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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.     s->min_qcoeff=-1023;

  165.     s->max_qcoeff= 1023;

  166. 

  167.     /* build all the huffman tables */

  168.     build_huffman_codes(m->huff_size_dc_luminance,

  169.                         m->huff_code_dc_luminance,

  170.                         bits_dc_luminance,

  171.                         val_dc_luminance);

  172.     build_huffman_codes(m->huff_size_dc_chrominance,

  173.                         m->huff_code_dc_chrominance,

  174.                         bits_dc_chrominance,

  175.                         val_dc_chrominance);

  176.     build_huffman_codes(m->huff_size_ac_luminance,

  177.                         m->huff_code_ac_luminance,

  178.                         bits_ac_luminance,

  179.                         val_ac_luminance);

  180.     build_huffman_codes(m->huff_size_ac_chrominance,

  181.                         m->huff_code_ac_chrominance,

  182.                         bits_ac_chrominance,

  183.                         val_ac_chrominance);

  184.     

  185.     s->mjpeg_ctx = m;

  186.     return 0;

  187. }

  188. 

  189. void mjpeg_close(MpegEncContext *s)

  190. {

  191.     free(s->mjpeg_ctx);

  192. }

  193. 

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

  195. {

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

  197.     put_bits(p, 8, code);

  198. }

  199. 

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

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

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

  203. {

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

  205.     int n, i;

  206. 

  207.     put_bits(p, 4, table_class);

  208.     put_bits(p, 4, table_id);

  209. 

  210.     n = 0;

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

  212.         n += bits_table[i];

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

  214.     }

  215. 

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

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

  218. 

  219.     return n + 17;

  220. }

  221. 

  222. static void jpeg_table_header(MpegEncContext *s)

  223. {

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

  225.     int i, j, size;

  226.     UINT8 *ptr;

  227. 

  228.     /* quant matrixes */

  229.     put_marker(p, DQT);

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

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

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

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

  234.         j = zigzag_direct[i];

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

  236.     }

  237. #if 0

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

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

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

  241.         j = zigzag_direct[i];

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

  243.     }

  244. #endif

  245. 

  246.     /* huffman table */

  247.     put_marker(p, DHT);

  248.     flush_put_bits(p);

  249.     ptr = pbBufPtr(p);

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

  251.     size = 2;

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

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

  254.     

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

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

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

  258.     ptr[1] = size;

  259. }

  260. 

  261. void mjpeg_picture_header(MpegEncContext *s)

  262. {

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

  264. 

  265.     if (s->mjpeg_write_tables) jpeg_table_header(s);

  266. 

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

  268. 

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

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

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

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

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

  274.     

  275.     /* Y component */

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

  277.     put_bits(&s->pb, 4, s->mjpeg_hsample[0]); /* H factor */

  278.     put_bits(&s->pb, 4, s->mjpeg_vsample[0]); /* V factor */

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

  280.     

  281.     /* Cb component */

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

  283.     put_bits(&s->pb, 4, s->mjpeg_hsample[1]); /* H factor */

  284.     put_bits(&s->pb, 4, s->mjpeg_vsample[1]); /* V factor */

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

  286. 

  287.     /* Cr component */

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

  289.     put_bits(&s->pb, 4, s->mjpeg_hsample[2]); /* H factor */

  290.     put_bits(&s->pb, 4, s->mjpeg_vsample[2]); /* V factor */

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

  292. 

  293.     /* scan header */

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

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

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

  297.     

  298.     /* Y component */

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

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

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

  302.     

  303.     /* Cb component */

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

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

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

  307.     

  308.     /* Cr component */

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

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

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

  312. 

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

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

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

  316. }

  317. 

  318. void mjpeg_picture_trailer(MpegEncContext *s)

  319. {

  320.     jflush_put_bits(&s->pb);

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

  322. }

  323. 

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

  325.                              UINT8 *huff_size, UINT16 *huff_code)

  326. {

  327.     int mant, nbits;

  328. 

  329.     if (val == 0) {

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

  331.     } else {

  332.         mant = val;

  333.         if (val < 0) {

  334.             val = -val;

  335.             mant--;

  336.         }

  337.         

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

  339.         nbits = 0;

  340.         while (val != 0) {

  341.             val = val >> 1;

  342.             nbits++;

  343.         }

  344.             

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

  346.         

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

  348.     }

  349. }

  350. 

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

  352. {

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

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

  355.     MJpegContext *m = s->mjpeg_ctx;

  356.     UINT8 *huff_size_ac;

  357.     UINT16 *huff_code_ac;

  358.     

  359.     /* DC coef */

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

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

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

  363.     if (n < 4) {

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

  365.         huff_size_ac = m->huff_size_ac_luminance;

  366.         huff_code_ac = m->huff_code_ac_luminance;

  367.     } else {

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

  369.         huff_size_ac = m->huff_size_ac_chrominance;

  370.         huff_code_ac = m->huff_code_ac_chrominance;

  371.     }

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

  373.     

  374.     /* AC coefs */

  375.     

  376.     run = 0;

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

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

  379.         j = zigzag_direct[i];

  380.         val = block[j];

  381.         if (val == 0) {

  382.             run++;

  383.         } else {

  384.             while (run >= 16) {

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

  386.                 run -= 16;

  387.             }

  388.             mant = val;

  389.             if (val < 0) {

  390.                 val = -val;

  391.                 mant--;

  392.             }

  393.             

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

  395.             nbits = 0;

  396.             while (val != 0) {

  397.                 val = val >> 1;

  398.                 nbits++;

  399.             }

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

  401. 

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

  403.         

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

  405.             run = 0;

  406.         }

  407.     }

  408. 

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

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

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

  412. }

  413. 

  414. void mjpeg_encode_mb(MpegEncContext *s, 

  415.                      DCTELEM block[6][64])

  416. {

  417.     int i;

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

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

  420.     }

  421. }

  422. 

  423. /******************************************/

  424. /* decoding */

  425. 

  426. /* compressed picture size */

  427. #define PICTURE_BUFFER_SIZE 100000

  428. 

  429. #define MAX_COMPONENTS 4

  430. 

  431. typedef struct MJpegDecodeContext {

  432.     GetBitContext gb;

  433.     UINT32 header_state;

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

  435.     UINT8 *buf_ptr;

  436.     int buffer_size;

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

  438.     INT16 quant_matrixes[4][64];

  439.     VLC vlcs[2][4];

  440. 

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

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

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

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

  445. 

  446.     int width, height;

  447.     int nb_components;

  448.     int component_id[MAX_COMPONENTS];

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

  450.     int v_count[MAX_COMPONENTS];

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

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

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

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

  455.     int linesize[MAX_COMPONENTS];

  456.     DCTELEM block[64] __align8;

  457.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  458. } MJpegDecodeContext;

  459. 

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

  461.                       int nb_codes)

  462. {

  463.     UINT8 huff_size[256];

  464.     UINT16 huff_code[256];

  465. 

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

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

  468.     

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

  470. }

  471. 

  472. static int mjpeg_decode_init(AVCodecContext *avctx)

  473. {

  474.     MJpegDecodeContext *s = avctx->priv_data;

  475. 

  476.     s->header_state = 0;

  477.     s->mpeg_enc_ctx_allocated = 0;

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

  479.                                                  account FF 00 case */

  480.     s->start_code = -1;

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

  482.     s->first_picture = 1;

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

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

  485. 

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

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

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

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

  490.     return 0;

  491. }

  492. 

  493. /* quantize tables */

  494. static int mjpeg_decode_dqt(MJpegDecodeContext *s,

  495.                             UINT8 *buf, int buf_size)

  496. {

  497.     int len, index, i, j;

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

  499. 

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

  501.     len -= 2;

  502. 

  503.     while (len >= 65) {

  504.         /* only 8 bit precision handled */

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

  506.             return -1;

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

  508.         if (index >= 4)

  509.             return -1;

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

  511.         /* read quant table */

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

  513.             j = zigzag_direct[i];

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

  515.         }

  516.         len -= 65;

  517.     }

  518.     return 0;

  519. }

  520. 

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

  522. static int mjpeg_decode_dht(MJpegDecodeContext *s,

  523.                             UINT8 *buf, int buf_size)

  524. {

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

  526.     UINT8 bits_table[17];

  527.     UINT8 val_table[256];

  528.     

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

  530. 

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

  532.     len -= 2;

  533. 

  534.     while (len > 0) {

  535.         if (len < 17)

  536.             return -1;

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

  538.         if (class >= 2)

  539.             return -1;

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

  541.         if (index >= 4)

  542.             return -1;

  543.         n = 0;

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

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

  546.             n += bits_table[i];

  547.         }

  548.         len -= 17;

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

  550.             return -1;

  551. 

  552.         code_max = 0;

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

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

  555.             if (v > code_max)

  556.                 code_max = v;

  557.             val_table[i] = v;

  558.         }

  559.         len -= n;

  560. 

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

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

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

  564.                class, index, code_max + 1);

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

  566.     }

  567.     return 0;

  568. }

  569. 

  570. static int mjpeg_decode_sof0(MJpegDecodeContext *s,

  571.                              UINT8 *buf, int buf_size)

  572. {

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

  574. 

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

  576. 

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

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

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

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

  581.         return -1;

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

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

  584. 

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

  586.     if (nb_components <= 0 ||

  587.         nb_components > MAX_COMPONENTS)

  588.         return -1;

  589.     s->nb_components = nb_components;

  590.     s->h_max = 1;

  591.     s->v_max = 1;

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

  593.         /* component id */

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

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

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

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

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

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

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

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

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

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

  604.             return -1;

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

  606.     }

  607. 

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

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

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

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

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

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

  614.         }

  615.         s->width = width;

  616.         s->height = height;

  617.         /* test interlaced mode */

  618.         if (s->first_picture &&

  619.             s->org_height != 0 &&

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

  621.             s->interlaced = 1;

  622.             s->bottom_field = 0;

  623.         }

  624. 

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

  626.             int w, h;

  627.             w = (s->width  + 8 * s->h_max - 1) / (8 * s->h_max);

  628.             h = (s->height + 8 * s->v_max - 1) / (8 * s->v_max);

  629.             w = w * 8 * s->h_count[i];

  630.             h = h * 8 * s->v_count[i];

  631.             if (s->interlaced)

  632.                 w *= 2;

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

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

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

  636.         }

  637.         s->first_picture = 0;

  638.     }

  639.     

  640.     return 0;

  641. }

  642. 

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

  644. {

  645.     VLC *dc_vlc;

  646.     int code, diff;

  647. 

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

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

  650.     if (code < 0)

  651.         return 0xffff;

  652.     if (code == 0) {

  653.         diff = 0;

  654.     } else {

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

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

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

  658.     }

  659.     return diff;

  660. }

  661. 

  662. /* decode block and dequantize */

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

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

  665. {

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

  667.     int run, val;

  668.     VLC *ac_vlc;

  669.     INT16 *quant_matrix;

  670. 

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

  672.     /* DC coef */

  673.     val = decode_dc(s, dc_index);

  674.     if (val == 0xffff) {

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

  676.         return -1;

  677.     }

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

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

  680.     block[0] = val;

  681.     /* AC coefs */

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

  683.     i = 1;

  684.     for(;;) {

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

  686.         if (code < 0) {

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

  688.             return -1;

  689.         }

  690.         /* EOB */

  691.         if (code == 0)

  692.             break;

  693.         if (code == 0xf0) {

  694.             i += 16;

  695.         } else {

  696.             run = code >> 4;

  697.             nbits = code & 0xf;

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

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

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

  701.             i += run;

  702.             if (i >= 64) {

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

  704.                 return -1;

  705.             }

  706.             j = zigzag_direct[i];

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

  708.             i++;

  709.             if (i >= 64)

  710.                 break;

  711.         }

  712.     }

  713.     return 0;

  714. }

  715. 

  716. static int mjpeg_decode_sos(MJpegDecodeContext *s,

  717.                             UINT8 *buf, int buf_size)

  718. {

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

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

  721.     int comp_index[4];

  722.     int dc_index[4];

  723.     int ac_index[4];

  724.     int nb_blocks[4];

  725.     int h_count[4];

  726.     int v_count[4];

  727.     

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

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

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

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

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

  733.     if (nb_components != 3)

  734.         return -1;

  735.     vmax = 0;

  736.     hmax = 0;

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

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

  739.         /* find component index */

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

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

  742.                 break;

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

  744.             return -1;

  745. 

  746.         comp_index[i] = index;

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

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

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

  750. 

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

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

  753.             return -1;

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

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

  756.             return -1;

  757.     }

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

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

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

  761. 

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

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

  764. 

  765.     if (nb_components > 1) {

  766.         /* interleaved stream */

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

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

  769.     } else {

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

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

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

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

  774.         nb_blocks[0] = 1;

  775.         h_count[0] = 1;

  776.         v_count[0] = 1;

  777.     }

  778. 

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

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

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

  782.                 UINT8 *ptr;

  783.                 int x, y, c;

  784.                 n = nb_blocks[i];

  785.                 c = comp_index[i];

  786.                 h = h_count[i];

  787.                 v = v_count[i];

  788.                 x = 0;

  789.                 y = 0;

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

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

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

  793.                                      dc_index[i], ac_index[i], 

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

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

  796.                         ret = -1;

  797.                         goto the_end;

  798.                     }

  799.                     ff_idct (s->block);

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

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

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

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

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

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

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

  807.                         x = 0;

  808.                         y++;

  809.                     }

  810.                 }

  811.             }

  812.         }

  813.     }

  814.     ret = 0;

  815.  the_end:

  816.     emms_c();

  817.     return ret;

  818. }

  819. 

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

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

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

  823.                        UINT32 *header_state)

  824. {

  825.     UINT8 *buf_ptr;

  826.     unsigned int state, v;

  827.     int val;

  828. 

  829.     state = *header_state;

  830.     buf_ptr = *pbuf_ptr;

  831.     if (state) {

  832.         /* get marker */

  833.     found:

  834.         if (buf_ptr < buf_end) {

  835.             val = *buf_ptr++;

  836.             state = 0;

  837.         } else {

  838.             val = -1;

  839.         }

  840.     } else {

  841.         while (buf_ptr < buf_end) {

  842.             v = *buf_ptr++;

  843.             if (v == 0xff) {

  844.                 state = 1;

  845.                 goto found;

  846.             }

  847.         }

  848.         val = -1;

  849.     }

  850.     *pbuf_ptr = buf_ptr;

  851.     *header_state = state;

  852.     return val;

  853. }

  854. 

  855. static int mjpeg_decode_frame(AVCodecContext *avctx, 

  856.                               void *data, int *data_size,

  857.                               UINT8 *buf, int buf_size)

  858. {

  859.     MJpegDecodeContext *s = avctx->priv_data;

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

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

  862.     AVPicture *picture = data;

  863. 

  864.     *data_size = 0;

  865. 

  866.     /* no supplementary picture */

  867.     if (buf_size == 0)

  868.         return 0;

  869. 

  870.     buf_ptr = buf;

  871.     buf_end = buf + buf_size;

  872.     while (buf_ptr < buf_end) {

  873.         buf_start = buf_ptr;

  874.         /* find start next marker */

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

  876.         /* copy to buffer */

  877.         len = buf_ptr - buf_start;

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

  879.             /* data too big : flush */

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

  881.             if (code > 0)

  882.                 s->start_code = code;

  883.         } else {

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

  885.             s->buf_ptr += len;

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

  887.             if (code == 0) {

  888.                 s->buf_ptr--;

  889.             } else if (code > 0) {

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

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

  892.                 start_code = s->start_code;

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

  894.                 s->start_code = code;

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

  896.                 switch(start_code) {

  897.                 case SOI:

  898.                     /* nothing to do on SOI */

  899.                     break;

  900.                 case DQT:

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

  902.                     break;

  903.                 case DHT:

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

  905.                     break;

  906.                 case SOF0:

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

  908.                     break;

  909.                 case SOS:

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

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

  912.                         int l;

  913.                         if (s->interlaced) {

  914.                             s->bottom_field ^= 1;

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

  916.                             if (s->bottom_field)

  917.                                 goto the_end;

  918.                         }

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

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

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

  922.                             if (s->interlaced)

  923.                                 l >>= 1;

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

  925.                         }

  926.                         *data_size = sizeof(AVPicture);

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

  928.                         if (s->interlaced)

  929.                             avctx->height *= 2;

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

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

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

  933.                         case 0x11:

  934.                             avctx->pix_fmt = PIX_FMT_YUV444P;

  935.                             break;

  936.                         case 0x21:

  937.                             avctx->pix_fmt = PIX_FMT_YUV422P;

  938.                             break;

  939.                         default:

  940.                         case 0x22:

  941.                             avctx->pix_fmt = PIX_FMT_YUV420P;

  942.                             break;

  943.                         }

  944.                         /* dummy quality */

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

  946.                         avctx->quality = 3; 

  947.                         goto the_end;

  948.                     }

  949.                     break;

  950.                 }

  951.             }

  952.         }

  953.     }

  954.  the_end:

  955.     return buf_ptr - buf;

  956. }

  957. 

  958. static int mjpeg_decode_end(AVCodecContext *avctx)

  959. {

  960.     MJpegDecodeContext *s = avctx->priv_data;

  961.     int i, j;

  962. 

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

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

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

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

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

  968.     }

  969.     return 0;

  970. }

  971. 

  972. AVCodec mjpeg_decoder = {

  973.     "mjpeg",

  974.     CODEC_TYPE_VIDEO,

  975.     CODEC_ID_MJPEG,

  976.     sizeof(MJpegDecodeContext),

  977.     mjpeg_decode_init,

  978.     NULL,

  979.     mjpeg_decode_end,

  980.     mjpeg_decode_frame,

  981. };