/*
  * SVQ1 decoder
  * ported to MPlayer by Arpi <arpi@thot.banki.hu>
  * ported to libavcodec by Nick Kurshev <nickols_k@mail.ru>
  *
  * Copyright (C) 2002 the xine project
  * Copyright (C) 2002 the ffmpeg project
  *
  * SVQ1 Encoder (c) 2004 Mike Melanson <melanson@pcisys.net>
  *
  * 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

  * Sorenson Vector Quantizer #1 (SVQ1) video codec.
  * For more information of the SVQ1 algorithm, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  */
 
 
 #include "avcodec.h"
 #include "dsputil.h"
 #include "mpegvideo.h"

 #include "mathops.h"

 
 #include "svq1.h"
 
 #undef NDEBUG
 #include <assert.h>
 
 extern const uint8_t mvtab[33][2];
 
 static VLC svq1_block_type;
 static VLC svq1_motion_component;
 static VLC svq1_intra_multistage[6];
 static VLC svq1_inter_multistage[6];
 static VLC svq1_intra_mean;
 static VLC svq1_inter_mean;
 
 /* motion vector (prediction) */
 typedef struct svq1_pmv_s {
   int           x;
   int           y;

 } svq1_pmv;

 
 static const uint16_t checksum_table[256] = {
   0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
   0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
   0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
   0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
   0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
   0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
   0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
   0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
   0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
   0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
   0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
   0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
   0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
   0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
   0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
   0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
   0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
   0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
   0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
   0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
   0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
   0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
   0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
   0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
   0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
   0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
   0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
   0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
   0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
   0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
   0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
   0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
 };
 
 static const uint8_t string_table[256] = {
   0x00, 0xD5, 0x7F, 0xAA, 0xFE, 0x2B, 0x81, 0x54,
   0x29, 0xFC, 0x56, 0x83, 0xD7, 0x02, 0xA8, 0x7D,
   0x52, 0x87, 0x2D, 0xF8, 0xAC, 0x79, 0xD3, 0x06,
   0x7B, 0xAE, 0x04, 0xD1, 0x85, 0x50, 0xFA, 0x2F,
   0xA4, 0x71, 0xDB, 0x0E, 0x5A, 0x8F, 0x25, 0xF0,
   0x8D, 0x58, 0xF2, 0x27, 0x73, 0xA6, 0x0C, 0xD9,
   0xF6, 0x23, 0x89, 0x5C, 0x08, 0xDD, 0x77, 0xA2,
   0xDF, 0x0A, 0xA0, 0x75, 0x21, 0xF4, 0x5E, 0x8B,
   0x9D, 0x48, 0xE2, 0x37, 0x63, 0xB6, 0x1C, 0xC9,
   0xB4, 0x61, 0xCB, 0x1E, 0x4A, 0x9F, 0x35, 0xE0,
   0xCF, 0x1A, 0xB0, 0x65, 0x31, 0xE4, 0x4E, 0x9B,
   0xE6, 0x33, 0x99, 0x4C, 0x18, 0xCD, 0x67, 0xB2,
   0x39, 0xEC, 0x46, 0x93, 0xC7, 0x12, 0xB8, 0x6D,
   0x10, 0xC5, 0x6F, 0xBA, 0xEE, 0x3B, 0x91, 0x44,
   0x6B, 0xBE, 0x14, 0xC1, 0x95, 0x40, 0xEA, 0x3F,
   0x42, 0x97, 0x3D, 0xE8, 0xBC, 0x69, 0xC3, 0x16,
   0xEF, 0x3A, 0x90, 0x45, 0x11, 0xC4, 0x6E, 0xBB,
   0xC6, 0x13, 0xB9, 0x6C, 0x38, 0xED, 0x47, 0x92,
   0xBD, 0x68, 0xC2, 0x17, 0x43, 0x96, 0x3C, 0xE9,
   0x94, 0x41, 0xEB, 0x3E, 0x6A, 0xBF, 0x15, 0xC0,
   0x4B, 0x9E, 0x34, 0xE1, 0xB5, 0x60, 0xCA, 0x1F,
   0x62, 0xB7, 0x1D, 0xC8, 0x9C, 0x49, 0xE3, 0x36,
   0x19, 0xCC, 0x66, 0xB3, 0xE7, 0x32, 0x98, 0x4D,
   0x30, 0xE5, 0x4F, 0x9A, 0xCE, 0x1B, 0xB1, 0x64,
   0x72, 0xA7, 0x0D, 0xD8, 0x8C, 0x59, 0xF3, 0x26,
   0x5B, 0x8E, 0x24, 0xF1, 0xA5, 0x70, 0xDA, 0x0F,
   0x20, 0xF5, 0x5F, 0x8A, 0xDE, 0x0B, 0xA1, 0x74,
   0x09, 0xDC, 0x76, 0xA3, 0xF7, 0x22, 0x88, 0x5D,
   0xD6, 0x03, 0xA9, 0x7C, 0x28, 0xFD, 0x57, 0x82,
   0xFF, 0x2A, 0x80, 0x55, 0x01, 0xD4, 0x7E, 0xAB,
   0x84, 0x51, 0xFB, 0x2E, 0x7A, 0xAF, 0x05, 0xD0,
   0xAD, 0x78, 0xD2, 0x07, 0x53, 0x86, 0x2C, 0xF9
 };
 
 #define SVQ1_PROCESS_VECTOR()\
     for (; level > 0; i++) {\
       /* process next depth */\
       if (i == m) {\
         m = n;\
         if (--level == 0)\
           break;\
       }\
       /* divide block if next bit set */\

       if (get_bits1 (bitbuf) == 0)\

         break;\
       /* add child nodes */\
       list[n++] = list[i];\

       list[n++] = list[i] + (((level & 1) ? pitch : 1) << ((level >> 1) + 1));\

     }
 
 #define SVQ1_ADD_CODEBOOK()\
           /* add codebook entries to vector */\
           for (j=0; j < stages; j++) {\
             n3  = codebook[entries[j]] ^ 0x80808080;\
             n1 += ((n3 & 0xFF00FF00) >> 8);\
             n2 +=  (n3 & 0x00FF00FF);\
           }\
 \
           /* clip to [0..255] */\
           if (n1 & 0xFF00FF00) {\
             n3  = ((( n1 >> 15) & 0x00010001) | 0x01000100) - 0x00010001;\
             n1 += 0x7F007F00;\
             n1 |= (((~n1 >> 15) & 0x00010001) | 0x01000100) - 0x00010001;\
             n1 &= (n3 & 0x00FF00FF);\
           }\
 \
           if (n2 & 0xFF00FF00) {\
             n3  = ((( n2 >> 15) & 0x00010001) | 0x01000100) - 0x00010001;\
             n2 += 0x7F007F00;\
             n2 |= (((~n2 >> 15) & 0x00010001) | 0x01000100) - 0x00010001;\
             n2 &= (n3 & 0x00FF00FF);\
           }
 
 #define SVQ1_DO_CODEBOOK_INTRA()\
       for (y=0; y < height; y++) {\
         for (x=0; x < (width / 4); x++, codebook++) {\
         n1 = n4;\
         n2 = n4;\
         SVQ1_ADD_CODEBOOK()\
         /* store result */\
         dst[x] = (n1 << 8) | n2;\
         }\
         dst += (pitch / 4);\
       }
 
 #define SVQ1_DO_CODEBOOK_NONINTRA()\
       for (y=0; y < height; y++) {\
         for (x=0; x < (width / 4); x++, codebook++) {\
         n3 = dst[x];\
         /* add mean value to vector */\
         n1 = ((n3 & 0xFF00FF00) >> 8) + n4;\
         n2 =  (n3 & 0x00FF00FF)          + n4;\
         SVQ1_ADD_CODEBOOK()\
         /* store result */\
         dst[x] = (n1 << 8) | n2;\
         }\
         dst += (pitch / 4);\
       }
 
 #define SVQ1_CALC_CODEBOOK_ENTRIES(cbook)\
       codebook = (const uint32_t *) cbook[level];\
       bit_cache = get_bits (bitbuf, 4*stages);\
       /* calculate codebook entries for this vector */\
       for (j=0; j < stages; j++) {\
         entries[j] = (((bit_cache >> (4*(stages - j - 1))) & 0xF) + 16*j) << (level + 1);\
       }\
       mean -= (stages * 128);\

       n4    = (mean << 16) + mean;

 
 static int svq1_decode_block_intra (GetBitContext *bitbuf, uint8_t *pixels, int pitch ) {
   uint32_t    bit_cache;
   uint8_t    *list[63];
   uint32_t   *dst;
   const uint32_t *codebook;
   int         entries[6];
   int         i, j, m, n;
   int         mean, stages;
   unsigned    x, y, width, height, level;
   uint32_t    n1, n2, n3, n4;
 
   /* initialize list for breadth first processing of vectors */
   list[0] = pixels;
 
   /* recursively process vector */
   for (i=0, m=1, n=1, level=5; i < n; i++) {
     SVQ1_PROCESS_VECTOR();
 
     /* destination address and vector size */
     dst = (uint32_t *) list[i];
     width = 1 << ((4 + level) /2);
     height = 1 << ((3 + level) /2);
 
     /* get number of stages (-1 skips vector, 0 for mean only) */
     stages = get_vlc2(bitbuf, svq1_intra_multistage[level].table, 3, 3) - 1;
 
     if (stages == -1) {
         for (y=0; y < height; y++) {
           memset (&dst[y*(pitch / 4)], 0, width);
         }
       continue;                 /* skip vector */
     }
 
     if ((stages > 0) && (level >= 4)) {

       av_dlog(NULL,

               "Error (svq1_decode_block_intra): invalid vector: stages=%i level=%i\n",
               stages, level);

       return -1;        /* invalid vector */
     }
 
     mean = get_vlc2(bitbuf, svq1_intra_mean.table, 8, 3);
 
     if (stages == 0) {
       for (y=0; y < height; y++) {
         memset (&dst[y*(pitch / 4)], mean, width);
       }
     } else {
       SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_intra_codebooks);
       SVQ1_DO_CODEBOOK_INTRA()
     }
   }
 
   return 0;
 }
 
 static int svq1_decode_block_non_intra (GetBitContext *bitbuf, uint8_t *pixels, int pitch ) {
   uint32_t    bit_cache;
   uint8_t    *list[63];
   uint32_t   *dst;
   const uint32_t *codebook;
   int         entries[6];
   int         i, j, m, n;
   int         mean, stages;
   int         x, y, width, height, level;
   uint32_t    n1, n2, n3, n4;
 
   /* initialize list for breadth first processing of vectors */
   list[0] = pixels;
 
   /* recursively process vector */
   for (i=0, m=1, n=1, level=5; i < n; i++) {
     SVQ1_PROCESS_VECTOR();
 
     /* destination address and vector size */
     dst = (uint32_t *) list[i];
     width = 1 << ((4 + level) /2);
     height = 1 << ((3 + level) /2);
 
     /* get number of stages (-1 skips vector, 0 for mean only) */
     stages = get_vlc2(bitbuf, svq1_inter_multistage[level].table, 3, 2) - 1;
 
     if (stages == -1) continue; /* skip vector */
 
     if ((stages > 0) && (level >= 4)) {

       av_dlog(NULL,

               "Error (svq1_decode_block_non_intra): invalid vector: stages=%i level=%i\n",
               stages, level);

       return -1;        /* invalid vector */
     }
 
     mean = get_vlc2(bitbuf, svq1_inter_mean.table, 9, 3) - 256;
 
     SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_inter_codebooks);
     SVQ1_DO_CODEBOOK_NONINTRA()
   }
   return 0;
 }
 

 static int svq1_decode_motion_vector (GetBitContext *bitbuf, svq1_pmv *mv, svq1_pmv **pmv) {

   int        diff;
   int        i;
 
   for (i=0; i < 2; i++) {
 
     /* get motion code */
     diff = get_vlc2(bitbuf, svq1_motion_component.table, 7, 2);
     if(diff<0)
         return -1;
     else if(diff){
         if(get_bits1(bitbuf)) diff= -diff;
     }
 
     /* add median of motion vector predictors and clip result */
     if (i == 1)
       mv->y = ((diff + mid_pred(pmv[0]->y, pmv[1]->y, pmv[2]->y)) << 26) >> 26;
     else
       mv->x = ((diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x)) << 26) >> 26;
   }
 
   return 0;
 }
 
 static void svq1_skip_block (uint8_t *current, uint8_t *previous, int pitch, int x, int y) {
   uint8_t *src;
   uint8_t *dst;
   int      i;
 
   src = &previous[x + y*pitch];
   dst = current;
 
   for (i=0; i < 16; i++) {
     memcpy (dst, src, 16);
     src += pitch;
     dst += pitch;
   }
 }
 
 static int svq1_motion_inter_block (MpegEncContext *s, GetBitContext *bitbuf,
                                uint8_t *current, uint8_t *previous, int pitch,

                                svq1_pmv *motion, int x, int y) {

   uint8_t    *src;
   uint8_t    *dst;

   svq1_pmv    mv;
   svq1_pmv   *pmv[3];

   int         result;
 
   /* predict and decode motion vector */
   pmv[0] = &motion[0];
   if (y == 0) {
     pmv[1] =
     pmv[2] = pmv[0];
   }
   else {
     pmv[1] = &motion[(x / 8) + 2];
     pmv[2] = &motion[(x / 8) + 4];
   }
 
   result = svq1_decode_motion_vector (bitbuf, &mv, pmv);
 
   if (result != 0)
     return result;
 
   motion[0].x                =
   motion[(x / 8) + 2].x      =
   motion[(x / 8) + 3].x      = mv.x;
   motion[0].y                =
   motion[(x / 8) + 2].y      =
   motion[(x / 8) + 3].y      = mv.y;
 
   if(y + (mv.y >> 1)<0)
      mv.y= 0;
   if(x + (mv.x >> 1)<0)
      mv.x= 0;
 
   src = &previous[(x + (mv.x >> 1)) + (y + (mv.y >> 1))*pitch];
   dst = current;
 
   s->dsp.put_pixels_tab[0][((mv.y & 1) << 1) | (mv.x & 1)](dst,src,pitch,16);
 
   return 0;
 }
 
 static int svq1_motion_inter_4v_block (MpegEncContext *s, GetBitContext *bitbuf,
                                   uint8_t *current, uint8_t *previous, int pitch,

                                   svq1_pmv *motion,int x, int y) {

   uint8_t    *src;
   uint8_t    *dst;

   svq1_pmv    mv;
   svq1_pmv   *pmv[4];

   int         i, result;
 
   /* predict and decode motion vector (0) */
   pmv[0] = &motion[0];
   if (y == 0) {
     pmv[1] =
     pmv[2] = pmv[0];
   }
   else {
     pmv[1] = &motion[(x / 8) + 2];
     pmv[2] = &motion[(x / 8) + 4];
   }
 
   result = svq1_decode_motion_vector (bitbuf, &mv, pmv);
 
   if (result != 0)
     return result;
 
   /* predict and decode motion vector (1) */
   pmv[0] = &mv;
   if (y == 0) {
     pmv[1] =
     pmv[2] = pmv[0];
   }
   else {
     pmv[1] = &motion[(x / 8) + 3];
   }
   result = svq1_decode_motion_vector (bitbuf, &motion[0], pmv);
 
   if (result != 0)
     return result;
 
   /* predict and decode motion vector (2) */
   pmv[1] = &motion[0];
   pmv[2] = &motion[(x / 8) + 1];
 
   result = svq1_decode_motion_vector (bitbuf, &motion[(x / 8) + 2], pmv);
 
   if (result != 0)
     return result;
 
   /* predict and decode motion vector (3) */
   pmv[2] = &motion[(x / 8) + 2];
   pmv[3] = &motion[(x / 8) + 3];
 
   result = svq1_decode_motion_vector (bitbuf, pmv[3], pmv);
 
   if (result != 0)
     return result;
 
   /* form predictions */
   for (i=0; i < 4; i++) {
     int mvx= pmv[i]->x + (i&1)*16;
     int mvy= pmv[i]->y + (i>>1)*16;
 
     ///XXX /FIXME clipping or padding?
     if(y + (mvy >> 1)<0)
        mvy= 0;
     if(x + (mvx >> 1)<0)
        mvx= 0;
 
     src = &previous[(x + (mvx >> 1)) + (y + (mvy >> 1))*pitch];
     dst = current;
 
     s->dsp.put_pixels_tab[1][((mvy & 1) << 1) | (mvx & 1)](dst,src,pitch,8);
 
     /* select next block */
     if (i & 1) {
       current  += 8*(pitch - 1);
     } else {
       current  += 8;
     }
   }
 
   return 0;
 }
 
 static int svq1_decode_delta_block (MpegEncContext *s, GetBitContext *bitbuf,
                         uint8_t *current, uint8_t *previous, int pitch,

                         svq1_pmv *motion, int x, int y) {

   uint32_t block_type;
   int      result = 0;
 
   /* get block type */
   block_type = get_vlc2(bitbuf, svq1_block_type.table, 2, 2);
 
   /* reset motion vectors */
   if (block_type == SVQ1_BLOCK_SKIP || block_type == SVQ1_BLOCK_INTRA) {
     motion[0].x                 =
     motion[0].y                 =
     motion[(x / 8) + 2].x =
     motion[(x / 8) + 2].y =
     motion[(x / 8) + 3].x =
     motion[(x / 8) + 3].y = 0;
   }
 
   switch (block_type) {
   case SVQ1_BLOCK_SKIP:
     svq1_skip_block (current, previous, pitch, x, y);
     break;
 
   case SVQ1_BLOCK_INTER:
     result = svq1_motion_inter_block (s, bitbuf, current, previous, pitch, motion, x, y);
 
     if (result != 0)
     {

       av_dlog(s->avctx, "Error in svq1_motion_inter_block %i\n", result);

       break;
     }
     result = svq1_decode_block_non_intra (bitbuf, current, pitch);
     break;
 
   case SVQ1_BLOCK_INTER_4V:
     result = svq1_motion_inter_4v_block (s, bitbuf, current, previous, pitch, motion, x, y);
 
     if (result != 0)
     {

       av_dlog(s->avctx, "Error in svq1_motion_inter_4v_block %i\n", result);

       break;
     }
     result = svq1_decode_block_non_intra (bitbuf, current, pitch);
     break;
 
   case SVQ1_BLOCK_INTRA:
     result = svq1_decode_block_intra (bitbuf, current, pitch);
     break;
   }
 
   return result;
 }
 

 uint16_t ff_svq1_packet_checksum (const uint8_t *data, const int length, int value) {

   int i;
 
   for (i=0; i < length; i++) {
     value = checksum_table[data[i] ^ (value >> 8)] ^ ((value & 0xFF) << 8);
   }
 
   return value;
 }
 
 static void svq1_parse_string (GetBitContext *bitbuf, uint8_t *out) {
   uint8_t seed;
   int     i;
 
   out[0] = get_bits (bitbuf, 8);
 
   seed = string_table[out[0]];
 
   for (i=1; i <= out[0]; i++) {
     out[i] = get_bits (bitbuf, 8) ^ seed;
     seed   = string_table[out[i] ^ seed];
   }
 }
 
 static int svq1_decode_frame_header (GetBitContext *bitbuf,MpegEncContext *s) {
   int frame_size_code;
 

   skip_bits(bitbuf, 8); /* temporal_reference */

 
   /* frame type */
   s->pict_type= get_bits (bitbuf, 2)+1;
   if(s->pict_type==4)
       return -1;
 

   if (s->pict_type == AV_PICTURE_TYPE_I) {

 
     /* unknown fields */
     if (s->f_code == 0x50 || s->f_code == 0x60) {
       int csum = get_bits (bitbuf, 16);
 

       csum = ff_svq1_packet_checksum (bitbuf->buffer, bitbuf->size_in_bits>>3, csum);

 
 //      av_log(s->avctx, AV_LOG_INFO, "%s checksum (%02x) for packet data\n",
 //              (csum == 0) ? "correct" : "incorrect", csum);
     }
 
     if ((s->f_code ^ 0x10) >= 0x50) {
       uint8_t msg[256];
 
       svq1_parse_string (bitbuf, msg);
 
       av_log(s->avctx, AV_LOG_INFO, "embedded message: \"%s\"\n", (char *) msg);
     }
 
     skip_bits (bitbuf, 2);
     skip_bits (bitbuf, 2);
     skip_bits1 (bitbuf);
 
     /* load frame size */
     frame_size_code = get_bits (bitbuf, 3);
 
     if (frame_size_code == 7) {
       /* load width, height (12 bits each) */
       s->width = get_bits (bitbuf, 12);
       s->height = get_bits (bitbuf, 12);
 
       if (!s->width || !s->height)
         return -1;
     } else {
       /* get width, height from table */
       s->width = ff_svq1_frame_size_table[frame_size_code].width;
       s->height = ff_svq1_frame_size_table[frame_size_code].height;
     }
   }
 
   /* unknown fields */

   if (get_bits1 (bitbuf) == 1) {

     skip_bits1 (bitbuf);       /* use packet checksum if (1) */
     skip_bits1 (bitbuf);       /* component checksums after image data if (1) */
 
     if (get_bits (bitbuf, 2) != 0)
       return -1;
   }
 

   if (get_bits1 (bitbuf) == 1) {

     skip_bits1 (bitbuf);
     skip_bits (bitbuf, 4);
     skip_bits1 (bitbuf);
     skip_bits (bitbuf, 2);
 

     while (get_bits1 (bitbuf) == 1) {

       skip_bits (bitbuf, 8);
     }
   }
 
   return 0;
 }
 
 static int svq1_decode_frame(AVCodecContext *avctx,
                              void *data, int *data_size,

                              AVPacket *avpkt)

 {

   const uint8_t *buf = avpkt->data;
   int buf_size = avpkt->size;

   MpegEncContext *s=avctx->priv_data;
   uint8_t        *current, *previous;
   int             result, i, x, y, width, height;
   AVFrame *pict = data;

   svq1_pmv *pmv;

 
   /* initialize bit buffer */
   init_get_bits(&s->gb,buf,buf_size*8);
 
   /* decode frame header */
   s->f_code = get_bits (&s->gb, 22);
 
   if ((s->f_code & ~0x70) || !(s->f_code & 0x60))
     return -1;
 
   /* swap some header bytes (why?) */
   if (s->f_code != 0x20) {
     uint32_t *src = (uint32_t *) (buf + 4);
 
     for (i=0; i < 4; i++) {
       src[i] = ((src[i] << 16) | (src[i] >> 16)) ^ src[7 - i];
     }
   }
 
   result = svq1_decode_frame_header (&s->gb, s);
 
   if (result != 0)
   {

     av_dlog(s->avctx, "Error in svq1_decode_frame_header %i\n",result);

     return result;
   }

   avcodec_set_dimensions(avctx, s->width, s->height);

 
   //FIXME this avoids some confusion for "B frames" without 2 references
   //this should be removed after libavcodec can handle more flexible picture types & ordering

   if(s->pict_type==AV_PICTURE_TYPE_B && s->last_picture_ptr==NULL) return buf_size;

 #if FF_API_HURRY_UP
   if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return buf_size;
 #endif

   if(  (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B)
      ||(avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I)

      || avctx->skip_frame >= AVDISCARD_ALL)
       return buf_size;
 
   if(MPV_frame_start(s, avctx) < 0)
       return -1;
 

   pmv = av_malloc((FFALIGN(s->width, 16)/8 + 3) * sizeof(*pmv));
   if (!pmv)
       return -1;
 

   /* decode y, u and v components */
   for (i=0; i < 3; i++) {
     int linesize;
     if (i == 0) {

       width  = FFALIGN(s->width, 16);
       height = FFALIGN(s->height, 16);

       linesize= s->linesize;
     } else {
       if(s->flags&CODEC_FLAG_GRAY) break;

       width  = FFALIGN(s->width/4, 16);
       height = FFALIGN(s->height/4, 16);

       linesize= s->uvlinesize;
     }
 
     current  = s->current_picture.data[i];
 

     if(s->pict_type==AV_PICTURE_TYPE_B){

         previous = s->next_picture.data[i];
     }else{
         previous = s->last_picture.data[i];
     }
 

     if (s->pict_type == AV_PICTURE_TYPE_I) {

       /* keyframe */
       for (y=0; y < height; y+=16) {
         for (x=0; x < width; x+=16) {
           result = svq1_decode_block_intra (&s->gb, &current[x], linesize);
           if (result != 0)
           {
             av_log(s->avctx, AV_LOG_INFO, "Error in svq1_decode_block %i (keyframe)\n",result);

             goto err;

           }
         }
         current += 16*linesize;
       }
     } else {
       /* delta frame */

       memset (pmv, 0, ((width / 8) + 3) * sizeof(svq1_pmv));

 
       for (y=0; y < height; y+=16) {
         for (x=0; x < width; x+=16) {
           result = svq1_decode_delta_block (s, &s->gb, &current[x], previous,
                                             linesize, pmv, x, y);
           if (result != 0)
           {

             av_dlog(s->avctx, "Error in svq1_decode_delta_block %i\n",result);

             goto err;

           }
         }
 
         pmv[0].x =
         pmv[0].y = 0;
 
         current += 16*linesize;
       }
     }
   }
 
   *pict = *(AVFrame*)&s->current_picture;
 
 
   MPV_frame_end(s);
 
   *data_size=sizeof(AVFrame);

   result = buf_size;
 err:
   av_free(pmv);
   return result;

 }
 

 static av_cold int svq1_decode_init(AVCodecContext *avctx)

 {
     MpegEncContext *s = avctx->priv_data;
     int i;

     int offset = 0;

 
     MPV_decode_defaults(s);
 
     s->avctx = avctx;
     s->width = (avctx->width+3)&~3;
     s->height = (avctx->height+3)&~3;
     s->codec_id= avctx->codec->id;
     avctx->pix_fmt = PIX_FMT_YUV410P;
     avctx->has_b_frames= 1; // not true, but DP frames and these behave like unidirectional b frames
     s->flags= avctx->flags;
     if (MPV_common_init(s) < 0) return -1;
 

     INIT_VLC_STATIC(&svq1_block_type, 2, 4,

         &ff_svq1_block_type_vlc[0][1], 2, 1,

         &ff_svq1_block_type_vlc[0][0], 2, 1, 6);

     INIT_VLC_STATIC(&svq1_motion_component, 7, 33,

         &mvtab[0][1], 2, 1,

         &mvtab[0][0], 2, 1, 176);

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

         static const uint8_t sizes[2][6] = {{14, 10, 14, 18, 16, 18}, {10, 10, 14, 14, 14, 16}};
         static VLC_TYPE table[168][2];
         svq1_intra_multistage[i].table = &table[offset];
         svq1_intra_multistage[i].table_allocated = sizes[0][i];
         offset += sizes[0][i];

         init_vlc(&svq1_intra_multistage[i], 3, 8,
             &ff_svq1_intra_multistage_vlc[i][0][1], 2, 1,

             &ff_svq1_intra_multistage_vlc[i][0][0], 2, 1, INIT_VLC_USE_NEW_STATIC);
         svq1_inter_multistage[i].table = &table[offset];
         svq1_inter_multistage[i].table_allocated = sizes[1][i];
         offset += sizes[1][i];

         init_vlc(&svq1_inter_multistage[i], 3, 8,
             &ff_svq1_inter_multistage_vlc[i][0][1], 2, 1,

             &ff_svq1_inter_multistage_vlc[i][0][0], 2, 1, INIT_VLC_USE_NEW_STATIC);

     }
 

     INIT_VLC_STATIC(&svq1_intra_mean, 8, 256,

         &ff_svq1_intra_mean_vlc[0][1], 4, 2,

         &ff_svq1_intra_mean_vlc[0][0], 4, 2, 632);

     INIT_VLC_STATIC(&svq1_inter_mean, 9, 512,

         &ff_svq1_inter_mean_vlc[0][1], 4, 2,

         &ff_svq1_inter_mean_vlc[0][0], 4, 2, 1434);

 
     return 0;
 }
 

 static av_cold int svq1_decode_end(AVCodecContext *avctx)

 {
     MpegEncContext *s = avctx->priv_data;
 
     MPV_common_end(s);
     return 0;
 }
 
 

 AVCodec ff_svq1_decoder = {

     "svq1",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_SVQ1,
     sizeof(MpegEncContext),
     svq1_decode_init,
     NULL,
     svq1_decode_end,
     svq1_decode_frame,
     CODEC_CAP_DR1,
     .flush= ff_mpeg_flush,

     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_YUV410P, PIX_FMT_NONE},

     .long_name= NULL_IF_CONFIG_SMALL("Sorenson Vector Quantizer 1 / Sorenson Video 1 / SVQ1"),

 };