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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. static void common_init(MpegEncContext *s)

  188. {

  189.     s->y_dc_scale_table=

  190.     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;

  191. }

  192. 

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

  194. {

  195.     mpeg1_encode_sequence_header(s);

  196. 

  197.     /* mpeg1 picture header */

  198.     put_header(s, PICTURE_START_CODE);

  199.     /* temporal reference */

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

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

  202.     s->fake_picture_number++;

  203.     

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

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

  206.     

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

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

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

  210.     }

  211.     

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

  213.     

  214.     /* only one slice */

  215.     put_header(s, SLICE_MIN_START_CODE);

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

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

  218. }

  219. 

  220. void mpeg1_encode_mb(MpegEncContext *s,

  221.                      DCTELEM block[6][64],

  222.                      int motion_x, int motion_y)

  223. {

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

  225. 

  226.     mb_x = s->mb_x;

  227.     mb_y = s->mb_y;

  228. 

  229.     /* compute cbp */

  230.     cbp = 0;

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

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

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

  234.     }

  235. 

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

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

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

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

  240.         s->mb_incr++;

  241.     } else {

  242.         /* output mb incr */

  243.         mb_incr = s->mb_incr;

  244. 

  245.         while (mb_incr > 33) {

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

  247.             mb_incr -= 33;

  248.         }

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

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

  251.         

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

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

  254.         } else {

  255.             if (s->mb_intra) {

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

  257.             } else {

  258.                 if (cbp != 0) {

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

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

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

  262.                     } else {

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

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

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

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

  267.                     }

  268.                 } else {

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

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

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

  272.                 }

  273.             }

  274.         }

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

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

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

  278.             }

  279.         }

  280.         s->mb_incr = 1;

  281.     }

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

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

  284. }

  285. 

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

  287. {

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

  289. 

  290.     if (val == 0) {

  291.         /* zero vector */

  292.         code = 0;

  293.         put_bits(&s->pb,

  294.                  mbMotionVectorTable[0][1], 

  295.                  mbMotionVectorTable[0][0]); 

  296.     } else {

  297.         bit_size = s->f_code - 1;

  298.         range = 1 << bit_size;

  299.         /* modulo encoding */

  300.         l = 16 * range;

  301.         m = 2 * l;

  302.         if (val < -l) {

  303.             val += m;

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

  305.             val -= m;

  306.         }

  307. 

  308.         if (val >= 0) {

  309.             val--;

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

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

  312.             sign = 0;

  313.         } else {

  314.             val = -val;

  315.             val--;

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

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

  318.             sign = 1;

  319.         }

  320.         put_bits(&s->pb,

  321.                  mbMotionVectorTable[code][1], 

  322.                  mbMotionVectorTable[code][0]); 

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

  324.         if (bit_size > 0) {

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

  326.         }

  327.     }

  328. }

  329. 

  330. void ff_mpeg1_encode_init(MpegEncContext *s)

  331. {

  332.     static int done=0;

  333. 

  334.     common_init(s);

  335. 

  336.     if(!done){

  337.         int f_code;

  338.         int mv;

  339. 	int i;

  340. 

  341.         done=1;

  342.         init_rl(&rl_mpeg1);

  343. 	

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

  345. 	{

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

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

  348. 	}

  349. 

  350. 	/* build unified dc encoding tables */

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

  352. 	{

  353. 		int adiff, index;

  354. 		int bits, code;

  355. 		int diff=i;

  356. 

  357. 		adiff = ABS(diff);

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

  359. 		index = vlc_dc_table[adiff];

  360. 

  361. 		bits= vlc_dc_lum_bits[index] + index;

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

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

  364. 		

  365. 		bits= vlc_dc_chroma_bits[index] + index;

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

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

  368. 	}

  369. 

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

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

  372.                 int len;

  373. 

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

  375.                 else{

  376.                     int val, bit_size, range, code;

  377. 

  378.                     bit_size = s->f_code - 1;

  379.                     range = 1 << bit_size;

  380. 

  381.                     val=mv;

  382.                     if (val < 0) 

  383.                         val = -val;

  384.                     val--;

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

  386.                     if(code<17){

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

  388.                     }else{

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

  390.                     }

  391.                 }

  392. 

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

  394.             }

  395.         }

  396.         

  397. 

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

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

  400.                 fcode_tab[mv+MAX_MV]= f_code;

  401.             }

  402.         }

  403.     }

  404.     s->mv_penalty= mv_penalty;

  405.     s->fcode_tab= fcode_tab;

  406.     s->min_qcoeff=-255;

  407.     s->max_qcoeff= 255;

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

  409.     s->inter_quant_bias= 0;

  410. }

  411. 

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

  413. {

  414.     if (component == 0) {

  415.         put_bits(

  416. 	    &s->pb, 

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

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

  419.     } else {

  420.         put_bits(

  421.             &s->pb, 

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

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

  424.     }

  425. }

  426. 

  427. static void mpeg1_encode_block(MpegEncContext *s, 

  428.                                DCTELEM *block, 

  429.                                int n)

  430. {

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

  432.     int code, component;

  433. //    RLTable *rl = &rl_mpeg1;

  434. 

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

  436. 

  437.     /* DC coef */

  438.     if (s->mb_intra) {

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

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

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

  442.         encode_dc(s, diff, component);

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

  444.         i = 1;

  445.     } else {

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

  447.            it is handled slightly differently */

  448.         level = block[0];

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

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

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

  452.                 i = 1;

  453.         } else {

  454.             i = 0;

  455.             last_non_zero = -1;

  456.             goto next_coef;

  457.         }

  458.     }

  459. 

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

  461.     last_non_zero = i - 1;

  462. 

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

  464.         j = zigzag_direct[i];

  465.         level = block[j];

  466.     next_coef:

  467. #if 0

  468.         if (level != 0)

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

  470. #endif            

  471.         /* encode using VLC */

  472.         if (level != 0) {

  473.             run = i - last_non_zero - 1;

  474. #ifdef ARCH_X86

  475.             asm volatile(

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

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

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

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

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

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

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

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

  484. 		: "g" (level)

  485. 	    );

  486. #else

  487.             sign = 0;

  488.             alevel = level;

  489.             if (alevel < 0) {

  490. 		sign = 1;

  491.                 alevel = -alevel;

  492. 	    }

  493. #endif

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

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

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

  497.             else

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

  499. 

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

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

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

  503.             } else {

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

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

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

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

  508.                 if (alevel < 128) {

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

  510.                 } else {

  511.                     if (level < 0) {

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

  513.                     } else {

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

  515.                     }

  516.                 }

  517.             }

  518.             last_non_zero = i;

  519.         }

  520.     }

  521.     /* end of block */

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

  523. }

  524. 

  525. /******************************************/

  526. /* decoding */

  527. 

  528. static VLC dc_lum_vlc;

  529. static VLC dc_chroma_vlc;

  530. static VLC mv_vlc;

  531. static VLC mbincr_vlc;

  532. static VLC mb_ptype_vlc;

  533. static VLC mb_btype_vlc;

  534. static VLC mb_pat_vlc;

  535. 

  536. void mpeg1_init_vlc(MpegEncContext *s)

  537. {

  538.     static int done = 0;

  539. 

  540.     if (!done) {

  541.         done = 1;

  542. 

  543.         init_vlc(&dc_lum_vlc, 9, 12, 

  544.                  vlc_dc_lum_bits, 1, 1,

  545.                  vlc_dc_lum_code, 2, 2);

  546.         init_vlc(&dc_chroma_vlc, 9, 12, 

  547.                  vlc_dc_chroma_bits, 1, 1,

  548.                  vlc_dc_chroma_code, 2, 2);

  549.         init_vlc(&mv_vlc, 9, 17, 

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

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

  552.         init_vlc(&mbincr_vlc, 9, 35, 

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

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

  555.         init_vlc(&mb_pat_vlc, 9, 63, 

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

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

  558.         

  559.         init_vlc(&mb_ptype_vlc, 6, 32, 

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

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

  562.         init_vlc(&mb_btype_vlc, 6, 32, 

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

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

  565.         init_rl(&rl_mpeg1);

  566.         init_rl(&rl_mpeg2);

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

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

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

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

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

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

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

  574.     }

  575. }

  576. 

  577. static inline int get_dmv(MpegEncContext *s)

  578. {

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

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

  581.     else

  582.         return 0;

  583. }

  584. 

  585. static inline int get_qscale(MpegEncContext *s)

  586. {

  587.     int qscale;

  588.     if (s->mpeg2) {

  589.         if (s->q_scale_type) {

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

  591.         } else {

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

  593.         }

  594.     } else {

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

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

  597.     }

  598.     return qscale;

  599. }

  600. 

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

  602. #define MT_FIELD 1

  603. #define MT_FRAME 2

  604. #define MT_16X8  2

  605. #define MT_DMV   3

  606. 

  607. static int mpeg_decode_mb(MpegEncContext *s,

  608.                           DCTELEM block[6][64])

  609. {

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

  611.     

  612.     /* skip mb handling */

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

  614.         /* read again increment */

  615.         s->mb_incr = 1;

  616.         for(;;) {

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

  618.             if (code < 0)

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

  620.             if (code >= 33) {

  621.                 if (code == 33) {

  622.                     s->mb_incr += 33;

  623.                 }

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

  625.             } else {

  626.                 s->mb_incr += code;

  627.                 break;

  628.             }

  629.         }

  630.     }

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

  632.         s->mb_x = 0;

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

  634.             return -1;

  635.         s->mb_y++;

  636.     }

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

  638. 

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

  640.         /* skip mb */

  641.         s->mb_intra = 0;

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

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

  644.         s->mv_type = MV_TYPE_16X16;

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

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

  647.             s->mv_dir = MV_DIR_FORWARD;

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

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

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

  651.         } else {

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

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

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

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

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

  657.         }

  658.         s->mb_skiped = 1;

  659.         return 0;

  660.     }

  661. 

  662.     switch(s->pict_type) {

  663.     default:

  664.     case I_TYPE:

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

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

  667.                 return -1;

  668.             mb_type = MB_QUANT | MB_INTRA;

  669.         } else {

  670.             mb_type = MB_INTRA;

  671.         }

  672.         break;

  673.     case P_TYPE:

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

  675.         if (mb_type < 0)

  676.             return -1;

  677.         break;

  678.     case B_TYPE:

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

  680.         if (mb_type < 0)

  681.             return -1;

  682.         break;

  683.     }

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

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

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

  687.         /* get additionnal motion vector type */

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

  689.             motion_type = MT_FRAME;

  690.         else

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

  692.     }

  693.     /* compute dct type */

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

  695.         !s->frame_pred_frame_dct &&

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

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

  698. #ifdef DEBUG

  699.         if (s->interlaced_dct)

  700.             printf("interlaced_dct\n");

  701. #endif

  702.     } else {

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

  704.     }

  705. 

  706.     if (mb_type & MB_QUANT) {

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

  708.     }

  709.     if (mb_type & MB_INTRA) {

  710.         if (s->concealment_motion_vectors) {

  711.             /* just parse them */

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

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

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

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

  716.         }

  717.         s->mb_intra = 1;

  718.         cbp = 0x3f;

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

  720.     } else {

  721.         s->mb_intra = 0;

  722.         cbp = 0;

  723.     }

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

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

  726.         s->mv_dir = MV_DIR_FORWARD;

  727.         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  735.         /* motion vectors */

  736.         s->mv_dir = 0;

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

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

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

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

  741.                 switch(motion_type) {

  742.                 case MT_FRAME: /* or MT_16X8 */

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

  744.                         /* MT_FRAME */

  745.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

  751.                             /* full_pel: only for mpeg1 */

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

  753.                                 val = val << 1;

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

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

  756.                         }

  757.                     } else {

  758.                         /* MT_16X8 */

  759.                         s->mv_type = MV_TYPE_16X8;

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

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

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

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

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

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

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

  767.                             }

  768.                         }

  769.                     }

  770.                     break;

  771.                 case MT_FIELD:

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

  773.                         s->mv_type = MV_TYPE_FIELD;

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

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

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

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

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

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

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

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

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

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

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

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

  786.                         }

  787.                     } else {

  788.                         s->mv_type = MV_TYPE_16X16;

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

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

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

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

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

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

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

  796.                         }

  797.                     }

  798.                     break;

  799.                 case MT_DMV:

  800.                     {

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

  802. 

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

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

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

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

  807.                         dmx = get_dmv(s);

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

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

  810.                         dmy = get_dmv(s);

  811.                         s->mv_type = MV_TYPE_DMV;

  812.                         /* XXX: totally broken */

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

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

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

  816. 

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

  818.                             /* top -> top pred */

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

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

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

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

  823.                             m = 4 - m;

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

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

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

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

  828.                         } else {

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

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

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

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

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

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

  835.                                 /* + 2 * cur_field */;

  836.                         }

  837.                     }

  838.                     break;

  839.                 }

  840.             }

  841.         }

  842.     }

  843. 

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

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

  846.     }

  847.     

  848.     if (mb_type & MB_PAT) {

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

  850.         if (cbp < 0)

  851.             return -1;

  852.         cbp++;

  853.     }

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

  855. 

  856.     if (s->mpeg2) {

  857.         if (s->mb_intra) {

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

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

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

  861.                         return -1;

  862.                 } else {

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

  864.                 }

  865.             }

  866.         } else {

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

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

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

  870.                         return -1;

  871.                 } else {

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

  873.                 }

  874.             }

  875.         }

  876.     } else {

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

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

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

  880.                     return -1;

  881.             } else {

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

  883.             }

  884.         }

  885.     }

  886.     return 0;

  887. }

  888. 

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

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

  891. {

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

  893. 

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

  895.     if (code < 0) {

  896.         return 0xffff;

  897.     }

  898.     if (code == 0) {

  899.         return pred;

  900.     }

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

  902.     shift = fcode - 1;

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

  904.     if (shift > 0)

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

  906.     val++;

  907.     if (sign)

  908.         val = -val;

  909.     val += pred;

  910.     

  911.     /* modulo decoding */

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

  913.     m = 2 * l;

  914.     if (val < -l) {

  915.         val += m;

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

  917.         val -= m;

  918.     }

  919.     return val;

  920. }

  921. 

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

  923. {

  924.     int code, diff;

  925. 

  926.     if (component == 0) {

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

  928.     } else {

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

  930.     }

  931.     if (code < 0)

  932.         return 0xffff;

  933.     if (code == 0) {

  934.         diff = 0;

  935.     } else {

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

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

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

  939.     }

  940.     return diff;

  941. }

  942. 

  943. static int mpeg1_decode_block(MpegEncContext *s, 

  944.                                DCTELEM *block, 

  945.                                int n)

  946. {

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

  948.     int code, component;

  949.     RLTable *rl = &rl_mpeg1;

  950. 

  951.     if (s->mb_intra) {

  952.         /* DC coef */

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

  954.         diff = decode_dc(s, component);

  955.         if (diff >= 0xffff)

  956.             return -1;

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

  958.         dc += diff;

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

  960.         block[0] = dc;

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

  962.         i = 1;

  963.     } else {

  964.         int v;

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

  966.         i = 0;

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

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

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

  970.         if (v & 2) {

  971.             run = 0;

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

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

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

  975.             goto add_coef;

  976.         }

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

  978.     }

  979. 

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

  981.     for(;;) {

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

  983.         if (code < 0) {

  984.             return -1;

  985.         }

  986.         if (code == 112) {

  987.             break;

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

  989.             /* escape */

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

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

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

  993.             if (level == -128) {

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

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

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

  997.             }

  998.         } else {

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

  1000.             level = rl->table_level[code];

  1001.             if (get_bits1(&s->gb))

  1002.                 level = -level;

  1003.         }

  1004.         i += run;

  1005.         if (i >= 64)

  1006.             return -1;

  1007.     add_coef:

  1008.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1009. 	j = zigzag_direct[i];

  1010.         block[j] = level;

  1011.         i++;

  1012.     }

  1013.     s->block_last_index[n] = i-1;

  1014.     return 0;

  1015. }

  1016. 

  1017. /* Also does unquantization here, since I will never support mpeg2

  1018.    encoding */

  1019. static int mpeg2_decode_block_non_intra(MpegEncContext *s, 

  1020.                                         DCTELEM *block, 

  1021.                                         int n)

  1022. {

  1023.     int level, i, j, run;

  1024.     int code;

  1025.     RLTable *rl = &rl_mpeg1;

  1026.     const UINT8 *scan_table;

  1027.     const UINT16 *matrix;

  1028.     int mismatch;

  1029. 

  1030.     if (s->alternate_scan)

  1031.         scan_table = ff_alternate_vertical_scan;

  1032.     else

  1033.         scan_table = zigzag_direct;

  1034.     mismatch = 1;

  1035. 

  1036.     {

  1037.         int v;

  1038.         OPEN_READER(re, &s->gb);

  1039.         i = 0;

  1040.         if (n < 4)

  1041.             matrix = s->inter_matrix;

  1042.         else

  1043.             matrix = s->chroma_inter_matrix;

  1044. 

  1045.         /* special case for the first coef. no need to add a second vlc table */

  1046.         UPDATE_CACHE(re, &s->gb);

  1047.         v= SHOW_UBITS(re, &s->gb, 2);

  1048.         if (v & 2) {

  1049.             run = 0;

  1050.             level = 1 - ((v & 1) << 1);

  1051.             SKIP_BITS(re, &s->gb, 2);

  1052.             CLOSE_READER(re, &s->gb);

  1053.             goto add_coef;

  1054.         }

  1055.         CLOSE_READER(re, &s->gb);

  1056.     }

  1057. 

  1058.     /* now quantify & encode AC coefs */

  1059.     for(;;) {

  1060.         code = get_vlc(&s->gb, &rl->vlc);

  1061.         if (code < 0)

  1062.             return -1;

  1063.         if (code == 112) {

  1064.             break;

  1065.         } else if (code == 111) {

  1066.             /* escape */

  1067.             run = get_bits(&s->gb, 6);

  1068.             level = get_bits(&s->gb, 12);

  1069.             level = (level << 20) >> 20;

  1070.         } else {

  1071.             run = rl->table_run[code];

  1072.             level = rl->table_level[code];

  1073.             if (get_bits1(&s->gb))

  1074.                 level = -level;

  1075.         }

  1076.         i += run;

  1077.         if (i >= 64)

  1078.             return -1;

  1079.     add_coef:

  1080. 	j = scan_table[i];

  1081.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1082.         /* XXX: optimize */

  1083.         if (level > 0) {

  1084.             level = ((level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1085.         } else {

  1086.             level = ((-level * 2 + 1) * s->qscale * matrix[j]) >> 5;

  1087.             level = -level;

  1088.         }

  1089.         /* XXX: is it really necessary to saturate since the encoder

  1090.            knows whats going on ? */

  1091.         mismatch ^= level;

  1092.         block[j] = level;

  1093.         i++;

  1094.     }

  1095.     block[63] ^= (mismatch & 1);

  1096.     s->block_last_index[n] = i;

  1097.     return 0;

  1098. }

  1099. 

  1100. static int mpeg2_decode_block_intra(MpegEncContext *s, 

  1101.                                     DCTELEM *block, 

  1102.                                     int n)

  1103. {

  1104.     int level, dc, diff, i, j, run;

  1105.     int code, component;

  1106.     RLTable *rl;

  1107.     const UINT8 *scan_table;

  1108.     const UINT16 *matrix;

  1109.     int mismatch;

  1110. 

  1111.     if (s->alternate_scan)

  1112.         scan_table = ff_alternate_vertical_scan;

  1113.     else

  1114.         scan_table = zigzag_direct;

  1115. 

  1116.     /* DC coef */

  1117.     component = (n <= 3 ? 0 : n - 4 + 1);

  1118.     diff = decode_dc(s, component);

  1119.     if (diff >= 0xffff)

  1120.         return -1;

  1121.     dc = s->last_dc[component];

  1122.     dc += diff;

  1123.     s->last_dc[component] = dc;

  1124.     block[0] = dc << (3 - s->intra_dc_precision);

  1125.     dprintf("dc=%d\n", block[0]);

  1126.     mismatch = block[0] ^ 1;

  1127.     i = 1;

  1128.     if (s->intra_vlc_format)

  1129.         rl = &rl_mpeg2;

  1130.     else

  1131.         rl = &rl_mpeg1;

  1132.     if (n < 4) 

  1133.         matrix = s->intra_matrix;

  1134.     else

  1135.         matrix = s->chroma_intra_matrix;

  1136. 

  1137.     /* now quantify & encode AC coefs */

  1138.     for(;;) {

  1139.         code = get_vlc(&s->gb, &rl->vlc);

  1140.         if (code < 0)

  1141.             return -1;

  1142.         if (code == 112) {

  1143.             break;

  1144.         } else if (code == 111) {

  1145.             /* escape */

  1146.             run = get_bits(&s->gb, 6);

  1147.             level = get_bits(&s->gb, 12);

  1148.             level = (level << 20) >> 20;

  1149.         } else {

  1150.             run = rl->table_run[code];

  1151.             level = rl->table_level[code];

  1152.             if (get_bits1(&s->gb))

  1153.                 level = -level;

  1154.         }

  1155.         i += run;

  1156.         if (i >= 64)

  1157.             return -1;

  1158. 	j = scan_table[i];

  1159.         dprintf("%d: run=%d level=%d\n", n, run, level);

  1160.         level = (level * s->qscale * matrix[j]) / 16;

  1161.         /* XXX: is it really necessary to saturate since the encoder

  1162.            knows whats going on ? */

  1163.         mismatch ^= level;

  1164.         block[j] = level;

  1165.         i++;

  1166.     }

  1167.     block[63] ^= (mismatch & 1);

  1168.     s->block_last_index[n] = i;

  1169.     return 0;

  1170. }

  1171. 

  1172. /* compressed picture size */

  1173. #define PICTURE_BUFFER_SIZE 100000

  1174. 

  1175. typedef struct Mpeg1Context {

  1176.     MpegEncContext mpeg_enc_ctx;

  1177.     UINT32 header_state;

  1178.     int start_code; /* current start code */

  1179.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  1180.     UINT8 *buf_ptr;

  1181.     int buffer_size;

  1182.     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */

  1183.     int repeat_field; /* true if we must repeat the field */

  1184. } Mpeg1Context;

  1185. 

  1186. static int mpeg_decode_init(AVCodecContext *avctx)

  1187. {

  1188.     Mpeg1Context *s = avctx->priv_data;

  1189.     

  1190.     common_init(&s->mpeg_enc_ctx);

  1191. 

  1192.     s->header_state = 0xff;

  1193.     s->mpeg_enc_ctx_allocated = 0;

  1194.     s->buffer_size = PICTURE_BUFFER_SIZE;

  1195.     s->start_code = -1;

  1196.     s->buf_ptr = s->buffer;

  1197.     s->mpeg_enc_ctx.picture_number = 0;

  1198.     s->repeat_field = 0;

  1199.     s->mpeg_enc_ctx.codec_id= avctx->codec->id;

  1200.     avctx->mbskip_table= s->mpeg_enc_ctx.mbskip_table;

  1201.     s->mpeg_enc_ctx.flags= avctx->flags;

  1202.     return 0;

  1203. }

  1204. 

  1205. /* return the 8 bit start code value and update the search

  1206.    state. Return -1 if no start code found */

  1207. static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1208.                            UINT32 *header_state)

  1209. {

  1210.     UINT8 *buf_ptr;

  1211.     unsigned int state, v;

  1212.     int val;

  1213. 

  1214.     state = *header_state;

  1215.     buf_ptr = *pbuf_ptr;

  1216.     while (buf_ptr < buf_end) {

  1217.         v = *buf_ptr++;

  1218.         if (state == 0x000001) {

  1219.             state = ((state << 8) | v) & 0xffffff;

  1220.             val = state;

  1221.             goto found;

  1222.         }

  1223.         state = ((state << 8) | v) & 0xffffff;

  1224.     }

  1225.     val = -1;

  1226.  found:

  1227.     *pbuf_ptr = buf_ptr;

  1228.     *header_state = state;

  1229.     return val;

  1230. }

  1231. 

  1232. static int mpeg1_decode_picture(AVCodecContext *avctx, 

  1233.                                 UINT8 *buf, int buf_size)

  1234. {

  1235.     Mpeg1Context *s1 = avctx->priv_data;

  1236.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1237.     int ref, f_code;

  1238. 

  1239.     init_get_bits(&s->gb, buf, buf_size);

  1240. 

  1241.     ref = get_bits(&s->gb, 10); /* temporal ref */

  1242.     s->pict_type = get_bits(&s->gb, 3);

  1243.     dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);

  1244.     skip_bits(&s->gb, 16);

  1245.     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {

  1246.         s->full_pel[0] = get_bits1(&s->gb);

  1247.         f_code = get_bits(&s->gb, 3);

  1248.         if (f_code == 0)

  1249.             return -1;

  1250.         s->mpeg_f_code[0][0] = f_code;

  1251.         s->mpeg_f_code[0][1] = f_code;

  1252.     }

  1253.     if (s->pict_type == B_TYPE) {

  1254.         s->full_pel[1] = get_bits1(&s->gb);

  1255.         f_code = get_bits(&s->gb, 3);

  1256.         if (f_code == 0)

  1257.             return -1;

  1258.         s->mpeg_f_code[1][0] = f_code;

  1259.         s->mpeg_f_code[1][1] = f_code;

  1260.     }

  1261.     s->y_dc_scale = 8;

  1262.     s->c_dc_scale = 8;

  1263.     s->first_slice = 1;

  1264.     return 0;

  1265. }

  1266. 

  1267. static void mpeg_decode_sequence_extension(MpegEncContext *s)

  1268. {

  1269.     int horiz_size_ext, vert_size_ext;

  1270.     int bit_rate_ext, vbv_buf_ext, low_delay;

  1271.     int frame_rate_ext_n, frame_rate_ext_d;

  1272. 

  1273.     skip_bits(&s->gb, 8); /* profil and level */

  1274.     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */

  1275.     skip_bits(&s->gb, 2); /* chroma_format */

  1276.     horiz_size_ext = get_bits(&s->gb, 2);

  1277.     vert_size_ext = get_bits(&s->gb, 2);

  1278.     s->width |= (horiz_size_ext << 12);

  1279.     s->height |= (vert_size_ext << 12);

  1280.     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */

  1281.     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;

  1282.     skip_bits1(&s->gb); /* marker */

  1283.     vbv_buf_ext = get_bits(&s->gb, 8);

  1284.     low_delay = get_bits1(&s->gb);

  1285.     frame_rate_ext_n = get_bits(&s->gb, 2);

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

  1287.     if (frame_rate_ext_d >= 1)

  1288.         s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;

  1289.     dprintf("sequence extension\n");

  1290.     s->mpeg2 = 1;

  1291.     s->avctx->sub_id = 2; /* indicates mpeg2 found */

  1292. }

  1293. 

  1294. static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)

  1295. {

  1296.     int i, v, j;

  1297. 

  1298.     dprintf("matrix extension\n");

  1299. 

  1300.     if (get_bits1(&s->gb)) {

  1301.         for(i=0;i<64;i++) {

  1302.             v = get_bits(&s->gb, 8);

  1303.             j = zigzag_direct[i];

  1304.             s->intra_matrix[j] = v;

  1305.             s->chroma_intra_matrix[j] = v;

  1306.         }

  1307.     }

  1308.     if (get_bits1(&s->gb)) {

  1309.         for(i=0;i<64;i++) {

  1310.             v = get_bits(&s->gb, 8);

  1311.             j = zigzag_direct[i];

  1312.             s->inter_matrix[j] = v;

  1313.             s->chroma_inter_matrix[j] = v;

  1314.         }

  1315.     }

  1316.     if (get_bits1(&s->gb)) {

  1317.         for(i=0;i<64;i++) {

  1318.             v = get_bits(&s->gb, 8);

  1319.             j = zigzag_direct[i];

  1320.             s->chroma_intra_matrix[j] = v;

  1321.         }

  1322.     }

  1323.     if (get_bits1(&s->gb)) {

  1324.         for(i=0;i<64;i++) {

  1325.             v = get_bits(&s->gb, 8);

  1326.             j = zigzag_direct[i];

  1327.             s->chroma_inter_matrix[j] = v;

  1328.         }

  1329.     }

  1330. }

  1331. 

  1332. static void mpeg_decode_picture_coding_extension(MpegEncContext *s)

  1333. {

  1334.     s->full_pel[0] = s->full_pel[1] = 0;

  1335.     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);

  1336.     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);

  1337.     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);

  1338.     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);

  1339.     s->intra_dc_precision = get_bits(&s->gb, 2);

  1340.     s->picture_structure = get_bits(&s->gb, 2);

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

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

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

  1344.     s->q_scale_type = get_bits1(&s->gb);

  1345.     s->intra_vlc_format = get_bits1(&s->gb);

  1346.     s->alternate_scan = get_bits1(&s->gb);

  1347.     s->repeat_first_field = get_bits1(&s->gb);

  1348.     s->chroma_420_type = get_bits1(&s->gb);

  1349.     s->progressive_frame = get_bits1(&s->gb);

  1350.     /* composite display not parsed */

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

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

  1353.     dprintf("top field first=%d\n", s->top_field_first);

  1354.     dprintf("repeat first field=%d\n", s->repeat_first_field);

  1355.     dprintf("conceal=%d\n", s->concealment_motion_vectors);

  1356.     dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);

  1357.     dprintf("alternate_scan=%d\n", s->alternate_scan);

  1358.     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);

  1359.     dprintf("progressive_frame=%d\n", s->progressive_frame);

  1360. }

  1361. 

  1362. static void mpeg_decode_extension(AVCodecContext *avctx, 

  1363.                                   UINT8 *buf, int buf_size)

  1364. {

  1365.     Mpeg1Context *s1 = avctx->priv_data;

  1366.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1367.     int ext_type;

  1368. 

  1369.     init_get_bits(&s->gb, buf, buf_size);

  1370.     

  1371.     ext_type = get_bits(&s->gb, 4);

  1372.     switch(ext_type) {

  1373.     case 0x1:

  1374.         /* sequence ext */

  1375.         mpeg_decode_sequence_extension(s);

  1376.         break;

  1377.     case 0x3:

  1378.         /* quant matrix extension */

  1379.         mpeg_decode_quant_matrix_extension(s);

  1380.         break;

  1381.     case 0x8:

  1382.         /* picture extension */

  1383.         mpeg_decode_picture_coding_extension(s);

  1384.         break;

  1385.     }

  1386. }

  1387. 

  1388. /* return 1 if end of frame */

  1389. static int mpeg_decode_slice(AVCodecContext *avctx, 

  1390.                               AVPicture *pict,

  1391.                               int start_code,

  1392.                               UINT8 *buf, int buf_size)

  1393. {

  1394.     Mpeg1Context *s1 = avctx->priv_data;

  1395.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1396.     int ret;

  1397. 

  1398.     start_code = (start_code - 1) & 0xff;

  1399.     if (start_code >= s->mb_height)

  1400.         return -1;

  1401.     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);

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

  1403.     s->last_dc[2] = s->last_dc[0];

  1404.     memset(s->last_mv, 0, sizeof(s->last_mv));

  1405.     s->mb_x = -1;

  1406.     s->mb_y = start_code;

  1407.     s->mb_incr = 0;

  1408.     /* start frame decoding */

  1409.     if (s->first_slice) {

  1410.         s->first_slice = 0;

  1411.         MPV_frame_start(s);

  1412.     }

  1413. 

  1414.     init_get_bits(&s->gb, buf, buf_size);

  1415. 

  1416.     s->qscale = get_qscale(s);

  1417.     /* extra slice info */

  1418.     while (get_bits1(&s->gb) != 0) {

  1419.         skip_bits(&s->gb, 8);

  1420.     }

  1421. 

  1422.     for(;;) {

  1423.         clear_blocks(s->block[0]);

  1424.         emms_c();

  1425.         ret = mpeg_decode_mb(s, s->block);

  1426.         dprintf("ret=%d\n", ret);

  1427.         if (ret < 0)

  1428.             return -1;

  1429.         if (ret == 1)

  1430.             break;

  1431.         MPV_decode_mb(s, s->block);

  1432.     }

  1433.     emms_c();

  1434. 

  1435.     /* end of slice reached */

  1436.     if (s->mb_x == (s->mb_width - 1) &&

  1437.         s->mb_y == (s->mb_height - 1)) {

  1438.         /* end of image */

  1439.         UINT8 **picture;

  1440. 

  1441.         MPV_frame_end(s);

  1442. 

  1443.         /* XXX: incorrect reported qscale for mpeg2 */

  1444.         if (s->pict_type == B_TYPE) {

  1445.             picture = s->current_picture;

  1446.             avctx->quality = s->qscale;

  1447.         } else {

  1448.             /* latency of 1 frame for I and P frames */

  1449.             /* XXX: use another variable than picture_number */

  1450.             if (s->picture_number == 0) {

  1451.                 picture = NULL;

  1452.             } else {

  1453.                 picture = s->last_picture;

  1454.                 avctx->quality = s->last_qscale;

  1455.             }

  1456.             s->last_qscale = s->qscale;

  1457.             s->picture_number++;

  1458.         }

  1459.         if (picture) {

  1460.             pict->data[0] = picture[0];

  1461.             pict->data[1] = picture[1];

  1462.             pict->data[2] = picture[2];

  1463.             pict->linesize[0] = s->linesize;

  1464.             pict->linesize[1] = s->linesize / 2;

  1465.             pict->linesize[2] = s->linesize / 2;

  1466.             return 1;

  1467.         } else {

  1468.             return 0;

  1469.         }

  1470.     } else {

  1471.         return 0;

  1472.     }

  1473. }

  1474. 

  1475. static int mpeg1_decode_sequence(AVCodecContext *avctx, 

  1476.                                  UINT8 *buf, int buf_size)

  1477. {

  1478.     Mpeg1Context *s1 = avctx->priv_data;

  1479.     MpegEncContext *s = &s1->mpeg_enc_ctx;

  1480.     int width, height, i, v, j;

  1481. 

  1482.     init_get_bits(&s->gb, buf, buf_size);

  1483. 

  1484.     width = get_bits(&s->gb, 12);

  1485.     height = get_bits(&s->gb, 12);

  1486.     skip_bits(&s->gb, 4);

  1487.     s->frame_rate_index = get_bits(&s->gb, 4);

  1488.     if (s->frame_rate_index == 0)

  1489.         return -1;

  1490.     s->bit_rate = get_bits(&s->gb, 18) * 400;

  1491.     if (get_bits1(&s->gb) == 0) /* marker */

  1492.         return -1;

  1493.     if (width <= 0 || height <= 0 ||

  1494.         (width % 2) != 0 || (height % 2) != 0)

  1495.         return -1;

  1496.     if (width != s->width ||

  1497.         height != s->height) {

  1498.         /* start new mpeg1 context decoding */

  1499.         s->out_format = FMT_MPEG1;

  1500.         if (s1->mpeg_enc_ctx_allocated) {

  1501.             MPV_common_end(s);

  1502.         }

  1503.         s->width = width;

  1504.         s->height = height;

  1505.         s->has_b_frames = 1;

  1506.         s->avctx = avctx;

  1507.         avctx->width = width;

  1508.         avctx->height = height;

  1509.         if (s->frame_rate_index >= 9) {

  1510.             /* at least give a valid frame rate (some old mpeg1 have this) */

  1511.             avctx->frame_rate = 25 * FRAME_RATE_BASE;

  1512.         } else {

  1513.             avctx->frame_rate = frame_rate_tab[s->frame_rate_index];

  1514.         }

  1515.         s->frame_rate = avctx->frame_rate;

  1516.         avctx->bit_rate = s->bit_rate;

  1517.         

  1518.         if (MPV_common_init(s) < 0)

  1519.             return -1;

  1520.         mpeg1_init_vlc(s);

  1521.         s1->mpeg_enc_ctx_allocated = 1;

  1522.     }

  1523. 

  1524.     skip_bits(&s->gb, 10); /* vbv_buffer_size */

  1525.     skip_bits(&s->gb, 1);

  1526. 

  1527.     /* get matrix */

  1528.     if (get_bits1(&s->gb)) {

  1529.         for(i=0;i<64;i++) {

  1530.             v = get_bits(&s->gb, 8);

  1531.             j = zigzag_direct[i];

  1532.             s->intra_matrix[j] = v;

  1533.             s->chroma_intra_matrix[j] = v;

  1534.         }

  1535. #ifdef DEBUG

  1536.         dprintf("intra matrix present\n");

  1537.         for(i=0;i<64;i++)

  1538.             dprintf(" %d", s->intra_matrix[zigzag_direct[i]]);

  1539.         printf("\n");

  1540. #endif

  1541.     } else {

  1542.         for(i=0;i<64;i++) {

  1543.             v = default_intra_matrix[i];

  1544.             s->intra_matrix[i] = v;

  1545.             s->chroma_intra_matrix[i] = v;

  1546.         }

  1547.     }

  1548.     if (get_bits1(&s->gb)) {

  1549.         for(i=0;i<64;i++) {

  1550.             v = get_bits(&s->gb, 8);

  1551.             j = zigzag_direct[i];

  1552.             s->inter_matrix[j] = v;

  1553.             s->chroma_inter_matrix[j] = v;

  1554.         }

  1555. #ifdef DEBUG

  1556.         dprintf("non intra matrix present\n");

  1557.         for(i=0;i<64;i++)

  1558.             dprintf(" %d", s->inter_matrix[zigzag_direct[i]]);

  1559.         printf("\n");

  1560. #endif

  1561.     } else {

  1562.         for(i=0;i<64;i++) {

  1563.             v = default_non_intra_matrix[i];

  1564.             s->inter_matrix[i] = v;

  1565.             s->chroma_inter_matrix[i] = v;

  1566.         }

  1567.     }

  1568. 

  1569.     /* we set mpeg2 parameters so that it emulates mpeg1 */

  1570.     s->progressive_sequence = 1;

  1571.     s->progressive_frame = 1;

  1572.     s->picture_structure = PICT_FRAME;

  1573.     s->frame_pred_frame_dct = 1;

  1574.     s->mpeg2 = 0;

  1575.     avctx->sub_id = 1; /* indicates mpeg1 */

  1576.     return 0;

  1577. }

  1578. 

  1579. /* handle buffering and image synchronisation */

  1580. static int mpeg_decode_frame(AVCodecContext *avctx, 

  1581.                              void *data, int *data_size,

  1582.                              UINT8 *buf, int buf_size)

  1583. {

  1584.     Mpeg1Context *s = avctx->priv_data;

  1585.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1586.     int len, start_code_found, ret, code, start_code, input_size;

  1587.     AVPicture *picture = data;

  1588.     MpegEncContext *s2 = &s->mpeg_enc_ctx;

  1589.             

  1590.     dprintf("fill_buffer\n");

  1591. 

  1592.     *data_size = 0;

  1593. 

  1594.     /* special case for last picture */

  1595.     if (buf_size == 0) {

  1596.         if (s2->picture_number > 0) {

  1597.             picture->data[0] = s2->next_picture[0];

  1598.             picture->data[1] = s2->next_picture[1];

  1599.             picture->data[2] = s2->next_picture[2];

  1600.             picture->linesize[0] = s2->linesize;

  1601.             picture->linesize[1] = s2->linesize / 2;

  1602.             picture->linesize[2] = s2->linesize / 2;

  1603.             *data_size = sizeof(AVPicture);

  1604.         }

  1605.         return 0;

  1606.     }

  1607. 

  1608.     buf_ptr = buf;

  1609.     buf_end = buf + buf_size;

  1610. 

  1611. #if 0    

  1612.     if (s->repeat_field % 2 == 1) { 

  1613.         s->repeat_field++;

  1614.         //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,

  1615.         //        s2->picture_number, s->repeat_field);

  1616.         if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {

  1617.             *data_size = sizeof(AVPicture);

  1618.             goto the_end;

  1619.         }

  1620.     }

  1621. #endif

  1622.     while (buf_ptr < buf_end) {

  1623.         buf_start = buf_ptr;

  1624.         /* find start next code */

  1625.         code = find_start_code(&buf_ptr, buf_end, &s->header_state);

  1626.         if (code >= 0) {

  1627.             start_code_found = 1;

  1628.         } else {

  1629.             start_code_found = 0;

  1630.         }

  1631.         /* copy to buffer */

  1632.         len = buf_ptr - buf_start;

  1633.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1634.             /* data too big : flush */

  1635.             s->buf_ptr = s->buffer;

  1636.             if (start_code_found)

  1637.                 s->start_code = code;

  1638.         } else {

  1639.             memcpy(s->buf_ptr, buf_start, len);

  1640.             s->buf_ptr += len;

  1641.             

  1642.             if (start_code_found) {

  1643.                 /* prepare data for next start code */

  1644.                 input_size = s->buf_ptr - s->buffer;

  1645.                 start_code = s->start_code;

  1646.                 s->buf_ptr = s->buffer;

  1647.                 s->start_code = code;

  1648.                 switch(start_code) {

  1649.                 case SEQ_START_CODE:

  1650.                     mpeg1_decode_sequence(avctx, s->buffer, 

  1651.                                           input_size);

  1652.                     break;

  1653.                             

  1654.                 case PICTURE_START_CODE:

  1655.                     /* we have a complete image : we try to decompress it */

  1656.                     mpeg1_decode_picture(avctx, 

  1657.                                          s->buffer, input_size);

  1658.                     break;

  1659.                 case EXT_START_CODE:

  1660.                     mpeg_decode_extension(avctx,

  1661.                                           s->buffer, input_size);

  1662.                     break;

  1663.                 default:

  1664.                     if (start_code >= SLICE_MIN_START_CODE &&

  1665.                         start_code <= SLICE_MAX_START_CODE) {

  1666.                         ret = mpeg_decode_slice(avctx, picture,

  1667.                                                 start_code, s->buffer, input_size);

  1668.                         if (ret == 1) {

  1669.                             /* got a picture: exit */

  1670.                             /* first check if we must repeat the frame */

  1671.                             avctx->repeat_pict = 0;

  1672. #if 0

  1673.                             if (s2->progressive_frame && s2->repeat_first_field) {

  1674.                                 //fprintf(stderr,"\nRepeat this frame: %d! pict: %d",avctx->frame_number,s2->picture_number);

  1675.                                 //s2->repeat_first_field = 0;

  1676.                                 //s2->progressive_frame = 0;

  1677.                                 if (++s->repeat_field > 2)

  1678.                                     s->repeat_field = 0;

  1679.                                 avctx->repeat_pict = 1;

  1680.                             }

  1681. #endif                      

  1682.                             if (s2->repeat_first_field) {

  1683.                                 if (s2->progressive_sequence) {

  1684.                                     if (s2->top_field_first)

  1685.                                         avctx->repeat_pict = 4;

  1686.                                     else

  1687.                                         avctx->repeat_pict = 2;

  1688.                                 } else if (s2->progressive_frame) {

  1689.                                     avctx->repeat_pict = 1;

  1690.                                 }

  1691.                             }         

  1692.                             *data_size = sizeof(AVPicture);

  1693.                             goto the_end;

  1694.                         }

  1695.                     }

  1696.                     break;

  1697.                 }

  1698.             }

  1699.         }

  1700.     }

  1701.  the_end:

  1702.     return buf_ptr - buf;

  1703. }

  1704. 

  1705. static int mpeg_decode_end(AVCodecContext *avctx)

  1706. {

  1707.     Mpeg1Context *s = avctx->priv_data;

  1708. 

  1709.     if (s->mpeg_enc_ctx_allocated)

  1710.         MPV_common_end(&s->mpeg_enc_ctx);

  1711.     return 0;

  1712. }

  1713. 

  1714. AVCodec mpeg_decoder = {

  1715.     "mpegvideo",

  1716.     CODEC_TYPE_VIDEO,

  1717.     CODEC_ID_MPEG1VIDEO,

  1718.     sizeof(Mpeg1Context),

  1719.     mpeg_decode_init,

  1720.     NULL,

  1721.     mpeg_decode_end,

  1722.     mpeg_decode_frame,

  1723. };