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FFmpeg/libavcodec/mjpeg.c

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  1. /*

  2.  * MJPEG encoder and decoder

  3.  * Copyright (c) 2000, 2001 Fabrice Bellard.

  4.  *

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

  6.  * modify it under the terms of the GNU Lesser General Public

  7.  * License as published by the Free Software Foundation; either

  8.  * version 2 of the License, or (at your option) any later version.

  9.  *

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

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

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

  13.  * Lesser General Public License for more details.

  14.  *

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

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

  17.  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  18.  *

  19.  * Support for external huffman table, various fixes (AVID workaround),

  20.  * aspecting and various markers support

  21.  *                                  by Alex Beregszaszi <alex@naxine.org>

  22.  */

  23. //#define DEBUG

  24. #include "avcodec.h"

  25. #include "dsputil.h"

  26. #include "mpegvideo.h"

  27. 

  28. #ifdef USE_FASTMEMCPY

  29. #include "fastmemcpy.h"

  30. #endif

  31. 

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

  33. /* not yet working */

  34. #undef TWOMATRIXES

  35. 

  36. typedef struct MJpegContext {

  37.     UINT8 huff_size_dc_luminance[12];

  38.     UINT16 huff_code_dc_luminance[12];

  39.     UINT8 huff_size_dc_chrominance[12];

  40.     UINT16 huff_code_dc_chrominance[12];

  41. 

  42.     UINT8 huff_size_ac_luminance[256];

  43.     UINT16 huff_code_ac_luminance[256];

  44.     UINT8 huff_size_ac_chrominance[256];

  45.     UINT16 huff_code_ac_chrominance[256];

  46. } MJpegContext;

  47. 

  48. /* JPEG marker codes */

  49. typedef enum {

  50.     /* start of frame */

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

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

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

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

  55. 

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

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

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

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

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

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

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

  63. 

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

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

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

  67. 

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

  69. 

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

  71. 

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

  73.     RST0  = 0xd0,

  74.     RST1  = 0xd1,

  75.     RST2  = 0xd2,

  76.     RST3  = 0xd3,

  77.     RST4  = 0xd4,

  78.     RST5  = 0xd5,

  79.     RST6  = 0xd6,

  80.     RST7  = 0xd7,

  81. 

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

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

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

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

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

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

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

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

  90. 

  91.     APP0  = 0xe0,

  92.     APP1  = 0xe1,

  93.     APP2  = 0xe2,

  94.     APP3  = 0xe3,

  95.     APP4  = 0xe4,

  96.     APP5  = 0xe5,

  97.     APP6  = 0xe6,

  98.     APP7  = 0xe7,

  99.     APP8  = 0xe8,

  100.     APP9  = 0xe9,

  101.     APP10 = 0xea,

  102.     APP11 = 0xeb,

  103.     APP12 = 0xec,

  104.     APP13 = 0xed,

  105.     APP14 = 0xee,

  106.     APP15 = 0xef,

  107. 

  108.     JPG0  = 0xf0,

  109.     JPG1  = 0xf1,

  110.     JPG2  = 0xf2,

  111.     JPG3  = 0xf3,

  112.     JPG4  = 0xf4,

  113.     JPG5  = 0xf5,

  114.     JPG6  = 0xf6,

  115.     JPG7  = 0xf7,

  116.     JPG8  = 0xf8,

  117.     JPG9  = 0xf9,

  118.     JPG10 = 0xfa,

  119.     JPG11 = 0xfb,

  120.     JPG12 = 0xfc,

  121.     JPG13 = 0xfd,

  122. 

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

  124. 

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

  126. 

  127.     /* 0x02 -> 0xbf reserved */

  128. } JPEG_MARKER;

  129. 

  130. #if 0

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

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

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

  134.  */

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

  136.     16,  11,  10,  16,  24,  40,  51,  61,

  137.     12,  12,  14,  19,  26,  58,  60,  55,

  138.     14,  13,  16,  24,  40,  57,  69,  56,

  139.     14,  17,  22,  29,  51,  87,  80,  62,

  140.     18,  22,  37,  56,  68, 109, 103,  77,

  141.     24,  35,  55,  64,  81, 104, 113,  92,

  142.     49,  64,  78,  87, 103, 121, 120, 101,

  143.     72,  92,  95,  98, 112, 100, 103,  99

  144. };

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

  146.     17,  18,  24,  47,  99,  99,  99,  99,

  147.     18,  21,  26,  66,  99,  99,  99,  99,

  148.     24,  26,  56,  99,  99,  99,  99,  99,

  149.     47,  66,  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.     99,  99,  99,  99,  99,  99,  99,  99

  154. };

  155. #endif

  156. 

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

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

  159. static const UINT8 bits_dc_luminance[17] =

  160. { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };

  161. static const UINT8 val_dc_luminance[] =

  162. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  163. 

  164. static const UINT8 bits_dc_chrominance[17] =

  165. { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };

  166. static const UINT8 val_dc_chrominance[] =

  167. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  168. 

  169. static const UINT8 bits_ac_luminance[17] =

  170. { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };

  171. static const UINT8 val_ac_luminance[] =

  172. { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

  173.   0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

  174.   0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,

  175.   0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,

  176.   0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,

  177.   0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,

  178.   0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

  179.   0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

  180.   0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

  181.   0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

  182.   0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

  183.   0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

  184.   0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

  185.   0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,

  186.   0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,

  187.   0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,

  188.   0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,

  189.   0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,

  190.   0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,

  191.   0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  192.   0xf9, 0xfa 

  193. };

  194. 

  195. static const UINT8 bits_ac_chrominance[17] =

  196. { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };

  197. 

  198. static const UINT8 val_ac_chrominance[] =

  199. { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

  200.   0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

  201.   0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

  202.   0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,

  203.   0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,

  204.   0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,

  205.   0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,

  206.   0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

  207.   0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

  208.   0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

  209.   0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

  210.   0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

  211.   0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,

  212.   0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,

  213.   0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,

  214.   0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,

  215.   0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,

  216.   0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,

  217.   0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,

  218.   0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  219.   0xf9, 0xfa 

  220. };

  221. 

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

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

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

  225. {

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

  227. 

  228.     code = 0;

  229.     k = 0;

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

  231.         nb = bits_table[i];

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

  233.             sym = val_table[k++];

  234.             huff_size[sym] = i;

  235.             huff_code[sym] = code;

  236.             code++;

  237.         }

  238.         code <<= 1;

  239.     }

  240. }

  241. 

  242. int mjpeg_init(MpegEncContext *s)

  243. {

  244.     MJpegContext *m;

  245.     

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

  247.     if (!m)

  248.         return -1;

  249.     

  250.     s->min_qcoeff=-1023;

  251.     s->max_qcoeff= 1023;

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

  253. 

  254.     /* build all the huffman tables */

  255.     build_huffman_codes(m->huff_size_dc_luminance,

  256.                         m->huff_code_dc_luminance,

  257.                         bits_dc_luminance,

  258.                         val_dc_luminance);

  259.     build_huffman_codes(m->huff_size_dc_chrominance,

  260.                         m->huff_code_dc_chrominance,

  261.                         bits_dc_chrominance,

  262.                         val_dc_chrominance);

  263.     build_huffman_codes(m->huff_size_ac_luminance,

  264.                         m->huff_code_ac_luminance,

  265.                         bits_ac_luminance,

  266.                         val_ac_luminance);

  267.     build_huffman_codes(m->huff_size_ac_chrominance,

  268.                         m->huff_code_ac_chrominance,

  269.                         bits_ac_chrominance,

  270.                         val_ac_chrominance);

  271.     

  272.     s->mjpeg_ctx = m;

  273.     return 0;

  274. }

  275. 

  276. void mjpeg_close(MpegEncContext *s)

  277. {

  278.     av_free(s->mjpeg_ctx);

  279. }

  280. 

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

  282. {

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

  284.     put_bits(p, 8, code);

  285. }

  286. 

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

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

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

  290. {

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

  292.     int n, i;

  293. 

  294.     put_bits(p, 4, table_class);

  295.     put_bits(p, 4, table_id);

  296. 

  297.     n = 0;

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

  299.         n += bits_table[i];

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

  301.     }

  302. 

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

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

  305. 

  306.     return n + 17;

  307. }

  308. 

  309. static void jpeg_table_header(MpegEncContext *s)

  310. {

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

  312.     int i, j, size;

  313.     UINT8 *ptr;

  314. 

  315.     /* quant matrixes */

  316.     put_marker(p, DQT);

  317. #ifdef TWOMATRIXES

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

  319. #else

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

  321. #endif

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

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

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

  325.         j = zigzag_direct[i];

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

  327.     }

  328. #ifdef TWOMATRIXES

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

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

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

  332.         j = zigzag_direct[i];

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

  334.     }

  335. #endif

  336. 

  337.     /* huffman table */

  338.     put_marker(p, DHT);

  339.     flush_put_bits(p);

  340.     ptr = pbBufPtr(p);

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

  342.     size = 2;

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

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

  345.     

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

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

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

  349.     ptr[1] = size;

  350. }

  351. 

  352. static void jpeg_put_comments(MpegEncContext *s)

  353. {

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

  355.     int size;

  356.     UINT8 *ptr;

  357. 

  358.     if (s->aspect_ratio_info)

  359.     {

  360.     /* JFIF header */

  361.     put_marker(p, APP0);

  362.     put_bits(p, 16, 16);

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

  364.     put_bits(p, 16, 0x0201); /* v 1.02 */

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

  366.     switch(s->aspect_ratio_info)

  367.     {

  368. 	case FF_ASPECT_4_3_625:

  369. 	case FF_ASPECT_4_3_525:

  370. 	    put_bits(p, 16, 4); 

  371. 	    put_bits(p, 16, 3);

  372. 	    break;

  373. 	case FF_ASPECT_16_9_625:

  374. 	case FF_ASPECT_16_9_525:

  375. 	    put_bits(p, 16, 16); 

  376. 	    put_bits(p, 16, 9);

  377. 	    break;

  378. 	case FF_ASPECT_EXTENDED:

  379. 	    put_bits(p, 16, s->aspected_width);

  380. 	    put_bits(p, 16, s->aspected_height);

  381. 	    break;

  382. 	case FF_ASPECT_SQUARE:

  383. 	default:

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

  385. 	    put_bits(p, 16, 1);

  386. 	    break;

  387.     }

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

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

  390.     }

  391. 

  392.     /* comment */

  393.     put_marker(p, COM);

  394.     flush_put_bits(p);

  395.     ptr = pbBufPtr(p);

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

  397. #define MJPEG_VERSION "FFmpeg" LIBAVCODEC_VERSION "b" LIBAVCODEC_BUILD_STR

  398.     put_string(p, MJPEG_VERSION);

  399.     size = strlen(MJPEG_VERSION)+3;

  400. #undef MJPEG_VERSION

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

  402.     ptr[1] = size;

  403. }

  404. 

  405. void mjpeg_picture_header(MpegEncContext *s)

  406. {

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

  408. 

  409.     if (!s->mjpeg_data_only_frames)

  410.     {

  411.     jpeg_put_comments(s);    

  412. 

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

  414. 

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

  416. 

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

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

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

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

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

  422.     

  423.     /* Y component */

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

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

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

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

  428.     

  429.     /* Cb component */

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

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

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

  433. #ifdef TWOMATRIXES

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

  435. #else

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

  437. #endif

  438. 

  439.     /* Cr component */

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

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

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

  443. #ifdef TWOMATRIXES

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

  445. #else

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

  447. #endif

  448.     }

  449. 

  450.     /* scan header */

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

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

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

  454.     

  455.     /* Y component */

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

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

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

  459.     

  460.     /* Cb component */

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

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

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

  464.     

  465.     /* Cr component */

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

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

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

  469. 

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

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

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

  473. }

  474. 

  475. void mjpeg_picture_trailer(MpegEncContext *s)

  476. {

  477.     jflush_put_bits(&s->pb);

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

  479. }

  480. 

  481. static inline void mjpeg_encode_dc(MpegEncContext *s, int val,

  482. 				   UINT8 *huff_size, UINT16 *huff_code)

  483. {

  484.     int mant, nbits;

  485. 

  486.     if (val == 0) {

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

  488.     } else {

  489.         mant = val;

  490.         if (val < 0) {

  491.             val = -val;

  492.             mant--;

  493.         }

  494.         

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

  496.         nbits = 0;

  497.         while (val != 0) {

  498.             val = val >> 1;

  499.             nbits++;

  500.         }

  501.             

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

  503.         

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

  505.     }

  506. }

  507. 

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

  509. {

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

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

  512.     MJpegContext *m = s->mjpeg_ctx;

  513.     UINT8 *huff_size_ac;

  514.     UINT16 *huff_code_ac;

  515.     

  516.     /* DC coef */

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

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

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

  520.     if (n < 4) {

  521.         mjpeg_encode_dc(s, val, m->huff_size_dc_luminance, m->huff_code_dc_luminance);

  522.         huff_size_ac = m->huff_size_ac_luminance;

  523.         huff_code_ac = m->huff_code_ac_luminance;

  524.     } else {

  525.         mjpeg_encode_dc(s, val, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);

  526.         huff_size_ac = m->huff_size_ac_chrominance;

  527.         huff_code_ac = m->huff_code_ac_chrominance;

  528.     }

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

  530.     

  531.     /* AC coefs */

  532.     

  533.     run = 0;

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

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

  536.         j = zigzag_direct[i];

  537.         val = block[j];

  538.         if (val == 0) {

  539.             run++;

  540.         } else {

  541.             while (run >= 16) {

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

  543.                 run -= 16;

  544.             }

  545.             mant = val;

  546.             if (val < 0) {

  547.                 val = -val;

  548.                 mant--;

  549.             }

  550.             

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

  552.             nbits = 0;

  553.             while (val != 0) {

  554.                 val = val >> 1;

  555.                 nbits++;

  556.             }

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

  558. 

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

  560.         

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

  562.             run = 0;

  563.         }

  564.     }

  565. 

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

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

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

  569. }

  570. 

  571. void mjpeg_encode_mb(MpegEncContext *s, 

  572.                      DCTELEM block[6][64])

  573. {

  574.     int i;

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

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

  577.     }

  578. }

  579. 

  580. /******************************************/

  581. /* decoding */

  582. 

  583. /* compressed picture size */

  584. #define PICTURE_BUFFER_SIZE 100000

  585. 

  586. #define MAX_COMPONENTS 4

  587. 

  588. typedef struct MJpegDecodeContext {

  589.     AVCodecContext *avctx;

  590.     GetBitContext gb;

  591.     UINT32 header_state;

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

  593.     UINT8 *buf_ptr;

  594.     int buffer_size;

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

  596.     INT16 quant_matrixes[4][64];

  597.     VLC vlcs[2][4];

  598. 

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

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

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

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

  603. 

  604.     int width, height;

  605.     int nb_components;

  606.     int component_id[MAX_COMPONENTS];

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

  608.     int v_count[MAX_COMPONENTS];

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

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

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

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

  613.     int linesize[MAX_COMPONENTS];

  614.     DCTELEM block[64] __align8;

  615.     UINT8 buffer[PICTURE_BUFFER_SIZE]; 

  616. 

  617.     int buggy_avid;

  618.     int restart_interval;

  619.     int restart_count;

  620.     int interleaved_rows;

  621. } MJpegDecodeContext;

  622. 

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

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

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

  626. 	skip_bits(gb, 8); \

  627. }

  628. 

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

  630. 

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

  632.                       int nb_codes)

  633. {

  634.     UINT8 huff_size[256];

  635.     UINT16 huff_code[256];

  636. 

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

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

  639.     

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

  641. }

  642. 

  643. static int mjpeg_decode_init(AVCodecContext *avctx)

  644. {

  645.     MJpegDecodeContext *s = avctx->priv_data;

  646. 

  647.     s->avctx = avctx;

  648. 

  649.     s->header_state = 0;

  650.     s->mpeg_enc_ctx_allocated = 0;

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

  652.                                                  account FF 00 case */

  653.     s->start_code = -1;

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

  655.     s->first_picture = 1;

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

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

  658. 

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

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

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

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

  663.     

  664.     if (avctx->flags & CODEC_FLAG_EXTERN_HUFF)

  665.     {

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

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

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

  669.     }

  670.     return 0;

  671. }

  672. 

  673. /* quantize tables */

  674. static int mjpeg_decode_dqt(MJpegDecodeContext *s,

  675.                             UINT8 *buf, int buf_size)

  676. {

  677.     int len, index, i, j;

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

  679.     

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

  681. 

  682.     while (len >= 65) {

  683.         /* only 8 bit precision handled */

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

  685. 	{

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

  687.             return -1;

  688. 	}

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

  690.         if (index >= 4)

  691.             return -1;

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

  693.         /* read quant table */

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

  695.             j = zigzag_direct[i];

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

  697.         }

  698.         len -= 65;

  699.     }

  700.     

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

  702. 

  703.     return 0;

  704. }

  705. 

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

  707. static int mjpeg_decode_dht(MJpegDecodeContext *s,

  708.                             UINT8 *buf, int buf_size)

  709. {

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

  711.     UINT8 bits_table[17];

  712.     UINT8 val_table[256];

  713.     

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

  715. 

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

  717.     len -= 2;

  718. 

  719.     while (len > 0) {

  720.         if (len < 17)

  721.             return -1;

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

  723.         if (class >= 2)

  724.             return -1;

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

  726.         if (index >= 4)

  727.             return -1;

  728.         n = 0;

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

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

  731.             n += bits_table[i];

  732.         }

  733.         len -= 17;

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

  735.             return -1;

  736. 

  737.         code_max = 0;

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

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

  740.             if (v > code_max)

  741.                 code_max = v;

  742.             val_table[i] = v;

  743.         }

  744.         len -= n;

  745. 

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

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

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

  749.                class, index, code_max + 1);

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

  751.     }

  752.     return 0;

  753. }

  754. 

  755. static int mjpeg_decode_sof0(MJpegDecodeContext *s,

  756.                              UINT8 *buf, int buf_size)

  757. {

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

  759. 

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

  761. 

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

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

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

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

  766.         return -1;

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

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

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

  770. 

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

  772.     if (nb_components <= 0 ||

  773.         nb_components > MAX_COMPONENTS)

  774.         return -1;

  775.     s->nb_components = nb_components;

  776.     s->h_max = 1;

  777.     s->v_max = 1;

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

  779.         /* component id */

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

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

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

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

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

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

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

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

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

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

  790.             return -1;

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

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

  793.     }

  794. 

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

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

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

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

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

  800.         s->width = width;

  801.         s->height = height;

  802.         /* test interlaced mode */

  803.         if (s->first_picture &&

  804.             s->org_height != 0 &&

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

  806.             s->interlaced = 1;

  807. 	    s->bottom_field = 0;

  808.         }

  809. 

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

  811.             int w, h;

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

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

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

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

  816.             if (s->interlaced)

  817.                 w *= 2;

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

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

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

  821.         }

  822.         s->first_picture = 0;

  823.     }

  824. 

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

  826.     {

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

  828.     }

  829.     

  830.     return 0;

  831. }

  832. 

  833. static inline int mjpeg_decode_dc(MJpegDecodeContext *s, int dc_index)

  834. {

  835.     int code, diff;

  836. 

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

  838.     if (code < 0)

  839.     {

  840. 	dprintf("mjpeg_decode_dc: bad vlc: %d:%d (%p)\n", 0, dc_index,

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

  842.         return 0xffff;

  843.     }

  844.     if (code == 0) {

  845.         diff = 0;

  846.     } else {

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

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

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

  850.     }

  851.     return diff;

  852. }

  853. 

  854. /* decode block and dequantize */

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

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

  857. {

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

  859.     int run, val;

  860.     VLC *ac_vlc;

  861.     INT16 *quant_matrix;

  862. 

  863.     /* DC coef */

  864.     val = mjpeg_decode_dc(s, dc_index);

  865.     if (val == 0xffff) {

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

  867.         return -1;

  868.     }

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

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

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

  872.     block[0] = val;

  873.     /* AC coefs */

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

  875.     i = 1;

  876.     for(;;) {

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

  878.         if (code < 0) {

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

  880.             return -1;

  881.         }

  882.         /* EOB */

  883.         if (code == 0)

  884.             break;

  885.         if (code == 0xf0) {

  886.             i += 16;

  887.         } else {

  888.             run = code >> 4;

  889.             nbits = code & 0xf;

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

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

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

  893.             i += run;

  894.             if (i >= 64) {

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

  896.                 return -1;

  897.             }

  898.             j = zigzag_direct[i];

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

  900.             i++;

  901.             if (i >= 64)

  902.                 break;

  903.         }

  904.     }

  905.     return 0;

  906. }

  907. 

  908. static int mjpeg_decode_sos(MJpegDecodeContext *s,

  909.                             UINT8 *buf, int buf_size)

  910. {

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

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

  913.     int comp_index[4];

  914.     int dc_index[4];

  915.     int ac_index[4];

  916.     int nb_blocks[4];

  917.     int h_count[4];

  918.     int v_count[4];

  919.     

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

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

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

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

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

  925.     if (nb_components != 3)

  926.     {

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

  928.         return -1;

  929.     }

  930.     vmax = 0;

  931.     hmax = 0;

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

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

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

  935.         /* find component index */

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

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

  938.                 break;

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

  940. 	{

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

  942.             return -1;

  943. 	}

  944. 

  945.         comp_index[i] = index;

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

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

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

  949. 

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

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

  952. 

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

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

  955. 	    goto out_of_range;

  956. 	switch(s->start_code)

  957. 	{

  958. 	    case SOF0:

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

  960. 		    goto out_of_range;

  961. 		break;

  962. 	    case SOF1:

  963. 	    case SOF2:

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

  965. 		    goto out_of_range;

  966. 		break;

  967. 	    case SOF3:

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

  969. 		    goto out_of_range;

  970. 		break;	

  971. 	}

  972.     }

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

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

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

  976. 

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

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

  979. 

  980.     if (nb_components > 1) {

  981.         /* interleaved stream */

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

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

  984.     } else {

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

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

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

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

  989.         nb_blocks[0] = 1;

  990.         h_count[0] = 1;

  991.         v_count[0] = 1;

  992.     }

  993. 

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

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

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

  997.                 UINT8 *ptr;

  998.                 int x, y, c;

  999.                 n = nb_blocks[i];

  1000.                 c = comp_index[i];

  1001.                 h = h_count[i];

  1002.                 v = v_count[i];

  1003.                 x = 0;

  1004.                 y = 0;

  1005. 		if (s->restart_interval && !s->restart_count)

  1006. 		    s->restart_count = s->restart_interval;

  1007.                 for(j=0;j<n;j++) {

  1008.                     memset(s->block, 0, sizeof(s->block));

  1009.                     if (decode_block(s, s->block, i, 

  1010.                                      dc_index[i], ac_index[i], 

  1011.                                      s->quant_index[c]) < 0) {

  1012.                         dprintf("error y=%d x=%d\n", mb_y, mb_x);

  1013.                         ret = -1;

  1014.                         goto the_end;

  1015.                     }

  1016. //		    dprintf("mb: %d %d processed\n", mb_y, mb_x);

  1017.                     ptr = s->current_picture[c] + 

  1018.                         (s->linesize[c] * (v * mb_y + y) * 8) + 

  1019.                         (h * mb_x + x) * 8;

  1020.                     if (s->interlaced && s->bottom_field)

  1021.                         ptr += s->linesize[c] >> 1;

  1022.                     ff_idct_put(ptr, s->linesize[c], s->block);

  1023.                     if (++x == h) {

  1024.                         x = 0;

  1025.                         y++;

  1026.                     }

  1027.                 }

  1028.             }

  1029.             if (s->restart_interval && !--s->restart_count) {

  1030.                 align_get_bits(&s->gb);

  1031.                 skip_bits(&s->gb, 16); /* skip RSTn */

  1032.                 for (j=0; j<nb_components; j++) /* reset dc */

  1033.                     s->last_dc[j] = 1024;

  1034.             }

  1035.         }

  1036.     }

  1037.     ret = 0;

  1038.  the_end:

  1039.     emms_c();

  1040.     return ret;

  1041.  out_of_range:

  1042.     dprintf("decode_sos: ac/dc index out of range\n");

  1043.     return -1;

  1044. }

  1045. 

  1046. static int mjpeg_decode_dri(MJpegDecodeContext *s,

  1047.                              UINT8 *buf, int buf_size)

  1048. {

  1049.     init_get_bits(&s->gb, buf, buf_size);

  1050. 

  1051.     if (get_bits(&s->gb, 16) != 4)

  1052. 	return -1;

  1053.     s->restart_interval = get_bits(&s->gb, 16);

  1054.     dprintf("restart interval: %d\n", s->restart_interval);

  1055. 

  1056.     return 0;

  1057. }

  1058. 

  1059. #define FOURCC(a,b,c,d) ((a << 24) | (b << 16) | (c << 8) | d)

  1060. static int mjpeg_decode_app(MJpegDecodeContext *s,

  1061.                              UINT8 *buf, int buf_size, int start_code)

  1062. {

  1063.     int len, id;

  1064. 

  1065.     init_get_bits(&s->gb, buf, buf_size);

  1066. 

  1067.     /* XXX: verify len field validity */

  1068.     len = get_bits(&s->gb, 16);

  1069.     if (len < 5)

  1070. 	return -1;

  1071. 

  1072.     id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);

  1073.     len -= 6;

  1074. 

  1075.     /* buggy AVID, it puts EOI only at every 10th frame */

  1076.     /* also this fourcc is used by non-avid files too, it means

  1077.        interleaving, but it's always present in AVID files */

  1078.     if (id == FOURCC('A','V','I','1'))

  1079.     {

  1080. 	/* structure:

  1081. 	    4bytes	AVI1

  1082. 	    1bytes	polarity

  1083. 	    1bytes	always zero

  1084. 	    4bytes	field_size

  1085. 	    4bytes	field_size_less_padding

  1086. 	*/

  1087.     	s->buggy_avid = 1;

  1088. 	if (s->first_picture)

  1089. 	    printf("mjpeg: workarounding buggy AVID\n");

  1090. 	s->interleaved_rows = get_bits(&s->gb, 8);

  1091. #if 0

  1092. 	skip_bits(&s->gb, 8);

  1093. 	skip_bits(&s->gb, 32);

  1094. 	skip_bits(&s->gb, 32);

  1095. 	len -= 10;

  1096. #endif

  1097. 	if (s->interleaved_rows)

  1098. 	    printf("mjpeg: interleaved rows: %d\n", s->interleaved_rows);

  1099. 	goto out;

  1100.     }

  1101.     

  1102.     len -= 2;

  1103.     

  1104.     if (id == FOURCC('J','F','I','F'))

  1105.     {

  1106. 	skip_bits(&s->gb, 8); /* the trailing zero-byte */

  1107. 	printf("mjpeg: JFIF header found (version: %x.%x)\n",

  1108. 	    get_bits(&s->gb, 8), get_bits(&s->gb, 8));

  1109. 	if (get_bits(&s->gb, 8) == 0)

  1110. 	{

  1111. 	    s->avctx->aspect_ratio_info = FF_ASPECT_EXTENDED;

  1112. 	    s->avctx->aspected_width = get_bits(&s->gb, 16);

  1113. 	    s->avctx->aspected_height = get_bits(&s->gb, 16);

  1114. 	}

  1115. 	else

  1116. 	{

  1117. 	    skip_bits(&s->gb, 16);

  1118. 	    skip_bits(&s->gb, 16);

  1119. 	}

  1120. 	skip_bits(&s->gb, 8);

  1121. 	skip_bits(&s->gb, 8);

  1122. 	goto out;

  1123.     }

  1124.     

  1125.     /* Apple MJPEG-A */

  1126.     if ((start_code == APP1) && (len > (0x28 - 8)))

  1127.     {

  1128. 	id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);

  1129. 	len -= 4;

  1130.         if (id == FOURCC('m','j','p','g')) /* Apple MJPEG-A */

  1131. 	{

  1132. #if 0

  1133. 	    skip_bits(&s->gb, 32); /* field size */

  1134. 	    skip_bits(&s->gb, 32); /* pad field size */

  1135. 	    skip_bits(&s->gb, 32); /* next off */

  1136. 	    skip_bits(&s->gb, 32); /* quant off */

  1137. 	    skip_bits(&s->gb, 32); /* huff off */

  1138. 	    skip_bits(&s->gb, 32); /* image off */

  1139. 	    skip_bits(&s->gb, 32); /* scan off */

  1140. 	    skip_bits(&s->gb, 32); /* data off */

  1141. #endif

  1142. 	    if (s->first_picture)

  1143. 		printf("mjpeg: Apple MJPEG-A header found\n");

  1144. 	}

  1145.     }

  1146. 

  1147. out:

  1148.     /* should check for further values.. */

  1149.     SKIP_REMAINING(&s->gb, len);

  1150. 

  1151.     return 0;

  1152. }

  1153. #undef FOURCC

  1154. 

  1155. static int mjpeg_decode_com(MJpegDecodeContext *s,

  1156.                              UINT8 *buf, int buf_size)

  1157. {

  1158.     int len, i;

  1159.     UINT8 *cbuf;

  1160. 

  1161.     init_get_bits(&s->gb, buf, buf_size);

  1162. 

  1163.     /* XXX: verify len field validity */

  1164.     len = get_bits(&s->gb, 16)-2;

  1165.     cbuf = av_malloc(len+1);

  1166. 

  1167.     for (i = 0; i < len; i++)

  1168. 	cbuf[i] = get_bits(&s->gb, 8);

  1169.     if (cbuf[i-1] == '\n')

  1170. 	cbuf[i-1] = 0;

  1171.     else

  1172. 	cbuf[i] = 0;

  1173. 

  1174.     printf("mjpeg comment: '%s'\n", cbuf);

  1175. 

  1176.     /* buggy avid, it puts EOI only at every 10th frame */

  1177.     if (!strcmp(cbuf, "AVID"))

  1178.     {

  1179. 	s->buggy_avid = 1;

  1180. 	if (s->first_picture)

  1181. 	    printf("mjpeg: workarounding buggy AVID\n");

  1182.     }

  1183.     

  1184.     av_free(cbuf);

  1185. 

  1186.     return 0;

  1187. }

  1188. 

  1189. /* return the 8 bit start code value and update the search

  1190.    state. Return -1 if no start code found */

  1191. static int find_marker(UINT8 **pbuf_ptr, UINT8 *buf_end, 

  1192.                        UINT32 *header_state)

  1193. {

  1194.     UINT8 *buf_ptr;

  1195.     unsigned int state, v;

  1196.     int val;

  1197. 

  1198.     state = *header_state;

  1199.     buf_ptr = *pbuf_ptr;

  1200. retry:

  1201.     if (state) {

  1202.         /* get marker */

  1203.     found:

  1204.         if (buf_ptr < buf_end) {

  1205.             val = *buf_ptr++;

  1206.             state = 0;

  1207.             if ((val >= RST0) && (val <= RST7))

  1208.                 goto retry;

  1209.         } else {

  1210.             val = -1;

  1211.         }

  1212.     } else {

  1213.         while (buf_ptr < buf_end) {

  1214.             v = *buf_ptr++;

  1215.             if (v == 0xff) {

  1216.                 state = 1;

  1217.                 goto found;

  1218.             }

  1219.         }

  1220.         val = -1;

  1221.     }

  1222.     *pbuf_ptr = buf_ptr;

  1223.     *header_state = state;

  1224.     return val;

  1225. }

  1226. 

  1227. static int mjpeg_decode_frame(AVCodecContext *avctx, 

  1228.                               void *data, int *data_size,

  1229.                               UINT8 *buf, int buf_size)

  1230. {

  1231.     MJpegDecodeContext *s = avctx->priv_data;

  1232.     UINT8 *buf_end, *buf_ptr, *buf_start;

  1233.     int len, code, input_size, i;

  1234.     AVPicture *picture = data;

  1235.     unsigned int start_code;

  1236. 

  1237.     *data_size = 0;

  1238. 

  1239.     /* no supplementary picture */

  1240.     if (buf_size == 0)

  1241.         return 0;

  1242. 

  1243.     buf_ptr = buf;

  1244.     buf_end = buf + buf_size;

  1245.     while (buf_ptr < buf_end) {

  1246.         buf_start = buf_ptr;

  1247.         /* find start next marker */

  1248.         code = find_marker(&buf_ptr, buf_end, &s->header_state);

  1249.         /* copy to buffer */

  1250.         len = buf_ptr - buf_start;

  1251.         if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {

  1252.             /* data too big : flush */

  1253.             s->buf_ptr = s->buffer;

  1254.             if (code > 0)

  1255.                 s->start_code = code;

  1256.         } else {

  1257.             memcpy(s->buf_ptr, buf_start, len);

  1258.             s->buf_ptr += len;

  1259.             if (code < 0) {

  1260.                 /* nothing to do: wait next marker */

  1261.             } else if (code == 0 || code == 0xff) {

  1262.                 /* if we got FF 00, we copy FF to the stream to unescape FF 00 */

  1263.                 /* valid marker code is between 00 and ff - alex */

  1264.                 s->buf_ptr--;

  1265.             } else {

  1266.                 /* prepare data for next start code */

  1267.                 input_size = s->buf_ptr - s->buffer;

  1268.                 start_code = s->start_code;

  1269.                 s->buf_ptr = s->buffer;

  1270.                 s->start_code = code;

  1271.                 dprintf("marker=%x\n", start_code);

  1272.                 switch(start_code) {

  1273.                 case SOI:

  1274. 		    s->restart_interval = 0;

  1275.                     /* nothing to do on SOI */

  1276.                     break;

  1277.                 case DQT:

  1278.                     mjpeg_decode_dqt(s, s->buffer, input_size);

  1279.                     break;

  1280.                 case DHT:

  1281.                     mjpeg_decode_dht(s, s->buffer, input_size);

  1282.                     break;

  1283.                 case SOF0:

  1284.                     mjpeg_decode_sof0(s, s->buffer, input_size);

  1285.                     break;

  1286.                 case SOS:

  1287.                     mjpeg_decode_sos(s, s->buffer, input_size);

  1288.                     if (s->start_code == EOI || s->buggy_avid || s->restart_interval) {

  1289.                         int l;

  1290.                         if (s->interlaced) {

  1291.                             s->bottom_field ^= 1;

  1292.                             /* if not bottom field, do not output image yet */

  1293.                             if (s->bottom_field)

  1294.                                 goto not_the_end;

  1295.                         }

  1296.                         for(i=0;i<3;i++) {

  1297.                             picture->data[i] = s->current_picture[i];

  1298.                             l = s->linesize[i];

  1299.                             if (s->interlaced)

  1300.                                 l >>= 1;

  1301.                             picture->linesize[i] = l;

  1302.                         }

  1303.                         *data_size = sizeof(AVPicture);

  1304.                         avctx->height = s->height;

  1305.                         if (s->interlaced)

  1306.                             avctx->height *= 2;

  1307.                         avctx->width = s->width;

  1308.                         /* XXX: not complete test ! */

  1309.                         switch((s->h_count[0] << 4) | s->v_count[0]) {

  1310.                         case 0x11:

  1311.                             avctx->pix_fmt = PIX_FMT_YUV444P;

  1312.                             break;

  1313.                         case 0x21:

  1314.                             avctx->pix_fmt = PIX_FMT_YUV422P;

  1315.                             break;

  1316.                         default:

  1317.                         case 0x22:

  1318.                             avctx->pix_fmt = PIX_FMT_YUV420P;

  1319.                             break;

  1320.                         }

  1321.                         /* dummy quality */

  1322.                         /* XXX: infer it with matrix */

  1323.                     	avctx->quality = 3; 

  1324.                         goto the_end;

  1325.                     }

  1326.                     break;

  1327. 		case DRI:

  1328. 		    mjpeg_decode_dri(s, s->buffer, input_size);

  1329. 		    break;

  1330. 		case SOF1:

  1331. 		case SOF2:

  1332. 		case SOF3:

  1333. 		case SOF5:

  1334. 		case SOF6:

  1335. 		case SOF7:

  1336. 		case SOF9:

  1337. 		case SOF10:

  1338. 		case SOF11:

  1339. 		case SOF13:

  1340. 		case SOF14:

  1341. 		case SOF15:

  1342. 		case JPG:

  1343. 		    printf("mjpeg: unsupported coding type (%x)\n", start_code);

  1344. 		    return -1;

  1345.                 }

  1346. #if 1

  1347. 		if (start_code >= 0xd0 && start_code <= 0xd7) {

  1348. 		    dprintf("restart marker: %d\n", start_code&0x0f);

  1349. 		} else if (s->first_picture) {

  1350. 		    /* APP fields */

  1351. 		    if (start_code >= 0xe0 && start_code <= 0xef)

  1352. 			mjpeg_decode_app(s, s->buffer, input_size, start_code);

  1353. 		    /* Comment */

  1354. 		    else if (start_code == COM)

  1355. 			mjpeg_decode_com(s, s->buffer, input_size);

  1356. 		}

  1357. #endif

  1358.             }

  1359.         }

  1360.  not_the_end:

  1361. 	;

  1362.     }

  1363.  the_end:

  1364.     return buf_ptr - buf;

  1365. }

  1366. 

  1367. static int mjpeg_decode_end(AVCodecContext *avctx)

  1368. {

  1369.     MJpegDecodeContext *s = avctx->priv_data;

  1370.     int i, j;

  1371. 

  1372.     for(i=0;i<MAX_COMPONENTS;i++)

  1373.         av_free(s->current_picture[i]);

  1374.     for(i=0;i<2;i++) {

  1375.         for(j=0;j<4;j++)

  1376.             free_vlc(&s->vlcs[i][j]);

  1377.     }

  1378.     return 0;

  1379. }

  1380. 

  1381. AVCodec mjpeg_decoder = {

  1382.     "mjpeg",

  1383.     CODEC_TYPE_VIDEO,

  1384.     CODEC_ID_MJPEG,

  1385.     sizeof(MJpegDecodeContext),

  1386.     mjpeg_decode_init,

  1387.     NULL,

  1388.     mjpeg_decode_end,

  1389.     mjpeg_decode_frame,

  1390.     0,

  1391.     NULL

  1392. };