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FFmpeg/libavcodec/mpeg12.c

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  1. /*

  2.  * MPEG1 encoder / MPEG2 decoder

  3.  * Copyright (c) 2000,2001 Gerard Lantau.

  4.  *

  5.  * This program is free software; you can redistribute it and/or modify

  6.  * it under the terms of the GNU General Public License as published by

  7.  * the Free Software Foundation; either version 2 of the License, or

  8.  * (at your option) any later version.

  9.  *

  10.  * This program is distributed in the hope that it will be useful,

  11.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  12.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  13.  * GNU General Public License for more details.

  14.  *

  15.  * You should have received a copy of the GNU General Public License

  16.  * along with this program; if not, write to the Free Software

  17.  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

  18.  */

  19. #include <stdlib.h>

  20. #include <stdio.h>

  21. #include <string.h>

  22. #include "avcodec.h"

  23. #include "dsputil.h"

  24. #include "mpegvideo.h"

  25. 

  26. #include "mpeg12data.h"

  27. 

  28. #ifdef USE_FASTMEMCPY

  29. #include "fastmemcpy.h"

  30. #endif

  31. //#define DEBUG

  32. 

  33. #ifdef DEBUG

  34. #define dprintf(fmt,args...) printf(fmt, ## args)

  35. #else

  36. #define dprintf(fmt,args...)

  37. #endif

  38. 

  39. /* Start codes. */

  40. #define SEQ_END_CODE		0x000001b7

  41. #define SEQ_START_CODE		0x000001b3

  42. #define GOP_START_CODE		0x000001b8

  43. #define PICTURE_START_CODE	0x00000100

  44. #define SLICE_MIN_START_CODE	0x00000101

  45. #define SLICE_MAX_START_CODE	0x000001af

  46. #define EXT_START_CODE		0x000001b5

  47. #define USER_START_CODE		0x000001b2

  48. 

  49. static void mpeg1_encode_block(MpegEncContext *s, 

  50.                          DCTELEM *block, 

  51.                          int component);

  52. static void mpeg1_encode_motion(MpegEncContext *s, int val);

  53. static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);

  54. static int mpeg1_decode_block(MpegEncContext *s, 

  55.                               DCTELEM *block, 

  56.                               int n);

  57. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  58.                                         DCTELEM *block, 

  59.                                         int n);

  60. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  61.                                     DCTELEM *block, 

  62.                                     int n);

  63. static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);

  64. 

  65. static void put_header(MpegEncContext *s, int header)

  66. {

  67.     align_put_bits(&s->pb);

  68.     put_bits(&s->pb, 32, header);

  69. }

  70. 

  71. /* put sequence header if needed */

  72. static void mpeg1_encode_sequence_header(MpegEncContext *s)

  73. {

  74.         unsigned int vbv_buffer_size;

  75.         unsigned int fps, v;

  76.         int n;

  77.         UINT64 time_code;

  78.         

  79.         if ((s->picture_number % s->gop_size) == 0) {

  80.             /* mpeg1 header repeated every gop */

  81.             put_header(s, SEQ_START_CODE);

  82.             

  83.             /* search closest frame rate */

  84.             {

  85.                 int i, dmin, d;

  86.                 s->frame_rate_index = 0;

  87.                 dmin = 0x7fffffff;

  88.                 for(i=1;i<9;i++) {

  89.                     d = abs(s->frame_rate - frame_rate_tab[i]);

  90.                     if (d < dmin) {

  91.                         dmin = d;

  92.                         s->frame_rate_index = i;

  93.                     }

  94.                 }

  95.             }

  96.  

  97.             put_bits(&s->pb, 12, s->width);

  98.             put_bits(&s->pb, 12, s->height);

  99.             put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */

  100.             put_bits(&s->pb, 4, s->frame_rate_index);

  101.             v = s->bit_rate / 400;

  102.             if (v > 0x3ffff)

  103.                 v = 0x3ffff;

  104.             put_bits(&s->pb, 18, v);

  105.             put_bits(&s->pb, 1, 1); /* marker */

  106.             /* vbv buffer size: slightly greater than an I frame. We add

  107.                some margin just in case */

  108.             vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8);

  109.             put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 

  110.             put_bits(&s->pb, 1, 1); /* constrained parameter flag */

  111.             put_bits(&s->pb, 1, 0); /* no custom intra matrix */

  112.             put_bits(&s->pb, 1, 0); /* no custom non intra matrix */

  113. 

  114.             put_header(s, GOP_START_CODE);

  115.             put_bits(&s->pb, 1, 0); /* do drop frame */

  116.             /* time code : we must convert from the real frame rate to a

  117.                fake mpeg frame rate in case of low frame rate */

  118.             fps = frame_rate_tab[s->frame_rate_index];

  119.             time_code = s->fake_picture_number * FRAME_RATE_BASE;

  120.             s->gop_picture_number = s->fake_picture_number;

  121.             put_bits(&s->pb, 5, (time_code / (fps * 3600)) % 24);

  122.             put_bits(&s->pb, 6, (time_code / (fps * 60)) % 60);

  123.             put_bits(&s->pb, 1, 1);

  124.             put_bits(&s->pb, 6, (time_code / fps) % 60);

  125.             put_bits(&s->pb, 6, (time_code % fps) / FRAME_RATE_BASE);

  126.             put_bits(&s->pb, 1, 1); /* closed gop */

  127.             put_bits(&s->pb, 1, 0); /* broken link */

  128.         }

  129. 

  130.         if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {

  131.             /* insert empty P pictures to slow down to the desired

  132.                frame rate. Each fake pictures takes about 20 bytes */

  133.             fps = frame_rate_tab[s->frame_rate_index];

  134.             n = ((s->picture_number * fps) / s->frame_rate) - 1;

  135.             while (s->fake_picture_number < n) {

  136.                 mpeg1_skip_picture(s, s->fake_picture_number - 

  137.                                    s->gop_picture_number); 

  138.                 s->fake_picture_number++;

  139.             }

  140. 

  141.         }

  142.         s->fake_picture_number++;

  143. }

  144. 

  145. 

  146. /* insert a fake P picture */

  147. static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)

  148. {

  149.     unsigned int mb_incr;

  150. 

  151.     /* mpeg1 picture header */

  152.     put_header(s, PICTURE_START_CODE);

  153.     /* temporal reference */

  154.     put_bits(&s->pb, 10, pict_num & 0x3ff); 

  155.     

  156.     put_bits(&s->pb, 3, P_TYPE);

  157.     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */

  158.     

  159.     put_bits(&s->pb, 1, 1); /* integer coordinates */

  160.     put_bits(&s->pb, 3, 1); /* forward_f_code */

  161.     

  162.     put_bits(&s->pb, 1, 0); /* extra bit picture */

  163.     

  164.     /* only one slice */

  165.     put_header(s, SLICE_MIN_START_CODE);

  166.     put_bits(&s->pb, 5, 1); /* quantizer scale */

  167.     put_bits(&s->pb, 1, 0); /* slice extra information */

  168.     

  169.     mb_incr = 1;

  170.     put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 

  171.              mbAddrIncrTable[mb_incr - 1][0]);

  172.     

  173.     /* empty macroblock */

  174.     put_bits(&s->pb, 3, 1); /* motion only */

  175.     

  176.     /* zero motion x & y */

  177.     put_bits(&s->pb, 1, 1); 

  178.     put_bits(&s->pb, 1, 1); 

  179. 

  180.     /* output a number of empty slice */

  181.     mb_incr = s->mb_width * s->mb_height - 1;

  182.     while (mb_incr > 33) {

  183.         put_bits(&s->pb, 11, 0x008);

  184.         mb_incr -= 33;

  185.     }

  186.     put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 

  187.              mbAddrIncrTable[mb_incr - 1][0]);

  188.     

  189.     /* empty macroblock */

  190.     put_bits(&s->pb, 3, 1); /* motion only */

  191.     

  192.     /* zero motion x & y */

  193.     put_bits(&s->pb, 1, 1); 

  194.     put_bits(&s->pb, 1, 1); 

  195. }

  196. 

  197. void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)

  198. {

  199.     static int done;

  200. 

  201.     if (!done) {

  202.         done = 1;

  203.         init_rl(&rl_mpeg1);

  204.     }

  205.     mpeg1_encode_sequence_header(s);

  206. 

  207.     /* mpeg1 picture header */

  208.     put_header(s, PICTURE_START_CODE);

  209.     /* temporal reference */

  210.     put_bits(&s->pb, 10, (s->fake_picture_number - 

  211.                           s->gop_picture_number) & 0x3ff); 

  212.     

  213.     put_bits(&s->pb, 3, s->pict_type);

  214.     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */

  215.     

  216.     if (s->pict_type == P_TYPE) {

  217.         put_bits(&s->pb, 1, 0); /* half pel coordinates */

  218.         put_bits(&s->pb, 3, s->f_code); /* forward_f_code */

  219.     }

  220.     

  221.     put_bits(&s->pb, 1, 0); /* extra bit picture */

  222.     

  223.     /* only one slice */

  224.     put_header(s, SLICE_MIN_START_CODE);

  225.     put_bits(&s->pb, 5, s->qscale); /* quantizer scale */

  226.     put_bits(&s->pb, 1, 0); /* slice extra information */

  227. }

  228. 

  229. void mpeg1_encode_mb(MpegEncContext *s,

  230.                      DCTELEM block[6][64],

  231.                      int motion_x, int motion_y)

  232. {

  233.     int mb_incr, i, cbp, mb_x, mb_y;

  234. 

  235.     mb_x = s->mb_x;

  236.     mb_y = s->mb_y;

  237. 

  238.     /* compute cbp */

  239.     cbp = 0;

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

  241.         if (s->block_last_index[i] >= 0)

  242.             cbp |= 1 << (5 - i);

  243.     }

  244. 

  245.     /* skip macroblock, except if first or last macroblock of a slice */

  246.     if ((cbp | motion_x | motion_y) == 0 &&

  247.         (!((mb_x | mb_y) == 0 ||

  248.            (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {

  249.         s->mb_incr++;

  250.     } else {

  251.         /* output mb incr */

  252.         mb_incr = s->mb_incr;

  253. 

  254.         while (mb_incr > 33) {

  255.             put_bits(&s->pb, 11, 0x008);

  256.             mb_incr -= 33;

  257.         }

  258.         put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 

  259.                  mbAddrIncrTable[mb_incr - 1][0]);

  260.         

  261.         if (s->pict_type == I_TYPE) {

  262.             put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */

  263.         } else {

  264.             if (s->mb_intra) {

  265.                 put_bits(&s->pb, 5, 0x03);

  266.             } else {

  267.                 if (cbp != 0) {

  268.                     if (motion_x == 0 && motion_y == 0) {

  269.                         put_bits(&s->pb, 2, 1); /* macroblock_pattern only */

  270.                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);

  271.                     } else {

  272.                         put_bits(&s->pb, 1, 1); /* motion + cbp */

  273.                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 

  274.                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 

  275.                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);

  276.                     }

  277.                 } else {

  278.                     put_bits(&s->pb, 3, 1); /* motion only */

  279.                     mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 

  280.                     mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 

  281.                 }

  282.             }

  283.         }

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

  285.             if (cbp & (1 << (5 - i))) {

  286.                 mpeg1_encode_block(s, block[i], i);

  287.             }

  288.         }

  289.         s->mb_incr = 1;

  290.     }

  291.     s->last_mv[0][0][0] = motion_x;

  292.     s->last_mv[0][0][1] = motion_y;

  293. }

  294. 

  295. static void mpeg1_encode_motion(MpegEncContext *s, int val)

  296. {

  297.     int code, bit_size, l, m, bits, range, sign;

  298. 

  299.     if (val == 0) {

  300.         /* zero vector */

  301.         code = 0;

  302.         put_bits(&s->pb,

  303.                  mbMotionVectorTable[0][1], 

  304.                  mbMotionVectorTable[0][0]); 

  305.     } else {

  306.         bit_size = s->f_code - 1;

  307.         range = 1 << bit_size;

  308.         /* modulo encoding */

  309.         l = 16 * range;

  310.         m = 2 * l;

  311.         if (val < -l) {

  312.             val += m;

  313.         } else if (val >= l) {

  314.             val -= m;

  315.         }

  316. 

  317.         if (val >= 0) {

  318.             val--;

  319.             code = (val >> bit_size) + 1;

  320.             bits = val & (range - 1);

  321.             sign = 0;

  322.         } else {

  323.             val = -val;

  324.             val--;

  325.             code = (val >> bit_size) + 1;

  326.             bits = val & (range - 1);

  327.             sign = 1;

  328.         }

  329.         put_bits(&s->pb,

  330.                  mbMotionVectorTable[code][1], 

  331.                  mbMotionVectorTable[code][0]); 

  332.         put_bits(&s->pb, 1, sign);

  333.         if (bit_size > 0) {

  334.             put_bits(&s->pb, bit_size, bits);

  335.         }

  336.     }

  337. }

  338. 

  339. static inline void encode_dc(MpegEncContext *s, int diff, int component)

  340. {

  341.     int adiff, index;

  342. 

  343.     adiff = abs(diff);

  344.     index = vlc_dc_table[adiff];

  345.     if (component == 0) {

  346.         put_bits(&s->pb, vlc_dc_lum_bits[index], vlc_dc_lum_code[index]);

  347.     } else {

  348.         put_bits(&s->pb, vlc_dc_chroma_bits[index], vlc_dc_chroma_code[index]);

  349.     }

  350.     if (diff > 0) {

  351.         put_bits(&s->pb, index, (diff & ((1 << index) - 1)));

  352.     } else if (diff < 0) {

  353.         put_bits(&s->pb, index, ((diff - 1) & ((1 << index) - 1)));

  354.     }

  355. }

  356. 

  357. static void mpeg1_encode_block(MpegEncContext *s, 

  358.                                DCTELEM *block, 

  359.                                int n)

  360. {

  361.     int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;

  362.     int code, component;

  363.     RLTable *rl = &rl_mpeg1;

  364. 

  365.     last_index = s->block_last_index[n];

  366. 

  367.     /* DC coef */

  368.     if (s->mb_intra) {

  369.         component = (n <= 3 ? 0 : n - 4 + 1);

  370.         dc = block[0]; /* overflow is impossible */

  371.         diff = dc - s->last_dc[component];

  372.         encode_dc(s, diff, component);

  373.         s->last_dc[component] = dc;

  374.         i = 1;

  375.     } else {

  376.         /* encode the first coefficient : needs to be done here because

  377.            it is handled slightly differently */

  378.         level = block[0];

  379.         if (abs(level) == 1) {

  380.                 code = ((UINT32)level >> 31); /* the sign bit */

  381.                 put_bits(&s->pb, 2, code | 0x02);

  382.                 i = 1;

  383.         } else {

  384.             i = 0;

  385.             last_non_zero = -1;

  386.             goto next_coef;

  387.         }

  388.     }

  389. 

  390.     /* now quantify & encode AC coefs */

  391.     last_non_zero = i - 1;

  392.     for(;i<=last_index;i++) {

  393.         j = zigzag_direct[i];

  394.         level = block[j];

  395.     next_coef:

  396. #if 0

  397.         if (level != 0)

  398.             dprintf("level[%d]=%d\n", i, level);

  399. #endif            

  400.         /* encode using VLC */

  401.         if (level != 0) {

  402.             run = i - last_non_zero - 1;

  403.             sign = 0;

  404.             alevel = level;

  405.             if (alevel < 0) {

  406. 		sign = 1;

  407.                 alevel = -alevel;

  408. 	    }

  409.             code = get_rl_index(rl, 0, run, alevel);

  410.             put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);

  411.             if (code != rl->n) {

  412.                 put_bits(&s->pb, 1, sign);

  413.             } else {

  414.                 /* escape: only clip in this case */

  415.                 put_bits(&s->pb, 6, run);

  416.                 if (alevel < 128) {

  417.                     put_bits(&s->pb, 8, level & 0xff);

  418.                 } else {

  419.                     if (level < 0) {

  420.                         put_bits(&s->pb, 16, 0x8001 + level + 255);

  421.                     } else {

  422.                         put_bits(&s->pb, 16, level & 0xffff);

  423.                     }

  424.                 }

  425.             }

  426.             last_non_zero = i;

  427.         }

  428.     }

  429.     /* end of block */

  430.     put_bits(&s->pb, 2, 0x2);

  431. }

  432. 

  433. /******************************************/

  434. /* decoding */

  435. 

  436. static VLC dc_lum_vlc;

  437. static VLC dc_chroma_vlc;

  438. static VLC mv_vlc;

  439. static VLC mbincr_vlc;

  440. static VLC mb_ptype_vlc;

  441. static VLC mb_btype_vlc;

  442. static VLC mb_pat_vlc;

  443. 

  444. void mpeg1_init_vlc(MpegEncContext *s)

  445. {

  446.     static int done = 0;

  447. 

  448.     if (!done) {

  449. 

  450.         init_vlc(&dc_lum_vlc, 9, 12, 

  451.                  vlc_dc_lum_bits, 1, 1,

  452.                  vlc_dc_lum_code, 2, 2);

  453.         init_vlc(&dc_chroma_vlc, 9, 12, 

  454.                  vlc_dc_chroma_bits, 1, 1,

  455.                  vlc_dc_chroma_code, 2, 2);

  456.         init_vlc(&mv_vlc, 9, 17, 

  457.                  &mbMotionVectorTable[0][1], 2, 1,

  458.                  &mbMotionVectorTable[0][0], 2, 1);

  459.         init_vlc(&mbincr_vlc, 9, 34, 

  460.                  &mbAddrIncrTable[0][1], 2, 1,

  461.                  &mbAddrIncrTable[0][0], 2, 1);

  462.         init_vlc(&mb_pat_vlc, 9, 63, 

  463.                  &mbPatTable[0][1], 2, 1,

  464.                  &mbPatTable[0][0], 2, 1);

  465.         

  466.         init_vlc(&mb_ptype_vlc, 6, 32, 

  467.                  &table_mb_ptype[0][1], 2, 1,

  468.                  &table_mb_ptype[0][0], 2, 1);

  469.         init_vlc(&mb_btype_vlc, 6, 32, 

  470.                  &table_mb_btype[0][1], 2, 1,

  471.                  &table_mb_btype[0][0], 2, 1);

  472.         init_rl(&rl_mpeg1);

  473.         init_rl(&rl_mpeg2);

  474.         /* cannot use generic init because we must add the EOB code */

  475.         init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2, 

  476.                  &rl_mpeg1.table_vlc[0][1], 4, 2,

  477.                  &rl_mpeg1.table_vlc[0][0], 4, 2);

  478.         init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2, 

  479.                  &rl_mpeg2.table_vlc[0][1], 4, 2,

  480.                  &rl_mpeg2.table_vlc[0][0], 4, 2);

  481.     }

  482. }

  483. 

  484. static inline int get_dmv(MpegEncContext *s)

  485. {

  486.     if(get_bits1(&s->gb)) 

  487.         return 1 - (get_bits1(&s->gb) << 1);

  488.     else

  489.         return 0;

  490. }

  491. 

  492. /* motion type (for mpeg2) */

  493. #define MT_FIELD 1

  494. #define MT_FRAME 2

  495. #define MT_16X8  2

  496. #define MT_DMV   3

  497. 

  498. static int mpeg_decode_mb(MpegEncContext *s,

  499.                           DCTELEM block[6][64])

  500. {

  501.     int i, j, k, cbp, val, code, mb_type, motion_type;

  502.     

  503.     /* skip mb handling */

  504.     if (s->mb_incr == 0) {

  505.         /* read again increment */

  506.         s->mb_incr = 1;

  507.         for(;;) {

  508.             code = get_vlc(&s->gb, &mbincr_vlc);

  509.             if (code < 0)

  510.                 return 1; /* error = end of slice */

  511.             if (code >= 33) {

  512.                 if (code == 33) {

  513.                     s->mb_incr += 33;

  514.                 }

  515.                 /* otherwise, stuffing, nothing to do */

  516.             } else {

  517.                 s->mb_incr += code;

  518.                 break;

  519.             }

  520.         }

  521.     }

  522.     if (++s->mb_x >= s->mb_width) {

  523.         s->mb_x = 0;

  524.         if (s->mb_y >= (s->mb_height - 1))

  525.             return -1;

  526.         s->mb_y++;

  527.     }

  528.     dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);

  529. 

  530.     if (--s->mb_incr != 0) {

  531.         /* skip mb */

  532.         s->mb_intra = 0;

  533.         for(i=0;i<6;i++)

  534.             s->block_last_index[i] = -1;

  535.         s->mv_type = MV_TYPE_16X16;

  536.         if (s->pict_type == P_TYPE) {

  537.             /* if P type, zero motion vector is implied */

  538.             s->mv_dir = MV_DIR_FORWARD;

  539.             s->mv[0][0][0] = s->mv[0][0][1] = 0;

  540.             s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;

  541.         } else {

  542.             /* if B type, reuse previous vectors and directions */

  543.             s->mv[0][0][0] = s->last_mv[0][0][0];

  544.             s->mv[0][0][1] = s->last_mv[0][0][1];

  545.             s->mv[1][0][0] = s->last_mv[1][0][0];

  546.             s->mv[1][0][1] = s->last_mv[1][0][1];

  547.         }

  548.         s->mb_skiped = 1;

  549.         return 0;

  550.     }

  551. 

  552.     switch(s->pict_type) {

  553.     default:

  554.     case I_TYPE:

  555.         if (get_bits1(&s->gb) == 0) {

  556.             if (get_bits1(&s->gb) == 0)

  557.                 return -1;

  558.             mb_type = MB_QUANT | MB_INTRA;

  559.         } else {

  560.             mb_type = MB_INTRA;

  561.         }

  562.         break;

  563.     case P_TYPE:

  564.         mb_type = get_vlc(&s->gb, &mb_ptype_vlc);

  565.         if (mb_type < 0)

  566.             return -1;

  567.         break;

  568.     case B_TYPE:

  569.         mb_type = get_vlc(&s->gb, &mb_btype_vlc);

  570.         if (mb_type < 0)

  571.             return -1;

  572.         break;

  573.     }

  574.     dprintf("mb_type=%x\n", mb_type);

  575.     motion_type = 0; /* avoid warning */

  576.     if (mb_type & (MB_FOR|MB_BACK)) {

  577.         /* get additionnal motion vector type */

  578.         if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct) 

  579.             motion_type = MT_FRAME;

  580.         else

  581.             motion_type = get_bits(&s->gb, 2);

  582.     }

  583.     /* compute dct type */

  584.     if (s->picture_structure == PICT_FRAME && 

  585.         !s->frame_pred_frame_dct &&

  586.         (mb_type & (MB_PAT | MB_INTRA))) {

  587.         s->interlaced_dct = get_bits1(&s->gb);

  588. #ifdef DEBUG

  589.         if (s->interlaced_dct)

  590.             printf("interlaced_dct\n");

  591. #endif

  592.     } else {

  593.         s->interlaced_dct = 0; /* frame based */

  594.     }

  595. 

  596.     if (mb_type & MB_QUANT) {

  597.         if (s->mpeg2) {

  598.             if (s->q_scale_type) {

  599.                 s->qscale = non_linear_qscale[get_bits(&s->gb, 5)];

  600.             } else {

  601.                 s->qscale = get_bits(&s->gb, 5) << 1;

  602.             }

  603.         } else {

  604.             /* for mpeg1, we use the generic unquant code */

  605.             s->qscale = get_bits(&s->gb, 5);

  606.         }

  607.     }

  608.     if (mb_type & MB_INTRA) {

  609.         if (s->concealment_motion_vectors) {

  610.             /* just parse them */

  611.             if (s->picture_structure != PICT_FRAME) 

  612.                 skip_bits1(&s->gb); /* field select */

  613.             mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);

  614.             mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);

  615.         }

  616.         s->mb_intra = 1;

  617.         cbp = 0x3f;

  618.         memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */

  619.     } else {

  620.         s->mb_intra = 0;

  621.         cbp = 0;

  622.     }

  623.     /* special case of implicit zero motion vector */

  624.     if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) {

  625.         s->mv_dir = MV_DIR_FORWARD;

  626.         s->mv_type = MV_TYPE_16X16;

  627.         s->last_mv[0][0][0] = 0;

  628.         s->last_mv[0][0][1] = 0;

  629.         s->mv[0][0][0] = 0;

  630.         s->mv[0][0][1] = 0;

  631.     } else if (mb_type & (MB_FOR | MB_BACK)) {

  632.         /* motion vectors */

  633.         s->mv_dir = 0;

  634.         for(i=0;i<2;i++) {

  635.             if (mb_type & (MB_FOR >> i)) {

  636.                 s->mv_dir |= (MV_DIR_FORWARD >> i);

  637.                 dprintf("mv_type=%d\n", motion_type);

  638.                 switch(motion_type) {

  639.                 case MT_FRAME: /* or MT_16X8 */

  640.                     if (s->picture_structure == PICT_FRAME) {

  641.                         /* MT_FRAME */

  642.                         s->mv_type = MV_TYPE_16X16;

  643.                         for(k=0;k<2;k++) {

  644.                             val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], 

  645.                                                      s->last_mv[i][0][k]);

  646.                             s->last_mv[i][0][k] = val;

  647.                             s->last_mv[i][1][k] = val;

  648.                             /* full_pel: only for mpeg1 */

  649.                             if (s->full_pel[i])

  650.                                 val = val << 1;

  651.                             s->mv[i][0][k] = val;

  652.                             dprintf("mv%d: %d\n", k, val);

  653.                         }

  654.                     } else {

  655.                         /* MT_16X8 */

  656.                         s->mv_type = MV_TYPE_16X8;

  657.                         for(j=0;j<2;j++) {

  658.                             s->field_select[i][j] = get_bits1(&s->gb);

  659.                             for(k=0;k<2;k++) {

  660.                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],

  661.                                                          s->last_mv[i][j][k]);

  662.                                 s->last_mv[i][j][k] = val;

  663.                                 s->mv[i][j][k] = val;

  664.                             }

  665.                         }

  666.                     }

  667.                     break;

  668.                 case MT_FIELD:

  669.                     if (s->picture_structure == PICT_FRAME) {

  670.                         s->mv_type = MV_TYPE_FIELD;

  671.                         for(j=0;j<2;j++) {

  672.                             s->field_select[i][j] = get_bits1(&s->gb);

  673.                             val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],

  674.                                                      s->last_mv[i][j][0]);

  675.                             s->last_mv[i][j][0] = val;

  676.                             s->mv[i][j][0] = val;

  677.                             dprintf("fmx=%d\n", val);

  678.                             val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],

  679.                                                      s->last_mv[i][j][1] >> 1);

  680.                             s->last_mv[i][j][1] = val << 1;

  681.                             s->mv[i][j][1] = val;

  682.                             dprintf("fmy=%d\n", val);

  683.                         }

  684.                     } else {

  685.                         s->mv_type = MV_TYPE_16X16;

  686.                         s->field_select[i][0] = get_bits1(&s->gb);

  687.                         for(k=0;k<2;k++) {

  688.                             val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],

  689.                                                      s->last_mv[i][0][k]);

  690.                             s->last_mv[i][0][k] = val;

  691.                             s->last_mv[i][1][k] = val;

  692.                             s->mv[i][0][k] = val;

  693.                         }

  694.                     }

  695.                     break;

  696.                 case MT_DMV:

  697.                     {

  698.                         int dmx, dmy, mx, my, m;

  699. 

  700.                         mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], 

  701.                                                 s->last_mv[i][0][0]);

  702.                         s->last_mv[i][0][0] = mx;

  703.                         s->last_mv[i][1][0] = mx;

  704.                         dmx = get_dmv(s);

  705.                         my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], 

  706.                                                 s->last_mv[i][0][1] >> 1);

  707.                         dmy = get_dmv(s);

  708.                         s->mv_type = MV_TYPE_DMV;

  709.                         /* XXX: totally broken */

  710.                         if (s->picture_structure == PICT_FRAME) {

  711.                             s->last_mv[i][0][1] = my << 1;

  712.                             s->last_mv[i][1][1] = my << 1;

  713. 

  714.                             m = s->top_field_first ? 1 : 3;

  715.                             /* top -> top pred */

  716.                             s->mv[i][0][0] = mx; 

  717.                             s->mv[i][0][1] = my << 1;

  718.                             s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;

  719.                             s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;

  720.                             m = 4 - m;

  721.                             s->mv[i][2][0] = mx;

  722.                             s->mv[i][2][1] = my << 1;

  723.                             s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;

  724.                             s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;

  725.                         } else {

  726.                             s->last_mv[i][0][1] = my;

  727.                             s->last_mv[i][1][1] = my;

  728.                             s->mv[i][0][0] = mx;

  729.                             s->mv[i][0][1] = my;

  730.                             s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;

  731.                             s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 

  732.                                 /* + 2 * cur_field */;

  733.                         }

  734.                     }

  735.                     break;

  736.                 }

  737.             }

  738.         }

  739.     }

  740. 

  741.     if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) {

  742.         skip_bits1(&s->gb); /* marker */

  743.     }

  744.     

  745.     if (mb_type & MB_PAT) {

  746.         cbp = get_vlc(&s->gb, &mb_pat_vlc);

  747.         if (cbp < 0)

  748.             return -1;

  749.         cbp++;

  750.     }

  751.     dprintf("cbp=%x\n", cbp);

  752. 

  753.     if (s->mpeg2) {

  754.         if (s->mb_intra) {

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

  756.                 if (cbp & (1 << (5 - i))) {

  757.                     if (mpeg2_decode_block_intra(s, block[i], i) < 0)

  758.                         return -1;

  759.                 }

  760.             }

  761.         } else {

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

  763.                 if (cbp & (1 << (5 - i))) {

  764.                     if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)

  765.                         return -1;

  766.                 }

  767.             }

  768.         }

  769.     } else {

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

  771.             if (cbp & (1 << (5 - i))) {

  772.                 if (mpeg1_decode_block(s, block[i], i) < 0)

  773.                     return -1;

  774.             }

  775.         }

  776.     }

  777.     return 0;

  778. }

  779. 

  780. /* as h263, but only 17 codes */

  781. static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)

  782. {

  783.     int code, sign, val, m, l, shift;

  784. 

  785.     code = get_vlc(&s->gb, &mv_vlc);

  786.     if (code < 0) {

  787.         return 0xffff;

  788.     }

  789.     if (code == 0) {

  790.         return pred;

  791.     }

  792.     sign = get_bits1(&s->gb);

  793.     shift = fcode - 1;

  794.     val = (code - 1) << shift;

  795.     if (shift > 0)

  796.         val |= get_bits(&s->gb, shift);

  797.     val++;

  798.     if (sign)

  799.         val = -val;

  800.     val += pred;

  801.     

  802.     /* modulo decoding */

  803.     l = (1 << shift) * 16;

  804.     m = 2 * l;

  805.     if (val < -l) {

  806.         val += m;

  807.     } else if (val >= l) {

  808.         val -= m;

  809.     }

  810.     return val;

  811. }

  812. 

  813. static inline int decode_dc(MpegEncContext *s, int component)

  814. {

  815.     int code, diff;

  816. 

  817.     if (component == 0) {

  818.         code = get_vlc(&s->gb, &dc_lum_vlc);

  819.     } else {

  820.         code = get_vlc(&s->gb, &dc_chroma_vlc);

  821.     }

  822.     if (code < 0)

  823.         return 0xffff;

  824.     if (code == 0) {

  825.         diff = 0;

  826.     } else {

  827.         diff = get_bits(&s->gb, code);

  828.         if ((diff & (1 << (code - 1))) == 0) 

  829.             diff = (-1 << code) | (diff + 1);

  830.     }

  831.     return diff;

  832. }

  833. 

  834. static int mpeg1_decode_block(MpegEncContext *s, 

  835.                                DCTELEM *block, 

  836.                                int n)

  837. {

  838.     int level, dc, diff, i, j, run;

  839.     int code, component;

  840.     RLTable *rl = &rl_mpeg1;

  841. 

  842.     if (s->mb_intra) {

  843.         /* DC coef */

  844.         component = (n <= 3 ? 0 : n - 4 + 1);

  845.         diff = decode_dc(s, component);

  846.         if (diff >= 0xffff)

  847.             return -1;

  848.         dc = s->last_dc[component];

  849.         dc += diff;

  850.         s->last_dc[component] = dc;

  851.         block[0] = dc;

  852.         dprintf("dc=%d diff=%d\n", dc, diff);

  853.         i = 1;

  854.     } else {

  855.         int bit_cnt, v;

  856.         UINT32 bit_buf;

  857.         UINT8 *buf_ptr;

  858.         i = 0;

  859.         /* special case for the first coef. no need to add a second vlc table */

  860.         SAVE_BITS(&s->gb);

  861.         SHOW_BITS(&s->gb, v, 2);

  862.         if (v & 2) {

  863.             run = 0;

  864.             level = 1 - ((v & 1) << 1);

  865.             FLUSH_BITS(2);

  866.             RESTORE_BITS(&s->gb);

  867.             goto add_coef;

  868.         }

  869.         RESTORE_BITS(&s->gb);

  870.     }

  871. 

  872.     /* now quantify & encode AC coefs */

  873.     for(;;) {

  874.         code = get_vlc(&s->gb, &rl->vlc);

  875.         if (code < 0) {

  876.             return -1;

  877.         }

  878.         if (code == 112) {

  879.             break;

  880.         } else if (code == 111) {

  881.             /* escape */

  882.             run = get_bits(&s->gb, 6);

  883.             level = get_bits(&s->gb, 8);

  884.             level = (level << 24) >> 24;

  885.             if (level == -128) {

  886.                 level = get_bits(&s->gb, 8) - 256;

  887.             } else if (level == 0) {

  888.                 level = get_bits(&s->gb, 8);

  889.             }

  890.         } else {

  891.             run = rl->table_run[code];

  892.             level = rl->table_level[code];

  893.             if (get_bits1(&s->gb))

  894.                 level = -level;

  895.         }

  896.         i += run;

  897.         if (i >= 64)

  898.             return -1;

  899.     add_coef:

  900.         dprintf("%d: run=%d level=%d\n", n, run, level);

  901. 	j = zigzag_direct[i];

  902.         block[j] = level;

  903.         i++;

  904.     }

  905.     s->block_last_index[n] = i;

  906.     return 0;

  907. }

  908. 

  909. /* Also does unquantization here, since I will never support mpeg2

  910.    encoding */

  911. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  912.                                         DCTELEM *block, 

  913.                                         int n)

  914. {

  915.     int level, i, j, run;

  916.     int code;

  917.     RLTable *rl = &rl_mpeg1;

  918.     const UINT8 *scan_table;

  919.     const UINT16 *matrix;

  920.     int mismatch;

  921. 

  922.     if (s->alternate_scan)

  923.         scan_table = ff_alternate_vertical_scan;

  924.     else

  925.         scan_table = zigzag_direct;

  926.     mismatch = 1;

  927. 

  928.     {

  929.         int bit_cnt, v;

  930.         UINT32 bit_buf;

  931.         UINT8 *buf_ptr;

  932.         i = 0;

  933.         if (n < 4) 

  934.             matrix = s->non_intra_matrix;

  935.         else

  936.             matrix = s->chroma_non_intra_matrix;

  937.             

  938.         /* special case for the first coef. no need to add a second vlc table */

  939.         SAVE_BITS(&s->gb);

  940.         SHOW_BITS(&s->gb, v, 2);

  941.         if (v & 2) {

  942.             run = 0;

  943.             level = 1 - ((v & 1) << 1);

  944.             FLUSH_BITS(2);

  945.             RESTORE_BITS(&s->gb);

  946.             goto add_coef;

  947.         }

  948.         RESTORE_BITS(&s->gb);

  949.     }

  950. 

  951.     /* now quantify & encode AC coefs */

  952.     for(;;) {

  953.         code = get_vlc(&s->gb, &rl->vlc);

  954.         if (code < 0)

  955.             return -1;

  956.         if (code == 112) {

  957.             break;

  958.         } else if (code == 111) {

  959.             /* escape */

  960.             run = get_bits(&s->gb, 6);

  961.             level = get_bits(&s->gb, 12);

  962.             level = (level << 20) >> 20;

  963.         } else {

  964.             run = rl->table_run[code];

  965.             level = rl->table_level[code];

  966.             if (get_bits1(&s->gb))

  967.                 level = -level;

  968.         }

  969.         i += run;

  970.         if (i >= 64)

  971.             return -1;

  972.     add_coef:

  973. 	j = scan_table[i];

  974.         dprintf("%d: run=%d level=%d\n", n, run, level);

  975.         level = ((level * 2 + 1) * s->qscale * matrix[j]) / 32;

  976.         /* XXX: is it really necessary to saturate since the encoder

  977.            knows whats going on ? */

  978.         mismatch ^= level;

  979.         block[j] = level;

  980.         i++;

  981.     }

  982.     block[63] ^= (mismatch & 1);

  983.     s->block_last_index[n] = i;

  984.     return 0;

  985. }

  986. 

  987. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  988.                                     DCTELEM *block, 

  989.                                     int n)

  990. {

  991.     int level, dc, diff, i, j, run;

  992.     int code, component;

  993.     RLTable *rl;

  994.     const UINT8 *scan_table;

  995.     const UINT16 *matrix;

  996.     int mismatch;

  997. 

  998.     if (s->alternate_scan)

  999.         scan_table = ff_alternate_vertical_scan;

  1000.     else

  1001.         scan_table = zigzag_direct;

  1002.     mismatch = 1;

  1003. 

  1004.     /* DC coef */

  1005.     component = (n <= 3 ? 0 : n - 4 + 1);

  1006.     diff = decode_dc(s, component);

  1007.     if (diff >= 0xffff)

  1008.         return -1;

  1009.     dc = s->last_dc[component];

  1010.     dc += diff;

  1011.     s->last_dc[component] = dc;

  1012.     block[0] = dc << (3 - s->intra_dc_precision);

  1013.     dprintf("dc=%d\n", block[0]);

  1014.     i = 1;

  1015.     if (s->intra_vlc_format)

  1016.         rl = &rl_mpeg2;

  1017.     else

  1018.         rl = &rl_mpeg1;

  1019.     if (n < 4) 

  1020.         matrix = s->intra_matrix;

  1021.     else

  1022.         matrix = s->chroma_intra_matrix;

  1023.         

  1024.     /* now quantify & encode AC coefs */

  1025.     for(;;) {

  1026.         code = get_vlc(&s->gb, &rl->vlc);

  1027.         if (code < 0)

  1028.             return -1;

  1029.         if (code == 112) {

  1030.             break;

  1031.         } else if (code == 111) {

  1032.             /* escape */

  1033.             run = get_bits(&s->gb, 6);

  1034.             level = get_bits(&s->gb, 12);

  1035.             level = (level << 20) >> 20;

  1036.         } else {

  1037.             run = rl->table_run[code];

  1038.             level = rl->table_level[code];

  1039.             if (get_bits1(&s->gb))

  1040.                 level = -level;

  1041.         }

  1042.         i += run;

  1043.         if (i >= 64)

  1044.             return -1;

  1045. 	j = scan_table[i];

  1046.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1047.         level = (level * s->qscale * matrix[j]) / 16;

  1048.         /* XXX: is it really necessary to saturate since the encoder

  1049.            knows whats going on ? */

  1050.         mismatch ^= level;

  1051.         block[j] = level;

  1052.         i++;

  1053.     }

  1054.     block[63] ^= (mismatch & 1);

  1055.     s->block_last_index[n] = i;

  1056.     return 0;

  1057. }

  1058. 

  1059. /* compressed picture size */

  1060. #define PICTURE_BUFFER_SIZE 100000

  1061. 

  1062. typedef struct Mpeg1Context {

  1063.     MpegEncContext mpeg_enc_ctx;

  1064.     UINT32 header_state;

  1065.     int start_code; /* current start code */

  1066.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  1067.     UINT8 *buf_ptr;

  1068.     int buffer_size;

  1069.     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */

  1070. } Mpeg1Context;

  1071. 

  1072. static int mpeg_decode_init(AVCodecContext *avctx)

  1073. {

  1074.     Mpeg1Context *s = avctx->priv_data;

  1075. 

  1076.     s->header_state = 0xff;

  1077.     s->mpeg_enc_ctx_allocated = 0;

  1078.     s->buffer_size = PICTURE_BUFFER_SIZE;

  1079.     s->start_code = -1;

  1080.     s->buf_ptr = s->buffer;

  1081.     s->mpeg_enc_ctx.picture_number = 0;

  1082.     return 0;

  1083. }

  1084. 

  1085. /* return the 8 bit start code value and update the search

  1086.    state. Return -1 if no start code found */

  1087. static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1088.                            UINT32 *header_state)

  1089. {

  1090.     UINT8 *buf_ptr;

  1091.     unsigned int state, v;

  1092.     int val;

  1093. 

  1094.     state = *header_state;

  1095.     buf_ptr = *pbuf_ptr;

  1096.     while (buf_ptr < buf_end) {

  1097.         v = *buf_ptr++;

  1098.         if (state == 0x000001) {

  1099.             state = ((state << 8) | v) & 0xffffff;

  1100.             val = state;

  1101.             goto found;

  1102.         }

  1103.         state = ((state << 8) | v) & 0xffffff;

  1104.     }

  1105.     val = -1;

  1106.  found:

  1107.     *pbuf_ptr = buf_ptr;

  1108.     *header_state = state;

  1109.     return val;

  1110. }

  1111. 

  1112. static int mpeg1_decode_picture(AVCodecContext *avctx, 

  1113.                                 UINT8 *buf, int buf_size)

  1114. {

  1115.     Mpeg1Context *s1 = avctx->priv_data;

  1116.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1117.     int ref, f_code;

  1118. 

  1119.     init_get_bits(&s->gb, buf, buf_size);

  1120. 

  1121.     ref = get_bits(&s->gb, 10); /* temporal ref */

  1122.     s->pict_type = get_bits(&s->gb, 3);

  1123.     dprintf("pict_type=%d\n", s->pict_type);

  1124.     skip_bits(&s->gb, 16);

  1125.     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {

  1126.         s->full_pel[0] = get_bits1(&s->gb);

  1127.         f_code = get_bits(&s->gb, 3);

  1128.         if (f_code == 0)

  1129.             return -1;

  1130.         s->mpeg_f_code[0][0] = f_code;

  1131.         s->mpeg_f_code[0][1] = f_code;

  1132.     }

  1133.     if (s->pict_type == B_TYPE) {

  1134.         s->full_pel[1] = get_bits1(&s->gb);

  1135.         f_code = get_bits(&s->gb, 3);

  1136.         if (f_code == 0)

  1137.             return -1;

  1138.         s->mpeg_f_code[1][0] = f_code;

  1139.         s->mpeg_f_code[1][1] = f_code;

  1140.     }

  1141.     s->y_dc_scale = 8;

  1142.     s->c_dc_scale = 8;

  1143.     s->first_slice = 1;

  1144.     return 0;

  1145. }

  1146. 

  1147. static void mpeg_decode_sequence_extension(MpegEncContext *s)

  1148. {

  1149.     int horiz_size_ext, vert_size_ext;

  1150.     int bit_rate_ext, vbv_buf_ext, low_delay;

  1151.     int frame_rate_ext_n, frame_rate_ext_d;

  1152. 

  1153.     skip_bits(&s->gb, 8); /* profil and level */

  1154.     skip_bits(&s->gb, 1); /* progressive_sequence */

  1155.     skip_bits(&s->gb, 2); /* chroma_format */

  1156.     horiz_size_ext = get_bits(&s->gb, 2);

  1157.     vert_size_ext = get_bits(&s->gb, 2);

  1158.     s->width |= (horiz_size_ext << 12);

  1159.     s->height |= (vert_size_ext << 12);

  1160.     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */

  1161.     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;

  1162.     skip_bits1(&s->gb); /* marker */

  1163.     vbv_buf_ext = get_bits(&s->gb, 8);

  1164.     low_delay = get_bits1(&s->gb);

  1165.     frame_rate_ext_n = get_bits(&s->gb, 2);

  1166.     frame_rate_ext_d = get_bits(&s->gb, 5);

  1167.     if (frame_rate_ext_d >= 1)

  1168.         s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;

  1169.     dprintf("sequence extension\n");

  1170.     s->mpeg2 = 1;

  1171. }

  1172. 

  1173. static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)

  1174. {

  1175.     int i, v;

  1176. 

  1177.     if (get_bits1(&s->gb)) {

  1178.         for(i=0;i<64;i++) {

  1179.             v = get_bits(&s->gb, 8);

  1180.             s->intra_matrix[i] = v;

  1181.             s->chroma_intra_matrix[i] = v;

  1182.         }

  1183.     }

  1184.     if (get_bits1(&s->gb)) {

  1185.         for(i=0;i<64;i++) {

  1186.             v = get_bits(&s->gb, 8);

  1187.             s->non_intra_matrix[i] = v;

  1188.             s->chroma_non_intra_matrix[i] = v;

  1189.         }

  1190.     }

  1191.     if (get_bits1(&s->gb)) {

  1192.         for(i=0;i<64;i++) {

  1193.             v = get_bits(&s->gb, 8);

  1194.             s->chroma_intra_matrix[i] = v;

  1195.         }

  1196.     }

  1197.     if (get_bits1(&s->gb)) {

  1198.         for(i=0;i<64;i++) {

  1199.             v = get_bits(&s->gb, 8);

  1200.             s->chroma_non_intra_matrix[i] = v;

  1201.         }

  1202.     }

  1203. }

  1204. 

  1205. static void mpeg_decode_picture_coding_extension(MpegEncContext *s)

  1206. {

  1207.     s->full_pel[0] = s->full_pel[1] = 0;

  1208.     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);

  1209.     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);

  1210.     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);

  1211.     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);

  1212.     s->intra_dc_precision = get_bits(&s->gb, 2);

  1213.     s->picture_structure = get_bits(&s->gb, 2);

  1214.     s->top_field_first = get_bits1(&s->gb);

  1215.     s->frame_pred_frame_dct = get_bits1(&s->gb);

  1216.     s->concealment_motion_vectors = get_bits1(&s->gb);

  1217.     s->q_scale_type = get_bits1(&s->gb);

  1218.     s->intra_vlc_format = get_bits1(&s->gb);

  1219.     s->alternate_scan = get_bits1(&s->gb);

  1220.     s->repeat_first_field = get_bits1(&s->gb);

  1221.     s->chroma_420_type = get_bits1(&s->gb);

  1222.     s->progressive_frame = get_bits1(&s->gb);

  1223.     /* composite display not parsed */

  1224.     dprintf("dc_preci=%d\n", s->intra_dc_precision);

  1225.     dprintf("pict_structure=%d\n", s->picture_structure);

  1226.     dprintf("conceal=%d\n", s->concealment_motion_vectors);

  1227.     dprintf("intrafmt=%d\n", s->intra_vlc_format);

  1228.     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);

  1229. }

  1230. 

  1231. static void mpeg_decode_extension(AVCodecContext *avctx, 

  1232.                                   UINT8 *buf, int buf_size)

  1233. {

  1234.     Mpeg1Context *s1 = avctx->priv_data;

  1235.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1236.     int ext_type;

  1237. 

  1238.     init_get_bits(&s->gb, buf, buf_size);

  1239.     

  1240.     ext_type = get_bits(&s->gb, 4);

  1241.     switch(ext_type) {

  1242.     case 0x1:

  1243.         /* sequence ext */

  1244.         mpeg_decode_sequence_extension(s);

  1245.         break;

  1246.     case 0x3:

  1247.         /* quant matrix extension */

  1248.         mpeg_decode_quant_matrix_extension(s);

  1249.         break;

  1250.     case 0x8:

  1251.         /* picture extension */

  1252.         mpeg_decode_picture_coding_extension(s);

  1253.         break;

  1254.     }

  1255. }

  1256. 

  1257. /* return 1 if end of frame */

  1258. static int mpeg_decode_slice(AVCodecContext *avctx, 

  1259.                               AVPicture *pict,

  1260.                               int start_code,

  1261.                               UINT8 *buf, int buf_size)

  1262. {

  1263.     Mpeg1Context *s1 = avctx->priv_data;

  1264.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1265.     int ret;

  1266. 

  1267.     start_code = (start_code - 1) & 0xff;

  1268.     if (start_code >= s->mb_height)

  1269.         return -1;

  1270.     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);

  1271.     s->last_dc[1] = s->last_dc[0];

  1272.     s->last_dc[2] = s->last_dc[0];

  1273.     memset(s->last_mv, 0, sizeof(s->last_mv));

  1274.     s->mb_x = -1;

  1275.     s->mb_y = start_code;

  1276.     s->mb_incr = 0;

  1277. 

  1278.     /* start frame decoding */

  1279.     if (s->first_slice) {

  1280.         s->first_slice = 0;

  1281.         MPV_frame_start(s);

  1282.     }

  1283. 

  1284.     init_get_bits(&s->gb, buf, buf_size);

  1285. 

  1286.     s->qscale = get_bits(&s->gb, 5);

  1287.     /* extra slice info */

  1288.     while (get_bits1(&s->gb) != 0) {

  1289.         skip_bits(&s->gb, 8);

  1290.     }

  1291. 

  1292.     for(;;) {

  1293.         memset(s->block, 0, sizeof(s->block));

  1294.         ret = mpeg_decode_mb(s, s->block);

  1295.         dprintf("ret=%d\n", ret);

  1296.         if (ret < 0)

  1297.             return -1;

  1298.         if (ret == 1)

  1299.             break;

  1300.         MPV_decode_mb(s, s->block);

  1301.     }

  1302.     

  1303.     /* end of slice reached */

  1304.     if (s->mb_x == (s->mb_width - 1) &&

  1305.         s->mb_y == (s->mb_height - 1)) {

  1306.         /* end of image */

  1307.         UINT8 **picture;

  1308. 

  1309.         MPV_frame_end(s);

  1310. 

  1311.         /* XXX: incorrect reported qscale for mpeg2 */

  1312.         if (s->pict_type == B_TYPE) {

  1313.             picture = s->current_picture;

  1314.             avctx->quality = s->qscale;

  1315.         } else {

  1316.             /* latency of 1 frame for I and P frames */

  1317.             /* XXX: use another variable than picture_number */

  1318.             if (s->picture_number == 0) {

  1319.                 picture = NULL;

  1320.             } else {

  1321.                 picture = s->last_picture;

  1322.                 avctx->quality = s->last_qscale;

  1323.             }

  1324.             s->last_qscale = s->qscale;

  1325.             s->picture_number++;

  1326.         }

  1327.         if (picture) {

  1328.             pict->data[0] = picture[0];

  1329.             pict->data[1] = picture[1];

  1330.             pict->data[2] = picture[2];

  1331.             pict->linesize[0] = s->linesize;

  1332.             pict->linesize[1] = s->linesize / 2;

  1333.             pict->linesize[2] = s->linesize / 2;

  1334.             return 1;

  1335.         } else {

  1336.             return 0;

  1337.         }

  1338.     } else {

  1339.         return 0;

  1340.     }

  1341. }

  1342. 

  1343. static int mpeg1_decode_sequence(AVCodecContext *avctx, 

  1344.                                  UINT8 *buf, int buf_size)

  1345. {

  1346.     Mpeg1Context *s1 = avctx->priv_data;

  1347.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1348.     int width, height, i, v;

  1349.     

  1350.     init_get_bits(&s->gb, buf, buf_size);

  1351. 

  1352.     width = get_bits(&s->gb, 12);

  1353.     height = get_bits(&s->gb, 12);

  1354.     skip_bits(&s->gb, 4);

  1355.     s->frame_rate_index = get_bits(&s->gb, 4);

  1356.     if (s->frame_rate_index == 0)

  1357.         return -1;

  1358.     s->bit_rate = get_bits(&s->gb, 18) * 400;

  1359.     if (get_bits1(&s->gb) == 0) /* marker */

  1360.         return -1;

  1361.     if (width <= 0 || height <= 0 ||

  1362.         (width % 2) != 0 || (height % 2) != 0)

  1363.         return -1;

  1364.     if (width != s->width ||

  1365.         height != s->height) {

  1366.         /* start new mpeg1 context decoding */

  1367.         s->out_format = FMT_MPEG1;

  1368.         if (s1->mpeg_enc_ctx_allocated) {

  1369.             MPV_common_end(s);

  1370.         }

  1371.         s->width = width;

  1372.         s->height = height;

  1373.         s->has_b_frames = 1;

  1374.         avctx->width = width;

  1375.         avctx->height = height;

  1376.         avctx->frame_rate = frame_rate_tab[s->frame_rate_index];

  1377.         avctx->bit_rate = s->bit_rate;

  1378.         

  1379.         if (MPV_common_init(s) < 0)

  1380.             return -1;

  1381.         mpeg1_init_vlc(s);

  1382.         s1->mpeg_enc_ctx_allocated = 1;

  1383.     }

  1384. 

  1385.     skip_bits(&s->gb, 10); /* vbv_buffer_size */

  1386.     skip_bits(&s->gb, 1);

  1387. 

  1388.     /* get matrix */

  1389.     if (get_bits1(&s->gb)) {

  1390.         for(i=0;i<64;i++) {

  1391.             v = get_bits(&s->gb, 8);

  1392.             s->intra_matrix[i] = v;

  1393.             s->chroma_intra_matrix[i] = v;

  1394.         }

  1395.     } else {

  1396.         for(i=0;i<64;i++) {

  1397.             v = default_intra_matrix[i];

  1398.             s->intra_matrix[i] = v;

  1399.             s->chroma_intra_matrix[i] = v;

  1400.         }

  1401.     }

  1402.     if (get_bits1(&s->gb)) {

  1403.         for(i=0;i<64;i++) {

  1404.             v = get_bits(&s->gb, 8);

  1405.             s->non_intra_matrix[i] = v;

  1406.             s->chroma_non_intra_matrix[i] = v;

  1407.         }

  1408.     } else {

  1409.         for(i=0;i<64;i++) {

  1410.             v = default_non_intra_matrix[i];

  1411.             s->non_intra_matrix[i] = v;

  1412.             s->chroma_non_intra_matrix[i] = v;

  1413.         }

  1414.     }

  1415. 

  1416.     /* we set mpeg2 parameters so that it emulates mpeg1 */

  1417.     s->progressive_sequence = 1;

  1418.     s->progressive_frame = 1;

  1419.     s->picture_structure = PICT_FRAME;

  1420.     s->frame_pred_frame_dct = 1;

  1421.     s->mpeg2 = 0;

  1422.     return 0;

  1423. }

  1424. 

  1425. /* handle buffering and image synchronisation */

  1426. static int mpeg_decode_frame(AVCodecContext *avctx, 

  1427.                              void *data, int *data_size,

  1428.                              UINT8 *buf, int buf_size)

  1429. {

  1430.     Mpeg1Context *s = avctx->priv_data;

  1431.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1432.     int len, start_code_found, ret, code, start_code, input_size;

  1433.     AVPicture *picture = data;

  1434. 

  1435.     dprintf("fill_buffer\n");

  1436. 

  1437.     *data_size = 0;

  1438.     /* special case for last picture */

  1439.     if (buf_size == 0) {

  1440.         MpegEncContext *s2 = &s->mpeg_enc_ctx;

  1441.         if (s2->picture_number > 0) {

  1442.             picture->data[0] = s2->next_picture[0];

  1443.             picture->data[1] = s2->next_picture[1];

  1444.             picture->data[2] = s2->next_picture[2];

  1445.             picture->linesize[0] = s2->linesize;

  1446.             picture->linesize[1] = s2->linesize / 2;

  1447.             picture->linesize[2] = s2->linesize / 2;

  1448.             *data_size = sizeof(AVPicture);

  1449.         }

  1450.         return 0;

  1451.     }

  1452. 

  1453.     buf_ptr = buf;

  1454.     buf_end = buf + buf_size;

  1455.     while (buf_ptr < buf_end) {

  1456.         buf_start = buf_ptr;

  1457.         /* find start next code */

  1458.         code = find_start_code(&buf_ptr, buf_end, &s->header_state);

  1459.         if (code >= 0) {

  1460.             start_code_found = 1;

  1461.         } else {

  1462.             start_code_found = 0;

  1463.         }

  1464.         /* copy to buffer */

  1465.         len = buf_ptr - buf_start;

  1466.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1467.             /* data too big : flush */

  1468.             s->buf_ptr = s->buffer;

  1469.             if (start_code_found)

  1470.                 s->start_code = code;

  1471.         } else {

  1472.             memcpy(s->buf_ptr, buf_start, len);

  1473.             s->buf_ptr += len;

  1474.             

  1475.             if (start_code_found) {

  1476.                 /* prepare data for next start code */

  1477.                 input_size = s->buf_ptr - s->buffer;

  1478.                 start_code = s->start_code;

  1479.                 s->buf_ptr = s->buffer;

  1480.                 s->start_code = code;

  1481.                 switch(start_code) {

  1482.                 case SEQ_START_CODE:

  1483.                     mpeg1_decode_sequence(avctx, s->buffer, 

  1484.                                           input_size);

  1485.                     break;

  1486.                             

  1487.                 case PICTURE_START_CODE:

  1488.                     /* we have a complete image : we try to decompress it */

  1489.                     mpeg1_decode_picture(avctx, 

  1490.                                          s->buffer, input_size);

  1491.                     break;

  1492.                 case EXT_START_CODE:

  1493.                     mpeg_decode_extension(avctx,

  1494.                                           s->buffer, input_size);

  1495.                     break;

  1496.                 default:

  1497.                     if (start_code >= SLICE_MIN_START_CODE &&

  1498.                         start_code <= SLICE_MAX_START_CODE) {

  1499.                         ret = mpeg_decode_slice(avctx, picture,

  1500.                                                 start_code, s->buffer, input_size);

  1501.                         if (ret == 1) {

  1502.                             /* got a picture: exit */

  1503.                             *data_size = sizeof(AVPicture);

  1504.                             goto the_end;

  1505.                         }

  1506.                     }

  1507.                     break;

  1508.                 }

  1509.             }

  1510.         }

  1511.     }

  1512.  the_end:

  1513.     return buf_ptr - buf;

  1514. }

  1515. 

  1516. static int mpeg_decode_end(AVCodecContext *avctx)

  1517. {

  1518.     Mpeg1Context *s = avctx->priv_data;

  1519. 

  1520.     if (s->mpeg_enc_ctx_allocated)

  1521.         MPV_common_end(&s->mpeg_enc_ctx);

  1522.     return 0;

  1523. }

  1524. 

  1525. AVCodec mpeg_decoder = {

  1526.     "mpegvideo",

  1527.     CODEC_TYPE_VIDEO,

  1528.     CODEC_ID_MPEG1VIDEO,

  1529.     sizeof(Mpeg1Context),

  1530.     mpeg_decode_init,

  1531.     NULL,

  1532.     mpeg_decode_end,

  1533.     mpeg_decode_frame,

  1534. };