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FFmpeg/libavcodec/mjpeg.c

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  1. /*

  2.  * MJPEG encoder and decoder

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

  4.  *

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

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

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

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

  9.  *

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

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

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

  13.  * GNU General Public License for more details.

  14.  *

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

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

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

  18.  */

  19. //#define DEBUG

  20. #include "avcodec.h"

  21. #include "dsputil.h"

  22. #include "mpegvideo.h"

  23. 

  24. typedef struct MJpegContext {

  25.     UINT8 huff_size_dc_luminance[12];

  26.     UINT16 huff_code_dc_luminance[12];

  27.     UINT8 huff_size_dc_chrominance[12];

  28.     UINT16 huff_code_dc_chrominance[12];

  29. 

  30.     UINT8 huff_size_ac_luminance[256];

  31.     UINT16 huff_code_ac_luminance[256];

  32.     UINT8 huff_size_ac_chrominance[256];

  33.     UINT16 huff_code_ac_chrominance[256];

  34. } MJpegContext;

  35. 

  36. #define SOF0 0xc0

  37. #define SOI 0xd8

  38. #define EOI 0xd9

  39. #define DQT 0xdb

  40. #define DHT 0xc4

  41. #define SOS 0xda

  42. 

  43. #if 0

  44. /* These are the sample quantization tables given in JPEG spec section K.1.

  45.  * The spec says that the values given produce "good" quality, and

  46.  * when divided by 2, "very good" quality.

  47.  */

  48. static const unsigned char std_luminance_quant_tbl[64] = {

  49.     16,  11,  10,  16,  24,  40,  51,  61,

  50.     12,  12,  14,  19,  26,  58,  60,  55,

  51.     14,  13,  16,  24,  40,  57,  69,  56,

  52.     14,  17,  22,  29,  51,  87,  80,  62,

  53.     18,  22,  37,  56,  68, 109, 103,  77,

  54.     24,  35,  55,  64,  81, 104, 113,  92,

  55.     49,  64,  78,  87, 103, 121, 120, 101,

  56.     72,  92,  95,  98, 112, 100, 103,  99

  57. };

  58. static const unsigned char std_chrominance_quant_tbl[64] = {

  59.     17,  18,  24,  47,  99,  99,  99,  99,

  60.     18,  21,  26,  66,  99,  99,  99,  99,

  61.     24,  26,  56,  99,  99,  99,  99,  99,

  62.     47,  66,  99,  99,  99,  99,  99,  99,

  63.     99,  99,  99,  99,  99,  99,  99,  99,

  64.     99,  99,  99,  99,  99,  99,  99,  99,

  65.     99,  99,  99,  99,  99,  99,  99,  99,

  66.     99,  99,  99,  99,  99,  99,  99,  99

  67. };

  68. #endif

  69. 

  70. /* Set up the standard Huffman tables (cf. JPEG standard section K.3) */

  71. /* IMPORTANT: these are only valid for 8-bit data precision! */

  72. static const UINT8 bits_dc_luminance[17] =

  73. { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };

  74. static const UINT8 val_dc_luminance[] =

  75. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  76. 

  77. static const UINT8 bits_dc_chrominance[17] =

  78. { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };

  79. static const UINT8 val_dc_chrominance[] =

  80. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  81. 

  82. static const UINT8 bits_ac_luminance[17] =

  83. { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };

  84. static const UINT8 val_ac_luminance[] =

  85. { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

  86.   0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

  87.   0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,

  88.   0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,

  89.   0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,

  90.   0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,

  91.   0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

  92.   0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

  93.   0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

  94.   0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

  95.   0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

  96.   0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

  97.   0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

  98.   0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,

  99.   0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,

  100.   0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,

  101.   0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,

  102.   0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,

  103.   0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,

  104.   0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  105.   0xf9, 0xfa 

  106. };

  107. 

  108. static const UINT8 bits_ac_chrominance[17] =

  109. { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };

  110. 

  111. static const UINT8 val_ac_chrominance[] =

  112. { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

  113.   0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

  114.   0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

  115.   0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,

  116.   0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,

  117.   0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,

  118.   0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,

  119.   0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

  120.   0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

  121.   0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

  122.   0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

  123.   0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

  124.   0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,

  125.   0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,

  126.   0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,

  127.   0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,

  128.   0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,

  129.   0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,

  130.   0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,

  131.   0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  132.   0xf9, 0xfa 

  133. };

  134. 

  135. 

  136. /* isn't this function nicer than the one in the libjpeg ? */

  137. static void build_huffman_codes(UINT8 *huff_size, UINT16 *huff_code,

  138.                                 const UINT8 *bits_table, const UINT8 *val_table)

  139. {

  140.     int i, j, k,nb, code, sym;

  141. 

  142.     code = 0;

  143.     k = 0;

  144.     for(i=1;i<=16;i++) {

  145.         nb = bits_table[i];

  146.         for(j=0;j<nb;j++) {

  147.             sym = val_table[k++];

  148.             huff_size[sym] = i;

  149.             huff_code[sym] = code;

  150.             code++;

  151.         }

  152.         code <<= 1;

  153.     }

  154. }

  155. 

  156. int mjpeg_init(MpegEncContext *s)

  157. {

  158.     MJpegContext *m;

  159.     

  160.     m = malloc(sizeof(MJpegContext));

  161.     if (!m)

  162.         return -1;

  163. 

  164.     /* build all the huffman tables */

  165.     build_huffman_codes(m->huff_size_dc_luminance,

  166.                         m->huff_code_dc_luminance,

  167.                         bits_dc_luminance,

  168.                         val_dc_luminance);

  169.     build_huffman_codes(m->huff_size_dc_chrominance,

  170.                         m->huff_code_dc_chrominance,

  171.                         bits_dc_chrominance,

  172.                         val_dc_chrominance);

  173.     build_huffman_codes(m->huff_size_ac_luminance,

  174.                         m->huff_code_ac_luminance,

  175.                         bits_ac_luminance,

  176.                         val_ac_luminance);

  177.     build_huffman_codes(m->huff_size_ac_chrominance,

  178.                         m->huff_code_ac_chrominance,

  179.                         bits_ac_chrominance,

  180.                         val_ac_chrominance);

  181.     

  182.     s->mjpeg_ctx = m;

  183.     return 0;

  184. }

  185. 

  186. void mjpeg_close(MpegEncContext *s)

  187. {

  188.     free(s->mjpeg_ctx);

  189. }

  190. 

  191. static inline void put_marker(PutBitContext *p, int code)

  192. {

  193.     put_bits(p, 8, 0xff);

  194.     put_bits(p, 8, code);

  195. }

  196. 

  197. /* table_class: 0 = DC coef, 1 = AC coefs */

  198. static int put_huffman_table(MpegEncContext *s, int table_class, int table_id,

  199.                              const UINT8 *bits_table, const UINT8 *value_table)

  200. {

  201.     PutBitContext *p = &s->pb;

  202.     int n, i;

  203. 

  204.     put_bits(p, 4, table_class);

  205.     put_bits(p, 4, table_id);

  206. 

  207.     n = 0;

  208.     for(i=1;i<=16;i++) {

  209.         n += bits_table[i];

  210.         put_bits(p, 8, bits_table[i]);

  211.     }

  212. 

  213.     for(i=0;i<n;i++)

  214.         put_bits(p, 8, value_table[i]);

  215. 

  216.     return n + 17;

  217. }

  218. 

  219. static void jpeg_table_header(MpegEncContext *s)

  220. {

  221.     PutBitContext *p = &s->pb;

  222.     int i, j, size;

  223.     UINT8 *ptr;

  224. 

  225.     /* quant matrixes */

  226.     put_marker(p, DQT);

  227.     put_bits(p, 16, 2 + 1 * (1 + 64));

  228.     put_bits(p, 4, 0); /* 8 bit precision */

  229.     put_bits(p, 4, 0); /* table 0 */

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

  231.         j = zigzag_direct[i];

  232.         put_bits(p, 8, s->intra_matrix[j]);

  233.     }

  234. #if 0

  235.     put_bits(p, 4, 0); /* 8 bit precision */

  236.     put_bits(p, 4, 1); /* table 1 */

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

  238.         j = zigzag_direct[i];

  239.         put_bits(p, 8, s->chroma_intra_matrix[j]);

  240.     }

  241. #endif

  242. 

  243.     /* huffman table */

  244.     put_marker(p, DHT);

  245.     flush_put_bits(p);

  246.     ptr = p->buf_ptr;

  247.     put_bits(p, 16, 0); /* patched later */

  248.     size = 2;

  249.     size += put_huffman_table(s, 0, 0, bits_dc_luminance, val_dc_luminance);

  250.     size += put_huffman_table(s, 0, 1, bits_dc_chrominance, val_dc_chrominance);

  251.     

  252.     size += put_huffman_table(s, 1, 0, bits_ac_luminance, val_ac_luminance);

  253.     size += put_huffman_table(s, 1, 1, bits_ac_chrominance, val_ac_chrominance);

  254.     ptr[0] = size >> 8;

  255.     ptr[1] = size;

  256. }

  257. 

  258. void mjpeg_picture_header(MpegEncContext *s)

  259. {

  260.     put_marker(&s->pb, SOI);

  261. 

  262.     jpeg_table_header(s);

  263. 

  264.     put_marker(&s->pb, SOF0);

  265. 

  266.     put_bits(&s->pb, 16, 17);

  267.     put_bits(&s->pb, 8, 8); /* 8 bits/component */

  268.     put_bits(&s->pb, 16, s->height);

  269.     put_bits(&s->pb, 16, s->width);

  270.     put_bits(&s->pb, 8, 3); /* 3 components */

  271.     

  272.     /* Y component */

  273.     put_bits(&s->pb, 8, 1); /* component number */

  274.     put_bits(&s->pb, 4, 2); /* H factor */

  275.     put_bits(&s->pb, 4, 2); /* V factor */

  276.     put_bits(&s->pb, 8, 0); /* select matrix */

  277.     

  278.     /* Cb component */

  279.     put_bits(&s->pb, 8, 2); /* component number */

  280.     put_bits(&s->pb, 4, 1); /* H factor */

  281.     put_bits(&s->pb, 4, 1); /* V factor */

  282.     put_bits(&s->pb, 8, 0); /* select matrix */

  283. 

  284.     /* Cr component */

  285.     put_bits(&s->pb, 8, 3); /* component number */

  286.     put_bits(&s->pb, 4, 1); /* H factor */

  287.     put_bits(&s->pb, 4, 1); /* V factor */

  288.     put_bits(&s->pb, 8, 0); /* select matrix */

  289. 

  290.     /* scan header */

  291.     put_marker(&s->pb, SOS);

  292.     put_bits(&s->pb, 16, 12); /* length */

  293.     put_bits(&s->pb, 8, 3); /* 3 components */

  294.     

  295.     /* Y component */

  296.     put_bits(&s->pb, 8, 1); /* index */

  297.     put_bits(&s->pb, 4, 0); /* DC huffman table index */

  298.     put_bits(&s->pb, 4, 0); /* AC huffman table index */

  299.     

  300.     /* Cb component */

  301.     put_bits(&s->pb, 8, 2); /* index */

  302.     put_bits(&s->pb, 4, 1); /* DC huffman table index */

  303.     put_bits(&s->pb, 4, 1); /* AC huffman table index */

  304.     

  305.     /* Cr component */

  306.     put_bits(&s->pb, 8, 3); /* index */

  307.     put_bits(&s->pb, 4, 1); /* DC huffman table index */

  308.     put_bits(&s->pb, 4, 1); /* AC huffman table index */

  309. 

  310.     put_bits(&s->pb, 8, 0); /* Ss (not used) */

  311.     put_bits(&s->pb, 8, 63); /* Se (not used) */

  312.     put_bits(&s->pb, 8, 0); /* (not used) */

  313. }

  314. 

  315. void mjpeg_picture_trailer(MpegEncContext *s)

  316. {

  317.     jflush_put_bits(&s->pb);

  318.     put_marker(&s->pb, EOI);

  319. }

  320. 

  321. static inline void encode_dc(MpegEncContext *s, int val, 

  322.                              UINT8 *huff_size, UINT16 *huff_code)

  323. {

  324.     int mant, nbits;

  325. 

  326.     if (val == 0) {

  327.         jput_bits(&s->pb, huff_size[0], huff_code[0]);

  328.     } else {

  329.         mant = val;

  330.         if (val < 0) {

  331.             val = -val;

  332.             mant--;

  333.         }

  334.         

  335.         /* compute the log (XXX: optimize) */

  336.         nbits = 0;

  337.         while (val != 0) {

  338.             val = val >> 1;

  339.             nbits++;

  340.         }

  341.             

  342.         jput_bits(&s->pb, huff_size[nbits], huff_code[nbits]);

  343.         

  344.         jput_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));

  345.     }

  346. }

  347. 

  348. static void encode_block(MpegEncContext *s, DCTELEM *block, int n)

  349. {

  350.     int mant, nbits, code, i, j;

  351.     int component, dc, run, last_index, val;

  352.     MJpegContext *m = s->mjpeg_ctx;

  353.     UINT8 *huff_size_ac;

  354.     UINT16 *huff_code_ac;

  355.     

  356.     /* DC coef */

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

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

  359.     val = dc - s->last_dc[component];

  360.     if (n < 4) {

  361.         encode_dc(s, val, m->huff_size_dc_luminance, m->huff_code_dc_luminance);

  362.         huff_size_ac = m->huff_size_ac_luminance;

  363.         huff_code_ac = m->huff_code_ac_luminance;

  364.     } else {

  365.         encode_dc(s, val, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);

  366.         huff_size_ac = m->huff_size_ac_chrominance;

  367.         huff_code_ac = m->huff_code_ac_chrominance;

  368.     }

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

  370.     

  371.     /* AC coefs */

  372.     

  373.     run = 0;

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

  375.     for(i=1;i<=last_index;i++) {

  376.         j = zigzag_direct[i];

  377.         val = block[j];

  378.         if (val == 0) {

  379.             run++;

  380.         } else {

  381.             while (run >= 16) {

  382.                 jput_bits(&s->pb, huff_size_ac[0xf0], huff_code_ac[0xf0]);

  383.                 run -= 16;

  384.             }

  385.             mant = val;

  386.             if (val < 0) {

  387.                 val = -val;

  388.                 mant--;

  389.             }

  390.             

  391.             /* compute the log (XXX: optimize) */

  392.             nbits = 0;

  393.             while (val != 0) {

  394.                 val = val >> 1;

  395.                 nbits++;

  396.             }

  397.             code = (run << 4) | nbits;

  398. 

  399.             jput_bits(&s->pb, huff_size_ac[code], huff_code_ac[code]);

  400.         

  401.             jput_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));

  402.             run = 0;

  403.         }

  404.     }

  405. 

  406.     /* output EOB only if not already 64 values */

  407.     if (last_index < 63 || run != 0)

  408.         jput_bits(&s->pb, huff_size_ac[0], huff_code_ac[0]);

  409. }

  410. 

  411. void mjpeg_encode_mb(MpegEncContext *s, 

  412.                      DCTELEM block[6][64])

  413. {

  414.     int i;

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

  416.         encode_block(s, block[i], i);

  417.     }

  418. }

  419. 

  420. /******************************************/

  421. /* decoding */

  422. 

  423. /* compressed picture size */

  424. #define PICTURE_BUFFER_SIZE 100000

  425. 

  426. #define MAX_COMPONENTS 4

  427. 

  428. typedef struct MJpegDecodeContext {

  429.     GetBitContext gb;

  430.     UINT32 header_state;

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

  432.     UINT8 *buf_ptr;

  433.     int buffer_size;

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

  435.     INT16 quant_matrixes[4][64];

  436.     VLC vlcs[2][4];

  437. 

  438.     int org_width, org_height;  /* size given at codec init */

  439.     int first_picture;    /* true if decoding first picture */

  440.     int interlaced;     /* true if interlaced */

  441.     int bottom_field;   /* true if bottom field */

  442. 

  443.     int width, height;

  444.     int nb_components;

  445.     int component_id[MAX_COMPONENTS];

  446.     int h_count[MAX_COMPONENTS]; /* horizontal and vertical count for each component */

  447.     int v_count[MAX_COMPONENTS];

  448.     int h_max, v_max; /* maximum h and v counts */

  449.     int quant_index[4];   /* quant table index for each component */

  450.     int last_dc[MAX_COMPONENTS]; /* last DEQUANTIZED dc (XXX: am I right to do that ?) */

  451.     UINT8 *current_picture[MAX_COMPONENTS]; /* picture structure */

  452.     int linesize[MAX_COMPONENTS];

  453.     DCTELEM block[64] __align8;

  454.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  455. } MJpegDecodeContext;

  456. 

  457. static void build_vlc(VLC *vlc, const UINT8 *bits_table, const UINT8 *val_table, 

  458.                       int nb_codes)

  459. {

  460.     UINT8 huff_size[256];

  461.     UINT16 huff_code[256];

  462. 

  463.     memset(huff_size, 0, sizeof(huff_size));

  464.     build_huffman_codes(huff_size, huff_code, bits_table, val_table);

  465.     

  466.     init_vlc(vlc, 9, nb_codes, huff_size, 1, 1, huff_code, 2, 2);

  467. }

  468. 

  469. static int mjpeg_decode_init(AVCodecContext *avctx)

  470. {

  471.     MJpegDecodeContext *s = avctx->priv_data;

  472. 

  473.     s->header_state = 0;

  474.     s->mpeg_enc_ctx_allocated = 0;

  475.     s->buffer_size = PICTURE_BUFFER_SIZE - 1; /* minus 1 to take into

  476.                                                  account FF 00 case */

  477.     s->start_code = -1;

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

  479.     s->first_picture = 1;

  480.     s->org_width = avctx->width;

  481.     s->org_height = avctx->height;

  482. 

  483.     build_vlc(&s->vlcs[0][0], bits_dc_luminance, val_dc_luminance, 12);

  484.     build_vlc(&s->vlcs[0][1], bits_dc_chrominance, val_dc_chrominance, 12);

  485.     build_vlc(&s->vlcs[1][0], bits_ac_luminance, val_ac_luminance, 251);

  486.     build_vlc(&s->vlcs[1][1], bits_ac_chrominance, val_ac_chrominance, 251);

  487.     return 0;

  488. }

  489. 

  490. /* quantize tables */

  491. static int mjpeg_decode_dqt(MJpegDecodeContext *s,

  492.                             UINT8 *buf, int buf_size)

  493. {

  494.     int len, index, i, j;

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

  496. 

  497.     len = get_bits(&s->gb, 16);

  498.     len -= 2;

  499. 

  500.     while (len >= 65) {

  501.         /* only 8 bit precision handled */

  502.         if (get_bits(&s->gb, 4) != 0)

  503.             return -1;

  504.         index = get_bits(&s->gb, 4);

  505.         if (index >= 4)

  506.             return -1;

  507.         dprintf("index=%d\n", index);

  508.         /* read quant table */

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

  510.             j = zigzag_direct[i];

  511.             s->quant_matrixes[index][j] = get_bits(&s->gb, 8);

  512.         }

  513.         len -= 65;

  514.     }

  515.     return 0;

  516. }

  517. 

  518. /* decode huffman tables and build VLC decoders */

  519. static int mjpeg_decode_dht(MJpegDecodeContext *s,

  520.                             UINT8 *buf, int buf_size)

  521. {

  522.     int len, index, i, class, n, v, code_max;

  523.     UINT8 bits_table[17];

  524.     UINT8 val_table[256];

  525.     

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

  527. 

  528.     len = get_bits(&s->gb, 16);

  529.     len -= 2;

  530. 

  531.     while (len > 0) {

  532.         if (len < 17)

  533.             return -1;

  534.         class = get_bits(&s->gb, 4);

  535.         if (class >= 2)

  536.             return -1;

  537.         index = get_bits(&s->gb, 4);

  538.         if (index >= 4)

  539.             return -1;

  540.         n = 0;

  541.         for(i=1;i<=16;i++) {

  542.             bits_table[i] = get_bits(&s->gb, 8);

  543.             n += bits_table[i];

  544.         }

  545.         len -= 17;

  546.         if (len < n || n > 256)

  547.             return -1;

  548. 

  549.         code_max = 0;

  550.         for(i=0;i<n;i++) {

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

  552.             if (v > code_max)

  553.                 code_max = v;

  554.             val_table[i] = v;

  555.         }

  556.         len -= n;

  557. 

  558.         /* build VLC and flush previous vlc if present */

  559.         free_vlc(&s->vlcs[class][index]);

  560.         dprintf("class=%d index=%d nb_codes=%d\n",

  561.                class, index, code_max + 1);

  562.         build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1);

  563.     }

  564.     return 0;

  565. }

  566. 

  567. static int mjpeg_decode_sof0(MJpegDecodeContext *s,

  568.                              UINT8 *buf, int buf_size)

  569. {

  570.     int len, nb_components, i, width, height;

  571. 

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

  573. 

  574.     /* XXX: verify len field validity */

  575.     len = get_bits(&s->gb, 16);

  576.     /* only 8 bits/component accepted */

  577.     if (get_bits(&s->gb, 8) != 8)

  578.         return -1;

  579.     height = get_bits(&s->gb, 16);

  580.     width = get_bits(&s->gb, 16);

  581. 

  582.     nb_components = get_bits(&s->gb, 8);

  583.     if (nb_components <= 0 ||

  584.         nb_components > MAX_COMPONENTS)

  585.         return -1;

  586.     s->nb_components = nb_components;

  587.     s->h_max = 1;

  588.     s->v_max = 1;

  589.     for(i=0;i<nb_components;i++) {

  590.         /* component id */

  591.         s->component_id[i] = get_bits(&s->gb, 8) - 1;

  592.         s->h_count[i] = get_bits(&s->gb, 4);

  593.         s->v_count[i] = get_bits(&s->gb, 4);

  594.         /* compute hmax and vmax (only used in interleaved case) */

  595.         if (s->h_count[i] > s->h_max)

  596.             s->h_max = s->h_count[i];

  597.         if (s->v_count[i] > s->v_max)

  598.             s->v_max = s->v_count[i];

  599.         s->quant_index[i] = get_bits(&s->gb, 8);

  600.         if (s->quant_index[i] >= 4)

  601.             return -1;

  602.         dprintf("component %d %d:%d\n", i, s->h_count[i], s->v_count[i]);

  603.     }

  604. 

  605.     /* if different size, realloc/alloc picture */

  606.     /* XXX: also check h_count and v_count */

  607.     if (width != s->width || height != s->height) {

  608.         for(i=0;i<MAX_COMPONENTS;i++) {

  609.             free(s->current_picture[i]);

  610.             s->current_picture[i] = NULL;

  611.         }

  612.         s->width = width;

  613.         s->height = height;

  614.         /* test interlaced mode */

  615.         if (s->first_picture &&

  616.             s->org_height != 0 &&

  617.             s->height < ((s->org_height * 3) / 4)) {

  618.             s->interlaced = 1;

  619.             s->bottom_field = 0;

  620.         }

  621. 

  622.         for(i=0;i<nb_components;i++) {

  623.             int w, h, hh, vv;

  624.             hh = s->h_max / s->h_count[i];

  625.             vv = s->v_max / s->v_count[i];

  626.             w = (s->width + 8 * hh - 1) / (8 * hh);

  627.             h = (s->height + 8 * vv - 1) / (8 * vv);

  628.             w = w * 8;

  629.             h = h * 8;

  630.             if (s->interlaced)

  631.                 w *= 2;

  632.             s->linesize[i] = w;

  633.             /* memory test is done in mjpeg_decode_sos() */

  634.             s->current_picture[i] = av_mallocz(w * h);

  635.         }

  636.         s->first_picture = 0;

  637.     }

  638.     

  639.     return 0;

  640. }

  641. 

  642. static inline int decode_dc(MJpegDecodeContext *s, int dc_index)

  643. {

  644.     VLC *dc_vlc;

  645.     int code, diff;

  646. 

  647.     dc_vlc = &s->vlcs[0][dc_index];

  648.     code = get_vlc(&s->gb, dc_vlc);

  649.     if (code < 0)

  650.         return 0xffff;

  651.     if (code == 0) {

  652.         diff = 0;

  653.     } else {

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

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

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

  657.     }

  658.     return diff;

  659. }

  660. 

  661. /* decode block and dequantize */

  662. static int decode_block(MJpegDecodeContext *s, DCTELEM *block, 

  663.                         int component, int dc_index, int ac_index, int quant_index)

  664. {

  665.     int nbits, code, i, j, level;

  666.     int run, val;

  667.     VLC *ac_vlc;

  668.     INT16 *quant_matrix;

  669. 

  670.     quant_matrix = s->quant_matrixes[quant_index];

  671.     /* DC coef */

  672.     val = decode_dc(s, dc_index);

  673.     if (val == 0xffff) {

  674.         dprintf("error dc\n");

  675.         return -1;

  676.     }

  677.     val = val * quant_matrix[0] + s->last_dc[component];

  678.     s->last_dc[component] = val;

  679.     block[0] = val;

  680.     /* AC coefs */

  681.     ac_vlc = &s->vlcs[1][ac_index];

  682.     i = 1;

  683.     for(;;) {

  684.         code = get_vlc(&s->gb, ac_vlc);

  685.         if (code < 0) {

  686.             dprintf("error ac\n");

  687.             return -1;

  688.         }

  689.         /* EOB */

  690.         if (code == 0)

  691.             break;

  692.         if (code == 0xf0) {

  693.             i += 16;

  694.         } else {

  695.             run = code >> 4;

  696.             nbits = code & 0xf;

  697.             level = get_bits(&s->gb, nbits);

  698.             if ((level & (1 << (nbits - 1))) == 0) 

  699.                 level = (-1 << nbits) | (level + 1);

  700.             i += run;

  701.             if (i >= 64) {

  702.                 dprintf("error count: %d\n", i);

  703.                 return -1;

  704.             }

  705.             j = zigzag_direct[i];

  706.             block[j] = level * quant_matrix[j];

  707.             i++;

  708.             if (i >= 64)

  709.                 break;

  710.         }

  711.     }

  712.     return 0;

  713. }

  714. 

  715. static int mjpeg_decode_sos(MJpegDecodeContext *s,

  716.                             UINT8 *buf, int buf_size)

  717. {

  718.     int len, nb_components, i, j, n, h, v, ret;

  719.     int mb_width, mb_height, mb_x, mb_y, vmax, hmax, index, id;

  720.     int comp_index[4];

  721.     int dc_index[4];

  722.     int ac_index[4];

  723.     int nb_blocks[4];

  724.     int h_count[4];

  725.     int v_count[4];

  726.     

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

  728.     /* XXX: verify len field validity */

  729.     len = get_bits(&s->gb, 16);

  730.     nb_components = get_bits(&s->gb, 8);

  731.     /* XXX: only interleaved scan accepted */

  732.     if (nb_components != 3)

  733.         return -1;

  734.     vmax = 0;

  735.     hmax = 0;

  736.     for(i=0;i<nb_components;i++) {

  737.         id = get_bits(&s->gb, 8) - 1;

  738.         /* find component index */

  739.         for(index=0;index<s->nb_components;index++)

  740.             if (id == s->component_id[index])

  741.                 break;

  742.         if (index == s->nb_components)

  743.             return -1;

  744. 

  745.         comp_index[i] = index;

  746.         nb_blocks[i] = s->h_count[index] * s->v_count[index];

  747.         h_count[i] = s->h_count[index];

  748.         v_count[i] = s->v_count[index];

  749. 

  750.         dc_index[i] = get_bits(&s->gb, 4);

  751.         if (dc_index[i] >= 4)

  752.             return -1;

  753.         ac_index[i] = get_bits(&s->gb, 4);

  754.         if (ac_index[i] >= 4)

  755.             return -1;

  756.     }

  757.     get_bits(&s->gb, 8); /* Ss */

  758.     get_bits(&s->gb, 8); /* Se */

  759.     get_bits(&s->gb, 8); /* not used */

  760. 

  761.     for(i=0;i<nb_components;i++) 

  762.         s->last_dc[i] = 1024;

  763. 

  764.     if (nb_components > 1) {

  765.         /* interleaved stream */

  766.         mb_width = (s->width + s->h_max * 8 - 1) / (s->h_max * 8);

  767.         mb_height = (s->height + s->v_max * 8 - 1) / (s->v_max * 8);

  768.     } else {

  769.         h = s->h_max / s->h_count[comp_index[0]];

  770.         v = s->v_max / s->v_count[comp_index[0]];

  771.         mb_width = (s->width + h * 8 - 1) / (h * 8);

  772.         mb_height = (s->height + v * 8 - 1) / (v * 8);

  773.         nb_blocks[0] = 1;

  774.         h_count[0] = 1;

  775.         v_count[0] = 1;

  776.     }

  777. 

  778.     for(mb_y = 0; mb_y < mb_height; mb_y++) {

  779.         for(mb_x = 0; mb_x < mb_width; mb_x++) {

  780.             for(i=0;i<nb_components;i++) {

  781.                 UINT8 *ptr;

  782.                 int x, y, c;

  783.                 n = nb_blocks[i];

  784.                 c = comp_index[i];

  785.                 h = h_count[i];

  786.                 v = v_count[i];

  787.                 x = 0;

  788.                 y = 0;

  789.                 for(j=0;j<n;j++) {

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

  791.                     if (decode_block(s, s->block, i, 

  792.                                      dc_index[i], ac_index[i], 

  793.                                      s->quant_index[c]) < 0) {

  794.                         dprintf("error %d %d\n", mb_y, mb_x);

  795.                         ret = -1;

  796.                         goto the_end;

  797.                     }

  798.                     ff_idct (s->block);

  799.                     ptr = s->current_picture[c] + 

  800.                         (s->linesize[c] * (v * mb_y + y) * 8) + 

  801.                         (h * mb_x + x) * 8;

  802.                     if (s->interlaced && s->bottom_field)

  803.                         ptr += s->linesize[c] >> 1;

  804.                     put_pixels_clamped(s->block, ptr, s->linesize[c]);

  805.                     if (++x == h) {

  806.                         x = 0;

  807.                         y++;

  808.                     }

  809.                 }

  810.             }

  811.         }

  812.     }

  813.     ret = 0;

  814.  the_end:

  815.     emms_c();

  816.     return ret;

  817. }

  818. 

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

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

  821. static int find_marker(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  822.                        UINT32 *header_state)

  823. {

  824.     UINT8 *buf_ptr;

  825.     unsigned int state, v;

  826.     int val;

  827. 

  828.     state = *header_state;

  829.     buf_ptr = *pbuf_ptr;

  830.     if (state) {

  831.         /* get marker */

  832.     found:

  833.         if (buf_ptr < buf_end) {

  834.             val = *buf_ptr++;

  835.             state = 0;

  836.         } else {

  837.             val = -1;

  838.         }

  839.     } else {

  840.         while (buf_ptr < buf_end) {

  841.             v = *buf_ptr++;

  842.             if (v == 0xff) {

  843.                 state = 1;

  844.                 goto found;

  845.             }

  846.         }

  847.         val = -1;

  848.     }

  849.     *pbuf_ptr = buf_ptr;

  850.     *header_state = state;

  851.     return val;

  852. }

  853. 

  854. static int mjpeg_decode_frame(AVCodecContext *avctx, 

  855.                               void *data, int *data_size,

  856.                               UINT8 *buf, int buf_size)

  857. {

  858.     MJpegDecodeContext *s = avctx->priv_data;

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

  860.     int len, code, start_code, input_size, i;

  861.     AVPicture *picture = data;

  862. 

  863.     *data_size = 0;

  864. 

  865.     /* no supplementary picture */

  866.     if (buf_size == 0)

  867.         return 0;

  868. 

  869.     buf_ptr = buf;

  870.     buf_end = buf + buf_size;

  871.     while (buf_ptr < buf_end) {

  872.         buf_start = buf_ptr;

  873.         /* find start next marker */

  874.         code = find_marker(&buf_ptr, buf_end, &s->header_state);

  875.         /* copy to buffer */

  876.         len = buf_ptr - buf_start;

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

  878.             /* data too big : flush */

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

  880.             if (code > 0)

  881.                 s->start_code = code;

  882.         } else {

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

  884.             s->buf_ptr += len;

  885.             /* if we got FF 00, we copy FF to the stream to unescape FF 00 */

  886.             if (code == 0) {

  887.                 s->buf_ptr--;

  888.             } else if (code > 0) {

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

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

  891.                 start_code = s->start_code;

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

  893.                 s->start_code = code;

  894.                 dprintf("marker=%x\n", start_code);

  895.                 switch(start_code) {

  896.                 case SOI:

  897.                     /* nothing to do on SOI */

  898.                     break;

  899.                 case DQT:

  900.                     mjpeg_decode_dqt(s, s->buffer, input_size);

  901.                     break;

  902.                 case DHT:

  903.                     mjpeg_decode_dht(s, s->buffer, input_size);

  904.                     break;

  905.                 case SOF0:

  906.                     mjpeg_decode_sof0(s, s->buffer, input_size);

  907.                     break;

  908.                 case SOS:

  909.                     mjpeg_decode_sos(s, s->buffer, input_size);

  910.                     if (s->start_code == EOI) {

  911.                         int l;

  912.                         if (s->interlaced) {

  913.                             s->bottom_field ^= 1;

  914.                             /* if not bottom field, do not output image yet */

  915.                             if (s->bottom_field)

  916.                                 goto the_end;

  917.                         }

  918.                         for(i=0;i<3;i++) {

  919.                             picture->data[i] = s->current_picture[i];

  920.                             l = s->linesize[i];

  921.                             if (s->interlaced)

  922.                                 l >>= 1;

  923.                             picture->linesize[i] = l;

  924.                         }

  925.                         *data_size = sizeof(AVPicture);

  926.                         avctx->height = s->height;

  927.                         if (s->interlaced)

  928.                             avctx->height *= 2;

  929.                         avctx->width = s->width;

  930.                         /* XXX: not complete test ! */

  931.                         switch((s->h_count[0] << 4) | s->v_count[0]) {

  932.                         case 0x11:

  933.                             avctx->pix_fmt = PIX_FMT_YUV444P;

  934.                             break;

  935.                         case 0x21:

  936.                             avctx->pix_fmt = PIX_FMT_YUV422P;

  937.                             break;

  938.                         default:

  939.                         case 0x22:

  940.                             avctx->pix_fmt = PIX_FMT_YUV420P;

  941.                             break;

  942.                         }

  943.                         /* dummy quality */

  944.                         /* XXX: infer it with matrix */

  945.                         avctx->quality = 3; 

  946.                         goto the_end;

  947.                     }

  948.                     break;

  949.                 }

  950.             }

  951.         }

  952.     }

  953.  the_end:

  954.     return buf_ptr - buf;

  955. }

  956. 

  957. static int mjpeg_decode_end(AVCodecContext *avctx)

  958. {

  959.     MJpegDecodeContext *s = avctx->priv_data;

  960.     int i, j;

  961. 

  962.     for(i=0;i<MAX_COMPONENTS;i++)

  963.         free(s->current_picture[i]);

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

  965.         for(j=0;j<4;j++)

  966.             free_vlc(&s->vlcs[i][j]);

  967.     }

  968.     return 0;

  969. }

  970. 

  971. AVCodec mjpeg_decoder = {

  972.     "mjpeg",

  973.     CODEC_TYPE_VIDEO,

  974.     CODEC_ID_MJPEG,

  975.     sizeof(MJpegDecodeContext),

  976.     mjpeg_decode_init,

  977.     NULL,

  978.     mjpeg_decode_end,

  979.     mjpeg_decode_frame,

  980. };