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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. static void mpeg1_encode_block(MpegEncContext *s, 

  37.                          DCTELEM *block, 

  38.                          int component);

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

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

  41. static int mpeg1_decode_block(MpegEncContext *s, 

  42.                               DCTELEM *block, 

  43.                               int n);

  44. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  45.                                         DCTELEM *block, 

  46.                                         int n);

  47. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  48.                                     DCTELEM *block, 

  49.                                     int n);

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

  51. 

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

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

  54. 

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

  56. {

  57.     align_put_bits(&s->pb);

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

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

  60. }

  61. 

  62. /* put sequence header if needed */

  63. static void mpeg1_encode_sequence_header(MpegEncContext *s)

  64. {

  65.         unsigned int vbv_buffer_size;

  66.         unsigned int fps, v;

  67.         int n;

  68.         UINT64 time_code;

  69.         

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

  71.             /* mpeg1 header repeated every gop */

  72.             put_header(s, SEQ_START_CODE);

  73.             

  74.             /* search closest frame rate */

  75.             {

  76.                 int i, dmin, d;

  77.                 s->frame_rate_index = 0;

  78.                 dmin = 0x7fffffff;

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

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

  81.                     if (d < dmin) {

  82.                         dmin = d;

  83.                         s->frame_rate_index = i;

  84.                     }

  85.                 }

  86.             }

  87.  

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

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

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

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

  92.             v = s->bit_rate / 400;

  93.             if (v > 0x3ffff)

  94.                 v = 0x3ffff;

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

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

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

  98.                some margin just in case */

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

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

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

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

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

  104. 

  105.             put_header(s, GOP_START_CODE);

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

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

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

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

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

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

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

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

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

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

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

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

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

  119.         }

  120. 

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

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

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

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

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

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

  127.                 mpeg1_skip_picture(s, s->fake_picture_number - 

  128.                                    s->gop_picture_number); 

  129.                 s->fake_picture_number++;

  130.             }

  131. 

  132.         }

  133. }

  134. 

  135. 

  136. /* insert a fake P picture */

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

  138. {

  139.     unsigned int mb_incr;

  140. 

  141.     /* mpeg1 picture header */

  142.     put_header(s, PICTURE_START_CODE);

  143.     /* temporal reference */

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

  145.     

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

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

  148.     

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

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

  151.     

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

  153.     

  154.     /* only one slice */

  155.     put_header(s, SLICE_MIN_START_CODE);

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

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

  158.     

  159.     mb_incr = 1;

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

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

  162.     

  163.     /* empty macroblock */

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

  165.     

  166.     /* zero motion x & y */

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

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

  169. 

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

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

  172.     while (mb_incr > 33) {

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

  174.         mb_incr -= 33;

  175.     }

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

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

  178.     

  179.     /* empty macroblock */

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

  181.     

  182.     /* zero motion x & y */

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

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

  185. }

  186. 

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

  188. {

  189.     static int done=0;

  190. 

  191.     if (!done) {

  192. 	int i;

  193.         done = 1;

  194.         init_rl(&rl_mpeg1);

  195. 	

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

  197. 	{

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

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

  200. 	}

  201. 

  202. 	/* build unified dc encoding tables */

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

  204. 	{

  205. 		int adiff, index;

  206. 		int bits, code;

  207. 		int diff=i;

  208. 

  209. 		adiff = ABS(diff);

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

  211. 		index = vlc_dc_table[adiff];

  212. 

  213. 		bits= vlc_dc_lum_bits[index] + index;

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

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

  216. 		

  217. 		bits= vlc_dc_chroma_bits[index] + index;

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

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

  220. 	}

  221.     }

  222.     mpeg1_encode_sequence_header(s);

  223. 

  224.     /* mpeg1 picture header */

  225.     put_header(s, PICTURE_START_CODE);

  226.     /* temporal reference */

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

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

  229.     s->fake_picture_number++;

  230.     

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

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

  233.     

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

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

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

  237.     }

  238.     

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

  240.     

  241.     /* only one slice */

  242.     put_header(s, SLICE_MIN_START_CODE);

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

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

  245. }

  246. 

  247. void mpeg1_encode_mb(MpegEncContext *s,

  248.                      DCTELEM block[6][64],

  249.                      int motion_x, int motion_y)

  250. {

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

  252. 

  253.     mb_x = s->mb_x;

  254.     mb_y = s->mb_y;

  255. 

  256.     /* compute cbp */

  257.     cbp = 0;

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

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

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

  261.     }

  262. 

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

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

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

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

  267.         s->mb_incr++;

  268.     } else {

  269.         /* output mb incr */

  270.         mb_incr = s->mb_incr;

  271. 

  272.         while (mb_incr > 33) {

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

  274.             mb_incr -= 33;

  275.         }

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

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

  278.         

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

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

  281.         } else {

  282.             if (s->mb_intra) {

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

  284.             } else {

  285.                 if (cbp != 0) {

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

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

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

  289.                     } else {

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

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

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

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

  294.                     }

  295.                 } else {

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

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

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

  299.                 }

  300.             }

  301.         }

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

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

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

  305.             }

  306.         }

  307.         s->mb_incr = 1;

  308.     }

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

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

  311. }

  312. 

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

  314. {

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

  316. 

  317.     if (val == 0) {

  318.         /* zero vector */

  319.         code = 0;

  320.         put_bits(&s->pb,

  321.                  mbMotionVectorTable[0][1], 

  322.                  mbMotionVectorTable[0][0]); 

  323.     } else {

  324.         bit_size = s->f_code - 1;

  325.         range = 1 << bit_size;

  326.         /* modulo encoding */

  327.         l = 16 * range;

  328.         m = 2 * l;

  329.         if (val < -l) {

  330.             val += m;

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

  332.             val -= m;

  333.         }

  334. 

  335.         if (val >= 0) {

  336.             val--;

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

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

  339.             sign = 0;

  340.         } else {

  341.             val = -val;

  342.             val--;

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

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

  345.             sign = 1;

  346.         }

  347.         put_bits(&s->pb,

  348.                  mbMotionVectorTable[code][1], 

  349.                  mbMotionVectorTable[code][0]); 

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

  351.         if (bit_size > 0) {

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

  353.         }

  354.     }

  355. }

  356. 

  357. void mpeg1_encode_init(MpegEncContext *s)

  358. {

  359.     static int done=0;

  360.     if(!done){

  361.         int f_code;

  362.         int mv;

  363. 

  364.         done=1;

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

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

  367.                 int len;

  368. 

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

  370.                 else{

  371.                     int val, bit_size, range, code;

  372. 

  373.                     bit_size = s->f_code - 1;

  374.                     range = 1 << bit_size;

  375. 

  376.                     val=mv;

  377.                     if (val < 0) 

  378.                         val = -val;

  379.                     val--;

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

  381.                     if(code<17){

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

  383.                     }else{

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

  385.                     }

  386.                 }

  387. 

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

  389.             }

  390.         }

  391.         

  392. 

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

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

  395.                 fcode_tab[mv+MAX_MV]= f_code;

  396.             }

  397.         }

  398.     }

  399.     s->mv_penalty= mv_penalty;

  400.     s->fcode_tab= fcode_tab;

  401.     s->min_qcoeff=-255;

  402.     s->max_qcoeff= 255;

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

  404.     s->inter_quant_bias= 0;

  405. }

  406.  

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

  408. {

  409.     if (component == 0) {

  410.         put_bits(

  411. 	    &s->pb, 

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

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

  414.     } else {

  415.         put_bits(

  416.             &s->pb, 

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

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

  419.     }

  420. }

  421. 

  422. static void mpeg1_encode_block(MpegEncContext *s, 

  423.                                DCTELEM *block, 

  424.                                int n)

  425. {

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

  427.     int code, component;

  428. //    RLTable *rl = &rl_mpeg1;

  429. 

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

  431. 

  432.     /* DC coef */

  433.     if (s->mb_intra) {

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

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

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

  437.         encode_dc(s, diff, component);

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

  439.         i = 1;

  440.     } else {

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

  442.            it is handled slightly differently */

  443.         level = block[0];

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

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

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

  447.                 i = 1;

  448.         } else {

  449.             i = 0;

  450.             last_non_zero = -1;

  451.             goto next_coef;

  452.         }

  453.     }

  454. 

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

  456.     last_non_zero = i - 1;

  457. 

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

  459.         j = zigzag_direct[i];

  460.         level = block[j];

  461.     next_coef:

  462. #if 0

  463.         if (level != 0)

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

  465. #endif            

  466.         /* encode using VLC */

  467.         if (level != 0) {

  468.             run = i - last_non_zero - 1;

  469. #ifdef ARCH_X86

  470.             asm volatile(

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

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

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

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

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

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

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

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

  479. 		: "g" (level)

  480. 	    );

  481. #else

  482.             sign = 0;

  483.             alevel = level;

  484.             if (alevel < 0) {

  485. 		sign = 1;

  486.                 alevel = -alevel;

  487. 	    }

  488. #endif

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

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

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

  492.             else

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

  494. 

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

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

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

  498.             } else {

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

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

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

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

  503.                 if (alevel < 128) {

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

  505.                 } else {

  506.                     if (level < 0) {

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

  508.                     } else {

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

  510.                     }

  511.                 }

  512.             }

  513.             last_non_zero = i;

  514.         }

  515.     }

  516.     /* end of block */

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

  518. }

  519. 

  520. /******************************************/

  521. /* decoding */

  522. 

  523. static VLC dc_lum_vlc;

  524. static VLC dc_chroma_vlc;

  525. static VLC mv_vlc;

  526. static VLC mbincr_vlc;

  527. static VLC mb_ptype_vlc;

  528. static VLC mb_btype_vlc;

  529. static VLC mb_pat_vlc;

  530. 

  531. void mpeg1_init_vlc(MpegEncContext *s)

  532. {

  533.     static int done = 0;

  534. 

  535.     if (!done) {

  536. 

  537.         init_vlc(&dc_lum_vlc, 9, 12, 

  538.                  vlc_dc_lum_bits, 1, 1,

  539.                  vlc_dc_lum_code, 2, 2);

  540.         init_vlc(&dc_chroma_vlc, 9, 12, 

  541.                  vlc_dc_chroma_bits, 1, 1,

  542.                  vlc_dc_chroma_code, 2, 2);

  543.         init_vlc(&mv_vlc, 9, 17, 

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

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

  546.         init_vlc(&mbincr_vlc, 9, 35, 

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

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

  549.         init_vlc(&mb_pat_vlc, 9, 63, 

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

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

  552.         

  553.         init_vlc(&mb_ptype_vlc, 6, 32, 

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

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

  556.         init_vlc(&mb_btype_vlc, 6, 32, 

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

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

  559.         init_rl(&rl_mpeg1);

  560.         init_rl(&rl_mpeg2);

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

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

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

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

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

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

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

  568.     }

  569. }

  570. 

  571. static inline int get_dmv(MpegEncContext *s)

  572. {

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

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

  575.     else

  576.         return 0;

  577. }

  578. 

  579. static inline int get_qscale(MpegEncContext *s)

  580. {

  581.     int qscale;

  582.     if (s->mpeg2) {

  583.         if (s->q_scale_type) {

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

  585.         } else {

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

  587.         }

  588.     } else {

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

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

  591.     }

  592.     return qscale;

  593. }

  594. 

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

  596. #define MT_FIELD 1

  597. #define MT_FRAME 2

  598. #define MT_16X8  2

  599. #define MT_DMV   3

  600. 

  601. static int mpeg_decode_mb(MpegEncContext *s,

  602.                           DCTELEM block[6][64])

  603. {

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

  605.     

  606.     /* skip mb handling */

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

  608.         /* read again increment */

  609.         s->mb_incr = 1;

  610.         for(;;) {

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

  612.             if (code < 0)

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

  614.             if (code >= 33) {

  615.                 if (code == 33) {

  616.                     s->mb_incr += 33;

  617.                 }

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

  619.             } else {

  620.                 s->mb_incr += code;

  621.                 break;

  622.             }

  623.         }

  624.     }

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

  626.         s->mb_x = 0;

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

  628.             return -1;

  629.         s->mb_y++;

  630.     }

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

  632. 

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

  634.         /* skip mb */

  635.         s->mb_intra = 0;

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

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

  638.         s->mv_type = MV_TYPE_16X16;

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

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

  641.             s->mv_dir = MV_DIR_FORWARD;

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

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

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

  645.         } else {

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

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

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

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

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

  651.         }

  652.         s->mb_skiped = 1;

  653.         return 0;

  654.     }

  655. 

  656.     switch(s->pict_type) {

  657.     default:

  658.     case I_TYPE:

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

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

  661.                 return -1;

  662.             mb_type = MB_QUANT | MB_INTRA;

  663.         } else {

  664.             mb_type = MB_INTRA;

  665.         }

  666.         break;

  667.     case P_TYPE:

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

  669.         if (mb_type < 0)

  670.             return -1;

  671.         break;

  672.     case B_TYPE:

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

  674.         if (mb_type < 0)

  675.             return -1;

  676.         break;

  677.     }

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

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

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

  681.         /* get additionnal motion vector type */

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

  683.             motion_type = MT_FRAME;

  684.         else

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

  686.     }

  687.     /* compute dct type */

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

  689.         !s->frame_pred_frame_dct &&

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

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

  692. #ifdef DEBUG

  693.         if (s->interlaced_dct)

  694.             printf("interlaced_dct\n");

  695. #endif

  696.     } else {

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

  698.     }

  699. 

  700.     if (mb_type & MB_QUANT) {

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

  702.     }

  703.     if (mb_type & MB_INTRA) {

  704.         if (s->concealment_motion_vectors) {

  705.             /* just parse them */

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

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

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

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

  710.         }

  711.         s->mb_intra = 1;

  712.         cbp = 0x3f;

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

  714.     } else {

  715.         s->mb_intra = 0;

  716.         cbp = 0;

  717.     }

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

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

  720.         s->mv_dir = MV_DIR_FORWARD;

  721.         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  729.         /* motion vectors */

  730.         s->mv_dir = 0;

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

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

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

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

  735.                 switch(motion_type) {

  736.                 case MT_FRAME: /* or MT_16X8 */

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

  738.                         /* MT_FRAME */

  739.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

  745.                             /* full_pel: only for mpeg1 */

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

  747.                                 val = val << 1;

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

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

  750.                         }

  751.                     } else {

  752.                         /* MT_16X8 */

  753.                         s->mv_type = MV_TYPE_16X8;

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

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

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

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

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

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

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

  761.                             }

  762.                         }

  763.                     }

  764.                     break;

  765.                 case MT_FIELD:

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

  767.                         s->mv_type = MV_TYPE_FIELD;

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

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

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

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

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

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

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

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

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

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

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

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

  780.                         }

  781.                     } else {

  782.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  790.                         }

  791.                     }

  792.                     break;

  793.                 case MT_DMV:

  794.                     {

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

  796. 

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

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

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

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

  801.                         dmx = get_dmv(s);

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

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

  804.                         dmy = get_dmv(s);

  805.                         s->mv_type = MV_TYPE_DMV;

  806.                         /* XXX: totally broken */

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

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

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

  810. 

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

  812.                             /* top -> top pred */

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

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

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

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

  817.                             m = 4 - m;

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

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

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

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

  822.                         } else {

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

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

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

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

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

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

  829.                                 /* + 2 * cur_field */;

  830.                         }

  831.                     }

  832.                     break;

  833.                 }

  834.             }

  835.         }

  836.     }

  837. 

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

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

  840.     }

  841.     

  842.     if (mb_type & MB_PAT) {

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

  844.         if (cbp < 0)

  845.             return -1;

  846.         cbp++;

  847.     }

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

  849. 

  850.     if (s->mpeg2) {

  851.         if (s->mb_intra) {

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

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

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

  855.                         return -1;

  856.                 } else {

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

  858.                 }

  859.             }

  860.         } else {

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

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

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

  864.                         return -1;

  865.                 } else {

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

  867.                 }

  868.             }

  869.         }

  870.     } else {

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

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

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

  874.                     return -1;

  875.             } else {

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

  877.             }

  878.         }

  879.     }

  880.     return 0;

  881. }

  882. 

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

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

  885. {

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

  887. 

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

  889.     if (code < 0) {

  890.         return 0xffff;

  891.     }

  892.     if (code == 0) {

  893.         return pred;

  894.     }

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

  896.     shift = fcode - 1;

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

  898.     if (shift > 0)

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

  900.     val++;

  901.     if (sign)

  902.         val = -val;

  903.     val += pred;

  904.     

  905.     /* modulo decoding */

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

  907.     m = 2 * l;

  908.     if (val < -l) {

  909.         val += m;

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

  911.         val -= m;

  912.     }

  913.     return val;

  914. }

  915. 

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

  917. {

  918.     int code, diff;

  919. 

  920.     if (component == 0) {

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

  922.     } else {

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

  924.     }

  925.     if (code < 0)

  926.         return 0xffff;

  927.     if (code == 0) {

  928.         diff = 0;

  929.     } else {

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

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

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

  933.     }

  934.     return diff;

  935. }

  936. 

  937. static int mpeg1_decode_block(MpegEncContext *s, 

  938.                                DCTELEM *block, 

  939.                                int n)

  940. {

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

  942.     int code, component;

  943.     RLTable *rl = &rl_mpeg1;

  944. 

  945.     if (s->mb_intra) {

  946.         /* DC coef */

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

  948.         diff = decode_dc(s, component);

  949.         if (diff >= 0xffff)

  950.             return -1;

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

  952.         dc += diff;

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

  954.         block[0] = dc;

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

  956.         i = 1;

  957.     } else {

  958.         int bit_cnt, v;

  959.         UINT32 bit_buf;

  960.         UINT8 *buf_ptr;

  961.         i = 0;

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

  963.         SAVE_BITS(&s->gb);

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

  965.         if (v & 2) {

  966.             run = 0;

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

  968.             FLUSH_BITS(2);

  969.             RESTORE_BITS(&s->gb);

  970.             goto add_coef;

  971.         }

  972.         RESTORE_BITS(&s->gb);

  973.     }

  974. 

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

  976.     for(;;) {

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

  978.         if (code < 0) {

  979.             return -1;

  980.         }

  981.         if (code == 112) {

  982.             break;

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

  984.             /* escape */

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

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

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

  988.             if (level == -128) {

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

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

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

  992.             }

  993.         } else {

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

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

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

  997.                 level = -level;

  998.         }

  999.         i += run;

  1000.         if (i >= 64)

  1001.             return -1;

  1002.     add_coef:

  1003.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1004. 	j = zigzag_direct[i];

  1005.         block[j] = level;

  1006.         i++;

  1007.     }

  1008.     s->block_last_index[n] = i-1;

  1009.     return 0;

  1010. }

  1011. 

  1012. /* Also does unquantization here, since I will never support mpeg2

  1013.    encoding */

  1014. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  1015.                                         DCTELEM *block, 

  1016.                                         int n)

  1017. {

  1018.     int level, i, j, run;

  1019.     int code;

  1020.     RLTable *rl = &rl_mpeg1;

  1021.     const UINT8 *scan_table;

  1022.     const UINT16 *matrix;

  1023.     int mismatch;

  1024. 

  1025.     if (s->alternate_scan)

  1026.         scan_table = ff_alternate_vertical_scan;

  1027.     else

  1028.         scan_table = zigzag_direct;

  1029.     mismatch = 1;

  1030. 

  1031.     {

  1032.         int bit_cnt, v;

  1033.         UINT32 bit_buf;

  1034.         UINT8 *buf_ptr;

  1035.         i = 0;

  1036.         if (n < 4) 

  1037.             matrix = s->inter_matrix;

  1038.         else

  1039.             matrix = s->chroma_inter_matrix;

  1040.             

  1041.         /* special case for the first coef. no need to add a second vlc table */

  1042.         SAVE_BITS(&s->gb);

  1043.         SHOW_BITS(&s->gb, v, 2);

  1044.         if (v & 2) {

  1045.             run = 0;

  1046.             level = 1 - ((v & 1) << 1);

  1047.             FLUSH_BITS(2);

  1048.             RESTORE_BITS(&s->gb);

  1049.             goto add_coef;

  1050.         }

  1051.         RESTORE_BITS(&s->gb);

  1052.     }

  1053. 

  1054.     /* now quantify & encode AC coefs */

  1055.     for(;;) {

  1056.         code = get_vlc(&s->gb, &rl->vlc);

  1057.         if (code < 0)

  1058.             return -1;

  1059.         if (code == 112) {

  1060.             break;

  1061.         } else if (code == 111) {

  1062.             /* escape */

  1063.             run = get_bits(&s->gb, 6);

  1064.             level = get_bits(&s->gb, 12);

  1065.             level = (level << 20) >> 20;

  1066.         } else {

  1067.             run = rl->table_run[code];

  1068.             level = rl->table_level[code];

  1069.             if (get_bits1(&s->gb))

  1070.                 level = -level;

  1071.         }

  1072.         i += run;

  1073.         if (i >= 64)

  1074.             return -1;

  1075.     add_coef:

  1076. 	j = scan_table[i];

  1077.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1078.         /* XXX: optimize */

  1079.         if (level > 0) {

  1080.             level = ((level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1081.         } else {

  1082.             level = ((-level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1083.             level = -level;

  1084.         }

  1085.         /* XXX: is it really necessary to saturate since the encoder

  1086.            knows whats going on ? */

  1087.         mismatch ^= level;

  1088.         block[j] = level;

  1089.         i++;

  1090.     }

  1091.     block[63] ^= (mismatch & 1);

  1092.     s->block_last_index[n] = i;

  1093.     return 0;

  1094. }

  1095. 

  1096. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  1097.                                     DCTELEM *block, 

  1098.                                     int n)

  1099. {

  1100.     int level, dc, diff, i, j, run;

  1101.     int code, component;

  1102.     RLTable *rl;

  1103.     const UINT8 *scan_table;

  1104.     const UINT16 *matrix;

  1105.     int mismatch;

  1106. 

  1107.     if (s->alternate_scan)

  1108.         scan_table = ff_alternate_vertical_scan;

  1109.     else

  1110.         scan_table = zigzag_direct;

  1111. 

  1112.     /* DC coef */

  1113.     component = (n <= 3 ? 0 : n - 4 + 1);

  1114.     diff = decode_dc(s, component);

  1115.     if (diff >= 0xffff)

  1116.         return -1;

  1117.     dc = s->last_dc[component];

  1118.     dc += diff;

  1119.     s->last_dc[component] = dc;

  1120.     block[0] = dc << (3 - s->intra_dc_precision);

  1121.     dprintf("dc=%d\n", block[0]);

  1122.     mismatch = block[0] ^ 1;

  1123.     i = 1;

  1124.     if (s->intra_vlc_format)

  1125.         rl = &rl_mpeg2;

  1126.     else

  1127.         rl = &rl_mpeg1;

  1128.     if (n < 4) 

  1129.         matrix = s->intra_matrix;

  1130.     else

  1131.         matrix = s->chroma_intra_matrix;

  1132. 

  1133.     /* now quantify & encode AC coefs */

  1134.     for(;;) {

  1135.         code = get_vlc(&s->gb, &rl->vlc);

  1136.         if (code < 0)

  1137.             return -1;

  1138.         if (code == 112) {

  1139.             break;

  1140.         } else if (code == 111) {

  1141.             /* escape */

  1142.             run = get_bits(&s->gb, 6);

  1143.             level = get_bits(&s->gb, 12);

  1144.             level = (level << 20) >> 20;

  1145.         } else {

  1146.             run = rl->table_run[code];

  1147.             level = rl->table_level[code];

  1148.             if (get_bits1(&s->gb))

  1149.                 level = -level;

  1150.         }

  1151.         i += run;

  1152.         if (i >= 64)

  1153.             return -1;

  1154. 	j = scan_table[i];

  1155.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1156.         level = (level * s->qscale * matrix[j]) / 16;

  1157.         /* XXX: is it really necessary to saturate since the encoder

  1158.            knows whats going on ? */

  1159.         mismatch ^= level;

  1160.         block[j] = level;

  1161.         i++;

  1162.     }

  1163.     block[63] ^= (mismatch & 1);

  1164.     s->block_last_index[n] = i;

  1165.     return 0;

  1166. }

  1167. 

  1168. /* compressed picture size */

  1169. #define PICTURE_BUFFER_SIZE 100000

  1170. 

  1171. typedef struct Mpeg1Context {

  1172.     MpegEncContext mpeg_enc_ctx;

  1173.     UINT32 header_state;

  1174.     int start_code; /* current start code */

  1175.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  1176.     UINT8 *buf_ptr;

  1177.     int buffer_size;

  1178.     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */

  1179.     int repeat_field; /* true if we must repeat the field */

  1180. } Mpeg1Context;

  1181. 

  1182. static int mpeg_decode_init(AVCodecContext *avctx)

  1183. {

  1184.     Mpeg1Context *s = avctx->priv_data;

  1185. 

  1186.     s->header_state = 0xff;

  1187.     s->mpeg_enc_ctx_allocated = 0;

  1188.     s->buffer_size = PICTURE_BUFFER_SIZE;

  1189.     s->start_code = -1;

  1190.     s->buf_ptr = s->buffer;

  1191.     s->mpeg_enc_ctx.picture_number = 0;

  1192.     s->repeat_field = 0;

  1193.     s->mpeg_enc_ctx.codec_id= avctx->codec->id;

  1194.     avctx->mbskip_table= s->mpeg_enc_ctx.mbskip_table;

  1195.     s->mpeg_enc_ctx.flags= avctx->flags;

  1196.     return 0;

  1197. }

  1198. 

  1199. /* return the 8 bit start code value and update the search

  1200.    state. Return -1 if no start code found */

  1201. static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1202.                            UINT32 *header_state)

  1203. {

  1204.     UINT8 *buf_ptr;

  1205.     unsigned int state, v;

  1206.     int val;

  1207. 

  1208.     state = *header_state;

  1209.     buf_ptr = *pbuf_ptr;

  1210.     while (buf_ptr < buf_end) {

  1211.         v = *buf_ptr++;

  1212.         if (state == 0x000001) {

  1213.             state = ((state << 8) | v) & 0xffffff;

  1214.             val = state;

  1215.             goto found;

  1216.         }

  1217.         state = ((state << 8) | v) & 0xffffff;

  1218.     }

  1219.     val = -1;

  1220.  found:

  1221.     *pbuf_ptr = buf_ptr;

  1222.     *header_state = state;

  1223.     return val;

  1224. }

  1225. 

  1226. static int mpeg1_decode_picture(AVCodecContext *avctx, 

  1227.                                 UINT8 *buf, int buf_size)

  1228. {

  1229.     Mpeg1Context *s1 = avctx->priv_data;

  1230.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1231.     int ref, f_code;

  1232. 

  1233.     init_get_bits(&s->gb, buf, buf_size);

  1234. 

  1235.     ref = get_bits(&s->gb, 10); /* temporal ref */

  1236.     s->pict_type = get_bits(&s->gb, 3);

  1237.     dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);

  1238.     skip_bits(&s->gb, 16);

  1239.     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {

  1240.         s->full_pel[0] = get_bits1(&s->gb);

  1241.         f_code = get_bits(&s->gb, 3);

  1242.         if (f_code == 0)

  1243.             return -1;

  1244.         s->mpeg_f_code[0][0] = f_code;

  1245.         s->mpeg_f_code[0][1] = f_code;

  1246.     }

  1247.     if (s->pict_type == B_TYPE) {

  1248.         s->full_pel[1] = get_bits1(&s->gb);

  1249.         f_code = get_bits(&s->gb, 3);

  1250.         if (f_code == 0)

  1251.             return -1;

  1252.         s->mpeg_f_code[1][0] = f_code;

  1253.         s->mpeg_f_code[1][1] = f_code;

  1254.     }

  1255.     s->y_dc_scale = 8;

  1256.     s->c_dc_scale = 8;

  1257.     s->first_slice = 1;

  1258.     return 0;

  1259. }

  1260. 

  1261. static void mpeg_decode_sequence_extension(MpegEncContext *s)

  1262. {

  1263.     int horiz_size_ext, vert_size_ext;

  1264.     int bit_rate_ext, vbv_buf_ext, low_delay;

  1265.     int frame_rate_ext_n, frame_rate_ext_d;

  1266. 

  1267.     skip_bits(&s->gb, 8); /* profil and level */

  1268.     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */

  1269.     skip_bits(&s->gb, 2); /* chroma_format */

  1270.     horiz_size_ext = get_bits(&s->gb, 2);

  1271.     vert_size_ext = get_bits(&s->gb, 2);

  1272.     s->width |= (horiz_size_ext << 12);

  1273.     s->height |= (vert_size_ext << 12);

  1274.     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */

  1275.     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;

  1276.     skip_bits1(&s->gb); /* marker */

  1277.     vbv_buf_ext = get_bits(&s->gb, 8);

  1278.     low_delay = get_bits1(&s->gb);

  1279.     frame_rate_ext_n = get_bits(&s->gb, 2);

  1280.     frame_rate_ext_d = get_bits(&s->gb, 5);

  1281.     if (frame_rate_ext_d >= 1)

  1282.         s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;

  1283.     dprintf("sequence extension\n");

  1284.     s->mpeg2 = 1;

  1285.     s->avctx->sub_id = 2; /* indicates mpeg2 found */

  1286. }

  1287. 

  1288. static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)

  1289. {

  1290.     int i, v, j;

  1291. 

  1292.     dprintf("matrix extension\n");

  1293. 

  1294.     if (get_bits1(&s->gb)) {

  1295.         for(i=0;i<64;i++) {

  1296.             v = get_bits(&s->gb, 8);

  1297.             j = zigzag_direct[i];

  1298.             s->intra_matrix[j] = v;

  1299.             s->chroma_intra_matrix[j] = v;

  1300.         }

  1301.     }

  1302.     if (get_bits1(&s->gb)) {

  1303.         for(i=0;i<64;i++) {

  1304.             v = get_bits(&s->gb, 8);

  1305.             j = zigzag_direct[i];

  1306.             s->inter_matrix[j] = v;

  1307.             s->chroma_inter_matrix[j] = v;

  1308.         }

  1309.     }

  1310.     if (get_bits1(&s->gb)) {

  1311.         for(i=0;i<64;i++) {

  1312.             v = get_bits(&s->gb, 8);

  1313.             j = zigzag_direct[i];

  1314.             s->chroma_intra_matrix[j] = v;

  1315.         }

  1316.     }

  1317.     if (get_bits1(&s->gb)) {

  1318.         for(i=0;i<64;i++) {

  1319.             v = get_bits(&s->gb, 8);

  1320.             j = zigzag_direct[i];

  1321.             s->chroma_inter_matrix[j] = v;

  1322.         }

  1323.     }

  1324. }

  1325. 

  1326. static void mpeg_decode_picture_coding_extension(MpegEncContext *s)

  1327. {

  1328.     s->full_pel[0] = s->full_pel[1] = 0;

  1329.     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);

  1330.     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);

  1331.     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);

  1332.     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);

  1333.     s->intra_dc_precision = get_bits(&s->gb, 2);

  1334.     s->picture_structure = get_bits(&s->gb, 2);

  1335.     s->top_field_first = get_bits1(&s->gb);

  1336.     s->frame_pred_frame_dct = get_bits1(&s->gb);

  1337.     s->concealment_motion_vectors = get_bits1(&s->gb);

  1338.     s->q_scale_type = get_bits1(&s->gb);

  1339.     s->intra_vlc_format = get_bits1(&s->gb);

  1340.     s->alternate_scan = get_bits1(&s->gb);

  1341.     s->repeat_first_field = get_bits1(&s->gb);

  1342.     s->chroma_420_type = get_bits1(&s->gb);

  1343.     s->progressive_frame = get_bits1(&s->gb);

  1344.     /* composite display not parsed */

  1345.     dprintf("intra_dc_precision=%d\n", s->intra_dc_precision);

  1346.     dprintf("picture_structure=%d\n", s->picture_structure);

  1347.     dprintf("top field first=%d\n", s->top_field_first);

  1348.     dprintf("repeat first field=%d\n", s->repeat_first_field);

  1349.     dprintf("conceal=%d\n", s->concealment_motion_vectors);

  1350.     dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);

  1351.     dprintf("alternate_scan=%d\n", s->alternate_scan);

  1352.     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);

  1353.     dprintf("progressive_frame=%d\n", s->progressive_frame);

  1354. }

  1355. 

  1356. static void mpeg_decode_extension(AVCodecContext *avctx, 

  1357.                                   UINT8 *buf, int buf_size)

  1358. {

  1359.     Mpeg1Context *s1 = avctx->priv_data;

  1360.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1361.     int ext_type;

  1362. 

  1363.     init_get_bits(&s->gb, buf, buf_size);

  1364.     

  1365.     ext_type = get_bits(&s->gb, 4);

  1366.     switch(ext_type) {

  1367.     case 0x1:

  1368.         /* sequence ext */

  1369.         mpeg_decode_sequence_extension(s);

  1370.         break;

  1371.     case 0x3:

  1372.         /* quant matrix extension */

  1373.         mpeg_decode_quant_matrix_extension(s);

  1374.         break;

  1375.     case 0x8:

  1376.         /* picture extension */

  1377.         mpeg_decode_picture_coding_extension(s);

  1378.         break;

  1379.     }

  1380. }

  1381. 

  1382. /* return 1 if end of frame */

  1383. static int mpeg_decode_slice(AVCodecContext *avctx, 

  1384.                               AVPicture *pict,

  1385.                               int start_code,

  1386.                               UINT8 *buf, int buf_size)

  1387. {

  1388.     Mpeg1Context *s1 = avctx->priv_data;

  1389.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1390.     int ret;

  1391. 

  1392.     start_code = (start_code - 1) & 0xff;

  1393.     if (start_code >= s->mb_height)

  1394.         return -1;

  1395.     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);

  1396.     s->last_dc[1] = s->last_dc[0];

  1397.     s->last_dc[2] = s->last_dc[0];

  1398.     memset(s->last_mv, 0, sizeof(s->last_mv));

  1399.     s->mb_x = -1;

  1400.     s->mb_y = start_code;

  1401.     s->mb_incr = 0;

  1402.     /* start frame decoding */

  1403.     if (s->first_slice) {

  1404.         s->first_slice = 0;

  1405.         MPV_frame_start(s);

  1406.     }

  1407. 

  1408.     init_get_bits(&s->gb, buf, buf_size);

  1409. 

  1410.     s->qscale = get_qscale(s);

  1411.     /* extra slice info */

  1412.     while (get_bits1(&s->gb) != 0) {

  1413.         skip_bits(&s->gb, 8);

  1414.     }

  1415. 

  1416.     for(;;) {

  1417.         clear_blocks(s->block[0]);

  1418.         emms_c();

  1419.         ret = mpeg_decode_mb(s, s->block);

  1420.         dprintf("ret=%d\n", ret);

  1421.         if (ret < 0)

  1422.             return -1;

  1423.         if (ret == 1)

  1424.             break;

  1425.         MPV_decode_mb(s, s->block);

  1426.     }

  1427.     emms_c();

  1428. 

  1429.     /* end of slice reached */

  1430.     if (s->mb_x == (s->mb_width - 1) &&

  1431.         s->mb_y == (s->mb_height - 1)) {

  1432.         /* end of image */

  1433.         UINT8 **picture;

  1434. 

  1435.         MPV_frame_end(s);

  1436. 

  1437.         /* XXX: incorrect reported qscale for mpeg2 */

  1438.         if (s->pict_type == B_TYPE) {

  1439.             picture = s->current_picture;

  1440.             avctx->quality = s->qscale;

  1441.         } else {

  1442.             /* latency of 1 frame for I and P frames */

  1443.             /* XXX: use another variable than picture_number */

  1444.             if (s->picture_number == 0) {

  1445.                 picture = NULL;

  1446.             } else {

  1447.                 picture = s->last_picture;

  1448.                 avctx->quality = s->last_qscale;

  1449.             }

  1450.             s->last_qscale = s->qscale;

  1451.             s->picture_number++;

  1452.         }

  1453.         if (picture) {

  1454.             pict->data[0] = picture[0];

  1455.             pict->data[1] = picture[1];

  1456.             pict->data[2] = picture[2];

  1457.             pict->linesize[0] = s->linesize;

  1458.             pict->linesize[1] = s->linesize / 2;

  1459.             pict->linesize[2] = s->linesize / 2;

  1460.             return 1;

  1461.         } else {

  1462.             return 0;

  1463.         }

  1464.     } else {

  1465.         return 0;

  1466.     }

  1467. }

  1468. 

  1469. static int mpeg1_decode_sequence(AVCodecContext *avctx, 

  1470.                                  UINT8 *buf, int buf_size)

  1471. {

  1472.     Mpeg1Context *s1 = avctx->priv_data;

  1473.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1474.     int width, height, i, v, j;

  1475. 

  1476.     init_get_bits(&s->gb, buf, buf_size);

  1477. 

  1478.     width = get_bits(&s->gb, 12);

  1479.     height = get_bits(&s->gb, 12);

  1480.     skip_bits(&s->gb, 4);

  1481.     s->frame_rate_index = get_bits(&s->gb, 4);

  1482.     if (s->frame_rate_index == 0)

  1483.         return -1;

  1484.     s->bit_rate = get_bits(&s->gb, 18) * 400;

  1485.     if (get_bits1(&s->gb) == 0) /* marker */

  1486.         return -1;

  1487.     if (width <= 0 || height <= 0 ||

  1488.         (width % 2) != 0 || (height % 2) != 0)

  1489.         return -1;

  1490.     if (width != s->width ||

  1491.         height != s->height) {

  1492.         /* start new mpeg1 context decoding */

  1493.         s->out_format = FMT_MPEG1;

  1494.         if (s1->mpeg_enc_ctx_allocated) {

  1495.             MPV_common_end(s);

  1496.         }

  1497.         s->width = width;

  1498.         s->height = height;

  1499.         s->has_b_frames = 1;

  1500.         s->avctx = avctx;

  1501.         avctx->width = width;

  1502.         avctx->height = height;

  1503.         if (s->frame_rate_index >= 9) {

  1504.             /* at least give a valid frame rate (some old mpeg1 have this) */

  1505.             avctx->frame_rate = 25 * FRAME_RATE_BASE;

  1506.         } else {

  1507.             avctx->frame_rate = frame_rate_tab[s->frame_rate_index];

  1508.         }

  1509.         s->frame_rate = avctx->frame_rate;

  1510.         avctx->bit_rate = s->bit_rate;

  1511.         

  1512.         if (MPV_common_init(s) < 0)

  1513.             return -1;

  1514.         mpeg1_init_vlc(s);

  1515.         s1->mpeg_enc_ctx_allocated = 1;

  1516.     }

  1517. 

  1518.     skip_bits(&s->gb, 10); /* vbv_buffer_size */

  1519.     skip_bits(&s->gb, 1);

  1520. 

  1521.     /* get matrix */

  1522.     if (get_bits1(&s->gb)) {

  1523.         for(i=0;i<64;i++) {

  1524.             v = get_bits(&s->gb, 8);

  1525.             j = zigzag_direct[i];

  1526.             s->intra_matrix[j] = v;

  1527.             s->chroma_intra_matrix[j] = v;

  1528.         }

  1529. #ifdef DEBUG

  1530.         dprintf("intra matrix present\n");

  1531.         for(i=0;i<64;i++)

  1532.             dprintf(" %d", s->intra_matrix[zigzag_direct[i]]);

  1533.         printf("\n");

  1534. #endif

  1535.     } else {

  1536.         for(i=0;i<64;i++) {

  1537.             v = default_intra_matrix[i];

  1538.             s->intra_matrix[i] = v;

  1539.             s->chroma_intra_matrix[i] = v;

  1540.         }

  1541.     }

  1542.     if (get_bits1(&s->gb)) {

  1543.         for(i=0;i<64;i++) {

  1544.             v = get_bits(&s->gb, 8);

  1545.             j = zigzag_direct[i];

  1546.             s->inter_matrix[j] = v;

  1547.             s->chroma_inter_matrix[j] = v;

  1548.         }

  1549. #ifdef DEBUG

  1550.         dprintf("non intra matrix present\n");

  1551.         for(i=0;i<64;i++)

  1552.             dprintf(" %d", s->inter_matrix[zigzag_direct[i]]);

  1553.         printf("\n");

  1554. #endif

  1555.     } else {

  1556.         for(i=0;i<64;i++) {

  1557.             v = default_non_intra_matrix[i];

  1558.             s->inter_matrix[i] = v;

  1559.             s->chroma_inter_matrix[i] = v;

  1560.         }

  1561.     }

  1562. 

  1563.     /* we set mpeg2 parameters so that it emulates mpeg1 */

  1564.     s->progressive_sequence = 1;

  1565.     s->progressive_frame = 1;

  1566.     s->picture_structure = PICT_FRAME;

  1567.     s->frame_pred_frame_dct = 1;

  1568.     s->mpeg2 = 0;

  1569.     avctx->sub_id = 1; /* indicates mpeg1 */

  1570.     return 0;

  1571. }

  1572. 

  1573. /* handle buffering and image synchronisation */

  1574. static int mpeg_decode_frame(AVCodecContext *avctx, 

  1575.                              void *data, int *data_size,

  1576.                              UINT8 *buf, int buf_size)

  1577. {

  1578.     Mpeg1Context *s = avctx->priv_data;

  1579.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1580.     int len, start_code_found, ret, code, start_code, input_size;

  1581.     AVPicture *picture = data;

  1582.     MpegEncContext *s2 = &s->mpeg_enc_ctx;

  1583.             

  1584.     dprintf("fill_buffer\n");

  1585. 

  1586.     *data_size = 0;

  1587. 

  1588.     /* special case for last picture */

  1589.     if (buf_size == 0) {

  1590.         if (s2->picture_number > 0) {

  1591.             picture->data[0] = s2->next_picture[0];

  1592.             picture->data[1] = s2->next_picture[1];

  1593.             picture->data[2] = s2->next_picture[2];

  1594.             picture->linesize[0] = s2->linesize;

  1595.             picture->linesize[1] = s2->linesize / 2;

  1596.             picture->linesize[2] = s2->linesize / 2;

  1597.             *data_size = sizeof(AVPicture);

  1598.         }

  1599.         return 0;

  1600.     }

  1601. 

  1602.     buf_ptr = buf;

  1603.     buf_end = buf + buf_size;

  1604. 

  1605. #if 0    

  1606.     if (s->repeat_field % 2 == 1) { 

  1607.         s->repeat_field++;

  1608.         //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,

  1609.         //        s2->picture_number, s->repeat_field);

  1610.         if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {

  1611.             *data_size = sizeof(AVPicture);

  1612.             goto the_end;

  1613.         }

  1614.     }

  1615. #endif

  1616.     while (buf_ptr < buf_end) {

  1617.         buf_start = buf_ptr;

  1618.         /* find start next code */

  1619.         code = find_start_code(&buf_ptr, buf_end, &s->header_state);

  1620.         if (code >= 0) {

  1621.             start_code_found = 1;

  1622.         } else {

  1623.             start_code_found = 0;

  1624.         }

  1625.         /* copy to buffer */

  1626.         len = buf_ptr - buf_start;

  1627.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1628.             /* data too big : flush */

  1629.             s->buf_ptr = s->buffer;

  1630.             if (start_code_found)

  1631.                 s->start_code = code;

  1632.         } else {

  1633.             memcpy(s->buf_ptr, buf_start, len);

  1634.             s->buf_ptr += len;

  1635.             

  1636.             if (start_code_found) {

  1637.                 /* prepare data for next start code */

  1638.                 input_size = s->buf_ptr - s->buffer;

  1639.                 start_code = s->start_code;

  1640.                 s->buf_ptr = s->buffer;

  1641.                 s->start_code = code;

  1642.                 switch(start_code) {

  1643.                 case SEQ_START_CODE:

  1644.                     mpeg1_decode_sequence(avctx, s->buffer, 

  1645.                                           input_size);

  1646.                     break;

  1647.                             

  1648.                 case PICTURE_START_CODE:

  1649.                     /* we have a complete image : we try to decompress it */

  1650.                     mpeg1_decode_picture(avctx, 

  1651.                                          s->buffer, input_size);

  1652.                     break;

  1653.                 case EXT_START_CODE:

  1654.                     mpeg_decode_extension(avctx,

  1655.                                           s->buffer, input_size);

  1656.                     break;

  1657.                 default:

  1658.                     if (start_code >= SLICE_MIN_START_CODE &&

  1659.                         start_code <= SLICE_MAX_START_CODE) {

  1660.                         ret = mpeg_decode_slice(avctx, picture,

  1661.                                                 start_code, s->buffer, input_size);

  1662.                         if (ret == 1) {

  1663.                             /* got a picture: exit */

  1664.                             /* first check if we must repeat the frame */

  1665.                             avctx->repeat_pict = 0;

  1666. #if 0

  1667.                             if (s2->progressive_frame && s2->repeat_first_field) {

  1668.                                 //fprintf(stderr,"\nRepeat this frame: %d! pict: %d",avctx->frame_number,s2->picture_number);

  1669.                                 //s2->repeat_first_field = 0;

  1670.                                 //s2->progressive_frame = 0;

  1671.                                 if (++s->repeat_field > 2)

  1672.                                     s->repeat_field = 0;

  1673.                                 avctx->repeat_pict = 1;

  1674.                             }

  1675. #endif                      

  1676.                             if (s2->repeat_first_field) {

  1677.                                 if (s2->progressive_sequence) {

  1678.                                     if (s2->top_field_first)

  1679.                                         avctx->repeat_pict = 4;

  1680.                                     else

  1681.                                         avctx->repeat_pict = 2;

  1682.                                 } else if (s2->progressive_frame) {

  1683.                                     avctx->repeat_pict = 1;

  1684.                                 }

  1685.                             }         

  1686.                             *data_size = sizeof(AVPicture);

  1687.                             goto the_end;

  1688.                         }

  1689.                     }

  1690.                     break;

  1691.                 }

  1692.             }

  1693.         }

  1694.     }

  1695.  the_end:

  1696.     return buf_ptr - buf;

  1697. }

  1698. 

  1699. static int mpeg_decode_end(AVCodecContext *avctx)

  1700. {

  1701.     Mpeg1Context *s = avctx->priv_data;

  1702. 

  1703.     if (s->mpeg_enc_ctx_allocated)

  1704.         MPV_common_end(&s->mpeg_enc_ctx);

  1705.     return 0;

  1706. }

  1707. 

  1708. AVCodec mpeg_decoder = {

  1709.     "mpegvideo",

  1710.     CODEC_TYPE_VIDEO,

  1711.     CODEC_ID_MPEG1VIDEO,

  1712.     sizeof(Mpeg1Context),

  1713.     mpeg_decode_init,

  1714.     NULL,

  1715.     mpeg_decode_end,

  1716.     mpeg_decode_frame,

  1717. };