msmpeg4: Split decoding related functions to a separate file

This fixes standalone compilation of the msmpeg4v2, msmpeg4v3
and wmv2 encoders, that previously failed to link due to the
decoder codepaths requiring error_resilience.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 953 insertions, 0 deletions

diff --git a/libavcodec/msmpeg4dec.c b/libavcodec/msmpeg4dec.c
new file mode 100644
index 0000000000..ebaf2e55e5
--- /dev/null
+++ b/libavcodec/msmpeg4dec.c
@@ -0,0 +1,953 @@
+/*
+ * 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 Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#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"
+
+#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
+
+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];
+}
+
+/****************************************/
+/* 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, int16_t block[6][64])
+{
+    int cbp, code, i;
+
+    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;
+                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;
+    } 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;
+        }
+    }
+
+    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, int16_t block[6][64])
+{
+    int cbp, code, i;
+    uint8_t *coded_val;
+    uint32_t * const mb_type_ptr = &s->current_picture.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 int done = 0;
+    int i;
+    MVTable *mv;
+
+    if (ff_h263_decode_init(avctx) < 0)
+        return -1;
+
+    ff_msmpeg4_common_init(s);
+
+    if (!done) {
+        done = 1;
+
+        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);
+    }
+
+    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, int16_t * 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)) && 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,
+    .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,
+    .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,
+    .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,
+    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Video 7"),
+    .pix_fmts       = ff_pixfmt_list_420,
+};