Initial revision

Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 1530 insertions, 0 deletions

diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
new file mode 100644
index 0000000000..3e2e523560
--- /dev/null
+++ b/libavcodec/mpeg12.c
@@ -0,0 +1,1530 @@
+/*
+ * MPEG1 encoder / MPEG2 decoder
+ * Copyright (c) 2000,2001 Gerard Lantau.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "avcodec.h"
+#include "dsputil.h"
+#include "mpegvideo.h"
+
+#include "mpeg12data.h"
+
+//#define DEBUG
+
+#ifdef DEBUG
+#define dprintf(fmt,args...) printf(fmt, ## args)
+#else
+#define dprintf(fmt,args...)
+#endif
+
+/* Start codes. */
+#define SEQ_END_CODE		0x000001b7
+#define SEQ_START_CODE		0x000001b3
+#define GOP_START_CODE		0x000001b8
+#define PICTURE_START_CODE	0x00000100
+#define SLICE_MIN_START_CODE	0x00000101
+#define SLICE_MAX_START_CODE	0x000001af
+#define EXT_START_CODE		0x000001b5
+#define USER_START_CODE		0x000001b2
+
+static void mpeg1_encode_block(MpegEncContext *s, 
+                         DCTELEM *block, 
+                         int component);
+static void mpeg1_encode_motion(MpegEncContext *s, int val);
+static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
+static int mpeg1_decode_block(MpegEncContext *s, 
+                              DCTELEM *block, 
+                              int n);
+static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
+                                        DCTELEM *block, 
+                                        int n);
+static int mpeg2_decode_block_intra(MpegEncContext *s, 
+                                    DCTELEM *block, 
+                                    int n);
+static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
+
+static void put_header(MpegEncContext *s, int header)
+{
+    align_put_bits(&s->pb);
+    put_bits(&s->pb, 32, header);
+}
+
+/* put sequence header if needed */
+static void mpeg1_encode_sequence_header(MpegEncContext *s)
+{
+        unsigned int vbv_buffer_size;
+        unsigned int fps, n, v;
+        UINT64 time_code;
+        
+        if ((s->picture_number % s->gop_size) == 0) {
+            /* mpeg1 header repeated every gop */
+            put_header(s, SEQ_START_CODE);
+            
+            /* search closest frame rate */
+            {
+                int i, dmin, d;
+                s->frame_rate_index = 0;
+                dmin = 0x7fffffff;
+                for(i=1;i<9;i++) {
+                    d = abs(s->frame_rate - frame_rate_tab[i]);
+                    if (d < dmin) {
+                        dmin = d;
+                        s->frame_rate_index = i;
+                    }
+                }
+            }
+ 
+            put_bits(&s->pb, 12, s->width);
+            put_bits(&s->pb, 12, s->height);
+            put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */
+            put_bits(&s->pb, 4, s->frame_rate_index);
+            v = s->bit_rate / 400;
+            if (v > 0x3ffff)
+                v = 0x3ffff;
+            put_bits(&s->pb, 18, v);
+            put_bits(&s->pb, 1, 1); /* marker */
+            /* vbv buffer size: slightly greater than an I frame. We add
+               some margin just in case */
+            vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8);
+            put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 
+            put_bits(&s->pb, 1, 1); /* constrained parameter flag */
+            put_bits(&s->pb, 1, 0); /* no custom intra matrix */
+            put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
+
+            put_header(s, GOP_START_CODE);
+            put_bits(&s->pb, 1, 0); /* do drop frame */
+            /* time code : we must convert from the real frame rate to a
+               fake mpeg frame rate in case of low frame rate */
+            fps = frame_rate_tab[s->frame_rate_index];
+            time_code = s->fake_picture_number * FRAME_RATE_BASE;
+            s->gop_picture_number = s->fake_picture_number;
+            put_bits(&s->pb, 5, (time_code / (fps * 3600)) % 24);
+            put_bits(&s->pb, 6, (time_code / (fps * 60)) % 60);
+            put_bits(&s->pb, 1, 1);
+            put_bits(&s->pb, 6, (time_code / fps) % 60);
+            put_bits(&s->pb, 6, (time_code % fps) / FRAME_RATE_BASE);
+            put_bits(&s->pb, 1, 1); /* closed gop */
+            put_bits(&s->pb, 1, 0); /* broken link */
+        }
+
+        if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {
+            /* insert empty P pictures to slow down to the desired
+               frame rate. Each fake pictures takes about 20 bytes */
+            fps = frame_rate_tab[s->frame_rate_index];
+            n = ((s->picture_number * fps) / s->frame_rate) - 1;
+            while (s->fake_picture_number < n) {
+                mpeg1_skip_picture(s, s->fake_picture_number - 
+                                   s->gop_picture_number); 
+                s->fake_picture_number++;
+            }
+
+        }
+        s->fake_picture_number++;
+}
+
+
+/* insert a fake P picture */
+static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
+{
+    unsigned int mb_incr;
+
+    /* mpeg1 picture header */
+    put_header(s, PICTURE_START_CODE);
+    /* temporal reference */
+    put_bits(&s->pb, 10, pict_num & 0x3ff); 
+    
+    put_bits(&s->pb, 3, P_TYPE);
+    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
+    
+    put_bits(&s->pb, 1, 1); /* integer coordinates */
+    put_bits(&s->pb, 3, 1); /* forward_f_code */
+    
+    put_bits(&s->pb, 1, 0); /* extra bit picture */
+    
+    /* only one slice */
+    put_header(s, SLICE_MIN_START_CODE);
+    put_bits(&s->pb, 5, 1); /* quantizer scale */
+    put_bits(&s->pb, 1, 0); /* slice extra information */
+    
+    mb_incr = 1;
+    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
+             mbAddrIncrTable[mb_incr - 1][0]);
+    
+    /* empty macroblock */
+    put_bits(&s->pb, 3, 1); /* motion only */
+    
+    /* zero motion x & y */
+    put_bits(&s->pb, 1, 1); 
+    put_bits(&s->pb, 1, 1); 
+
+    /* output a number of empty slice */
+    mb_incr = s->mb_width * s->mb_height - 1;
+    while (mb_incr > 33) {
+        put_bits(&s->pb, 11, 0x008);
+        mb_incr -= 33;
+    }
+    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
+             mbAddrIncrTable[mb_incr - 1][0]);
+    
+    /* empty macroblock */
+    put_bits(&s->pb, 3, 1); /* motion only */
+    
+    /* zero motion x & y */
+    put_bits(&s->pb, 1, 1); 
+    put_bits(&s->pb, 1, 1); 
+}
+
+void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
+{
+    static int done;
+
+    if (!done) {
+        done = 1;
+        init_rl(&rl_mpeg1);
+    }
+    mpeg1_encode_sequence_header(s);
+
+    /* mpeg1 picture header */
+    put_header(s, PICTURE_START_CODE);
+    /* temporal reference */
+    put_bits(&s->pb, 10, (s->fake_picture_number - 
+                          s->gop_picture_number) & 0x3ff); 
+    
+    put_bits(&s->pb, 3, s->pict_type);
+    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
+    
+    if (s->pict_type == P_TYPE) {
+        put_bits(&s->pb, 1, 0); /* half pel coordinates */
+        put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
+    }
+    
+    put_bits(&s->pb, 1, 0); /* extra bit picture */
+    
+    /* only one slice */
+    put_header(s, SLICE_MIN_START_CODE);
+    put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
+    put_bits(&s->pb, 1, 0); /* slice extra information */
+}
+
+void mpeg1_encode_mb(MpegEncContext *s,
+                     DCTELEM block[6][64],
+                     int motion_x, int motion_y)
+{
+    int mb_incr, i, cbp, mb_x, mb_y;
+
+    mb_x = s->mb_x;
+    mb_y = s->mb_y;
+
+    /* compute cbp */
+    cbp = 0;
+    for(i=0;i<6;i++) {
+        if (s->block_last_index[i] >= 0)
+            cbp |= 1 << (5 - i);
+    }
+
+    /* skip macroblock, except if first or last macroblock of a slice */
+    if ((cbp | motion_x | motion_y) == 0 &&
+        (!((mb_x | mb_y) == 0 ||
+           (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {
+        s->mb_incr++;
+    } else {
+        /* output mb incr */
+        mb_incr = s->mb_incr;
+
+        while (mb_incr > 33) {
+            put_bits(&s->pb, 11, 0x008);
+            mb_incr -= 33;
+        }
+        put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
+                 mbAddrIncrTable[mb_incr - 1][0]);
+        
+        if (s->pict_type == I_TYPE) {
+            put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
+        } else {
+            if (s->mb_intra) {
+                put_bits(&s->pb, 5, 0x03);
+            } else {
+                if (cbp != 0) {
+                    if (motion_x == 0 && motion_y == 0) {
+                        put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
+                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
+                    } else {
+                        put_bits(&s->pb, 1, 1); /* motion + cbp */
+                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
+                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
+                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
+                    }
+                } else {
+                    put_bits(&s->pb, 3, 1); /* motion only */
+                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
+                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
+                }
+            }
+        }
+        for(i=0;i<6;i++) {
+            if (cbp & (1 << (5 - i))) {
+                mpeg1_encode_block(s, block[i], i);
+            }
+        }
+        s->mb_incr = 1;
+    }
+    s->last_mv[0][0][0] = motion_x;
+    s->last_mv[0][0][1] = motion_y;
+}
+
+static void mpeg1_encode_motion(MpegEncContext *s, int val)
+{
+    int code, bit_size, l, m, bits, range, sign;
+
+    if (val == 0) {
+        /* zero vector */
+        code = 0;
+        put_bits(&s->pb,
+                 mbMotionVectorTable[0][1], 
+                 mbMotionVectorTable[0][0]); 
+    } else {
+        bit_size = s->f_code - 1;
+        range = 1 << bit_size;
+        /* modulo encoding */
+        l = 16 * range;
+        m = 2 * l;
+        if (val < -l) {
+            val += m;
+        } else if (val >= l) {
+            val -= m;
+        }
+
+        if (val >= 0) {
+            val--;
+            code = (val >> bit_size) + 1;
+            bits = val & (range - 1);
+            sign = 0;
+        } else {
+            val = -val;
+            val--;
+            code = (val >> bit_size) + 1;
+            bits = val & (range - 1);
+            sign = 1;
+        }
+        put_bits(&s->pb,
+                 mbMotionVectorTable[code][1], 
+                 mbMotionVectorTable[code][0]); 
+        put_bits(&s->pb, 1, sign);
+        if (bit_size > 0) {
+            put_bits(&s->pb, bit_size, bits);
+        }
+    }
+}
+
+static inline void encode_dc(MpegEncContext *s, int diff, int component)
+{
+    int adiff, index;
+
+    adiff = abs(diff);
+    index = vlc_dc_table[adiff];
+    if (component == 0) {
+        put_bits(&s->pb, vlc_dc_lum_bits[index], vlc_dc_lum_code[index]);
+    } else {
+        put_bits(&s->pb, vlc_dc_chroma_bits[index], vlc_dc_chroma_code[index]);
+    }
+    if (diff > 0) {
+        put_bits(&s->pb, index, (diff & ((1 << index) - 1)));
+    } else if (diff < 0) {
+        put_bits(&s->pb, index, ((diff - 1) & ((1 << index) - 1)));
+    }
+}
+
+static void mpeg1_encode_block(MpegEncContext *s, 
+                               DCTELEM *block, 
+                               int n)
+{
+    int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
+    int code, component;
+    RLTable *rl = &rl_mpeg1;
+
+    last_index = s->block_last_index[n];
+
+    /* DC coef */
+    if (s->mb_intra) {
+        component = (n <= 3 ? 0 : n - 4 + 1);
+        dc = block[0]; /* overflow is impossible */
+        diff = dc - s->last_dc[component];
+        encode_dc(s, diff, component);
+        s->last_dc[component] = dc;
+        i = 1;
+    } else {
+        /* encode the first coefficient : needs to be done here because
+           it is handled slightly differently */
+        level = block[0];
+        if (abs(level) == 1) {
+                code = ((UINT32)level >> 31); /* the sign bit */
+                put_bits(&s->pb, 2, code | 0x02);
+                i = 1;
+        } else {
+            i = 0;
+            last_non_zero = -1;
+            goto next_coef;
+        }
+    }
+
+    /* now quantify & encode AC coefs */
+    last_non_zero = i - 1;
+    for(;i<=last_index;i++) {
+        j = zigzag_direct[i];
+        level = block[j];
+    next_coef:
+#if 0
+        if (level != 0)
+            dprintf("level[%d]=%d\n", i, level);
+#endif            
+        /* encode using VLC */
+        if (level != 0) {
+            run = i - last_non_zero - 1;
+            sign = 0;
+            alevel = level;
+            if (alevel < 0) {
+		sign = 1;
+                alevel = -alevel;
+	    }
+            code = get_rl_index(rl, 0, run, alevel);
+            put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
+            if (code != rl->n) {
+                put_bits(&s->pb, 1, sign);
+            } else {
+                /* escape: only clip in this case */
+                put_bits(&s->pb, 6, run);
+                if (alevel < 128) {
+                    put_bits(&s->pb, 8, level & 0xff);
+                } else {
+                    if (level < 0) {
+                        put_bits(&s->pb, 16, 0x8001 + level + 255);
+                    } else {
+                        put_bits(&s->pb, 16, level & 0xffff);
+                    }
+                }
+            }
+            last_non_zero = i;
+        }
+    }
+    /* end of block */
+    put_bits(&s->pb, 2, 0x2);
+}
+
+/******************************************/
+/* decoding */
+
+static VLC dc_lum_vlc;
+static VLC dc_chroma_vlc;
+static VLC mv_vlc;
+static VLC mbincr_vlc;
+static VLC mb_ptype_vlc;
+static VLC mb_btype_vlc;
+static VLC mb_pat_vlc;
+
+void mpeg1_init_vlc(MpegEncContext *s)
+{
+    static int done = 0;
+
+    if (!done) {
+
+        init_vlc(&dc_lum_vlc, 9, 12, 
+                 vlc_dc_lum_bits, 1, 1,
+                 vlc_dc_lum_code, 2, 2);
+        init_vlc(&dc_chroma_vlc, 9, 12, 
+                 vlc_dc_chroma_bits, 1, 1,
+                 vlc_dc_chroma_code, 2, 2);
+        init_vlc(&mv_vlc, 9, 17, 
+                 &mbMotionVectorTable[0][1], 2, 1,
+                 &mbMotionVectorTable[0][0], 2, 1);
+        init_vlc(&mbincr_vlc, 9, 34, 
+                 &mbAddrIncrTable[0][1], 2, 1,
+                 &mbAddrIncrTable[0][0], 2, 1);
+        init_vlc(&mb_pat_vlc, 9, 63, 
+                 &mbPatTable[0][1], 2, 1,
+                 &mbPatTable[0][0], 2, 1);
+        
+        init_vlc(&mb_ptype_vlc, 6, 32, 
+                 &table_mb_ptype[0][1], 2, 1,
+                 &table_mb_ptype[0][0], 2, 1);
+        init_vlc(&mb_btype_vlc, 6, 32, 
+                 &table_mb_btype[0][1], 2, 1,
+                 &table_mb_btype[0][0], 2, 1);
+        init_rl(&rl_mpeg1);
+        init_rl(&rl_mpeg2);
+        /* cannot use generic init because we must add the EOB code */
+        init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2, 
+                 &rl_mpeg1.table_vlc[0][1], 4, 2,
+                 &rl_mpeg1.table_vlc[0][0], 4, 2);
+        init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2, 
+                 &rl_mpeg2.table_vlc[0][1], 4, 2,
+                 &rl_mpeg2.table_vlc[0][0], 4, 2);
+    }
+}
+
+static inline int get_dmv(MpegEncContext *s)
+{
+    if(get_bits(&s->gb, 1)) 
+        return 1 - (get_bits(&s->gb, 1) << 1);
+    else
+        return 0;
+}
+
+/* motion type (for mpeg2) */
+#define MT_FIELD 1
+#define MT_FRAME 2
+#define MT_16X8  2
+#define MT_DMV   3
+
+static int mpeg_decode_mb(MpegEncContext *s,
+                          DCTELEM block[6][64])
+{
+    int i, j, k, cbp, val, code, mb_type, motion_type;
+    
+    /* skip mb handling */
+    if (s->mb_incr == 0) {
+        /* read again increment */
+        s->mb_incr = 1;
+        for(;;) {
+            code = get_vlc(&s->gb, &mbincr_vlc);
+            if (code < 0)
+                return 1; /* error = end of slice */
+            if (code >= 33) {
+                if (code == 33) {
+                    s->mb_incr += 33;
+                }
+                /* otherwise, stuffing, nothing to do */
+            } else {
+                s->mb_incr += code;
+                break;
+            }
+        }
+    }
+    if (++s->mb_x >= s->mb_width) {
+        s->mb_x = 0;
+        if (s->mb_y >= (s->mb_height - 1))
+            return -1;
+        s->mb_y++;
+    }
+    dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
+
+    if (--s->mb_incr != 0) {
+        /* skip mb */
+        s->mb_intra = 0;
+        for(i=0;i<6;i++)
+            s->block_last_index[i] = -1;
+        s->mv_type = MV_TYPE_16X16;
+        if (s->pict_type == P_TYPE) {
+            /* if P type, zero motion vector is implied */
+            s->mv_dir = MV_DIR_FORWARD;
+            s->mv[0][0][0] = s->mv[0][0][1] = 0;
+            s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
+        } else {
+            /* if B type, reuse previous vectors and directions */
+            s->mv[0][0][0] = s->last_mv[0][0][0];
+            s->mv[0][0][1] = s->last_mv[0][0][1];
+            s->mv[1][0][0] = s->last_mv[1][0][0];
+            s->mv[1][0][1] = s->last_mv[1][0][1];
+        }
+        return 0;
+    }
+
+    switch(s->pict_type) {
+    default:
+    case I_TYPE:
+        if (get_bits(&s->gb, 1) == 0) {
+            if (get_bits(&s->gb, 1) == 0)
+                return -1;
+            mb_type = MB_QUANT | MB_INTRA;
+        } else {
+            mb_type = MB_INTRA;
+        }
+        break;
+    case P_TYPE:
+        mb_type = get_vlc(&s->gb, &mb_ptype_vlc);
+        if (mb_type < 0)
+            return -1;
+        break;
+    case B_TYPE:
+        mb_type = get_vlc(&s->gb, &mb_btype_vlc);
+        if (mb_type < 0)
+            return -1;
+        break;
+    }
+    dprintf("mb_type=%x\n", mb_type);
+    motion_type = 0; /* avoid warning */
+    if (mb_type & (MB_FOR|MB_BACK)) {
+        /* get additionnal motion vector type */
+        if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct) 
+            motion_type = MT_FRAME;
+        else
+            motion_type = get_bits(&s->gb, 2);
+    }
+    /* compute dct type */
+    if (s->picture_structure == PICT_FRAME && 
+        !s->frame_pred_frame_dct &&
+        (mb_type & (MB_PAT | MB_INTRA))) {
+        s->interlaced_dct = get_bits(&s->gb, 1);
+#ifdef DEBUG
+        if (s->interlaced_dct)
+            printf("interlaced_dct\n");
+#endif
+    } else {
+        s->interlaced_dct = 0; /* frame based */
+    }
+
+    if (mb_type & MB_QUANT) {
+        if (s->mpeg2) {
+            if (s->q_scale_type) {
+                s->qscale = non_linear_qscale[get_bits(&s->gb, 5)];
+            } else {
+                s->qscale = get_bits(&s->gb, 5) << 1;
+            }
+        } else {
+            /* for mpeg1, we use the generic unquant code */
+            s->qscale = get_bits(&s->gb, 5);
+        }
+    }
+    if (mb_type & MB_INTRA) {
+        if (s->concealment_motion_vectors) {
+            /* just parse them */
+            if (s->picture_structure != PICT_FRAME) 
+                get_bits(&s->gb, 1); /* field select */
+            mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);
+            mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);
+        }
+        s->mb_intra = 1;
+        cbp = 0x3f;
+        memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
+    } else {
+        s->mb_intra = 0;
+        cbp = 0;
+    }
+    /* special case of implicit zero motion vector */
+    if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) {
+        s->mv_dir = MV_DIR_FORWARD;
+        s->mv_type = MV_TYPE_16X16;
+        s->last_mv[0][0][0] = 0;
+        s->last_mv[0][0][1] = 0;
+        s->mv[0][0][0] = 0;
+        s->mv[0][0][1] = 0;
+    } else if (mb_type & (MB_FOR | MB_BACK)) {
+        /* motion vectors */
+        s->mv_dir = 0;
+        for(i=0;i<2;i++) {
+            if (mb_type & (MB_FOR >> i)) {
+                s->mv_dir |= (MV_DIR_FORWARD >> i);
+                dprintf("mv_type=%d\n", motion_type);
+                switch(motion_type) {
+                case MT_FRAME: /* or MT_16X8 */
+                    if (s->picture_structure == PICT_FRAME) {
+                        /* MT_FRAME */
+                        s->mv_type = MV_TYPE_16X16;
+                        for(k=0;k<2;k++) {
+                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], 
+                                                     s->last_mv[i][0][k]);
+                            s->last_mv[i][0][k] = val;
+                            s->last_mv[i][1][k] = val;
+                            /* full_pel: only for mpeg1 */
+                            if (s->full_pel[i])
+                                val = val << 1;
+                            s->mv[i][0][k] = val;
+                            dprintf("mv%d: %d\n", k, val);
+                        }
+                    } else {
+                        /* MT_16X8 */
+                        s->mv_type = MV_TYPE_16X8;
+                        for(j=0;j<2;j++) {
+                            s->field_select[i][j] = get_bits(&s->gb, 1);
+                            for(k=0;k<2;k++) {
+                                val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
+                                                         s->last_mv[i][j][k]);
+                                s->last_mv[i][j][k] = val;
+                                s->mv[i][j][k] = val;
+                            }
+                        }
+                    }
+                    break;
+                case MT_FIELD:
+                    if (s->picture_structure == PICT_FRAME) {
+                        s->mv_type = MV_TYPE_FIELD;
+                        for(j=0;j<2;j++) {
+                            s->field_select[i][j] = get_bits(&s->gb, 1);
+                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
+                                                     s->last_mv[i][j][0]);
+                            s->last_mv[i][j][0] = val;
+                            s->mv[i][j][0] = val;
+                            dprintf("fmx=%d\n", val);
+                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
+                                                     s->last_mv[i][j][1] >> 1);
+                            s->last_mv[i][j][1] = val << 1;
+                            s->mv[i][j][1] = val;
+                            dprintf("fmy=%d\n", val);
+                        }
+                    } else {
+                        s->mv_type = MV_TYPE_16X16;
+                        s->field_select[i][0] = get_bits(&s->gb, 1);
+                        for(k=0;k<2;k++) {
+                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
+                                                     s->last_mv[i][0][k]);
+                            s->last_mv[i][0][k] = val;
+                            s->last_mv[i][1][k] = val;
+                            s->mv[i][0][k] = val;
+                        }
+                    }
+                    break;
+                case MT_DMV:
+                    {
+                        int dmx, dmy, mx, my, m;
+
+                        mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], 
+                                                s->last_mv[i][0][0]);
+                        s->last_mv[i][0][0] = mx;
+                        s->last_mv[i][1][0] = mx;
+                        dmx = get_dmv(s);
+                        my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], 
+                                                s->last_mv[i][0][1] >> 1);
+                        dmy = get_dmv(s);
+                        s->mv_type = MV_TYPE_DMV;
+                        /* XXX: totally broken */
+                        if (s->picture_structure == PICT_FRAME) {
+                            s->last_mv[i][0][1] = my << 1;
+                            s->last_mv[i][1][1] = my << 1;
+
+                            m = s->top_field_first ? 1 : 3;
+                            /* top -> top pred */
+                            s->mv[i][0][0] = mx; 
+                            s->mv[i][0][1] = my << 1;
+                            s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
+                            s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
+                            m = 4 - m;
+                            s->mv[i][2][0] = mx;
+                            s->mv[i][2][1] = my << 1;
+                            s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
+                            s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
+                        } else {
+                            s->last_mv[i][0][1] = my;
+                            s->last_mv[i][1][1] = my;
+                            s->mv[i][0][0] = mx;
+                            s->mv[i][0][1] = my;
+                            s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;
+                            s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 
+                                /* + 2 * cur_field */;
+                        }
+                    }
+                    break;
+                }
+            }
+        }
+    }
+
+    if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) {
+        get_bits(&s->gb, 1); /* marker */
+    }
+    
+    if (mb_type & MB_PAT) {
+        cbp = get_vlc(&s->gb, &mb_pat_vlc);
+        if (cbp < 0)
+            return -1;
+        cbp++;
+    }
+    dprintf("cbp=%x\n", cbp);
+
+    if (s->mpeg2) {
+        if (s->mb_intra) {
+            for(i=0;i<6;i++) {
+                if (cbp & (1 << (5 - i))) {
+                    if (mpeg2_decode_block_intra(s, block[i], i) < 0)
+                        return -1;
+                }
+            }
+        } else {
+            for(i=0;i<6;i++) {
+                if (cbp & (1 << (5 - i))) {
+                    if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
+                        return -1;
+                }
+            }
+        }
+    } else {
+        for(i=0;i<6;i++) {
+            if (cbp & (1 << (5 - i))) {
+                if (mpeg1_decode_block(s, block[i], i) < 0)
+                    return -1;
+            }
+        }
+    }
+    return 0;
+}
+
+/* as h263, but only 17 codes */
+static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
+{
+    int code, sign, val, m, l, shift;
+
+    code = get_vlc(&s->gb, &mv_vlc);
+    if (code < 0) {
+        return 0xffff;
+    }
+    if (code == 0) {
+        return pred;
+    }
+    sign = get_bits(&s->gb, 1);
+    shift = fcode - 1;
+    val = (code - 1) << shift;
+    if (shift > 0)
+        val |= get_bits(&s->gb, shift);
+    val++;
+    if (sign)
+        val = -val;
+    val += pred;
+    
+    /* modulo decoding */
+    l = (1 << shift) * 16;
+    m = 2 * l;
+    if (val < -l) {
+        val += m;
+    } else if (val >= l) {
+        val -= m;
+    }
+    return val;
+}
+
+static inline int decode_dc(MpegEncContext *s, int component)
+{
+    int code, diff;
+
+    if (component == 0) {
+        code = get_vlc(&s->gb, &dc_lum_vlc);
+    } else {
+        code = get_vlc(&s->gb, &dc_chroma_vlc);
+    }
+    if (code < 0)
+        return 0xffff;
+    if (code == 0) {
+        diff = 0;
+    } else {
+        diff = get_bits(&s->gb, code);
+        if ((diff & (1 << (code - 1))) == 0) 
+            diff = (-1 << code) | (diff + 1);
+    }
+    return diff;
+}
+
+static int mpeg1_decode_block(MpegEncContext *s, 
+                               DCTELEM *block, 
+                               int n)
+{
+    int level, dc, diff, i, j, run;
+    int code, component;
+    RLTable *rl = &rl_mpeg1;
+
+    if (s->mb_intra) {
+        /* DC coef */
+        component = (n <= 3 ? 0 : n - 4 + 1);
+        diff = decode_dc(s, component);
+        if (diff >= 0xffff)
+            return -1;
+        dc = s->last_dc[component];
+        dc += diff;
+        s->last_dc[component] = dc;
+        block[0] = dc;
+        dprintf("dc=%d diff=%d\n", dc, diff);
+        i = 1;
+    } else {
+        int bit_cnt, v;
+        UINT32 bit_buf;
+        UINT8 *buf_ptr;
+        i = 0;
+        /* special case for the first coef. no need to add a second vlc table */
+        SAVE_BITS(&s->gb);
+        SHOW_BITS(&s->gb, v, 2);
+        if (v & 2) {
+            run = 0;
+            level = 1 - ((v & 1) << 1);
+            FLUSH_BITS(2);
+            RESTORE_BITS(&s->gb);
+            goto add_coef;
+        }
+        RESTORE_BITS(&s->gb);
+    }
+
+    /* now quantify & encode AC coefs */
+    for(;;) {
+        code = get_vlc(&s->gb, &rl->vlc);
+        if (code < 0) {
+            return -1;
+        }
+        if (code == 112) {
+            break;
+        } else if (code == 111) {
+            /* escape */
+            run = get_bits(&s->gb, 6);
+            level = get_bits(&s->gb, 8);
+            level = (level << 24) >> 24;
+            if (level == -128) {
+                level = get_bits(&s->gb, 8) - 256;
+            } else if (level == 0) {
+                level = get_bits(&s->gb, 8);
+            }
+        } else {
+            run = rl->table_run[code];
+            level = rl->table_level[code];
+            if (get_bits(&s->gb, 1))
+                level = -level;
+        }
+        i += run;
+        if (i >= 64)
+            return -1;
+    add_coef:
+        dprintf("%d: run=%d level=%d\n", n, run, level);
+	j = zigzag_direct[i];
+        block[j] = level;
+        i++;
+    }
+    s->block_last_index[n] = i;
+    return 0;
+}
+
+/* Also does unquantization here, since I will never support mpeg2
+   encoding */
+static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
+                                        DCTELEM *block, 
+                                        int n)
+{
+    int level, i, j, run;
+    int code;
+    RLTable *rl = &rl_mpeg1;
+    const UINT8 *scan_table;
+    const UINT16 *matrix;
+    int mismatch;
+
+    if (s->alternate_scan)
+        scan_table = ff_alternate_vertical_scan;
+    else
+        scan_table = zigzag_direct;
+    mismatch = 1;
+
+    {
+        int bit_cnt, v;
+        UINT32 bit_buf;
+        UINT8 *buf_ptr;
+        i = 0;
+        if (n < 4) 
+            matrix = s->non_intra_matrix;
+        else
+            matrix = s->chroma_non_intra_matrix;
+            
+        /* special case for the first coef. no need to add a second vlc table */
+        SAVE_BITS(&s->gb);
+        SHOW_BITS(&s->gb, v, 2);
+        if (v & 2) {
+            run = 0;
+            level = 1 - ((v & 1) << 1);
+            FLUSH_BITS(2);
+            RESTORE_BITS(&s->gb);
+            goto add_coef;
+        }
+        RESTORE_BITS(&s->gb);
+    }
+
+    /* now quantify & encode AC coefs */
+    for(;;) {
+        code = get_vlc(&s->gb, &rl->vlc);
+        if (code < 0)
+            return -1;
+        if (code == 112) {
+            break;
+        } else if (code == 111) {
+            /* escape */
+            run = get_bits(&s->gb, 6);
+            level = get_bits(&s->gb, 12);
+            level = (level << 20) >> 20;
+        } else {
+            run = rl->table_run[code];
+            level = rl->table_level[code];
+            if (get_bits(&s->gb, 1))
+                level = -level;
+        }
+        i += run;
+        if (i >= 64)
+            return -1;
+    add_coef:
+	j = scan_table[i];
+        dprintf("%d: run=%d level=%d\n", n, run, level);
+        level = ((level * 2 + 1) * s->qscale * matrix[j]) / 32;
+        /* XXX: is it really necessary to saturate since the encoder
+           knows whats going on ? */
+        mismatch ^= level;
+        block[j] = level;
+        i++;
+    }
+    block[63] ^= (mismatch & 1);
+    s->block_last_index[n] = i;
+    return 0;
+}
+
+static int mpeg2_decode_block_intra(MpegEncContext *s, 
+                                    DCTELEM *block, 
+                                    int n)
+{
+    int level, dc, diff, i, j, run;
+    int code, component;
+    RLTable *rl;
+    const UINT8 *scan_table;
+    const UINT16 *matrix;
+    int mismatch;
+
+    if (s->alternate_scan)
+        scan_table = ff_alternate_vertical_scan;
+    else
+        scan_table = zigzag_direct;
+    mismatch = 1;
+
+    /* DC coef */
+    component = (n <= 3 ? 0 : n - 4 + 1);
+    diff = decode_dc(s, component);
+    if (diff >= 0xffff)
+        return -1;
+    dc = s->last_dc[component];
+    dc += diff;
+    s->last_dc[component] = dc;
+    block[0] = dc << (3 - s->intra_dc_precision);
+    dprintf("dc=%d\n", block[0]);
+    i = 1;
+    if (s->intra_vlc_format)
+        rl = &rl_mpeg2;
+    else
+        rl = &rl_mpeg1;
+    if (n < 4) 
+        matrix = s->intra_matrix;
+    else
+        matrix = s->chroma_intra_matrix;
+        
+    /* now quantify & encode AC coefs */
+    for(;;) {
+        code = get_vlc(&s->gb, &rl->vlc);
+        if (code < 0)
+            return -1;
+        if (code == 112) {
+            break;
+        } else if (code == 111) {
+            /* escape */
+            run = get_bits(&s->gb, 6);
+            level = get_bits(&s->gb, 12);
+            level = (level << 20) >> 20;
+        } else {
+            run = rl->table_run[code];
+            level = rl->table_level[code];
+            if (get_bits(&s->gb, 1))
+                level = -level;
+        }
+        i += run;
+        if (i >= 64)
+            return -1;
+	j = scan_table[i];
+        dprintf("%d: run=%d level=%d\n", n, run, level);
+        level = (level * s->qscale * matrix[j]) / 16;
+        /* XXX: is it really necessary to saturate since the encoder
+           knows whats going on ? */
+        mismatch ^= level;
+        block[j] = level;
+        i++;
+    }
+    block[63] ^= (mismatch & 1);
+    s->block_last_index[n] = i;
+    return 0;
+}
+
+/* compressed picture size */
+#define PICTURE_BUFFER_SIZE 100000
+
+typedef struct Mpeg1Context {
+    MpegEncContext mpeg_enc_ctx;
+    UINT32 header_state;
+    int start_code; /* current start code */
+    UINT8 buffer[PICTURE_BUFFER_SIZE]; 
+    UINT8 *buf_ptr;
+    int buffer_size;
+    int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
+} Mpeg1Context;
+
+static int mpeg_decode_init(AVCodecContext *avctx)
+{
+    Mpeg1Context *s = avctx->priv_data;
+
+    s->header_state = 0xff;
+    s->mpeg_enc_ctx_allocated = 0;
+    s->buffer_size = PICTURE_BUFFER_SIZE;
+    s->start_code = -1;
+    s->buf_ptr = s->buffer;
+    s->mpeg_enc_ctx.picture_number = 0;
+    return 0;
+}
+
+/* return the 8 bit start code value and update the search
+   state. Return -1 if no start code found */
+static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 
+                           UINT32 *header_state)
+{
+    UINT8 *buf_ptr;
+    unsigned int state, v;
+    int val;
+
+    state = *header_state;
+    buf_ptr = *pbuf_ptr;
+    while (buf_ptr < buf_end) {
+        v = *buf_ptr++;
+        if (state == 0x000001) {
+            state = ((state << 8) | v) & 0xffffff;
+            val = state;
+            goto found;
+        }
+        state = ((state << 8) | v) & 0xffffff;
+    }
+    val = -1;
+ found:
+    *pbuf_ptr = buf_ptr;
+    *header_state = state;
+    return val;
+}
+
+static int mpeg1_decode_picture(AVCodecContext *avctx, 
+                                UINT8 *buf, int buf_size)
+{
+    Mpeg1Context *s1 = avctx->priv_data;
+    MpegEncContext *s = &s1->mpeg_enc_ctx;
+    int ref, f_code;
+
+    init_get_bits(&s->gb, buf, buf_size);
+
+    ref = get_bits(&s->gb, 10); /* temporal ref */
+    s->pict_type = get_bits(&s->gb, 3);
+    dprintf("pict_type=%d\n", s->pict_type);
+    get_bits(&s->gb, 16);
+    if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
+        s->full_pel[0] = get_bits(&s->gb, 1);
+        f_code = get_bits(&s->gb, 3);
+        if (f_code == 0)
+            return -1;
+        s->mpeg_f_code[0][0] = f_code;
+        s->mpeg_f_code[0][1] = f_code;
+    }
+    if (s->pict_type == B_TYPE) {
+        s->full_pel[1] = get_bits(&s->gb, 1);
+        f_code = get_bits(&s->gb, 3);
+        if (f_code == 0)
+            return -1;
+        s->mpeg_f_code[1][0] = f_code;
+        s->mpeg_f_code[1][1] = f_code;
+    }
+    s->y_dc_scale = 8;
+    s->c_dc_scale = 8;
+    s->first_slice = 1;
+    return 0;
+}
+
+static void mpeg_decode_sequence_extension(MpegEncContext *s)
+{
+    int horiz_size_ext, vert_size_ext;
+    int bit_rate_ext, vbv_buf_ext, low_delay;
+    int frame_rate_ext_n, frame_rate_ext_d;
+
+    get_bits(&s->gb, 8); /* profil and level */
+    get_bits(&s->gb, 1); /* progressive_sequence */
+    get_bits(&s->gb, 2); /* chroma_format */
+    horiz_size_ext = get_bits(&s->gb, 2);
+    vert_size_ext = get_bits(&s->gb, 2);
+    s->width |= (horiz_size_ext << 12);
+    s->height |= (vert_size_ext << 12);
+    bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */
+    s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
+    get_bits(&s->gb, 1); /* marker */
+    vbv_buf_ext = get_bits(&s->gb, 8);
+    low_delay = get_bits(&s->gb, 1);
+    frame_rate_ext_n = get_bits(&s->gb, 2);
+    frame_rate_ext_d = get_bits(&s->gb, 5);
+    if (frame_rate_ext_d >= 1)
+        s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;
+    dprintf("sequence extension\n");
+    s->mpeg2 = 1;
+}
+
+static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
+{
+    int i, v;
+
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->intra_matrix[i] = v;
+            s->chroma_intra_matrix[i] = v;
+        }
+    }
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->non_intra_matrix[i] = v;
+            s->chroma_non_intra_matrix[i] = v;
+        }
+    }
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->chroma_intra_matrix[i] = v;
+        }
+    }
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->chroma_non_intra_matrix[i] = v;
+        }
+    }
+}
+
+static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
+{
+    s->full_pel[0] = s->full_pel[1] = 0;
+    s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
+    s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
+    s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
+    s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
+    s->intra_dc_precision = get_bits(&s->gb, 2);
+    s->picture_structure = get_bits(&s->gb, 2);
+    s->top_field_first = get_bits(&s->gb, 1);
+    s->frame_pred_frame_dct = get_bits(&s->gb, 1);
+    s->concealment_motion_vectors = get_bits(&s->gb, 1);
+    s->q_scale_type = get_bits(&s->gb, 1);
+    s->intra_vlc_format = get_bits(&s->gb, 1);
+    s->alternate_scan = get_bits(&s->gb, 1);
+    s->repeat_first_field = get_bits(&s->gb, 1);
+    s->chroma_420_type = get_bits(&s->gb, 1);
+    s->progressive_frame = get_bits(&s->gb, 1);
+    /* composite display not parsed */
+    dprintf("dc_preci=%d\n", s->intra_dc_precision);
+    dprintf("pict_structure=%d\n", s->picture_structure);
+    dprintf("conceal=%d\n", s->concealment_motion_vectors);
+    dprintf("intrafmt=%d\n", s->intra_vlc_format);
+    dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
+}
+
+static void mpeg_decode_extension(AVCodecContext *avctx, 
+                                  UINT8 *buf, int buf_size)
+{
+    Mpeg1Context *s1 = avctx->priv_data;
+    MpegEncContext *s = &s1->mpeg_enc_ctx;
+    int ext_type;
+
+    init_get_bits(&s->gb, buf, buf_size);
+    
+    ext_type = get_bits(&s->gb, 4);
+    switch(ext_type) {
+    case 0x1:
+        /* sequence ext */
+        mpeg_decode_sequence_extension(s);
+        break;
+    case 0x3:
+        /* quant matrix extension */
+        mpeg_decode_quant_matrix_extension(s);
+        break;
+    case 0x8:
+        /* picture extension */
+        mpeg_decode_picture_coding_extension(s);
+        break;
+    }
+}
+
+/* return 1 if end of frame */
+static int mpeg_decode_slice(AVCodecContext *avctx, 
+                              AVPicture *pict,
+                              int start_code,
+                              UINT8 *buf, int buf_size)
+{
+    Mpeg1Context *s1 = avctx->priv_data;
+    MpegEncContext *s = &s1->mpeg_enc_ctx;
+    int ret;
+    DCTELEM block[6][64];
+
+    start_code = (start_code - 1) & 0xff;
+    if (start_code >= s->mb_height)
+        return -1;
+    s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
+    s->last_dc[1] = s->last_dc[0];
+    s->last_dc[2] = s->last_dc[0];
+    memset(s->last_mv, 0, sizeof(s->last_mv));
+    s->mb_x = -1;
+    s->mb_y = start_code;
+    s->mb_incr = 0;
+
+    /* start frame decoding */
+    if (s->first_slice) {
+        s->first_slice = 0;
+        MPV_frame_start(s);
+    }
+
+    init_get_bits(&s->gb, buf, buf_size);
+
+    s->qscale = get_bits(&s->gb, 5);
+    /* extra slice info */
+    while (get_bits(&s->gb, 1) != 0) {
+        get_bits(&s->gb, 8);
+    }
+
+    for(;;) {
+        memset(block, 0, sizeof(block));
+        ret = mpeg_decode_mb(s, block);
+        dprintf("ret=%d\n", ret);
+        if (ret < 0)
+            return -1;
+        if (ret == 1)
+            break;
+        MPV_decode_mb(s, block);
+    }
+    
+    /* end of slice reached */
+    if (s->mb_x == (s->mb_width - 1) &&
+        s->mb_y == (s->mb_height - 1)) {
+        /* end of image */
+        UINT8 **picture;
+
+        MPV_frame_end(s);
+
+        /* XXX: incorrect reported qscale for mpeg2 */
+        if (s->pict_type == B_TYPE) {
+            picture = s->current_picture;
+            avctx->quality = s->qscale;
+        } else {
+            /* latency of 1 frame for I and P frames */
+            /* XXX: use another variable than picture_number */
+            if (s->picture_number == 0) {
+                picture = NULL;
+            } else {
+                picture = s->last_picture;
+                avctx->quality = s->last_qscale;
+            }
+            s->last_qscale = s->qscale;
+            s->picture_number++;
+        }
+        if (picture) {
+            pict->data[0] = picture[0];
+            pict->data[1] = picture[1];
+            pict->data[2] = picture[2];
+            pict->linesize[0] = s->linesize;
+            pict->linesize[1] = s->linesize / 2;
+            pict->linesize[2] = s->linesize / 2;
+            return 1;
+        } else {
+            return 0;
+        }
+    } else {
+        return 0;
+    }
+}
+
+static int mpeg1_decode_sequence(AVCodecContext *avctx, 
+                                 UINT8 *buf, int buf_size)
+{
+    Mpeg1Context *s1 = avctx->priv_data;
+    MpegEncContext *s = &s1->mpeg_enc_ctx;
+    int width, height, i, v;
+    
+    init_get_bits(&s->gb, buf, buf_size);
+
+    width = get_bits(&s->gb, 12);
+    height = get_bits(&s->gb, 12);
+    get_bits(&s->gb, 4);
+    s->frame_rate_index = get_bits(&s->gb, 4);
+    if (s->frame_rate_index == 0)
+        return -1;
+    s->bit_rate = get_bits(&s->gb, 18) * 400;
+    if (get_bits(&s->gb, 1) == 0) /* marker */
+        return -1;
+    if (width <= 0 || height <= 0 ||
+        (width % 2) != 0 || (height % 2) != 0)
+        return -1;
+    if (width != s->width ||
+        height != s->height) {
+        /* start new mpeg1 context decoding */
+        s->out_format = FMT_MPEG1;
+        if (s1->mpeg_enc_ctx_allocated) {
+            MPV_common_end(s);
+        }
+        s->width = width;
+        s->height = height;
+        s->has_b_frames = 1;
+        avctx->width = width;
+        avctx->height = height;
+        avctx->frame_rate = frame_rate_tab[s->frame_rate_index];
+        avctx->bit_rate = s->bit_rate;
+        
+        if (MPV_common_init(s) < 0)
+            return -1;
+        mpeg1_init_vlc(s);
+        s1->mpeg_enc_ctx_allocated = 1;
+    }
+
+    get_bits(&s->gb, 10); /* vbv_buffer_size */
+    get_bits(&s->gb, 1);
+
+    /* get matrix */
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->intra_matrix[i] = v;
+            s->chroma_intra_matrix[i] = v;
+        }
+    } else {
+        for(i=0;i<64;i++) {
+            v = default_intra_matrix[i];
+            s->intra_matrix[i] = v;
+            s->chroma_intra_matrix[i] = v;
+        }
+    }
+    if (get_bits(&s->gb, 1)) {
+        for(i=0;i<64;i++) {
+            v = get_bits(&s->gb, 8);
+            s->non_intra_matrix[i] = v;
+            s->chroma_non_intra_matrix[i] = v;
+        }
+    } else {
+        for(i=0;i<64;i++) {
+            v = default_non_intra_matrix[i];
+            s->non_intra_matrix[i] = v;
+            s->chroma_non_intra_matrix[i] = v;
+        }
+    }
+
+    /* we set mpeg2 parameters so that it emulates mpeg1 */
+    s->progressive_sequence = 1;
+    s->progressive_frame = 1;
+    s->picture_structure = PICT_FRAME;
+    s->frame_pred_frame_dct = 1;
+    s->mpeg2 = 0;
+    return 0;
+}
+
+/* handle buffering and image synchronisation */
+static int mpeg_decode_frame(AVCodecContext *avctx, 
+                             void *data, int *data_size,
+                             UINT8 *buf, int buf_size)
+{
+    Mpeg1Context *s = avctx->priv_data;
+    UINT8 *buf_end, *buf_ptr, *buf_start;
+    int len, start_code_found, ret, code, start_code, input_size;
+    AVPicture *picture = data;
+
+    dprintf("fill_buffer\n");
+
+    *data_size = 0;
+    /* special case for last picture */
+    if (buf_size == 0) {
+        MpegEncContext *s2 = &s->mpeg_enc_ctx;
+        if (s2->picture_number > 0) {
+            picture->data[0] = s2->next_picture[0];
+            picture->data[1] = s2->next_picture[1];
+            picture->data[2] = s2->next_picture[2];
+            picture->linesize[0] = s2->linesize;
+            picture->linesize[1] = s2->linesize / 2;
+            picture->linesize[2] = s2->linesize / 2;
+            *data_size = sizeof(AVPicture);
+        }
+        return 0;
+    }
+
+    buf_ptr = buf;
+    buf_end = buf + buf_size;
+    while (buf_ptr < buf_end) {
+        buf_start = buf_ptr;
+        /* find start next code */
+        code = find_start_code(&buf_ptr, buf_end, &s->header_state);
+        if (code >= 0) {
+            start_code_found = 1;
+        } else {
+            start_code_found = 0;
+        }
+        /* copy to buffer */
+        len = buf_ptr - buf_start;
+        if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {
+            /* data too big : flush */
+            s->buf_ptr = s->buffer;
+            if (start_code_found)
+                s->start_code = code;
+        } else {
+            memcpy(s->buf_ptr, buf_start, len);
+            s->buf_ptr += len;
+            
+            if (start_code_found) {
+                /* prepare data for next start code */
+                input_size = s->buf_ptr - s->buffer;
+                start_code = s->start_code;
+                s->buf_ptr = s->buffer;
+                s->start_code = code;
+                switch(start_code) {
+                case SEQ_START_CODE:
+                    mpeg1_decode_sequence(avctx, s->buffer, 
+                                          input_size);
+                    break;
+                            
+                case PICTURE_START_CODE:
+                    /* we have a complete image : we try to decompress it */
+                    mpeg1_decode_picture(avctx, 
+                                         s->buffer, input_size);
+                    break;
+                case EXT_START_CODE:
+                    mpeg_decode_extension(avctx,
+                                          s->buffer, input_size);
+                    break;
+                default:
+                    if (start_code >= SLICE_MIN_START_CODE &&
+                        start_code <= SLICE_MAX_START_CODE) {
+                        ret = mpeg_decode_slice(avctx, picture,
+                                                start_code, s->buffer, input_size);
+                        if (ret == 1) {
+                            /* got a picture: exit */
+                            *data_size = sizeof(AVPicture);
+                            goto the_end;
+                        }
+                    }
+                    break;
+                }
+            }
+        }
+    }
+ the_end:
+    return buf_ptr - buf;
+}
+
+static int mpeg_decode_end(AVCodecContext *avctx)
+{
+    Mpeg1Context *s = avctx->priv_data;
+
+    if (s->mpeg_enc_ctx_allocated)
+        MPV_common_end(&s->mpeg_enc_ctx);
+    return 0;
+}
+
+AVCodec mpeg_decoder = {
+    "mpegvideo",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_MPEG1VIDEO,
+    sizeof(Mpeg1Context),
+    mpeg_decode_init,
+    NULL,
+    mpeg_decode_end,
+    mpeg_decode_frame,
+};