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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.  * Support for external huffman table and various fixes (AVID workaround) by

  20.  *                                    Alex Beregszaszi <alex@naxine.org>

  21.  */

  22. //#define DEBUG

  23. #include "avcodec.h"

  24. #include "dsputil.h"

  25. #include "mpegvideo.h"

  26. 

  27. #ifdef USE_FASTMEMCPY

  28. #include "fastmemcpy.h"

  29. #endif

  30. 

  31. /* use two quantizer table (one for luminance and one for chrominance) */

  32. /* not yet working */

  33. #undef TWOMATRIXES

  34. 

  35. typedef struct MJpegContext {

  36.     UINT8 huff_size_dc_luminance[12];

  37.     UINT16 huff_code_dc_luminance[12];

  38.     UINT8 huff_size_dc_chrominance[12];

  39.     UINT16 huff_code_dc_chrominance[12];

  40. 

  41.     UINT8 huff_size_ac_luminance[256];

  42.     UINT16 huff_code_ac_luminance[256];

  43.     UINT8 huff_size_ac_chrominance[256];

  44.     UINT16 huff_code_ac_chrominance[256];

  45. } MJpegContext;

  46. 

  47. /* JPEG marker codes */

  48. typedef enum {

  49.     /* start of frame */

  50.     SOF0  = 0xc0,	/* baseline */

  51.     SOF1  = 0xc1,	/* extended sequential, huffman */

  52.     SOF2  = 0xc2,	/* progressive, huffman */

  53.     SOF3  = 0xc3,	/* lossless, huffman */

  54. 

  55.     SOF5  = 0xc5,	/* differential sequential, huffman */

  56.     SOF6  = 0xc6,	/* differential progressive, huffman */

  57.     SOF7  = 0xc7,	/* differential lossless, huffman */

  58.     JPG   = 0xc8,	/* reserved for JPEG extension */

  59.     SOF9  = 0xc9,	/* extended sequential, arithmetic */

  60.     SOF10 = 0xca,	/* progressive, arithmetic */

  61.     SOF11 = 0xcb,	/* lossless, arithmetic */

  62. 

  63.     SOF13 = 0xcd,	/* differential sequential, arithmetic */

  64.     SOF14 = 0xce,	/* differential progressive, arithmetic */

  65.     SOF15 = 0xcf,	/* differential lossless, arithmetic */

  66. 

  67.     DHT   = 0xc4,	/* define huffman tables */

  68. 

  69.     DAC   = 0xcc,	/* define arithmetic-coding conditioning */

  70. 

  71.     /* restart with modulo 8 count "m" */

  72.     RST0  = 0xd0,

  73.     RST1  = 0xd1,

  74.     RST2  = 0xd2,

  75.     RST3  = 0xd3,

  76.     RST4  = 0xd4,

  77.     RST5  = 0xd5,

  78.     RST6  = 0xd6,

  79.     RST7  = 0xd7,

  80. 

  81.     SOI   = 0xd8,	/* start of image */

  82.     EOI   = 0xd9,	/* end of image */

  83.     SOS   = 0xda,	/* start of scan */

  84.     DQT   = 0xdb,	/* define quantization tables */

  85.     DNL   = 0xdc,	/* define number of lines */

  86.     DRI   = 0xdd,	/* define restart interval */

  87.     DHP   = 0xde,	/* define hierarchical progression */

  88.     EXP   = 0xdf,	/* expand reference components */

  89. 

  90.     APP0  = 0xe0,

  91.     APP1  = 0xe1,

  92.     APP2  = 0xe2,

  93.     APP3  = 0xe3,

  94.     APP4  = 0xe4,

  95.     APP5  = 0xe5,

  96.     APP6  = 0xe6,

  97.     APP7  = 0xe7,

  98.     APP8  = 0xe8,

  99.     APP9  = 0xe9,

  100.     APP10 = 0xea,

  101.     APP11 = 0xeb,

  102.     APP12 = 0xec,

  103.     APP13 = 0xed,

  104.     APP14 = 0xee,

  105.     APP15 = 0xef,

  106. 

  107.     JPG0  = 0xf0,

  108.     JPG1  = 0xf1,

  109.     JPG2  = 0xf2,

  110.     JPG3  = 0xf3,

  111.     JPG4  = 0xf4,

  112.     JPG5  = 0xf5,

  113.     JPG6  = 0xf6,

  114.     JPG7  = 0xf7,

  115.     JPG8  = 0xf8,

  116.     JPG9  = 0xf9,

  117.     JPG10 = 0xfa,

  118.     JPG11 = 0xfb,

  119.     JPG12 = 0xfc,

  120.     JPG13 = 0xfd,

  121. 

  122.     COM   = 0xfe,	/* comment */

  123. 

  124.     TEM   = 0x01,	/* temporary private use for arithmetic coding */

  125. 

  126.     /* 0x02 -> 0xbf reserved */

  127. } JPEG_MARKER;

  128. 

  129. #if 0

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

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

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

  133.  */

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

  135.     16,  11,  10,  16,  24,  40,  51,  61,

  136.     12,  12,  14,  19,  26,  58,  60,  55,

  137.     14,  13,  16,  24,  40,  57,  69,  56,

  138.     14,  17,  22,  29,  51,  87,  80,  62,

  139.     18,  22,  37,  56,  68, 109, 103,  77,

  140.     24,  35,  55,  64,  81, 104, 113,  92,

  141.     49,  64,  78,  87, 103, 121, 120, 101,

  142.     72,  92,  95,  98, 112, 100, 103,  99

  143. };

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

  145.     17,  18,  24,  47,  99,  99,  99,  99,

  146.     18,  21,  26,  66,  99,  99,  99,  99,

  147.     24,  26,  56,  99,  99,  99,  99,  99,

  148.     47,  66,  99,  99,  99,  99,  99,  99,

  149.     99,  99,  99,  99,  99,  99,  99,  99,

  150.     99,  99,  99,  99,  99,  99,  99,  99,

  151.     99,  99,  99,  99,  99,  99,  99,  99,

  152.     99,  99,  99,  99,  99,  99,  99,  99

  153. };

  154. #endif

  155. 

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

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

  158. static const UINT8 bits_dc_luminance[17] =

  159. { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };

  160. static const UINT8 val_dc_luminance[] =

  161. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  162. 

  163. static const UINT8 bits_dc_chrominance[17] =

  164. { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };

  165. static const UINT8 val_dc_chrominance[] =

  166. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  167. 

  168. static const UINT8 bits_ac_luminance[17] =

  169. { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };

  170. static const UINT8 val_ac_luminance[] =

  171. { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

  172.   0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

  173.   0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,

  174.   0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,

  175.   0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,

  176.   0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,

  177.   0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

  178.   0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

  179.   0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

  180.   0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

  181.   0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

  182.   0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

  183.   0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

  184.   0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,

  185.   0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,

  186.   0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,

  187.   0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,

  188.   0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,

  189.   0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,

  190.   0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  191.   0xf9, 0xfa 

  192. };

  193. 

  194. static const UINT8 bits_ac_chrominance[17] =

  195. { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };

  196. 

  197. static const UINT8 val_ac_chrominance[] =

  198. { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

  199.   0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

  200.   0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

  201.   0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,

  202.   0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,

  203.   0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,

  204.   0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,

  205.   0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

  206.   0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

  207.   0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

  208.   0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

  209.   0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

  210.   0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,

  211.   0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,

  212.   0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,

  213.   0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,

  214.   0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,

  215.   0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,

  216.   0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,

  217.   0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  218.   0xf9, 0xfa 

  219. };

  220. 

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

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

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

  224. {

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

  226. 

  227.     code = 0;

  228.     k = 0;

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

  230.         nb = bits_table[i];

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

  232.             sym = val_table[k++];

  233.             huff_size[sym] = i;

  234.             huff_code[sym] = code;

  235.             code++;

  236.         }

  237.         code <<= 1;

  238.     }

  239. }

  240. 

  241. int mjpeg_init(MpegEncContext *s)

  242. {

  243.     MJpegContext *m;

  244.     

  245.     m = av_malloc(sizeof(MJpegContext));

  246.     if (!m)

  247.         return -1;

  248.     

  249.     s->min_qcoeff=-1023;

  250.     s->max_qcoeff= 1023;

  251.     s->intra_quant_bias= 1<<(QUANT_BIAS_SHIFT-1); //(a + x/2)/x

  252. 

  253.     /* build all the huffman tables */

  254.     build_huffman_codes(m->huff_size_dc_luminance,

  255.                         m->huff_code_dc_luminance,

  256.                         bits_dc_luminance,

  257.                         val_dc_luminance);

  258.     build_huffman_codes(m->huff_size_dc_chrominance,

  259.                         m->huff_code_dc_chrominance,

  260.                         bits_dc_chrominance,

  261.                         val_dc_chrominance);

  262.     build_huffman_codes(m->huff_size_ac_luminance,

  263.                         m->huff_code_ac_luminance,

  264.                         bits_ac_luminance,

  265.                         val_ac_luminance);

  266.     build_huffman_codes(m->huff_size_ac_chrominance,

  267.                         m->huff_code_ac_chrominance,

  268.                         bits_ac_chrominance,

  269.                         val_ac_chrominance);

  270.     

  271.     s->mjpeg_ctx = m;

  272.     return 0;

  273. }

  274. 

  275. void mjpeg_close(MpegEncContext *s)

  276. {

  277.     av_free(s->mjpeg_ctx);

  278. }

  279. 

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

  281. {

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

  283.     put_bits(p, 8, code);

  284. }

  285. 

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

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

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

  289. {

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

  291.     int n, i;

  292. 

  293.     put_bits(p, 4, table_class);

  294.     put_bits(p, 4, table_id);

  295. 

  296.     n = 0;

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

  298.         n += bits_table[i];

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

  300.     }

  301. 

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

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

  304. 

  305.     return n + 17;

  306. }

  307. 

  308. static void jpeg_table_header(MpegEncContext *s)

  309. {

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

  311.     int i, j, size;

  312.     UINT8 *ptr;

  313. 

  314.     /* quant matrixes */

  315.     put_marker(p, DQT);

  316. #ifdef TWOMATRIXES

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

  318. #else

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

  320. #endif

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

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

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

  324.         j = zigzag_direct[i];

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

  326.     }

  327. #ifdef TWOMATRIXES

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

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

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

  331.         j = zigzag_direct[i];

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

  333.     }

  334. #endif

  335. 

  336.     /* huffman table */

  337.     put_marker(p, DHT);

  338.     flush_put_bits(p);

  339.     ptr = pbBufPtr(p);

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

  341.     size = 2;

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

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

  344.     

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

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

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

  348.     ptr[1] = size;

  349. }

  350. 

  351. static void jpeg_put_comments(MpegEncContext *s)

  352. {

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

  354.     int size;

  355.     UINT8 *ptr;

  356. 

  357. #if 0

  358.     /* JFIF header */

  359.     put_marker(p, APP0);

  360.     put_bits(p, 16, 16);

  361.     put_string(p, "JFIF"); /* this puts the trailing zero-byte too */

  362.     put_bits(p, 16, 0x101);

  363.     put_bits(p, 8, 0); /* units type: 0 - aspect ratio */

  364.     put_bits(p, 16, 1); /* aspect: 1:1 */

  365.     put_bits(p, 16, 1);

  366.     put_bits(p, 8, 0); /* thumbnail width */

  367.     put_bits(p, 8, 0); /* thumbnail height */

  368. #endif

  369. 

  370.     /* comment */

  371.     put_marker(p, COM);

  372.     flush_put_bits(p);

  373.     ptr = pbBufPtr(p);

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

  375. #define VERSION "FFmpeg" LIBAVCODEC_VERSION "b" LIBAVCODEC_BUILD_STR

  376.     put_string(p, VERSION);

  377.     size = strlen(VERSION)+3;

  378. #undef VERSION

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

  380.     ptr[1] = size;

  381. }

  382. 

  383. void mjpeg_picture_header(MpegEncContext *s)

  384. {

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

  386. 

  387.     if (!s->mjpeg_data_only_frames)

  388.     {

  389.     jpeg_put_comments(s);    

  390. 

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

  392. 

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

  394. 

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

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

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

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

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

  400.     

  401.     /* Y component */

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

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

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

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

  406.     

  407.     /* Cb component */

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

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

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

  411. #ifdef TWOMATRIXES

  412.     put_bits(&s->pb, 8, 1); /* select matrix */

  413. #else

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

  415. #endif

  416. 

  417.     /* Cr component */

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

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

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

  421. #ifdef TWOMATRIXES

  422.     put_bits(&s->pb, 8, 1); /* select matrix */

  423. #else

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

  425. #endif

  426.     }

  427. 

  428.     /* scan header */

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

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

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

  432.     

  433.     /* Y component */

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

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

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

  437.     

  438.     /* Cb component */

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

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

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

  442.     

  443.     /* Cr component */

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

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

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

  447. 

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

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

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

  451. }

  452. 

  453. void mjpeg_picture_trailer(MpegEncContext *s)

  454. {

  455.     jflush_put_bits(&s->pb);

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

  457. }

  458. 

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

  460.                              UINT8 *huff_size, UINT16 *huff_code)

  461. {

  462.     int mant, nbits;

  463. 

  464.     if (val == 0) {

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

  466.     } else {

  467.         mant = val;

  468.         if (val < 0) {

  469.             val = -val;

  470.             mant--;

  471.         }

  472.         

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

  474.         nbits = 0;

  475.         while (val != 0) {

  476.             val = val >> 1;

  477.             nbits++;

  478.         }

  479.             

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

  481.         

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

  483.     }

  484. }

  485. 

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

  487. {

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

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

  490.     MJpegContext *m = s->mjpeg_ctx;

  491.     UINT8 *huff_size_ac;

  492.     UINT16 *huff_code_ac;

  493.     

  494.     /* DC coef */

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

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

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

  498.     if (n < 4) {

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

  500.         huff_size_ac = m->huff_size_ac_luminance;

  501.         huff_code_ac = m->huff_code_ac_luminance;

  502.     } else {

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

  504.         huff_size_ac = m->huff_size_ac_chrominance;

  505.         huff_code_ac = m->huff_code_ac_chrominance;

  506.     }

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

  508.     

  509.     /* AC coefs */

  510.     

  511.     run = 0;

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

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

  514.         j = zigzag_direct[i];

  515.         val = block[j];

  516.         if (val == 0) {

  517.             run++;

  518.         } else {

  519.             while (run >= 16) {

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

  521.                 run -= 16;

  522.             }

  523.             mant = val;

  524.             if (val < 0) {

  525.                 val = -val;

  526.                 mant--;

  527.             }

  528.             

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

  530.             nbits = 0;

  531.             while (val != 0) {

  532.                 val = val >> 1;

  533.                 nbits++;

  534.             }

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

  536. 

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

  538.         

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

  540.             run = 0;

  541.         }

  542.     }

  543. 

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

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

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

  547. }

  548. 

  549. void mjpeg_encode_mb(MpegEncContext *s, 

  550.                      DCTELEM block[6][64])

  551. {

  552.     int i;

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

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

  555.     }

  556. }

  557. 

  558. /******************************************/

  559. /* decoding */

  560. 

  561. /* compressed picture size */

  562. #define PICTURE_BUFFER_SIZE 100000

  563. 

  564. #define MAX_COMPONENTS 4

  565. 

  566. typedef struct MJpegDecodeContext {

  567.     AVCodecContext *avctx;

  568.     GetBitContext gb;

  569.     UINT32 header_state;

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

  571.     UINT8 *buf_ptr;

  572.     int buffer_size;

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

  574.     INT16 quant_matrixes[4][64];

  575.     VLC vlcs[2][4];

  576. 

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

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

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

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

  581. 

  582.     int width, height;

  583.     int nb_components;

  584.     int component_id[MAX_COMPONENTS];

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

  586.     int v_count[MAX_COMPONENTS];

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

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

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

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

  591.     int linesize[MAX_COMPONENTS];

  592.     DCTELEM block[64] __align8;

  593.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  594. 

  595.     int buggy_avid;

  596.     int restart_interval;

  597.     int restart_count;

  598.     int interleaved_rows;

  599. } MJpegDecodeContext;

  600. 

  601. #define SKIP_REMAINING(gb, len) { \

  602.     dprintf("reamining %d bytes in marker\n", len); \

  603.     if (len) while (--len) \

  604. 	skip_bits(gb, 8); \

  605. }

  606. 

  607. static int mjpeg_decode_dht(MJpegDecodeContext *s, UINT8 *buf, int buf_size);

  608. 

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

  610.                       int nb_codes)

  611. {

  612.     UINT8 huff_size[256];

  613.     UINT16 huff_code[256];

  614. 

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

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

  617.     

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

  619. }

  620. 

  621. static int mjpeg_decode_init(AVCodecContext *avctx)

  622. {

  623.     MJpegDecodeContext *s = avctx->priv_data;

  624. 

  625.     s->avctx = avctx;

  626. 

  627.     s->header_state = 0;

  628.     s->mpeg_enc_ctx_allocated = 0;

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

  630.                                                  account FF 00 case */

  631.     s->start_code = -1;

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

  633.     s->first_picture = 1;

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

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

  636. 

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

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

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

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

  641.     

  642.     if (avctx->flags & CODEC_FLAG_EXTERN_HUFF)

  643.     {

  644. 	printf("mjpeg: using external huffman table\n");

  645. 	mjpeg_decode_dht(s, avctx->extradata, avctx->extradata_size);

  646. 	/* should check for error - but dunno */

  647.     }

  648.     return 0;

  649. }

  650. 

  651. /* quantize tables */

  652. static int mjpeg_decode_dqt(MJpegDecodeContext *s,

  653.                             UINT8 *buf, int buf_size)

  654. {

  655.     int len, index, i, j;

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

  657.     

  658.     len = get_bits(&s->gb, 16) - 2;

  659. 

  660.     while (len >= 65) {

  661.         /* only 8 bit precision handled */

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

  663. 	{

  664. 	    dprintf("dqt: 16bit precision\n");

  665.             return -1;

  666. 	}

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

  668.         if (index >= 4)

  669.             return -1;

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

  671.         /* read quant table */

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

  673.             j = zigzag_direct[i];

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

  675.         }

  676.         len -= 65;

  677.     }

  678.     

  679.     SKIP_REMAINING(&s->gb, len);

  680. 

  681.     return 0;

  682. }

  683. 

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

  685. static int mjpeg_decode_dht(MJpegDecodeContext *s,

  686.                             UINT8 *buf, int buf_size)

  687. {

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

  689.     UINT8 bits_table[17];

  690.     UINT8 val_table[256];

  691.     

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

  693. 

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

  695.     len -= 2;

  696. 

  697.     while (len > 0) {

  698.         if (len < 17)

  699.             return -1;

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

  701.         if (class >= 2)

  702.             return -1;

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

  704.         if (index >= 4)

  705.             return -1;

  706.         n = 0;

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

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

  709.             n += bits_table[i];

  710.         }

  711.         len -= 17;

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

  713.             return -1;

  714. 

  715.         code_max = 0;

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

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

  718.             if (v > code_max)

  719.                 code_max = v;

  720.             val_table[i] = v;

  721.         }

  722.         len -= n;

  723. 

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

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

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

  727.                class, index, code_max + 1);

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

  729.     }

  730.     return 0;

  731. }

  732. 

  733. static int mjpeg_decode_sof0(MJpegDecodeContext *s,

  734.                              UINT8 *buf, int buf_size)

  735. {

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

  737. 

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

  739. 

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

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

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

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

  744.         return -1;

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

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

  747.     dprintf("sof0: picture: %dx%d\n", width, height);

  748. 

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

  750.     if (nb_components <= 0 ||

  751.         nb_components > MAX_COMPONENTS)

  752.         return -1;

  753.     s->nb_components = nb_components;

  754.     s->h_max = 1;

  755.     s->v_max = 1;

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

  757.         /* component id */

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

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

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

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

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

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

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

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

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

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

  768.             return -1;

  769.         dprintf("component %d %d:%d id: %d quant:%d\n", i, s->h_count[i],

  770. 	    s->v_count[i], s->component_id[i], s->quant_index[i]);

  771.     }

  772. 

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

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

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

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

  777.             av_freep(&s->current_picture[i]);

  778.         s->width = width;

  779.         s->height = height;

  780.         /* test interlaced mode */

  781.         if (s->first_picture &&

  782.             s->org_height != 0 &&

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

  784.             s->interlaced = 1;

  785. 	    s->bottom_field = 0;

  786.         }

  787. 

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

  789.             int w, h;

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

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

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

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

  794.             if (s->interlaced)

  795.                 w *= 2;

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

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

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

  799.         }

  800.         s->first_picture = 0;

  801.     }

  802. 

  803.     if (len != (8+(3*nb_components)))

  804.     {

  805. 	dprintf("decode_sof0: error, len(%d) mismatch\n", len);

  806.     }

  807.     

  808.     return 0;

  809. }

  810. 

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

  812. {

  813.     int code, diff;

  814. 

  815.     code = get_vlc(&s->gb, &s->vlcs[0][dc_index]);

  816.     if (code < 0)

  817.     {

  818. 	dprintf("decode_dc: bad vlc: %d:%d (%x)\n", 0, dc_index,

  819. 	    &s->vlcs[0][dc_index]);

  820.         return 0xffff;

  821.     }

  822.     if (code == 0) {

  823.         diff = 0;

  824.     } else {

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

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

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

  828.     }

  829.     return diff;

  830. }

  831. 

  832. /* decode block and dequantize */

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

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

  835. {

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

  837.     int run, val;

  838.     VLC *ac_vlc;

  839.     INT16 *quant_matrix;

  840. 

  841.     /* DC coef */

  842.     val = decode_dc(s, dc_index);

  843.     if (val == 0xffff) {

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

  845.         return -1;

  846.     }

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

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

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

  850.     block[0] = val;

  851.     /* AC coefs */

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

  853.     i = 1;

  854.     for(;;) {

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

  856.         if (code < 0) {

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

  858.             return -1;

  859.         }

  860.         /* EOB */

  861.         if (code == 0)

  862.             break;

  863.         if (code == 0xf0) {

  864.             i += 16;

  865.         } else {

  866.             run = code >> 4;

  867.             nbits = code & 0xf;

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

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

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

  871.             i += run;

  872.             if (i >= 64) {

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

  874.                 return -1;

  875.             }

  876.             j = zigzag_direct[i];

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

  878.             i++;

  879.             if (i >= 64)

  880.                 break;

  881.         }

  882.     }

  883.     return 0;

  884. }

  885. 

  886. static int mjpeg_decode_sos(MJpegDecodeContext *s,

  887.                             UINT8 *buf, int buf_size)

  888. {

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

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

  891.     int comp_index[4];

  892.     int dc_index[4];

  893.     int ac_index[4];

  894.     int nb_blocks[4];

  895.     int h_count[4];

  896.     int v_count[4];

  897.     

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

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

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

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

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

  903.     if (nb_components != 3)

  904.     {

  905. 	dprintf("decode_sos: components(%d) mismatch\n", nb_components);

  906.         return -1;

  907.     }

  908.     vmax = 0;

  909.     hmax = 0;

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

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

  912. 	dprintf("component: %d\n", id);

  913.         /* find component index */

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

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

  916.                 break;

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

  918. 	{

  919. 	    dprintf("decode_sos: index(%d) out of components\n", index);

  920.             return -1;

  921. 	}

  922. 

  923.         comp_index[i] = index;

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

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

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

  927. 

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

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

  930. 

  931. 	if (dc_index[i] < 0 || ac_index[i] < 0 ||

  932. 	    dc_index[i] >= 4 || ac_index[i] >= 4)

  933. 	    goto out_of_range;

  934. 	switch(s->start_code)

  935. 	{

  936. 	    case SOF0:

  937. 		if (dc_index[i] > 1 || ac_index[i] > 1)

  938. 		    goto out_of_range;

  939. 		break;

  940. 	    case SOF1:

  941. 	    case SOF2:

  942. 		if (dc_index[i] > 3 || ac_index[i] > 3)

  943. 		    goto out_of_range;

  944. 		break;

  945. 	    case SOF3:

  946. 		if (dc_index[i] > 3 || ac_index[i] != 0)

  947. 		    goto out_of_range;

  948. 		break;	

  949. 	}

  950.     }

  951.     skip_bits(&s->gb, 8); /* Ss */

  952.     skip_bits(&s->gb, 8); /* Se */

  953.     skip_bits(&s->gb, 8); /* Ah and Al (each are 4 bits) */

  954. 

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

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

  957. 

  958.     if (nb_components > 1) {

  959.         /* interleaved stream */

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

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

  962.     } else {

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

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

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

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

  967.         nb_blocks[0] = 1;

  968.         h_count[0] = 1;

  969.         v_count[0] = 1;

  970.     }

  971. 

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

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

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

  975.                 UINT8 *ptr;

  976.                 int x, y, c;

  977.                 n = nb_blocks[i];

  978.                 c = comp_index[i];

  979.                 h = h_count[i];

  980.                 v = v_count[i];

  981.                 x = 0;

  982.                 y = 0;

  983. 		if (s->restart_interval && !s->restart_count)

  984. 		    s->restart_count = s->restart_interval;

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

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

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

  988.                                      dc_index[i], ac_index[i], 

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

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

  991.                         ret = -1;

  992.                         goto the_end;

  993.                     }

  994. //		    dprintf("mb: %d %d processed\n", mb_y, mb_x);

  995.                     ff_idct (s->block);

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

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

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

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

  1000.                         ptr += s->linesize[c] >> 1;

  1001.                     put_pixels_clamped(s->block, ptr, s->linesize[c]);

  1002.                     if (++x == h) {

  1003.                         x = 0;

  1004.                         y++;

  1005.                     }

  1006.                 }

  1007.             }

  1008.         }

  1009.     }

  1010.     ret = 0;

  1011.  the_end:

  1012.     emms_c();

  1013.     return ret;

  1014.  out_of_range:

  1015.     dprintf("decode_sos: ac/dc index out of range\n");

  1016.     return -1;

  1017. }

  1018. 

  1019. static int mjpeg_decode_dri(MJpegDecodeContext *s,

  1020.                              UINT8 *buf, int buf_size)

  1021. {

  1022.     init_get_bits(&s->gb, buf, buf_size);

  1023. 

  1024.     if (get_bits(&s->gb, 16) != 4)

  1025. 	return -1;

  1026.     s->restart_interval = get_bits(&s->gb, 16);

  1027.     printf("restart interval: %d\n", s->restart_interval);

  1028. 

  1029.     return 0;

  1030. }

  1031. 

  1032. #define FOURCC(a,b,c,d) ((a << 24) | (b << 16) | (c << 8) | d)

  1033. static int mjpeg_decode_app(MJpegDecodeContext *s,

  1034.                              UINT8 *buf, int buf_size, int start_code)

  1035. {

  1036.     int len, id;

  1037. 

  1038.     init_get_bits(&s->gb, buf, buf_size);

  1039. 

  1040.     /* XXX: verify len field validity */

  1041.     len = get_bits(&s->gb, 16);

  1042.     if (len < 5)

  1043. 	return -1;

  1044. 

  1045.     id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);

  1046.     len -= 6;

  1047. 

  1048.     /* buggy AVID, it puts EOI only at every 10th frame */

  1049.     /* also this fourcc is used by non-avid files too, it means

  1050.        interleaving, but it's always present in AVID files */

  1051.     if (id == FOURCC('A','V','I','1'))

  1052.     {

  1053. 	/* structure:

  1054. 	    4bytes	AVI1

  1055. 	    1bytes	polarity

  1056. 	    1bytes	always zero

  1057. 	    4bytes	field_size

  1058. 	    4bytes	field_size_less_padding

  1059. 	*/

  1060.     	s->buggy_avid = 1;

  1061. 	if (s->first_picture)

  1062. 	    printf("mjpeg: workarounding buggy AVID\n");

  1063. 	s->interleaved_rows = get_bits(&s->gb, 8);

  1064. #if 0

  1065. 	skip_bits(&s->gb, 8);

  1066. 	skip_bits(&s->gb, 32);

  1067. 	skip_bits(&s->gb, 32);

  1068. 	len -= 10;

  1069. #endif

  1070. 	if (s->interleaved_rows)

  1071. 	    printf("mjpeg: interleaved rows: %d\n", s->interleaved_rows);

  1072. 	goto out;

  1073.     }

  1074.     

  1075.     len -= 2;

  1076.     

  1077.     if (id == FOURCC('J','F','I','F'))

  1078.     {

  1079. 	skip_bits(&s->gb, 8); /* the trailing zero-byte */

  1080. 	printf("mjpeg: JFIF header found (version: %x.%x)\n",

  1081. 	    get_bits(&s->gb, 8), get_bits(&s->gb, 8));

  1082. 	goto out;

  1083.     }

  1084.     

  1085.     /* Apple MJPEG-A */

  1086.     if ((start_code == APP1) && (len > (0x28 - 8)))

  1087.     {

  1088. 	id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);

  1089. 	len -= 4;

  1090.         if (id == FOURCC('m','j','p','g')) /* Apple MJPEG-A */

  1091. 	{

  1092. #if 0

  1093. 	    skip_bits(&s->gb, 32); /* field size */

  1094. 	    skip_bits(&s->gb, 32); /* pad field size */

  1095. 	    skip_bits(&s->gb, 32); /* next off */

  1096. 	    skip_bits(&s->gb, 32); /* quant off */

  1097. 	    skip_bits(&s->gb, 32); /* huff off */

  1098. 	    skip_bits(&s->gb, 32); /* image off */

  1099. 	    skip_bits(&s->gb, 32); /* scan off */

  1100. 	    skip_bits(&s->gb, 32); /* data off */

  1101. #endif

  1102. 	    if (s->first_picture)

  1103. 		printf("mjpeg: Apple MJPEG-A header found\n");

  1104. 	}

  1105.     }

  1106. 

  1107. out:

  1108.     /* should check for further values.. */

  1109.     SKIP_REMAINING(&s->gb, len);

  1110. 

  1111.     return 0;

  1112. }

  1113. #undef FOURCC

  1114. 

  1115. static int mjpeg_decode_com(MJpegDecodeContext *s,

  1116.                              UINT8 *buf, int buf_size)

  1117. {

  1118.     int len, i;

  1119.     UINT8 *cbuf;

  1120. 

  1121.     init_get_bits(&s->gb, buf, buf_size);

  1122. 

  1123.     /* XXX: verify len field validity */

  1124.     len = get_bits(&s->gb, 16)-2;

  1125.     cbuf = av_malloc(len+1);

  1126. 

  1127.     for (i = 0; i < len; i++)

  1128. 	cbuf[i] = get_bits(&s->gb, 8);

  1129.     if (cbuf[i-1] == '\n')

  1130. 	cbuf[i-1] = 0;

  1131.     else

  1132. 	cbuf[i] = 0;

  1133. 

  1134.     printf("mjpeg comment: '%s'\n", cbuf);

  1135. 

  1136.     /* buggy avid, it puts EOI only at every 10th frame */

  1137.     if (!strcmp(cbuf, "AVID"))

  1138.     {

  1139. 	s->buggy_avid = 1;

  1140. 	if (s->first_picture)

  1141. 	    printf("mjpeg: workarounding buggy AVID\n");

  1142.     }

  1143.     

  1144.     av_free(cbuf);

  1145. 

  1146.     return 0;

  1147. }

  1148. 

  1149. /* return the 8 bit start code value and update the search

  1150.    state. Return -1 if no start code found */

  1151. static int find_marker(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1152.                        UINT32 *header_state)

  1153. {

  1154.     UINT8 *buf_ptr;

  1155.     unsigned int state, v;

  1156.     int val;

  1157. 

  1158.     state = *header_state;

  1159.     buf_ptr = *pbuf_ptr;

  1160.     if (state) {

  1161.         /* get marker */

  1162.     found:

  1163.         if (buf_ptr < buf_end) {

  1164.             val = *buf_ptr++;

  1165.             state = 0;

  1166.         } else {

  1167.             val = -1;

  1168.         }

  1169.     } else {

  1170.         while (buf_ptr < buf_end) {

  1171.             v = *buf_ptr++;

  1172.             if (v == 0xff) {

  1173.                 state = 1;

  1174.                 goto found;

  1175.             }

  1176.         }

  1177.         val = -1;

  1178.     }

  1179.     *pbuf_ptr = buf_ptr;

  1180.     *header_state = state;

  1181.     return val;

  1182. }

  1183. 

  1184. static int mjpeg_decode_frame(AVCodecContext *avctx, 

  1185.                               void *data, int *data_size,

  1186.                               UINT8 *buf, int buf_size)

  1187. {

  1188.     MJpegDecodeContext *s = avctx->priv_data;

  1189.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1190.     int len, code, input_size, i;

  1191.     AVPicture *picture = data;

  1192.     unsigned int start_code;

  1193. 

  1194.     *data_size = 0;

  1195. 

  1196.     /* no supplementary picture */

  1197.     if (buf_size == 0)

  1198.         return 0;

  1199. 

  1200.     buf_ptr = buf;

  1201.     buf_end = buf + buf_size;

  1202.     while (buf_ptr < buf_end) {

  1203.         buf_start = buf_ptr;

  1204.         /* find start next marker */

  1205.         code = find_marker(&buf_ptr, buf_end, &s->header_state);

  1206.         /* copy to buffer */

  1207.         len = buf_ptr - buf_start;

  1208.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1209.             /* data too big : flush */

  1210.             s->buf_ptr = s->buffer;

  1211.             if (code > 0)

  1212.                 s->start_code = code;

  1213.         } else {

  1214.             memcpy(s->buf_ptr, buf_start, len);

  1215.             s->buf_ptr += len;

  1216.             /* if we got FF 00, we copy FF to the stream to unescape FF 00 */

  1217. 	    /* valid marker code is between 00 and ff - alex */

  1218. 	    if (code <= 0 || code >= 0xff) {

  1219.                 s->buf_ptr--;

  1220.             } else {

  1221.                 /* prepare data for next start code */

  1222.                 input_size = s->buf_ptr - s->buffer;

  1223.                 start_code = s->start_code;

  1224.                 s->buf_ptr = s->buffer;

  1225.                 s->start_code = code;

  1226.                 dprintf("marker=%x\n", start_code);

  1227.                 switch(start_code) {

  1228.                 case SOI:

  1229. 		    s->restart_interval = 0;

  1230.                     /* nothing to do on SOI */

  1231.                     break;

  1232.                 case DQT:

  1233.                     mjpeg_decode_dqt(s, s->buffer, input_size);

  1234.                     break;

  1235.                 case DHT:

  1236.                     mjpeg_decode_dht(s, s->buffer, input_size);

  1237.                     break;

  1238.                 case SOF0:

  1239.                     mjpeg_decode_sof0(s, s->buffer, input_size);

  1240.                     break;

  1241.                 case SOS:

  1242.                     mjpeg_decode_sos(s, s->buffer, input_size);

  1243.                     if (s->start_code == EOI || s->buggy_avid || s->restart_interval) {

  1244.                         int l;

  1245.                         if (s->interlaced) {

  1246.                             s->bottom_field ^= 1;

  1247.                             /* if not bottom field, do not output image yet */

  1248.                             if (s->bottom_field)

  1249.                                 goto the_end;

  1250.                         }

  1251.                         for(i=0;i<3;i++) {

  1252.                             picture->data[i] = s->current_picture[i];

  1253.                             l = s->linesize[i];

  1254.                             if (s->interlaced)

  1255.                                 l >>= 1;

  1256.                             picture->linesize[i] = l;

  1257.                         }

  1258.                         *data_size = sizeof(AVPicture);

  1259.                         avctx->height = s->height;

  1260.                         if (s->interlaced)

  1261.                             avctx->height *= 2;

  1262.                         avctx->width = s->width;

  1263.                         /* XXX: not complete test ! */

  1264.                         switch((s->h_count[0] << 4) | s->v_count[0]) {

  1265.                         case 0x11:

  1266.                             avctx->pix_fmt = PIX_FMT_YUV444P;

  1267.                             break;

  1268.                         case 0x21:

  1269.                             avctx->pix_fmt = PIX_FMT_YUV422P;

  1270.                             break;

  1271.                         default:

  1272.                         case 0x22:

  1273.                             avctx->pix_fmt = PIX_FMT_YUV420P;

  1274.                             break;

  1275.                         }

  1276.                         /* dummy quality */

  1277.                         /* XXX: infer it with matrix */

  1278.                     	avctx->quality = 3; 

  1279.                         goto the_end;

  1280.                     }

  1281.                     break;

  1282. 		case DRI:

  1283. 		    mjpeg_decode_dri(s, s->buffer, input_size);

  1284. 		    break;

  1285. 		case SOF1:

  1286. 		case SOF2:

  1287. 		case SOF3:

  1288. 		case SOF5:

  1289. 		case SOF6:

  1290. 		case SOF7:

  1291. 		case SOF9:

  1292. 		case SOF10:

  1293. 		case SOF11:

  1294. 		case SOF13:

  1295. 		case SOF14:

  1296. 		case SOF15:

  1297. 		case JPG:

  1298. 		    printf("mjpeg: unsupported coding type (%x)\n", start_code);

  1299. 		    return -1;

  1300.                 }

  1301. #if 1

  1302. 		if (start_code >= 0xd0 && start_code <= 0xd7)

  1303. 		{

  1304. 		    dprintf("restart marker: %d\n", start_code&0x0f);

  1305. 		}

  1306. 		else if (s->first_picture)

  1307. 		{

  1308. 		    /* APP fields */

  1309. 		    if (start_code >= 0xe0 && start_code <= 0xef)

  1310. 			mjpeg_decode_app(s, s->buffer, input_size, start_code);

  1311. 		    /* Comment */

  1312. 		    else if (start_code == COM)

  1313. 			mjpeg_decode_com(s, s->buffer, input_size);

  1314. 		}

  1315. #endif

  1316.             }

  1317.         }

  1318.     }

  1319.  the_end:

  1320.     return buf_ptr - buf;

  1321. }

  1322. 

  1323. static int mjpeg_decode_end(AVCodecContext *avctx)

  1324. {

  1325.     MJpegDecodeContext *s = avctx->priv_data;

  1326.     int i, j;

  1327. 

  1328.     for(i=0;i<MAX_COMPONENTS;i++)

  1329.         av_free(s->current_picture[i]);

  1330.     for(i=0;i<2;i++) {

  1331.         for(j=0;j<4;j++)

  1332.             free_vlc(&s->vlcs[i][j]);

  1333.     }

  1334.     return 0;

  1335. }

  1336. 

  1337. AVCodec mjpeg_decoder = {

  1338.     "mjpeg",

  1339.     CODEC_TYPE_VIDEO,

  1340.     CODEC_ID_MJPEG,

  1341.     sizeof(MJpegDecodeContext),

  1342.     mjpeg_decode_init,

  1343.     NULL,

  1344.     mjpeg_decode_end,

  1345.     mjpeg_decode_frame,

  1346.     0,

  1347.     NULL

  1348. };