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FFmpeg/libavcodec/mpeg12.c

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  1. /*

  2.  * MPEG1 encoder / MPEG2 decoder

  3.  * Copyright (c) 2000,2001 Fabrice Bellard.

  4.  *

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

  6.  * modify it under the terms of the GNU Lesser General Public

  7.  * License as published by the Free Software Foundation; either

  8.  * version 2 of the License, or (at your option) any later version.

  9.  *

  10.  * This library 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 GNU

  13.  * Lesser General Public License for more details.

  14.  *

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

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

  17.  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  18.  */

  19. //#define DEBUG

  20. #include "avcodec.h"

  21. #include "dsputil.h"

  22. #include "mpegvideo.h"

  23. 

  24. #include "mpeg12data.h"

  25. 

  26. /* Start codes. */

  27. #define SEQ_END_CODE		0x000001b7

  28. #define SEQ_START_CODE		0x000001b3

  29. #define GOP_START_CODE		0x000001b8

  30. #define PICTURE_START_CODE	0x00000100

  31. #define SLICE_MIN_START_CODE	0x00000101

  32. #define SLICE_MAX_START_CODE	0x000001af

  33. #define EXT_START_CODE		0x000001b5

  34. #define USER_START_CODE		0x000001b2

  35. 

  36. #define DC_VLC_BITS 9

  37. #define MV_VLC_BITS 9

  38. #define MBINCR_VLC_BITS 9

  39. #define MB_PAT_VLC_BITS 9

  40. #define MB_PTYPE_VLC_BITS 6

  41. #define MB_BTYPE_VLC_BITS 6

  42. #define TEX_VLC_BITS 9

  43. 

  44. static void mpeg1_encode_block(MpegEncContext *s, 

  45.                          DCTELEM *block, 

  46.                          int component);

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

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

  49. static int mpeg1_decode_block(MpegEncContext *s, 

  50.                               DCTELEM *block, 

  51.                               int n);

  52. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  53.                                         DCTELEM *block, 

  54.                                         int n);

  55. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  56.                                     DCTELEM *block, 

  57.                                     int n);

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

  59. 

  60. static UINT16 mv_penalty[MAX_FCODE+1][MAX_MV*2+1];

  61. static UINT8 fcode_tab[MAX_MV*2+1];

  62. 

  63. static void init_2d_vlc_rl(RLTable *rl)

  64. {

  65.     int i;

  66.     

  67.     init_vlc(&rl->vlc, TEX_VLC_BITS, rl->n + 2, 

  68.              &rl->table_vlc[0][1], 4, 2,

  69.              &rl->table_vlc[0][0], 4, 2);

  70. 

  71.     

  72.     rl->rl_vlc[0]= av_malloc(rl->vlc.table_size*sizeof(RL_VLC_ELEM));

  73.     for(i=0; i<rl->vlc.table_size; i++){

  74.         int code= rl->vlc.table[i][0];

  75.         int len = rl->vlc.table[i][1];

  76.         int level, run;

  77.     

  78.         if(len==0){ // illegal code

  79.             run= 65;

  80.             level= MAX_LEVEL;

  81.         }else if(len<0){ //more bits needed

  82.             run= 0;

  83.             level= code;

  84.         }else{

  85.             if(code==rl->n){ //esc

  86.                 run= 65;

  87.                 level= 0;

  88.             }else if(code==rl->n+1){ //eob

  89.                 run= 192;

  90.                 level= 1;

  91.             }else{

  92.                 run=   rl->table_run  [code] + 1;

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

  94.             }

  95.         }

  96.         rl->rl_vlc[0][i].len= len;

  97.         rl->rl_vlc[0][i].level= level;

  98.         rl->rl_vlc[0][i].run= run;

  99.     }

  100. }

  101. 

  102. 

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

  104. {

  105.     align_put_bits(&s->pb);

  106.     put_bits(&s->pb, 16, header>>16);

  107.     put_bits(&s->pb, 16, header&0xFFFF);

  108. }

  109. 

  110. /* put sequence header if needed */

  111. static void mpeg1_encode_sequence_header(MpegEncContext *s)

  112. {

  113.         unsigned int vbv_buffer_size;

  114.         unsigned int fps, v;

  115.         int n;

  116.         UINT64 time_code;

  117.         

  118.         if (s->picture_in_gop_number == 0) {

  119.             /* mpeg1 header repeated every gop */

  120.             put_header(s, SEQ_START_CODE);

  121.             

  122.             /* search closest frame rate */

  123.             {

  124.                 int i, dmin, d;

  125.                 s->frame_rate_index = 0;

  126.                 dmin = 0x7fffffff;

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

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

  129.                     if (d < dmin) {

  130.                         dmin = d;

  131.                         s->frame_rate_index = i;

  132.                     }

  133.                 }

  134.             }

  135.  

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

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

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

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

  140.             v = s->bit_rate / 400;

  141.             if (v > 0x3ffff)

  142.                 v = 0x3ffff;

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

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

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

  146.                some margin just in case */

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

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

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

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

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

  152. 

  153.             put_header(s, GOP_START_CODE);

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

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

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

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

  158.             time_code = (INT64)s->fake_picture_number * FRAME_RATE_BASE;

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

  160.             put_bits(&s->pb, 5, (UINT32)((time_code / (fps * 3600)) % 24));

  161.             put_bits(&s->pb, 6, (UINT32)((time_code / (fps * 60)) % 60));

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

  163.             put_bits(&s->pb, 6, (UINT32)((time_code / fps) % 60));

  164.             put_bits(&s->pb, 6, (UINT32)((time_code % fps) / FRAME_RATE_BASE));

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

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

  167.         }

  168. 

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

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

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

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

  173.             n = (((INT64)s->picture_number * fps) / s->frame_rate) - 1;

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

  175.                 mpeg1_skip_picture(s, s->fake_picture_number - 

  176.                                    s->gop_picture_number); 

  177.                 s->fake_picture_number++;

  178.             }

  179. 

  180.         }

  181. }

  182. 

  183. 

  184. /* insert a fake P picture */

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

  186. {

  187.     unsigned int mb_incr;

  188. 

  189.     /* mpeg1 picture header */

  190.     put_header(s, PICTURE_START_CODE);

  191.     /* temporal reference */

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

  193.     

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

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

  196.     

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

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

  199.     

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

  201.     

  202.     /* only one slice */

  203.     put_header(s, SLICE_MIN_START_CODE);

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

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

  206.     

  207.     mb_incr = 1;

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

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

  210.     

  211.     /* empty macroblock */

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

  213.     

  214.     /* zero motion x & y */

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

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

  217. 

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

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

  220.     while (mb_incr > 33) {

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

  222.         mb_incr -= 33;

  223.     }

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

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

  226.     

  227.     /* empty macroblock */

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

  229.     

  230.     /* zero motion x & y */

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

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

  233. }

  234. 

  235. static void common_init(MpegEncContext *s)

  236. {

  237.     s->y_dc_scale_table=

  238.     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;

  239. }

  240. 

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

  242. {

  243.     mpeg1_encode_sequence_header(s);

  244. 

  245.     /* mpeg1 picture header */

  246.     put_header(s, PICTURE_START_CODE);

  247.     /* temporal reference */

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

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

  250.     s->fake_picture_number++;

  251.     

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

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

  254.     

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

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

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

  258.     }

  259.     

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

  261.     

  262.     /* only one slice */

  263.     put_header(s, SLICE_MIN_START_CODE);

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

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

  266. }

  267. 

  268. void mpeg1_encode_mb(MpegEncContext *s,

  269.                      DCTELEM block[6][64],

  270.                      int motion_x, int motion_y)

  271. {

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

  273. 

  274.     mb_x = s->mb_x;

  275.     mb_y = s->mb_y;

  276. 

  277.     /* compute cbp */

  278.     cbp = 0;

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

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

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

  282.     }

  283. 

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

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

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

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

  288.         s->mb_incr++;

  289.     } else {

  290.         /* output mb incr */

  291.         mb_incr = s->mb_incr;

  292. 

  293.         while (mb_incr > 33) {

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

  295.             mb_incr -= 33;

  296.         }

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

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

  299.         

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

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

  302.         } else {

  303.             if (s->mb_intra) {

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

  305.             } else {

  306.                 if (cbp != 0) {

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

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

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

  310.                     } else {

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

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

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

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

  315.                     }

  316.                 } else {

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

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

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

  320.                 }

  321.             }

  322.         }

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

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

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

  326.             }

  327.         }

  328.         s->mb_incr = 1;

  329.     }

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

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

  332. }

  333. 

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

  335. {

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

  337. 

  338.     if (val == 0) {

  339.         /* zero vector */

  340.         code = 0;

  341.         put_bits(&s->pb,

  342.                  mbMotionVectorTable[0][1], 

  343.                  mbMotionVectorTable[0][0]); 

  344.     } else {

  345.         bit_size = s->f_code - 1;

  346.         range = 1 << bit_size;

  347.         /* modulo encoding */

  348.         l = 16 * range;

  349.         m = 2 * l;

  350.         if (val < -l) {

  351.             val += m;

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

  353.             val -= m;

  354.         }

  355. 

  356.         if (val >= 0) {

  357.             val--;

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

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

  360.             sign = 0;

  361.         } else {

  362.             val = -val;

  363.             val--;

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

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

  366.             sign = 1;

  367.         }

  368.         put_bits(&s->pb,

  369.                  mbMotionVectorTable[code][1], 

  370.                  mbMotionVectorTable[code][0]); 

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

  372.         if (bit_size > 0) {

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

  374.         }

  375.     }

  376. }

  377. 

  378. void ff_mpeg1_encode_init(MpegEncContext *s)

  379. {

  380.     static int done=0;

  381. 

  382.     common_init(s);

  383. 

  384.     if(!done){

  385.         int f_code;

  386.         int mv;

  387. 	int i;

  388. 

  389.         done=1;

  390.         init_rl(&rl_mpeg1);

  391. 	

  392. 	for(i=0; i<64; i++)

  393. 	{

  394. 		mpeg1_max_level[0][i]= rl_mpeg1.max_level[0][i];

  395. 		mpeg1_index_run[0][i]= rl_mpeg1.index_run[0][i];

  396. 	}

  397. 

  398. 	/* build unified dc encoding tables */

  399. 	for(i=-255; i<256; i++)

  400. 	{

  401. 		int adiff, index;

  402. 		int bits, code;

  403. 		int diff=i;

  404. 

  405. 		adiff = ABS(diff);

  406. 		if(diff<0) diff--;

  407. 		index = vlc_dc_table[adiff];

  408. 

  409. 		bits= vlc_dc_lum_bits[index] + index;

  410. 		code= (vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1));

  411. 		mpeg1_lum_dc_uni[i+255]= bits + (code<<8);

  412. 		

  413. 		bits= vlc_dc_chroma_bits[index] + index;

  414. 		code= (vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1));

  415. 		mpeg1_chr_dc_uni[i+255]= bits + (code<<8);

  416. 	}

  417. 

  418.         for(f_code=1; f_code<=MAX_FCODE; f_code++){

  419.             for(mv=-MAX_MV; mv<=MAX_MV; mv++){

  420.                 int len;

  421. 

  422.                 if(mv==0) len= mbMotionVectorTable[0][1];

  423.                 else{

  424.                     int val, bit_size, range, code;

  425. 

  426.                     bit_size = s->f_code - 1;

  427.                     range = 1 << bit_size;

  428. 

  429.                     val=mv;

  430.                     if (val < 0) 

  431.                         val = -val;

  432.                     val--;

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

  434.                     if(code<17){

  435.                         len= mbMotionVectorTable[code][1] + 1 + bit_size;

  436.                     }else{

  437.                         len= mbMotionVectorTable[16][1] + 2 + bit_size;

  438.                     }

  439.                 }

  440. 

  441.                 mv_penalty[f_code][mv+MAX_MV]= len;

  442.             }

  443.         }

  444.         

  445. 

  446.         for(f_code=MAX_FCODE; f_code>0; f_code--){

  447.             for(mv=-(8<<f_code); mv<(8<<f_code); mv++){

  448.                 fcode_tab[mv+MAX_MV]= f_code;

  449.             }

  450.         }

  451.     }

  452.     s->mv_penalty= mv_penalty;

  453.     s->fcode_tab= fcode_tab;

  454.     s->min_qcoeff=-255;

  455.     s->max_qcoeff= 255;

  456.     s->intra_quant_bias= 3<<(QUANT_BIAS_SHIFT-3); //(a + x*3/8)/x

  457.     s->inter_quant_bias= 0;

  458. }

  459. 

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

  461. {

  462.     if (component == 0) {

  463.         put_bits(

  464. 	    &s->pb, 

  465. 	    mpeg1_lum_dc_uni[diff+255]&0xFF,

  466. 	    mpeg1_lum_dc_uni[diff+255]>>8);

  467.     } else {

  468.         put_bits(

  469.             &s->pb, 

  470. 	    mpeg1_chr_dc_uni[diff+255]&0xFF,

  471. 	    mpeg1_chr_dc_uni[diff+255]>>8);

  472.     }

  473. }

  474. 

  475. static void mpeg1_encode_block(MpegEncContext *s, 

  476.                                DCTELEM *block, 

  477.                                int n)

  478. {

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

  480.     int code, component;

  481. //    RLTable *rl = &rl_mpeg1;

  482. 

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

  484. 

  485.     /* DC coef */

  486.     if (s->mb_intra) {

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

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

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

  490.         encode_dc(s, diff, component);

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

  492.         i = 1;

  493.     } else {

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

  495.            it is handled slightly differently */

  496.         level = block[0];

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

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

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

  500.                 i = 1;

  501.         } else {

  502.             i = 0;

  503.             last_non_zero = -1;

  504.             goto next_coef;

  505.         }

  506.     }

  507. 

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

  509.     last_non_zero = i - 1;

  510. 

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

  512.         j = zigzag_direct[i];

  513.         level = block[j];

  514.     next_coef:

  515. #if 0

  516.         if (level != 0)

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

  518. #endif            

  519.         /* encode using VLC */

  520.         if (level != 0) {

  521.             run = i - last_non_zero - 1;

  522. #ifdef ARCH_X86

  523.             asm volatile(

  524. 		"movl %2, %1		\n\t"

  525. 		"movl %1, %0		\n\t"

  526. 		"addl %1, %1		\n\t"

  527. 		"sbbl %1, %1		\n\t"

  528. 		"xorl %1, %0		\n\t"

  529. 		"subl %1, %0		\n\t"

  530. 		"andl $1, %1		\n\t"

  531. 		: "=&r" (alevel), "=&r" (sign)

  532. 		: "g" (level)

  533. 	    );

  534. #else

  535.             sign = 0;

  536.             alevel = level;

  537.             if (alevel < 0) {

  538. 		sign = 1;

  539.                 alevel = -alevel;

  540. 	    }

  541. #endif

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

  543.             if (alevel > mpeg1_max_level[0][run])

  544.                 code= 111; /*rl->n*/

  545.             else

  546.                 code= mpeg1_index_run[0][run] + alevel - 1;

  547. 

  548.             if (code < 111 /* rl->n */) {

  549. 	    	/* store the vlc & sign at once */

  550.                 put_bits(&s->pb, mpeg1_vlc[code][1]+1, (mpeg1_vlc[code][0]<<1) + sign);

  551.             } else {

  552. 		/* escape seems to be pretty rare <5% so i dont optimize it */

  553.                 put_bits(&s->pb, mpeg1_vlc[111/*rl->n*/][1], mpeg1_vlc[111/*rl->n*/][0]);

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

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

  556.                 if (alevel < 128) {

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

  558.                 } else {

  559.                     if (level < 0) {

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

  561.                     } else {

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

  563.                     }

  564.                 }

  565.             }

  566.             last_non_zero = i;

  567.         }

  568.     }

  569.     /* end of block */

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

  571. }

  572. 

  573. /******************************************/

  574. /* decoding */

  575. 

  576. static VLC dc_lum_vlc;

  577. static VLC dc_chroma_vlc;

  578. static VLC mv_vlc;

  579. static VLC mbincr_vlc;

  580. static VLC mb_ptype_vlc;

  581. static VLC mb_btype_vlc;

  582. static VLC mb_pat_vlc;

  583. 

  584. void mpeg1_init_vlc(MpegEncContext *s)

  585. {

  586.     static int done = 0;

  587. 

  588.     if (!done) {

  589.         done = 1;

  590. 

  591.         init_vlc(&dc_lum_vlc, DC_VLC_BITS, 12, 

  592.                  vlc_dc_lum_bits, 1, 1,

  593.                  vlc_dc_lum_code, 2, 2);

  594.         init_vlc(&dc_chroma_vlc,  DC_VLC_BITS, 12, 

  595.                  vlc_dc_chroma_bits, 1, 1,

  596.                  vlc_dc_chroma_code, 2, 2);

  597.         init_vlc(&mv_vlc, MV_VLC_BITS, 17, 

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

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

  600.         init_vlc(&mbincr_vlc, MBINCR_VLC_BITS, 35, 

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

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

  603.         init_vlc(&mb_pat_vlc, MB_PAT_VLC_BITS, 63, 

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

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

  606.         

  607.         init_vlc(&mb_ptype_vlc, MB_PTYPE_VLC_BITS, 32, 

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

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

  610.         init_vlc(&mb_btype_vlc, MB_BTYPE_VLC_BITS, 32, 

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

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

  613.         init_rl(&rl_mpeg1);

  614.         init_rl(&rl_mpeg2);

  615. 

  616.         init_2d_vlc_rl(&rl_mpeg1);

  617.         init_2d_vlc_rl(&rl_mpeg2);

  618.     }

  619. }

  620. 

  621. static inline int get_dmv(MpegEncContext *s)

  622. {

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

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

  625.     else

  626.         return 0;

  627. }

  628. 

  629. static inline int get_qscale(MpegEncContext *s)

  630. {

  631.     int qscale;

  632.     if (s->mpeg2) {

  633.         if (s->q_scale_type) {

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

  635.         } else {

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

  637.         }

  638.     } else {

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

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

  641.     }

  642.     return qscale;

  643. }

  644. 

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

  646. #define MT_FIELD 1

  647. #define MT_FRAME 2

  648. #define MT_16X8  2

  649. #define MT_DMV   3

  650. 

  651. static int mpeg_decode_mb(MpegEncContext *s,

  652.                           DCTELEM block[6][64])

  653. {

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

  655.     

  656.     /* skip mb handling */

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

  658.         /* read again increment */

  659.         s->mb_incr = 1;

  660.         for(;;) {

  661.             code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);

  662.             if (code < 0)

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

  664.             if (code >= 33) {

  665.                 if (code == 33) {

  666.                     s->mb_incr += 33;

  667.                 }

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

  669.             } else {

  670.                 s->mb_incr += code;

  671.                 break;

  672.             }

  673.         }

  674.     }

  675.     if(s->mb_x==-1 /* first MB in a slice */ && s->mb_incr>1){

  676.         s->mb_x+= (s->mb_incr - 1) % s->mb_width;

  677.         s->mb_y+= (s->mb_incr - 1) / s->mb_width;

  678.         s->mb_incr= 1;

  679.     }

  680. 

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

  682.         s->mb_x = 0;

  683.         if (s->mb_y >= (s->mb_height - 1)){

  684.             fprintf(stderr, "slice too long\n");

  685.             return -1;

  686.         }

  687.         s->mb_y++;

  688.     }

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

  690. 

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

  692.         /* skip mb */

  693.         s->mb_intra = 0;

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

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

  696.         s->mv_type = MV_TYPE_16X16;

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

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

  699.             s->mv_dir = MV_DIR_FORWARD;

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

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

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

  703.         } else {

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

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

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

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

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

  709.         }

  710.         s->mb_skiped = 1;

  711.         return 0;

  712.     }

  713. 

  714.     switch(s->pict_type) {

  715.     default:

  716.     case I_TYPE:

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

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

  719.                 return -1;

  720.             mb_type = MB_QUANT | MB_INTRA;

  721.         } else {

  722.             mb_type = MB_INTRA;

  723.         }

  724.         break;

  725.     case P_TYPE:

  726.         mb_type = get_vlc2(&s->gb, mb_ptype_vlc.table, MB_PTYPE_VLC_BITS, 1);

  727.         if (mb_type < 0){

  728.             fprintf(stderr, "invalid mb type in P Frame at %d %d\n", s->mb_x, s->mb_y);

  729.             return -1;

  730.         }

  731.         break;

  732.     case B_TYPE:

  733.         mb_type = get_vlc2(&s->gb, mb_btype_vlc.table, MB_BTYPE_VLC_BITS, 1);

  734.         if (mb_type < 0){

  735.             fprintf(stderr, "invalid mb type in B Frame at %d %d\n", s->mb_x, s->mb_y);

  736.             return -1;

  737.         }

  738.         break;

  739.     }

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

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

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

  743.         /* get additionnal motion vector type */

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

  745.             motion_type = MT_FRAME;

  746.         else

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

  748.     }

  749.     /* compute dct type */

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

  751.         !s->frame_pred_frame_dct &&

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

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

  754. #ifdef DEBUG

  755.         if (s->interlaced_dct)

  756.             printf("interlaced_dct\n");

  757. #endif

  758.     } else {

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

  760.     }

  761. 

  762.     if (mb_type & MB_QUANT) {

  763.         s->qscale = get_qscale(s);

  764.     }

  765.     if (mb_type & MB_INTRA) {

  766.         if (s->concealment_motion_vectors) {

  767.             /* just parse them */

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

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

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

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

  772.         }

  773.         s->mb_intra = 1;

  774.         cbp = 0x3f;

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

  776.     } else {

  777.         s->mb_intra = 0;

  778.         cbp = 0;

  779.     }

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

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

  782.         s->mv_dir = MV_DIR_FORWARD;

  783.         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  791.         /* motion vectors */

  792.         s->mv_dir = 0;

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

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

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

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

  797.                 switch(motion_type) {

  798.                 case MT_FRAME: /* or MT_16X8 */

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

  800.                         /* MT_FRAME */

  801.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

  807.                             /* full_pel: only for mpeg1 */

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

  809.                                 val = val << 1;

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

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

  812.                         }

  813.                     } else {

  814.                         /* MT_16X8 */

  815.                         s->mv_type = MV_TYPE_16X8;

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

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

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

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

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

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

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

  823.                             }

  824.                         }

  825.                     }

  826.                     break;

  827.                 case MT_FIELD:

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

  829.                         s->mv_type = MV_TYPE_FIELD;

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

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

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

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

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

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

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

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

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

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

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

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

  842.                         }

  843.                     } else {

  844.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  852.                         }

  853.                     }

  854.                     break;

  855.                 case MT_DMV:

  856.                     {

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

  858. 

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

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

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

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

  863.                         dmx = get_dmv(s);

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

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

  866.                         dmy = get_dmv(s);

  867.                         s->mv_type = MV_TYPE_DMV;

  868.                         /* XXX: totally broken */

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

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

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

  872. 

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

  874.                             /* top -> top pred */

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

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

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

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

  879.                             m = 4 - m;

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

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

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

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

  884.                         } else {

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

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

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

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

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

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

  891.                                 /* + 2 * cur_field */;

  892.                         }

  893.                     }

  894.                     break;

  895.                 }

  896.             }

  897.         }

  898.     }

  899. 

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

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

  902.     }

  903.     

  904.     if (mb_type & MB_PAT) {

  905.         cbp = get_vlc2(&s->gb, mb_pat_vlc.table, MB_PAT_VLC_BITS, 1);

  906.         if (cbp < 0){

  907.             fprintf(stderr, "invalid cbp at %d %d\n", s->mb_x, s->mb_y);

  908.             return -1;

  909.         }

  910.         cbp++;

  911.     }

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

  913. 

  914.     if (s->mpeg2) {

  915.         if (s->mb_intra) {

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

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

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

  919.                         return -1;

  920.                 } else {

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

  922.                 }

  923.             }

  924.         } else {

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

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

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

  928.                         return -1;

  929.                 } else {

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

  931.                 }

  932.             }

  933.         }

  934.     } else {

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

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

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

  938.                     return -1;

  939.             } else {

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

  941.             }

  942.         }

  943.     }

  944.     return 0;

  945. }

  946. 

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

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

  949. {

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

  951. 

  952.     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);

  953.     if (code < 0) {

  954.         return 0xffff;

  955.     }

  956.     if (code == 0) {

  957.         return pred;

  958.     }

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

  960.     shift = fcode - 1;

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

  962.     if (shift > 0)

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

  964.     val++;

  965.     if (sign)

  966.         val = -val;

  967.     val += pred;

  968.     

  969.     /* modulo decoding */

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

  971.     m = 2 * l;

  972.     if (val < -l) {

  973.         val += m;

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

  975.         val -= m;

  976.     }

  977.     return val;

  978. }

  979. 

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

  981. {

  982.     int code, diff;

  983. 

  984.     if (component == 0) {

  985.         code = get_vlc2(&s->gb, dc_lum_vlc.table, DC_VLC_BITS, 2);

  986.     } else {

  987.         code = get_vlc2(&s->gb, dc_chroma_vlc.table, DC_VLC_BITS, 2);

  988.     }

  989.     if (code < 0){

  990.         fprintf(stderr, "invalid dc code at %d %d\n", s->mb_x, s->mb_y);

  991.         return 0xffff;

  992.     }

  993.     if (code == 0) {

  994.         diff = 0;

  995.     } else {

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

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

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

  999.     }

  1000.     return diff;

  1001. }

  1002. 

  1003. static int mpeg1_decode_block(MpegEncContext *s, 

  1004.                                DCTELEM *block, 

  1005.                                int n)

  1006. {

  1007.     int level, dc, diff, i, j, run;

  1008.     int code, component;

  1009.     RLTable *rl = &rl_mpeg1;

  1010. 

  1011.     if (s->mb_intra) {

  1012.         /* DC coef */

  1013.         component = (n <= 3 ? 0 : n - 4 + 1);

  1014.         diff = decode_dc(s, component);

  1015.         if (diff >= 0xffff)

  1016.             return -1;

  1017.         dc = s->last_dc[component];

  1018.         dc += diff;

  1019.         s->last_dc[component] = dc;

  1020.         block[0] = dc;

  1021.         dprintf("dc=%d diff=%d\n", dc, diff);

  1022.         i = 1;

  1023.     } else {

  1024.         int v;

  1025.         OPEN_READER(re, &s->gb);

  1026.         i = 0;

  1027.         /* special case for the first coef. no need to add a second vlc table */

  1028.         UPDATE_CACHE(re, &s->gb);

  1029.         v= SHOW_UBITS(re, &s->gb, 2);

  1030.         if (v & 2) {

  1031.             run = 0;

  1032.             level = 1 - ((v & 1) << 1);

  1033.             SKIP_BITS(re, &s->gb, 2);

  1034.             CLOSE_READER(re, &s->gb);

  1035.             goto add_coef;

  1036.         }

  1037.         CLOSE_READER(re, &s->gb);

  1038.     }

  1039. 

  1040.     /* now quantify & encode AC coefs */

  1041.     for(;;) {

  1042.         code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);

  1043.         if (code < 0) {

  1044.             return -1;

  1045.         }

  1046.         if (code == 112) {

  1047.             break;

  1048.         } else if (code == 111) {

  1049.             /* escape */

  1050.             run = get_bits(&s->gb, 6);

  1051.             level = get_bits(&s->gb, 8);

  1052.             level= (level + ((-1)<<7)) ^ ((-1)<<7); //sign extension

  1053.             if (level == -128) {

  1054.                 level = get_bits(&s->gb, 8) - 256;

  1055.             } else if (level == 0) {

  1056.                 level = get_bits(&s->gb, 8);

  1057.             }

  1058.         } else {

  1059.             run = rl->table_run[code];

  1060.             level = rl->table_level[code];

  1061.             if (get_bits1(&s->gb))

  1062.                 level = -level;

  1063.         }

  1064.         i += run;

  1065.         if (i >= 64)

  1066.             return -1;

  1067.     add_coef:

  1068.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1069. 	j = zigzag_direct[i];

  1070.         block[j] = level;

  1071.         i++;

  1072.     }

  1073.     s->block_last_index[n] = i-1;

  1074.     return 0;

  1075. }

  1076. 

  1077. /* Also does unquantization here, since I will never support mpeg2

  1078.    encoding */

  1079. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  1080.                                         DCTELEM *block, 

  1081.                                         int n)

  1082. {

  1083.     int level, i, j, run;

  1084.     int code;

  1085.     RLTable *rl = &rl_mpeg1;

  1086.     const UINT8 *scan_table;

  1087.     const UINT16 *matrix;

  1088.     int mismatch;

  1089. 

  1090.     if (s->alternate_scan)

  1091.         scan_table = ff_alternate_vertical_scan;

  1092.     else

  1093.         scan_table = zigzag_direct;

  1094.     mismatch = 1;

  1095. 

  1096.     {

  1097.         int v;

  1098.         OPEN_READER(re, &s->gb);

  1099.         i = 0;

  1100.         if (n < 4)

  1101.             matrix = s->inter_matrix;

  1102.         else

  1103.             matrix = s->chroma_inter_matrix;

  1104. 

  1105.         /* special case for the first coef. no need to add a second vlc table */

  1106.         UPDATE_CACHE(re, &s->gb);

  1107.         v= SHOW_UBITS(re, &s->gb, 2);

  1108.         if (v & 2) {

  1109.             run = 0;

  1110.             level = 1 - ((v & 1) << 1);

  1111.             SKIP_BITS(re, &s->gb, 2);

  1112.             CLOSE_READER(re, &s->gb);

  1113.             goto add_coef;

  1114.         }

  1115.         CLOSE_READER(re, &s->gb);

  1116.     }

  1117. 

  1118.     /* now quantify & encode AC coefs */

  1119.     for(;;) {

  1120.         code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);

  1121.         if (code < 0){

  1122.             fprintf(stderr, "invalid ac code at %d %d\n", s->mb_x, s->mb_y);

  1123.             return -1;

  1124.         }

  1125.         if (code == 112) {

  1126.             break;

  1127.         } else if (code == 111) {

  1128.             /* escape */

  1129.             run = get_bits(&s->gb, 6);

  1130.             level = get_bits(&s->gb, 12);

  1131.             level= (level + ((-1)<<11)) ^ ((-1)<<11); //sign extension

  1132.         } else {

  1133.             run = rl->table_run[code];

  1134.             level = rl->table_level[code];

  1135.             if (get_bits1(&s->gb))

  1136.                 level = -level;

  1137.         }

  1138.         i += run;

  1139.         if (i >= 64){

  1140.             fprintf(stderr, "run too long at %d %d\n", s->mb_x, s->mb_y);

  1141.             return -1;

  1142.         }

  1143.     add_coef:

  1144. 	j = scan_table[i];

  1145.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1146.         /* XXX: optimize */

  1147.         if (level > 0) {

  1148.             level = ((level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1149.         } else {

  1150.             level = ((-level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1151.             level = -level;

  1152.         }

  1153.         /* XXX: is it really necessary to saturate since the encoder

  1154.            knows whats going on ? */

  1155.         mismatch ^= level;

  1156.         block[j] = level;

  1157.         i++;

  1158.     }

  1159.     block[63] ^= (mismatch & 1);

  1160.     s->block_last_index[n] = i;

  1161.     return 0;

  1162. }

  1163. 

  1164. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  1165.                                     DCTELEM *block, 

  1166.                                     int n)

  1167. {

  1168.     int level, dc, diff, i, j, run;

  1169.     int code, component;

  1170.     RLTable *rl;

  1171.     const UINT8 *scan_table;

  1172.     const UINT16 *matrix;

  1173.     int mismatch;

  1174. 

  1175.     if (s->alternate_scan)

  1176.         scan_table = ff_alternate_vertical_scan;

  1177.     else

  1178.         scan_table = zigzag_direct;

  1179. 

  1180.     /* DC coef */

  1181.     component = (n <= 3 ? 0 : n - 4 + 1);

  1182.     diff = decode_dc(s, component);

  1183.     if (diff >= 0xffff)

  1184.         return -1;

  1185.     dc = s->last_dc[component];

  1186.     dc += diff;

  1187.     s->last_dc[component] = dc;

  1188.     block[0] = dc << (3 - s->intra_dc_precision);

  1189.     dprintf("dc=%d\n", block[0]);

  1190.     mismatch = block[0] ^ 1;

  1191.     i = 1;

  1192.     if (s->intra_vlc_format)

  1193.         rl = &rl_mpeg2;

  1194.     else

  1195.         rl = &rl_mpeg1;

  1196.     if (n < 4) 

  1197.         matrix = s->intra_matrix;

  1198.     else

  1199.         matrix = s->chroma_intra_matrix;

  1200. 

  1201.     /* now quantify & encode AC coefs */

  1202.     for(;;) {

  1203.         code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);

  1204.         if (code < 0){

  1205.             fprintf(stderr, "invalid ac code at %d %d\n", s->mb_x, s->mb_y);

  1206.             return -1;

  1207.         }

  1208.         if (code == 112) {

  1209.             break;

  1210.         } else if (code == 111) {

  1211.             /* escape */

  1212.             run = get_bits(&s->gb, 6);

  1213.             level = get_bits(&s->gb, 12);

  1214.             level= (level + ((-1)<<11)) ^ ((-1)<<11); //sign extension

  1215.         } else {

  1216.             run = rl->table_run[code];

  1217.             level = rl->table_level[code];

  1218.             if (get_bits1(&s->gb))

  1219.                 level = -level;

  1220.         }

  1221.         i += run;

  1222.         if (i >= 64){

  1223.             fprintf(stderr, "run too long at %d %d\n", s->mb_x, s->mb_y);

  1224.             return -1;

  1225.         }

  1226. 	j = scan_table[i];

  1227.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1228.         level = (level * s->qscale * matrix[j]) / 16;

  1229.         /* XXX: is it really necessary to saturate since the encoder

  1230.            knows whats going on ? */

  1231.         mismatch ^= level;

  1232.         block[j] = level;

  1233.         i++;

  1234.     }

  1235.     block[63] ^= (mismatch & 1);

  1236.     s->block_last_index[n] = i;

  1237.     return 0;

  1238. }

  1239. 

  1240. /* compressed picture size */

  1241. #define PICTURE_BUFFER_SIZE 100000

  1242. 

  1243. typedef struct Mpeg1Context {

  1244.     MpegEncContext mpeg_enc_ctx;

  1245.     UINT32 header_state;

  1246.     int start_code; /* current start code */

  1247.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  1248.     UINT8 *buf_ptr;

  1249.     int buffer_size;

  1250.     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */

  1251.     int repeat_field; /* true if we must repeat the field */

  1252. } Mpeg1Context;

  1253. 

  1254. static int mpeg_decode_init(AVCodecContext *avctx)

  1255. {

  1256.     Mpeg1Context *s = avctx->priv_data;

  1257.     

  1258.     s->mpeg_enc_ctx.flags= avctx->flags;

  1259.     common_init(&s->mpeg_enc_ctx);

  1260. 

  1261.     s->header_state = 0xff;

  1262.     s->mpeg_enc_ctx_allocated = 0;

  1263.     s->buffer_size = PICTURE_BUFFER_SIZE;

  1264.     s->start_code = -1;

  1265.     s->buf_ptr = s->buffer;

  1266.     s->mpeg_enc_ctx.picture_number = 0;

  1267.     s->repeat_field = 0;

  1268.     s->mpeg_enc_ctx.codec_id= avctx->codec->id;

  1269.     avctx->mbskip_table= s->mpeg_enc_ctx.mbskip_table;

  1270.     return 0;

  1271. }

  1272. 

  1273. /* return the 8 bit start code value and update the search

  1274.    state. Return -1 if no start code found */

  1275. static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1276.                            UINT32 *header_state)

  1277. {

  1278.     UINT8 *buf_ptr;

  1279.     unsigned int state, v;

  1280.     int val;

  1281. 

  1282.     state = *header_state;

  1283.     buf_ptr = *pbuf_ptr;

  1284.     while (buf_ptr < buf_end) {

  1285.         v = *buf_ptr++;

  1286.         if (state == 0x000001) {

  1287.             state = ((state << 8) | v) & 0xffffff;

  1288.             val = state;

  1289.             goto found;

  1290.         }

  1291.         state = ((state << 8) | v) & 0xffffff;

  1292.     }

  1293.     val = -1;

  1294.  found:

  1295.     *pbuf_ptr = buf_ptr;

  1296.     *header_state = state;

  1297.     return val;

  1298. }

  1299. 

  1300. static int mpeg1_decode_picture(AVCodecContext *avctx, 

  1301.                                 UINT8 *buf, int buf_size)

  1302. {

  1303.     Mpeg1Context *s1 = avctx->priv_data;

  1304.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1305.     int ref, f_code;

  1306. 

  1307.     init_get_bits(&s->gb, buf, buf_size);

  1308. 

  1309.     ref = get_bits(&s->gb, 10); /* temporal ref */

  1310.     s->pict_type = get_bits(&s->gb, 3);

  1311.     dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);

  1312.     skip_bits(&s->gb, 16);

  1313.     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {

  1314.         s->full_pel[0] = get_bits1(&s->gb);

  1315.         f_code = get_bits(&s->gb, 3);

  1316.         if (f_code == 0)

  1317.             return -1;

  1318.         s->mpeg_f_code[0][0] = f_code;

  1319.         s->mpeg_f_code[0][1] = f_code;

  1320.     }

  1321.     if (s->pict_type == B_TYPE) {

  1322.         s->full_pel[1] = get_bits1(&s->gb);

  1323.         f_code = get_bits(&s->gb, 3);

  1324.         if (f_code == 0)

  1325.             return -1;

  1326.         s->mpeg_f_code[1][0] = f_code;

  1327.         s->mpeg_f_code[1][1] = f_code;

  1328.     }

  1329.     s->y_dc_scale = 8;

  1330.     s->c_dc_scale = 8;

  1331.     s->first_slice = 1;

  1332.     return 0;

  1333. }

  1334. 

  1335. static void mpeg_decode_sequence_extension(MpegEncContext *s)

  1336. {

  1337.     int horiz_size_ext, vert_size_ext;

  1338.     int bit_rate_ext, vbv_buf_ext, low_delay;

  1339.     int frame_rate_ext_n, frame_rate_ext_d;

  1340. 

  1341.     skip_bits(&s->gb, 8); /* profil and level */

  1342.     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */

  1343.     skip_bits(&s->gb, 2); /* chroma_format */

  1344.     horiz_size_ext = get_bits(&s->gb, 2);

  1345.     vert_size_ext = get_bits(&s->gb, 2);

  1346.     s->width |= (horiz_size_ext << 12);

  1347.     s->height |= (vert_size_ext << 12);

  1348.     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */

  1349.     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;

  1350.     skip_bits1(&s->gb); /* marker */

  1351.     vbv_buf_ext = get_bits(&s->gb, 8);

  1352.     low_delay = get_bits1(&s->gb);

  1353.     frame_rate_ext_n = get_bits(&s->gb, 2);

  1354.     frame_rate_ext_d = get_bits(&s->gb, 5);

  1355.     if (frame_rate_ext_d >= 1)

  1356.         s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;

  1357.     dprintf("sequence extension\n");

  1358.     s->mpeg2 = 1;

  1359.     s->avctx->sub_id = 2; /* indicates mpeg2 found */

  1360. }

  1361. 

  1362. static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)

  1363. {

  1364.     int i, v, j;

  1365. 

  1366.     dprintf("matrix extension\n");

  1367. 

  1368.     if (get_bits1(&s->gb)) {

  1369.         for(i=0;i<64;i++) {

  1370.             v = get_bits(&s->gb, 8);

  1371.             j = zigzag_direct[i];

  1372.             s->intra_matrix[j] = v;

  1373.             s->chroma_intra_matrix[j] = v;

  1374.         }

  1375.     }

  1376.     if (get_bits1(&s->gb)) {

  1377.         for(i=0;i<64;i++) {

  1378.             v = get_bits(&s->gb, 8);

  1379.             j = zigzag_direct[i];

  1380.             s->inter_matrix[j] = v;

  1381.             s->chroma_inter_matrix[j] = v;

  1382.         }

  1383.     }

  1384.     if (get_bits1(&s->gb)) {

  1385.         for(i=0;i<64;i++) {

  1386.             v = get_bits(&s->gb, 8);

  1387.             j = zigzag_direct[i];

  1388.             s->chroma_intra_matrix[j] = v;

  1389.         }

  1390.     }

  1391.     if (get_bits1(&s->gb)) {

  1392.         for(i=0;i<64;i++) {

  1393.             v = get_bits(&s->gb, 8);

  1394.             j = zigzag_direct[i];

  1395.             s->chroma_inter_matrix[j] = v;

  1396.         }

  1397.     }

  1398. }

  1399. 

  1400. static void mpeg_decode_picture_coding_extension(MpegEncContext *s)

  1401. {

  1402.     s->full_pel[0] = s->full_pel[1] = 0;

  1403.     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);

  1404.     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);

  1405.     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);

  1406.     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);

  1407.     s->intra_dc_precision = get_bits(&s->gb, 2);

  1408.     s->picture_structure = get_bits(&s->gb, 2);

  1409.     s->top_field_first = get_bits1(&s->gb);

  1410.     s->frame_pred_frame_dct = get_bits1(&s->gb);

  1411.     s->concealment_motion_vectors = get_bits1(&s->gb);

  1412.     s->q_scale_type = get_bits1(&s->gb);

  1413.     s->intra_vlc_format = get_bits1(&s->gb);

  1414.     s->alternate_scan = get_bits1(&s->gb);

  1415.     s->repeat_first_field = get_bits1(&s->gb);

  1416.     s->chroma_420_type = get_bits1(&s->gb);

  1417.     s->progressive_frame = get_bits1(&s->gb);

  1418.     /* composite display not parsed */

  1419.     dprintf("intra_dc_precision=%d\n", s->intra_dc_precision);

  1420.     dprintf("picture_structure=%d\n", s->picture_structure);

  1421.     dprintf("top field first=%d\n", s->top_field_first);

  1422.     dprintf("repeat first field=%d\n", s->repeat_first_field);

  1423.     dprintf("conceal=%d\n", s->concealment_motion_vectors);

  1424.     dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);

  1425.     dprintf("alternate_scan=%d\n", s->alternate_scan);

  1426.     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);

  1427.     dprintf("progressive_frame=%d\n", s->progressive_frame);

  1428. }

  1429. 

  1430. static void mpeg_decode_extension(AVCodecContext *avctx, 

  1431.                                   UINT8 *buf, int buf_size)

  1432. {

  1433.     Mpeg1Context *s1 = avctx->priv_data;

  1434.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1435.     int ext_type;

  1436. 

  1437.     init_get_bits(&s->gb, buf, buf_size);

  1438.     

  1439.     ext_type = get_bits(&s->gb, 4);

  1440.     switch(ext_type) {

  1441.     case 0x1:

  1442.         /* sequence ext */

  1443.         mpeg_decode_sequence_extension(s);

  1444.         break;

  1445.     case 0x3:

  1446.         /* quant matrix extension */

  1447.         mpeg_decode_quant_matrix_extension(s);

  1448.         break;

  1449.     case 0x8:

  1450.         /* picture extension */

  1451.         mpeg_decode_picture_coding_extension(s);

  1452.         break;

  1453.     }

  1454. }

  1455. 

  1456. /* return 1 if end of frame */

  1457. static int mpeg_decode_slice(AVCodecContext *avctx, 

  1458.                               AVPicture *pict,

  1459.                               int start_code,

  1460.                               UINT8 *buf, int buf_size)

  1461. {

  1462.     Mpeg1Context *s1 = avctx->priv_data;

  1463.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1464.     int ret;

  1465. 

  1466.     start_code = (start_code - 1) & 0xff;

  1467.     if (start_code >= s->mb_height){

  1468.         fprintf(stderr, "slice below image\n");

  1469.         return -1;

  1470.     }

  1471.     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);

  1472.     s->last_dc[1] = s->last_dc[0];

  1473.     s->last_dc[2] = s->last_dc[0];

  1474.     memset(s->last_mv, 0, sizeof(s->last_mv));

  1475.     s->mb_x = -1;

  1476.     s->mb_y = start_code;

  1477.     s->mb_incr = 0;

  1478.     /* start frame decoding */

  1479.     if (s->first_slice) {

  1480.         s->first_slice = 0;

  1481.         MPV_frame_start(s, avctx);

  1482.     }

  1483. 

  1484.     init_get_bits(&s->gb, buf, buf_size);

  1485. 

  1486.     s->qscale = get_qscale(s);

  1487.     /* extra slice info */

  1488.     while (get_bits1(&s->gb) != 0) {

  1489.         skip_bits(&s->gb, 8);

  1490.     }

  1491. 

  1492.     for(;;) {

  1493.         clear_blocks(s->block[0]);

  1494.         emms_c();

  1495.         ret = mpeg_decode_mb(s, s->block);

  1496.         dprintf("ret=%d\n", ret);

  1497.         if (ret < 0)

  1498.             return -1;

  1499.         if (ret == 1)

  1500.             break;

  1501.         MPV_decode_mb(s, s->block);

  1502.     }

  1503.     emms_c();

  1504. 

  1505.     /* end of slice reached */

  1506.     if (s->mb_x == (s->mb_width - 1) &&

  1507.         s->mb_y == (s->mb_height - 1)) {

  1508.         /* end of image */

  1509.         UINT8 **picture;

  1510. 

  1511.         MPV_frame_end(s);

  1512. 

  1513.         /* XXX: incorrect reported qscale for mpeg2 */

  1514.         if (s->pict_type == B_TYPE) {

  1515.             picture = s->current_picture;

  1516.             avctx->quality = s->qscale;

  1517.         } else {

  1518.             /* latency of 1 frame for I and P frames */

  1519.             /* XXX: use another variable than picture_number */

  1520.             if (s->picture_number == 0) {

  1521.                 picture = NULL;

  1522.             } else {

  1523.                 picture = s->last_picture;

  1524.                 avctx->quality = s->last_qscale;

  1525.             }

  1526.             s->last_qscale = s->qscale;

  1527.             s->picture_number++;

  1528.         }

  1529.         if (picture) {

  1530.             pict->data[0] = picture[0];

  1531.             pict->data[1] = picture[1];

  1532.             pict->data[2] = picture[2];

  1533.             pict->linesize[0] = s->linesize;

  1534.             pict->linesize[1] = s->uvlinesize;

  1535.             pict->linesize[2] = s->uvlinesize;

  1536.             return 1;

  1537.         } else {

  1538.             return 0;

  1539.         }

  1540.     } else {

  1541.         return 0;

  1542.     }

  1543. }

  1544. 

  1545. static int mpeg1_decode_sequence(AVCodecContext *avctx, 

  1546.                                  UINT8 *buf, int buf_size)

  1547. {

  1548.     Mpeg1Context *s1 = avctx->priv_data;

  1549.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1550.     int width, height, i, v, j;

  1551. 

  1552.     init_get_bits(&s->gb, buf, buf_size);

  1553. 

  1554.     width = get_bits(&s->gb, 12);

  1555.     height = get_bits(&s->gb, 12);

  1556.     skip_bits(&s->gb, 4);

  1557.     s->frame_rate_index = get_bits(&s->gb, 4);

  1558.     if (s->frame_rate_index == 0)

  1559.         return -1;

  1560.     s->bit_rate = get_bits(&s->gb, 18) * 400;

  1561.     if (get_bits1(&s->gb) == 0) /* marker */

  1562.         return -1;

  1563.     if (width <= 0 || height <= 0 ||

  1564.         (width % 2) != 0 || (height % 2) != 0)

  1565.         return -1;

  1566.     if (width != s->width ||

  1567.         height != s->height) {

  1568.         /* start new mpeg1 context decoding */

  1569.         s->out_format = FMT_MPEG1;

  1570.         if (s1->mpeg_enc_ctx_allocated) {

  1571.             MPV_common_end(s);

  1572.         }

  1573.         s->width = width;

  1574.         s->height = height;

  1575.         avctx->has_b_frames= s->has_b_frames = 1;

  1576.         s->avctx = avctx;

  1577.         avctx->width = width;

  1578.         avctx->height = height;

  1579.         if (s->frame_rate_index >= 9) {

  1580.             /* at least give a valid frame rate (some old mpeg1 have this) */

  1581.             avctx->frame_rate = 25 * FRAME_RATE_BASE;

  1582.         } else {

  1583.             avctx->frame_rate = frame_rate_tab[s->frame_rate_index];

  1584.         }

  1585.         s->frame_rate = avctx->frame_rate;

  1586.         avctx->bit_rate = s->bit_rate;

  1587.         

  1588.         if (MPV_common_init(s) < 0)

  1589.             return -1;

  1590.         mpeg1_init_vlc(s);

  1591.         s1->mpeg_enc_ctx_allocated = 1;

  1592.     }

  1593. 

  1594.     skip_bits(&s->gb, 10); /* vbv_buffer_size */

  1595.     skip_bits(&s->gb, 1);

  1596. 

  1597.     /* get matrix */

  1598.     if (get_bits1(&s->gb)) {

  1599.         for(i=0;i<64;i++) {

  1600.             v = get_bits(&s->gb, 8);

  1601.             j = zigzag_direct[i];

  1602.             s->intra_matrix[j] = v;

  1603.             s->chroma_intra_matrix[j] = v;

  1604.         }

  1605. #ifdef DEBUG

  1606.         dprintf("intra matrix present\n");

  1607.         for(i=0;i<64;i++)

  1608.             dprintf(" %d", s->intra_matrix[zigzag_direct[i]]);

  1609.         printf("\n");

  1610. #endif

  1611.     } else {

  1612.         for(i=0;i<64;i++) {

  1613.             v = ff_mpeg1_default_intra_matrix[i];

  1614.             s->intra_matrix[i] = v;

  1615.             s->chroma_intra_matrix[i] = v;

  1616.         }

  1617.     }

  1618.     if (get_bits1(&s->gb)) {

  1619.         for(i=0;i<64;i++) {

  1620.             v = get_bits(&s->gb, 8);

  1621.             j = zigzag_direct[i];

  1622.             s->inter_matrix[j] = v;

  1623.             s->chroma_inter_matrix[j] = v;

  1624.         }

  1625. #ifdef DEBUG

  1626.         dprintf("non intra matrix present\n");

  1627.         for(i=0;i<64;i++)

  1628.             dprintf(" %d", s->inter_matrix[zigzag_direct[i]]);

  1629.         printf("\n");

  1630. #endif

  1631.     } else {

  1632.         for(i=0;i<64;i++) {

  1633.             v = ff_mpeg1_default_non_intra_matrix[i];

  1634.             s->inter_matrix[i] = v;

  1635.             s->chroma_inter_matrix[i] = v;

  1636.         }

  1637.     }

  1638. 

  1639.     /* we set mpeg2 parameters so that it emulates mpeg1 */

  1640.     s->progressive_sequence = 1;

  1641.     s->progressive_frame = 1;

  1642.     s->picture_structure = PICT_FRAME;

  1643.     s->frame_pred_frame_dct = 1;

  1644.     s->mpeg2 = 0;

  1645.     avctx->sub_id = 1; /* indicates mpeg1 */

  1646.     return 0;

  1647. }

  1648. 

  1649. /* handle buffering and image synchronisation */

  1650. static int mpeg_decode_frame(AVCodecContext *avctx, 

  1651.                              void *data, int *data_size,

  1652.                              UINT8 *buf, int buf_size)

  1653. {

  1654.     Mpeg1Context *s = avctx->priv_data;

  1655.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1656.     int len, start_code_found, ret, code, start_code, input_size;

  1657.     AVPicture *picture = data;

  1658.     MpegEncContext *s2 = &s->mpeg_enc_ctx;

  1659.             

  1660.     dprintf("fill_buffer\n");

  1661. 

  1662.     *data_size = 0;

  1663. 

  1664.     /* special case for last picture */

  1665.     if (buf_size == 0) {

  1666.         if (s2->picture_number > 0) {

  1667.             picture->data[0] = s2->next_picture[0];

  1668.             picture->data[1] = s2->next_picture[1];

  1669.             picture->data[2] = s2->next_picture[2];

  1670.             picture->linesize[0] = s2->linesize;

  1671.             picture->linesize[1] = s2->uvlinesize;

  1672.             picture->linesize[2] = s2->uvlinesize;

  1673.             *data_size = sizeof(AVPicture);

  1674.         }

  1675.         return 0;

  1676.     }

  1677. 

  1678.     buf_ptr = buf;

  1679.     buf_end = buf + buf_size;

  1680. 

  1681. #if 0    

  1682.     if (s->repeat_field % 2 == 1) { 

  1683.         s->repeat_field++;

  1684.         //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,

  1685.         //        s2->picture_number, s->repeat_field);

  1686.         if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {

  1687.             *data_size = sizeof(AVPicture);

  1688.             goto the_end;

  1689.         }

  1690.     }

  1691. #endif

  1692.     while (buf_ptr < buf_end) {

  1693.         buf_start = buf_ptr;

  1694.         /* find start next code */

  1695.         code = find_start_code(&buf_ptr, buf_end, &s->header_state);

  1696.         if (code >= 0) {

  1697.             start_code_found = 1;

  1698.         } else {

  1699.             start_code_found = 0;

  1700.         }

  1701.         /* copy to buffer */

  1702.         len = buf_ptr - buf_start;

  1703.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1704.             /* data too big : flush */

  1705.             s->buf_ptr = s->buffer;

  1706.             if (start_code_found)

  1707.                 s->start_code = code;

  1708.         } else {

  1709.             memcpy(s->buf_ptr, buf_start, len);

  1710.             s->buf_ptr += len;

  1711.             

  1712.             if (start_code_found) {

  1713.                 /* prepare data for next start code */

  1714.                 input_size = s->buf_ptr - s->buffer;

  1715.                 start_code = s->start_code;

  1716.                 s->buf_ptr = s->buffer;

  1717.                 s->start_code = code;

  1718.                 switch(start_code) {

  1719.                 case SEQ_START_CODE:

  1720.                     mpeg1_decode_sequence(avctx, s->buffer, 

  1721.                                           input_size);

  1722.                     break;

  1723.                             

  1724.                 case PICTURE_START_CODE:

  1725.                     /* we have a complete image : we try to decompress it */

  1726.                     mpeg1_decode_picture(avctx, 

  1727.                                          s->buffer, input_size);

  1728.                     break;

  1729.                 case EXT_START_CODE:

  1730.                     mpeg_decode_extension(avctx,

  1731.                                           s->buffer, input_size);

  1732.                     break;

  1733.                 default:

  1734.                     if (start_code >= SLICE_MIN_START_CODE &&

  1735.                         start_code <= SLICE_MAX_START_CODE) {

  1736.                         ret = mpeg_decode_slice(avctx, picture,

  1737.                                                 start_code, s->buffer, input_size);

  1738.                         if (ret == 1) {

  1739.                             /* got a picture: exit */

  1740.                             /* first check if we must repeat the frame */

  1741.                             avctx->repeat_pict = 0;

  1742. #if 0

  1743.                             if (s2->progressive_frame && s2->repeat_first_field) {

  1744.                                 //fprintf(stderr,"\nRepeat this frame: %d! pict: %d",avctx->frame_number,s2->picture_number);

  1745.                                 //s2->repeat_first_field = 0;

  1746.                                 //s2->progressive_frame = 0;

  1747.                                 if (++s->repeat_field > 2)

  1748.                                     s->repeat_field = 0;

  1749.                                 avctx->repeat_pict = 1;

  1750.                             }

  1751. #endif                      

  1752.                             if (s2->repeat_first_field) {

  1753.                                 if (s2->progressive_sequence) {

  1754.                                     if (s2->top_field_first)

  1755.                                         avctx->repeat_pict = 4;

  1756.                                     else

  1757.                                         avctx->repeat_pict = 2;

  1758.                                 } else if (s2->progressive_frame) {

  1759.                                     avctx->repeat_pict = 1;

  1760.                                 }

  1761.                             }         

  1762.                             *data_size = sizeof(AVPicture);

  1763.                             goto the_end;

  1764.                         }else if(ret==-1){

  1765.                             printf("Error while decoding slice\n");

  1766.                         }

  1767.                     }

  1768.                     break;

  1769.                 }

  1770.             }

  1771.         }

  1772.     }

  1773.  the_end:

  1774.     return buf_ptr - buf;

  1775. }

  1776. 

  1777. static int mpeg_decode_end(AVCodecContext *avctx)

  1778. {

  1779.     Mpeg1Context *s = avctx->priv_data;

  1780. 

  1781.     if (s->mpeg_enc_ctx_allocated)

  1782.         MPV_common_end(&s->mpeg_enc_ctx);

  1783.     return 0;

  1784. }

  1785. 

  1786. AVCodec mpeg_decoder = {

  1787.     "mpegvideo",

  1788.     CODEC_TYPE_VIDEO,

  1789.     CODEC_ID_MPEG1VIDEO,

  1790.     sizeof(Mpeg1Context),

  1791.     mpeg_decode_init,

  1792.     NULL,

  1793.     mpeg_decode_end,

  1794.     mpeg_decode_frame,

  1795.     CODEC_CAP_DR1,

  1796. };