;
        pred   = ff_msmpeg4_pred_dc(s, n, &dc_val, dir_ptr);
        level += pred;

        /* update predictor */
        if (n < 4) {
            *dc_val = level * s->y_dc_scale;
        } else {
            *dc_val = level * s->c_dc_scale;
        }
    }

    return level;
}

//#define ERROR_DETAILS
int ff_msmpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
                              int n, int coded, const uint8_t *scan_table)
{
    int level, i, last, run, run_diff;
    int av_uninit(dc_pred_dir);
    RLTable *rl;
    RL_VLC_ELEM *rl_vlc;
    int qmul, qadd;

    if (s->mb_intra) {
        qmul=1;
        qadd=0;

        /* DC coef */
        level = msmpeg4_decode_dc(s, n, &dc_pred_dir);

        if (level < 0){
            av_log(s->avctx, AV_LOG_ERROR, "dc overflow- block: %d qscale: %d//\n", n, s->qscale);
            if(s->inter_intra_pred) level=0;
            else                    return -1;
        }
        if (n < 4) {
            rl = &ff_rl_table[s->rl_table_index];
            if(level > 256*s->y_dc_scale){
                av_log(s->avctx, AV_LOG_ERROR, "dc overflow+ L qscale: %d//\n", s->qscale);
                if(!s->inter_intra_pred) return -1;
            }
        } else {
            rl = &ff_rl_table[3 + s->rl_chroma_table_index];
            if(level > 256*s->c_dc_scale){
                av_log(s->avctx, AV_LOG_ERROR, "dc overflow+ C qscale: %d//\n", s->qscale);
                if(!s->inter_intra_pred) return -1;
            }
        }
        block[0] = level;

        run_diff = s->msmpeg4_version >= 4;
        i = 0;
        if (!coded) {
            goto not_coded;
        }
        if (s->ac_pred) {
            if (dc_pred_dir == 0)
                scan_table = s->intra_v_scantable.permutated; /* left */
            else
                scan_table = s->intra_h_scantable.permutated; /* top */
        } else {
            scan_table = s->intra_scantable.permutated;
        }
        rl_vlc= rl->rl_vlc[0];
    } else {
        qmul = s->qscale << 1;
        qadd = (s->qscale - 1) | 1;
        i = -1;
        rl = &ff_rl_table[3 + s->rl_table_index];

        if(s->msmpeg4_version==2)
            run_diff = 0;
        else
            run_diff = 1;

        if (!coded) {
            s->block_last_index[n] = i;
            return 0;
        }
        if(!scan_table)
            scan_table = s->inter_scantable.permutated;
        rl_vlc= rl->rl_vlc[s->qscale];
    }
  {
    OPEN_READER(re, &s->gb);
    for(;;) {
        UPDATE_CACHE(re, &s->gb);
        GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
        if (level==0) {
            int cache;
            cache= GET_CACHE(re, &s->gb);
            /* escape */
            if (s->msmpeg4_version==1 || (cache&0x80000000)==0) {
                if (s->msmpeg4_version==1 || (cache&0x40000000)==0) {
                    /* third escape */
                    if(s->msmpeg4_version!=1) LAST_SKIP_BITS(re, &s->gb, 2);
                    UPDATE_CACHE(re, &s->gb);
                    if(s->msmpeg4_version<=3){
                        last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
                        run=   SHOW_UBITS(re, &s->gb, 6); SKIP_CACHE(re, &s->gb, 6);
                        level= SHOW_SBITS(re, &s->gb, 8);
                        SKIP_COUNTER(re, &s->gb, 1+6+8);
                    }else{
                        int sign;
                        last=  SHOW_UBITS(re, &s->gb, 1); SKIP_BITS(re, &s->gb, 1);
                        if(!s->esc3_level_length){
                            int ll;
                            av_dlog(s->avctx, "ESC-3 %X at %d %d\n",
                                    show_bits(&s->gb, 24), s->mb_x, s->mb_y);
                            if(s->qscale<8){
                                ll= SHOW_UBITS(re, &s->gb, 3); SKIP_BITS(re, &s->gb, 3);
                                if(ll==0){
                                    ll= 8+SHOW_UBITS(re, &s->gb, 1); SKIP_BITS(re, &s->gb, 1);
                                }
                            }else{
                                ll=2;
                                while(ll<8 && SHOW_UBITS(re, &s->gb, 1)==0){
                                    ll++;
                                    SKIP_BITS(re, &s->gb, 1);
                                }
                                if(ll<8) SKIP_BITS(re, &s->gb, 1);
                            }

                            s->esc3_level_length= ll;
                            s->esc3_run_length= SHOW_UBITS(re, &s->gb, 2) + 3; SKIP_BITS(re, &s->gb, 2);
                            UPDATE_CACHE(re, &s->gb);
                        }
                        run=   SHOW_UBITS(re, &s->gb, s->esc3_run_length);
                        SKIP_BITS(re, &s->gb, s->esc3_run_length);

                        sign=  SHOW_UBITS(re, &s->gb, 1);
                        SKIP_BITS(re, &s->gb, 1);

                        level= SHOW_UBITS(re, &s->gb, s->esc3_level_length);
                        SKIP_BITS(re, &s->gb, s->esc3_level_length);
                        if(sign) level= -level;
                    }

#if 0 // waste of time / this will detect very few errors
                    {
                        const int abs_level= FFABS(level);
                        const int run1= run - rl->max_run[last][abs_level] - run_diff;
                        if(abs_level<=MAX_LEVEL && run<=MAX_RUN){
                            if(abs_level <= rl->max_level[last][run]){
                                av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
                                return DECODING_AC_LOST;
                            }
                            if(abs_level <= rl->max_level[last][run]*2){
                                av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
                                return DECODING_AC_LOST;
                            }
                            if(run1>=0 && abs_level <= rl->max_level[last][run1]){
                                av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
                                return DECODING_AC_LOST;
                            }
                        }
                    }
#endif
                    //level = level * qmul + (level>0) * qadd - (level<=0) * qadd ;
                    if (level>0) level= level * qmul + qadd;
                    else         level= level * qmul - qadd;
#if 0 // waste of time too :(
                    if(level>2048 || level<-2048){
                        av_log(s->avctx, AV_LOG_ERROR, "|level| overflow in 3. esc\n");
                        return DECODING_AC_LOST;
                    }
#endif
                    i+= run + 1;
                    if(last) i+=192;
#ifdef ERROR_DETAILS
                if(run==66)
                    av_log(s->avctx, AV_LOG_ERROR, "illegal vlc code in ESC3 level=%d\n", level);
                else if((i>62 && i<192) || i>192+63)
                    av_log(s->avctx, AV_LOG_ERROR, "run overflow in ESC3 i=%d run=%d level=%d\n", i, run, level);
#endif
                } else {
                    /* second escape */
                    SKIP_BITS(re, &s->gb, 2);
                    GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
                    i+= run + rl->max_run[run>>7][level/qmul] + run_diff; //FIXME opt indexing
                    level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                    LAST_SKIP_BITS(re, &s->gb, 1);
#ifdef ERROR_DETAILS
                if(run==66)
                    av_log(s->avctx, AV_LOG_ERROR, "illegal vlc code in ESC2 level=%d\n", level);
                else if((i>62 && i<192) || i>192+63)
                    av_log(s->avctx, AV_LOG_ERROR, "run overflow in ESC2 i=%d run=%d level=%d\n", i, run, level);
#endif
                }
            } else {
                /* first escape */
                SKIP_BITS(re, &s->gb, 1);
                GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
                i+= run;
                level = level + rl->max_level[run>>7][(run-1)&63] * qmul;//FIXME opt indexing
                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                LAST_SKIP_BITS(re, &s->gb, 1);
#ifdef ERROR_DETAILS
                if(run==66)
                    av_log(s->avctx, AV_LOG_ERROR, "illegal vlc code in ESC1 level=%d\n", level);
                else if((i>62 && i<192) || i>192+63)
                    av_log(s->avctx, AV_LOG_ERROR, "run overflow in ESC1 i=%d run=%d level=%d\n", i, run, level);
#endif
            }
        } else {
            i+= run;
            level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
            LAST_SKIP_BITS(re, &s->gb, 1);
#ifdef ERROR_DETAILS
                if(run==66)
                    av_log(s->avctx, AV_LOG_ERROR, "illegal vlc code level=%d\n", level);
                else if((i>62 && i<192) || i>192+63)
                    av_log(s->avctx, AV_LOG_ERROR, "run overflow i=%d run=%d level=%d\n", i, run, level);
#endif
        }
        if (i > 62){
            i-= 192;
            if(i&(~63)){
                const int left= get_bits_left(&s->gb);
                if(((i+192 == 64 && level/qmul==-1) || !(s->err_recognition&(AV_EF_BITSTREAM|AV_EF_COMPLIANT))) && left>=0){
                    av_log(s->avctx, AV_LOG_ERROR, "ignoring overflow at %d %d\n", s->mb_x, s->mb_y);
                    break;
                }else{
                    av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
                    return -1;
                }
            }

            block[scan_table[i]] = level;
            break;
        }

        block[scan_table[i]] = level;
    }
    CLOSE_READER(re, &s->gb);
  }
 not_coded:
    if (s->mb_intra) {
        ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
        if (s->ac_pred) {
            i = 63; /* XXX: not optimal */
        }
    }
    if(s->msmpeg4_version>=4 && i>0) i=63; //FIXME/XXX optimize
    s->block_last_index[n] = i;

    return 0;
}

int ff_msmpeg4_decode_motion(MpegEncContext * s,
                                 int *mx_ptr, int *my_ptr)
{
    MVTable *mv;
    int code, mx, my;

    mv = &ff_mv_tables[s->mv_table_index];

    code = get_vlc2(&s->gb, mv->vlc.table, MV_VLC_BITS, 2);
    if (code < 0){
        av_log(s->avctx, AV_LOG_ERROR, "illegal MV code at %d %d\n", s->mb_x, s->mb_y);
        return -1;
    }
    if (code == mv->n) {
        mx = get_bits(&s->gb, 6);
        my = get_bits(&s->gb, 6);
    } else {
        mx = mv->table_mvx[code];
        my = mv->table_mvy[code];
    }

    mx += *mx_ptr - 32;
    my += *my_ptr - 32;
    /* WARNING : they do not do exactly modulo encoding */
    if (mx <= -64)
        mx += 64;
    else if (mx >= 64)
        mx -= 64;

    if (my <= -64)
        my += 64;
    else if (my >= 64)
        my -= 64;
    *mx_ptr = mx;
    *my_ptr = my;
    return 0;
}

AVCodec ff_msmpeg4v1_decoder = {
    .name           = "msmpeg4v1",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_MSMPEG4V1,
    .priv_data_size = sizeof(MpegEncContext),
    .init           = ff_msmpeg4_decode_init,
    .close          = ff_h263_decode_end,
    .decode         = ff_h263_decode_frame,
    .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
    .max_lowres     = 3,
    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 1"),
    .pix_fmts       = ff_pixfmt_list_420,
};

AVCodec ff_msmpeg4v2_decoder = {
    .name           = "msmpeg4v2",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_MSMPEG4V2,
    .priv_data_size = sizeof(MpegEncContext),
    .init           = ff_msmpeg4_decode_init,
    .close          = ff_h263_decode_end,
    .decode         = ff_h263_decode_frame,
    .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
    .max_lowres     = 3,
    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 2"),
    .pix_fmts       = ff_pixfmt_list_420,
};

AVCodec ff_msmpeg4v3_decoder = {
    .name           = "msmpeg4",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_MSMPEG4V3,
    .priv_data_size = sizeof(MpegEncContext),
    .init           = ff_msmpeg4_decode_init,
    .close          = ff_h263_decode_end,
    .decode         = ff_h263_decode_frame,
    .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
    .max_lowres     = 3,
    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 3"),
    .pix_fmts       = ff_pixfmt_list_420,
};

AVCodec ff_wmv1_decoder = {
    .name           = "wmv1",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_WMV1,
    .priv_data_size = sizeof(MpegEncContext),
    .init           = ff_msmpeg4_decode_init,
    .close          = ff_h263_decode_end,
    .decode         = ff_h263_decode_frame,
    .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
    .max_lowres     = 3,
    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Video 7"),
    .pix_fmts       = ff_pixfmt_list_420,
};