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FFmpeg/libavcodec/xan.c

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  1. /*

  2.  * Wing Commander/Xan Video Decoder

  3.  * Copyright (C) 2003 the ffmpeg project

  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.  */

  20. 

  21. /**

  22.  * @file xan.c

  23.  * Xan video decoder for Wing Commander III & IV computer games

  24.  * by Mario Brito (mbrito@student.dei.uc.pt)

  25.  * and Mike Melanson (melanson@pcisys.net)

  26.  *

  27.  * The xan_wc3 decoder outputs the following colorspaces natively:

  28.  *   PAL8 (default), RGB555, RGB565, RGB24, BGR24, RGBA32, YUV444P

  29.  */

  30. 

  31. #include <stdio.h>

  32. #include <stdlib.h>

  33. #include <string.h>

  34. #include <unistd.h>

  35. 

  36. #include "common.h"

  37. #include "avcodec.h"

  38. #include "dsputil.h"

  39. 

  40. #define PALETTE_COUNT 256

  41. #define PALETTE_CONTROL_SIZE ((256 * 3) + 1)

  42. 

  43. typedef struct XanContext {

  44. 

  45.     AVCodecContext *avctx;

  46.     DSPContext dsp;

  47.     AVFrame last_frame;

  48.     AVFrame current_frame;

  49. 

  50.     unsigned char *buf;

  51.     int size;

  52. 

  53.     unsigned char palette[PALETTE_COUNT * 4];

  54. 

  55.     /* scratch space */

  56.     unsigned char *buffer1;

  57.     unsigned char *buffer2;

  58. 

  59. } XanContext;

  60. 

  61. #define BE_16(x)  ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])

  62. #define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])

  63. #define LE_32(x)  ((((uint8_t*)(x))[3] << 24) | \

  64.                    (((uint8_t*)(x))[2] << 16) | \

  65.                    (((uint8_t*)(x))[1] << 8) | \

  66.                     ((uint8_t*)(x))[0])

  67. 

  68. /* RGB -> YUV conversion stuff */

  69. #define SCALEFACTOR 65536

  70. #define CENTERSAMPLE 128

  71. 

  72. #define COMPUTE_Y(r, g, b) \

  73.   (unsigned char) \

  74.   ((y_r_table[r] + y_g_table[g] + y_b_table[b]) / SCALEFACTOR)

  75. #define COMPUTE_U(r, g, b) \

  76.   (unsigned char) \

  77.   ((u_r_table[r] + u_g_table[g] + u_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)

  78. #define COMPUTE_V(r, g, b) \

  79.   (unsigned char) \

  80.   ((v_r_table[r] + v_g_table[g] + v_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)

  81. 

  82. #define Y_R (SCALEFACTOR *  0.29900)

  83. #define Y_G (SCALEFACTOR *  0.58700)

  84. #define Y_B (SCALEFACTOR *  0.11400)

  85. 

  86. #define U_R (SCALEFACTOR * -0.16874)

  87. #define U_G (SCALEFACTOR * -0.33126)

  88. #define U_B (SCALEFACTOR *  0.50000)

  89. 

  90. #define V_R (SCALEFACTOR *  0.50000)

  91. #define V_G (SCALEFACTOR * -0.41869)

  92. #define V_B (SCALEFACTOR * -0.08131)

  93. 

  94. /*

  95.  * Precalculate all of the YUV tables since it requires fewer than

  96.  * 10 kilobytes to store them.

  97.  */

  98. static int y_r_table[256];

  99. static int y_g_table[256];

  100. static int y_b_table[256];

  101. 

  102. static int u_r_table[256];

  103. static int u_g_table[256];

  104. static int u_b_table[256];

  105. 

  106. static int v_r_table[256];

  107. static int v_g_table[256];

  108. static int v_b_table[256];

  109. 

  110. static int xan_decode_init(AVCodecContext *avctx)

  111. {

  112.     XanContext *s = avctx->priv_data;

  113.     int i;

  114. 

  115.     s->avctx = avctx;

  116. 

  117.     if ((avctx->codec->id == CODEC_ID_XAN_WC3) && 

  118.         (s->avctx->extradata_size != sizeof(AVPaletteControl))) {

  119.         printf (" WC3 Xan video: expected extradata_size of %d\n",

  120.             sizeof(AVPaletteControl));

  121.         return -1;

  122.     }

  123. 

  124.     avctx->pix_fmt = PIX_FMT_PAL8;

  125.     avctx->has_b_frames = 0;

  126.     dsputil_init(&s->dsp, avctx);

  127. 

  128.     /* initialize the RGB -> YUV tables */

  129.     for (i = 0; i < 256; i++) {

  130.         y_r_table[i] = Y_R * i;

  131.         y_g_table[i] = Y_G * i;

  132.         y_b_table[i] = Y_B * i;

  133. 

  134.         u_r_table[i] = U_R * i;

  135.         u_g_table[i] = U_G * i;

  136.         u_b_table[i] = U_B * i;

  137. 

  138.         v_r_table[i] = V_R * i;

  139.         v_g_table[i] = V_G * i;

  140.         v_b_table[i] = V_B * i;

  141.     }

  142. 

  143.     s->buffer1 = av_malloc(avctx->width * avctx->height);

  144.     s->buffer2 = av_malloc(avctx->width * avctx->height);

  145.     if (!s->buffer1 || !s->buffer2)

  146.         return -1;

  147. 

  148.     return 0;

  149. }

  150. 

  151. /* This function is used in lieu of memcpy(). This decoder can not use 

  152.  * memcpy because the memory locations often overlap and

  153.  * memcpy doesn't like that; it's not uncommon, for example, for

  154.  * dest = src+1, to turn byte A into  pattern AAAAAAAA.

  155.  * This was originally repz movsb in Intel x86 ASM. */

  156. static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)

  157. {

  158.     int i;

  159. 

  160.     for (i = 0; i < count; i++)

  161.         dest[i] = src[i];

  162. }

  163. 

  164. static int xan_huffman_decode(unsigned char *dest, unsigned char *src)

  165. {

  166.     unsigned char byte = *src++;

  167.     unsigned char ival = byte + 0x16;

  168.     unsigned char * ptr = src + byte*2;

  169.     unsigned char val = ival;

  170.     int counter = 0;

  171. 

  172.     unsigned char bits = *ptr++;

  173. 

  174.     while ( val != 0x16 ) {

  175.         if ( (1 << counter) & bits )

  176.             val = src[byte + val - 0x17];

  177.         else

  178.             val = src[val - 0x17];

  179. 

  180.         if ( val < 0x16 ) {

  181.             *dest++ = val;

  182.             val = ival;

  183.         }

  184. 

  185.         if (counter++ == 7) {

  186.             counter = 0;

  187.             bits = *ptr++;

  188.         }

  189.     }

  190. 

  191.     return 0;

  192. }

  193. 

  194. static void xan_unpack(unsigned char *dest, unsigned char *src)

  195. {

  196.     unsigned char opcode;

  197.     int size;

  198.     int offset;

  199.     int byte1, byte2, byte3;

  200. 

  201.     for (;;) {

  202.         opcode = *src++;

  203. 

  204.         if ( (opcode & 0x80) == 0 ) {

  205. 

  206.             offset = *src++;

  207. 

  208.             size = opcode & 3;

  209.             bytecopy(dest, src, size);  dest += size;  src += size;

  210. 

  211.             size = ((opcode & 0x1c) >> 2) + 3;

  212.             bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);

  213.             dest += size;

  214. 

  215.         } else if ( (opcode & 0x40) == 0 ) {

  216. 

  217.             byte1 = *src++;

  218.             byte2 = *src++;

  219. 

  220.             size = byte1 >> 6;

  221.             bytecopy (dest, src, size);  dest += size;  src += size;

  222. 

  223.             size = (opcode & 0x3f) + 4;

  224.             bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);

  225.             dest += size;

  226. 

  227.         } else if ( (opcode & 0x20) == 0 ) {

  228. 

  229.             byte1 = *src++;

  230.             byte2 = *src++;

  231.             byte3 = *src++;

  232. 

  233.             size = opcode & 3;

  234.             bytecopy (dest, src, size);  dest += size;  src += size;

  235. 

  236.             size = byte3 + 5 + ((opcode & 0xc) << 6);

  237.             bytecopy (dest,

  238.                 dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),

  239.                 size);

  240.             dest += size;

  241.         } else {

  242.             size = ((opcode & 0x1f) << 2) + 4;

  243. 

  244.             if (size > 0x70)

  245.                 break;

  246. 

  247.             bytecopy (dest, src, size);  dest += size;  src += size;

  248.         }

  249.     }

  250. 

  251.     size = opcode & 3;

  252.     bytecopy(dest, src, size);  dest += size;  src += size;

  253. }

  254. 

  255. static void inline xan_wc3_build_palette(XanContext *s, 

  256.     unsigned char *palette_data)

  257. {

  258.     int i;

  259.     unsigned char r, g, b;

  260.     unsigned short *palette16;

  261.     unsigned int *palette32;

  262. 

  263.     /* transform the palette passed through the palette control structure

  264.      * into the necessary internal format depending on colorspace */

  265. 

  266.     switch (s->avctx->pix_fmt) {

  267. 

  268.     case PIX_FMT_RGB555:

  269.         palette16 = (unsigned short *)s->palette;

  270.         for (i = 0; i < PALETTE_COUNT; i++) {

  271.             r = *palette_data++;

  272.             g = *palette_data++;

  273.             b = *palette_data++;

  274.             palette16[i] = 

  275.                 ((r >> 3) << 10) |

  276.                 ((g >> 3) <<  5) |

  277.                 ((g >> 3) <<  0);

  278.         }

  279.         break;

  280. 

  281.     case PIX_FMT_RGB565:

  282.         palette16 = (unsigned short *)s->palette;

  283.         for (i = 0; i < PALETTE_COUNT; i++) {

  284.             r = *palette_data++;

  285.             g = *palette_data++;

  286.             b = *palette_data++;

  287.             palette16[i] = 

  288.                 ((r >> 3) << 11) |

  289.                 ((g >> 2) <<  5) |

  290.                 ((g >> 3) <<  0);

  291.         }

  292.         break;

  293. 

  294.     case PIX_FMT_RGB24:

  295.         for (i = 0; i < PALETTE_COUNT; i++) {

  296.             s->palette[i * 4 + 0] = *palette_data++;

  297.             s->palette[i * 4 + 1] = *palette_data++;

  298.             s->palette[i * 4 + 2] = *palette_data++;

  299.         }

  300.         break;

  301. 

  302.     case PIX_FMT_BGR24:

  303.         for (i = 0; i < PALETTE_COUNT; i++) {

  304.             r = *palette_data++;

  305.             g = *palette_data++;

  306.             b = *palette_data++;

  307.             s->palette[i * 4 + 0] = b;

  308.             s->palette[i * 4 + 1] = g;

  309.             s->palette[i * 4 + 2] = r;

  310.         }

  311.         break;

  312. 

  313.     case PIX_FMT_PAL8:

  314.     case PIX_FMT_RGBA32:

  315.         palette32 = (unsigned int *)s->palette;

  316.         for (i = 0; i < PALETTE_COUNT; i++) {

  317.             r = *palette_data++;

  318.             g = *palette_data++;

  319.             b = *palette_data++;

  320.             palette32[i] = (r << 16) | (g << 8) | (b);

  321.         }

  322.         break;

  323. 

  324.     case PIX_FMT_YUV444P:

  325.         for (i = 0; i < PALETTE_COUNT; i++) {

  326.             r = *palette_data++;

  327.             g = *palette_data++;

  328.             b = *palette_data++;

  329.             s->palette[i * 4 + 0] = COMPUTE_Y(r, g, b);

  330.             s->palette[i * 4 + 1] = COMPUTE_U(r, g, b);

  331.             s->palette[i * 4 + 2] = COMPUTE_V(r, g, b);

  332.         }

  333.         break;

  334. 

  335.     default:

  336.         printf (" Xan WC3: Unhandled colorspace\n");

  337.         break;

  338.     }

  339. }

  340. 

  341. static void inline xan_wc3_output_pixel_run(XanContext *s, 

  342.     unsigned char *pixel_buffer, int x, int y, int pixel_count)

  343. {

  344.     int stride;

  345.     int line_inc;

  346.     int index;

  347.     int current_x;

  348.     int width = s->avctx->width;

  349.     unsigned char pix;

  350.     unsigned char *palette_plane;

  351.     unsigned char *y_plane;

  352.     unsigned char *u_plane;

  353.     unsigned char *v_plane;

  354.     unsigned char *rgb_plane;

  355.     unsigned short *rgb16_plane;

  356.     unsigned short *palette16;

  357.     unsigned int *rgb32_plane;

  358.     unsigned int *palette32;

  359. 

  360.     switch (s->avctx->pix_fmt) {

  361. 

  362.     case PIX_FMT_PAL8:

  363.         palette_plane = s->current_frame.data[0];

  364.         stride = s->current_frame.linesize[0];

  365.         line_inc = stride - width;

  366.         index = y * stride + x;

  367.         current_x = x;

  368.         while(pixel_count--) {

  369. 

  370.             /* don't do a memcpy() here; keyframes generally copy an entire

  371.              * frame of data and the stride needs to be accounted for */

  372.             palette_plane[index++] = *pixel_buffer++;

  373. 

  374.             current_x++;

  375.             if (current_x >= width) {

  376.                 /* reset accounting variables */

  377.                 index += line_inc;

  378.                 current_x = 0;

  379.             }

  380.         }

  381.         break;

  382. 

  383.     case PIX_FMT_RGB555:

  384.     case PIX_FMT_RGB565:

  385.         rgb16_plane = (unsigned short *)s->current_frame.data[0];

  386.         palette16 = (unsigned short *)s->palette;

  387.         stride = s->current_frame.linesize[0] / 2;

  388.         line_inc = stride - width;

  389.         index = y * stride + x;

  390.         current_x = x;

  391.         while(pixel_count--) {

  392. 

  393.             rgb16_plane[index++] = palette16[*pixel_buffer++];

  394. 

  395.             current_x++;

  396.             if (current_x >= width) {

  397.                 /* reset accounting variables */

  398.                 index += line_inc;

  399.                 current_x = 0;

  400.             }

  401.         }

  402.         break;

  403. 

  404.     case PIX_FMT_RGB24:

  405.     case PIX_FMT_BGR24:

  406.         rgb_plane = s->current_frame.data[0];

  407.         stride = s->current_frame.linesize[0];

  408.         line_inc = stride - width * 3;

  409.         index = y * stride + x * 3;

  410.         current_x = x;

  411.         while(pixel_count--) {

  412.             pix = *pixel_buffer++;

  413. 

  414.             rgb_plane[index++] = s->palette[pix * 4 + 0];

  415.             rgb_plane[index++] = s->palette[pix * 4 + 1];

  416.             rgb_plane[index++] = s->palette[pix * 4 + 2];

  417. 

  418.             current_x++;

  419.             if (current_x >= width) {

  420.                 /* reset accounting variables */

  421.                 index += line_inc;

  422.                 current_x = 0;

  423.             }

  424.         }

  425.         break;

  426. 

  427.     case PIX_FMT_RGBA32:

  428.         rgb32_plane = (unsigned int *)s->current_frame.data[0];

  429.         palette32 = (unsigned int *)s->palette;

  430.         stride = s->current_frame.linesize[0] / 4;

  431.         line_inc = stride - width;

  432.         index = y * stride + x;

  433.         current_x = x;

  434.         while(pixel_count--) {

  435. 

  436.             rgb32_plane[index++] = palette32[*pixel_buffer++];

  437. 

  438.             current_x++;

  439.             if (current_x >= width) {

  440.                 /* reset accounting variables */

  441.                 index += line_inc;

  442.                 current_x = 0;

  443.             }

  444.         }

  445.         break;

  446. 

  447.     case PIX_FMT_YUV444P:

  448.         y_plane = s->current_frame.data[0];

  449.         u_plane = s->current_frame.data[1];

  450.         v_plane = s->current_frame.data[2];

  451.         stride = s->current_frame.linesize[0];

  452.         line_inc = stride - width;

  453.         index = y * stride + x;

  454.         current_x = x;

  455.         while(pixel_count--) {

  456.             pix = *pixel_buffer++;

  457. 

  458.             y_plane[index] = s->palette[pix * 4 + 0];

  459.             u_plane[index] = s->palette[pix * 4 + 1];

  460.             v_plane[index] = s->palette[pix * 4 + 2];

  461. 

  462.             index++;

  463.             current_x++;

  464.             if (current_x >= width) {

  465.                 /* reset accounting variables */

  466.                 index += line_inc;

  467.                 current_x = 0;

  468.             }

  469.         }

  470.         break;

  471. 

  472.     default:

  473.         printf (" Xan WC3: Unhandled colorspace\n");

  474.         break;

  475.     }

  476. }

  477. 

  478. static void inline xan_wc3_copy_pixel_run(XanContext *s, 

  479.     int x, int y, int pixel_count, int motion_x, int motion_y)

  480. {

  481.     int stride;

  482.     int line_inc;

  483.     int curframe_index, prevframe_index;

  484.     int curframe_x, prevframe_x;

  485.     int width = s->avctx->width;

  486.     unsigned char *palette_plane, *prev_palette_plane;

  487.     unsigned char *y_plane, *u_plane, *v_plane;

  488.     unsigned char *prev_y_plane, *prev_u_plane, *prev_v_plane;

  489.     unsigned char *rgb_plane, *prev_rgb_plane;

  490.     unsigned short *rgb16_plane, *prev_rgb16_plane;

  491.     unsigned int *rgb32_plane, *prev_rgb32_plane;

  492. 

  493.     switch (s->avctx->pix_fmt) {

  494. 

  495.     case PIX_FMT_PAL8:

  496.         palette_plane = s->current_frame.data[0];

  497.         prev_palette_plane = s->last_frame.data[0];

  498.         stride = s->current_frame.linesize[0];

  499.         line_inc = stride - width;

  500.         curframe_index = y * stride + x;

  501.         curframe_x = x;

  502.         prevframe_index = (y + motion_y) * stride + x + motion_x;

  503.         prevframe_x = x + motion_x;

  504.         while(pixel_count--) {

  505. 

  506.             palette_plane[curframe_index++] = 

  507.                 prev_palette_plane[prevframe_index++];

  508. 

  509.             curframe_x++;

  510.             if (curframe_x >= width) {

  511.                 /* reset accounting variables */

  512.                 curframe_index += line_inc;

  513.                 curframe_x = 0;

  514.             }

  515. 

  516.             prevframe_x++;

  517.             if (prevframe_x >= width) {

  518.                 /* reset accounting variables */

  519.                 prevframe_index += line_inc;

  520.                 prevframe_x = 0;

  521.             }

  522.         }

  523.         break;

  524. 

  525.     case PIX_FMT_RGB555:

  526.     case PIX_FMT_RGB565:

  527.         rgb16_plane = (unsigned short *)s->current_frame.data[0];

  528.         prev_rgb16_plane = (unsigned short *)s->last_frame.data[0];

  529.         stride = s->current_frame.linesize[0] / 2;

  530.         line_inc = stride - width;

  531.         curframe_index = y * stride + x;

  532.         curframe_x = x;

  533.         prevframe_index = (y + motion_y) * stride + x + motion_x;

  534.         prevframe_x = x + motion_x;

  535.         while(pixel_count--) {

  536. 

  537.             rgb16_plane[curframe_index++] = 

  538.                 prev_rgb16_plane[prevframe_index++];

  539. 

  540.             curframe_x++;

  541.             if (curframe_x >= width) {

  542.                 /* reset accounting variables */

  543.                 curframe_index += line_inc;

  544.                 curframe_x = 0;

  545.             }

  546. 

  547.             prevframe_x++;

  548.             if (prevframe_x >= width) {

  549.                 /* reset accounting variables */

  550.                 prevframe_index += line_inc;

  551.                 prevframe_x = 0;

  552.             }

  553.         }

  554.         break;

  555. 

  556.     case PIX_FMT_RGB24:

  557.     case PIX_FMT_BGR24:

  558.         rgb_plane = s->current_frame.data[0];

  559.         prev_rgb_plane = s->last_frame.data[0];

  560.         stride = s->current_frame.linesize[0];

  561.         line_inc = stride - width * 3;

  562.         curframe_index = y * stride + x * 3;

  563.         curframe_x = x;

  564.         prevframe_index = (y + motion_y) * stride + 

  565.             (3 * (x + motion_x));

  566.         prevframe_x = x + motion_x;

  567.         while(pixel_count--) {

  568. 

  569.             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];

  570.             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];

  571.             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];

  572. 

  573.             curframe_x++;

  574.             if (curframe_x >= width) {

  575.                 /* reset accounting variables */

  576.                 curframe_index += line_inc;

  577.                 curframe_x = 0;

  578.             }

  579. 

  580.             prevframe_x++;

  581.             if (prevframe_x >= width) {

  582.                 /* reset accounting variables */

  583.                 prevframe_index += line_inc;

  584.                 prevframe_x = 0;

  585.             }

  586.         }

  587.         break;

  588. 

  589.     case PIX_FMT_RGBA32:

  590.         rgb32_plane = (unsigned int *)s->current_frame.data[0];

  591.         prev_rgb32_plane = (unsigned int *)s->last_frame.data[0];

  592.         stride = s->current_frame.linesize[0] / 4;

  593.         line_inc = stride - width;

  594.         curframe_index = y * stride + x;

  595.         curframe_x = x;

  596.         prevframe_index = (y + motion_y) * stride + x + motion_x;

  597.         prevframe_x = x + motion_x;

  598.         while(pixel_count--) {

  599. 

  600.             rgb32_plane[curframe_index++] = 

  601.                 prev_rgb32_plane[prevframe_index++];

  602. 

  603.             curframe_x++;

  604.             if (curframe_x >= width) {

  605.                 /* reset accounting variables */

  606.                 curframe_index += line_inc;

  607.                 curframe_x = 0;

  608.             }

  609. 

  610.             prevframe_x++;

  611.             if (prevframe_x >= width) {

  612.                 /* reset accounting variables */

  613.                 prevframe_index += line_inc;

  614.                 prevframe_x = 0;

  615.             }

  616.         }

  617.         break;

  618. 

  619.     case PIX_FMT_YUV444P:

  620.         y_plane = s->current_frame.data[0];

  621.         u_plane = s->current_frame.data[1];

  622.         v_plane = s->current_frame.data[2];

  623.         prev_y_plane = s->last_frame.data[0];

  624.         prev_u_plane = s->last_frame.data[1];

  625.         prev_v_plane = s->last_frame.data[2];

  626.         stride = s->current_frame.linesize[0];

  627.         line_inc = stride - width;

  628.         curframe_index = y * stride + x;

  629.         curframe_x = x;

  630.         prevframe_index = (y + motion_y) * stride + x + motion_x;

  631.         prevframe_x = x + motion_x;

  632.         while(pixel_count--) {

  633. 

  634.             y_plane[curframe_index] = prev_y_plane[prevframe_index];

  635.             u_plane[curframe_index] = prev_u_plane[prevframe_index];

  636.             v_plane[curframe_index] = prev_v_plane[prevframe_index];

  637. 

  638.             curframe_index++;

  639.             curframe_x++;

  640.             if (curframe_x >= width) {

  641.                 /* reset accounting variables */

  642.                 curframe_index += line_inc;

  643.                 curframe_x = 0;

  644.             }

  645. 

  646.             prevframe_index++;

  647.             prevframe_x++;

  648.             if (prevframe_x >= width) {

  649.                 /* reset accounting variables */

  650.                 prevframe_index += line_inc;

  651.                 prevframe_x = 0;

  652.             }

  653.         }

  654.         break;

  655. 

  656.     default:

  657.         printf (" Xan WC3: Unhandled colorspace\n");

  658.         break;

  659.     }

  660. }

  661. 

  662. static void xan_wc3_decode_frame(XanContext *s) {

  663. 

  664.     int width = s->avctx->width;

  665.     int height = s->avctx->height;

  666.     int total_pixels = width * height;

  667.     unsigned char opcode;

  668.     unsigned char flag = 0;

  669.     int size = 0;

  670.     int motion_x, motion_y;

  671.     int x, y;

  672. 

  673.     unsigned char *opcode_buffer = s->buffer1;

  674.     unsigned char *imagedata_buffer = s->buffer2;

  675. 

  676.     /* pointers to segments inside the compressed chunk */

  677.     unsigned char *huffman_segment;

  678.     unsigned char *size_segment;

  679.     unsigned char *vector_segment;

  680.     unsigned char *imagedata_segment;

  681. 

  682.     huffman_segment =   s->buf + LE_16(&s->buf[0]);

  683.     size_segment =      s->buf + LE_16(&s->buf[2]);

  684.     vector_segment =    s->buf + LE_16(&s->buf[4]);

  685.     imagedata_segment = s->buf + LE_16(&s->buf[6]);

  686. 

  687.     xan_huffman_decode(opcode_buffer, huffman_segment);

  688. 

  689.     if (imagedata_segment[0] == 2)

  690.         xan_unpack(imagedata_buffer, &imagedata_segment[1]);

  691.     else

  692.         imagedata_buffer = &imagedata_segment[1];

  693. 

  694.     /* use the decoded data segments to build the frame */

  695.     x = y = 0;

  696.     while (total_pixels) {

  697. 

  698.         opcode = *opcode_buffer++;

  699.         size = 0;

  700. 

  701.         switch (opcode) {

  702. 

  703.         case 0:

  704.             flag ^= 1;

  705.             continue;

  706. 

  707.         case 1:

  708.         case 2:

  709.         case 3:

  710.         case 4:

  711.         case 5:

  712.         case 6:

  713.         case 7:

  714.         case 8:

  715.             size = opcode;

  716.             break;

  717. 

  718.         case 12:

  719.         case 13:

  720.         case 14:

  721.         case 15:

  722.         case 16:

  723.         case 17:

  724.         case 18:

  725.             size += (opcode - 10);

  726.             break;

  727. 

  728.         case 9:

  729.         case 19:

  730.             size = *size_segment++;

  731.             break;

  732. 

  733.         case 10:

  734.         case 20:

  735.             size = BE_16(&size_segment[0]);

  736.             size_segment += 2;

  737.             break;

  738. 

  739.         case 11:

  740.         case 21:

  741.             size = (size_segment[0] << 16) | (size_segment[1] << 8) |

  742.                 size_segment[2];

  743.             size_segment += 3;

  744.             break;

  745.         }

  746. 

  747.         if (opcode < 12) {

  748.             flag ^= 1;

  749.             if (flag) {

  750.                 /* run of (size) pixels is unchanged from last frame */

  751.                 xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);

  752.             } else {

  753.                 /* output a run of pixels from imagedata_buffer */

  754.                 xan_wc3_output_pixel_run(s, imagedata_buffer, x, y, size);

  755.                 imagedata_buffer += size;

  756.             }

  757.         } else {

  758.             /* run-based motion compensation from last frame */

  759.             motion_x = (*vector_segment >> 4) & 0xF;

  760.             motion_y = *vector_segment & 0xF;

  761.             vector_segment++;

  762. 

  763.             /* sign extension */

  764.             if (motion_x & 0x8)

  765.                 motion_x |= 0xFFFFFFF0;

  766.             if (motion_y & 0x8)

  767.                 motion_y |= 0xFFFFFFF0;

  768. 

  769.             /* copy a run of pixels from the previous frame */

  770.             xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);

  771. 

  772.             flag = 0;

  773.         }

  774. 

  775.         /* coordinate accounting */

  776.         total_pixels -= size;

  777.         while (size) {

  778.             if (x + size >= width) {

  779.                 y++;

  780.                 size -= (width - x);

  781.                 x = 0;

  782.             } else {

  783.                 x += size;

  784.                 size = 0;

  785.             }

  786.         }

  787.     }

  788. 

  789.     /* for PAL8, make the palette available on the way out */

  790.     if (s->avctx->pix_fmt == PIX_FMT_PAL8)

  791.         memcpy(s->current_frame.data[1], s->palette, PALETTE_COUNT * 4);

  792. }

  793. 

  794. static void xan_wc4_decode_frame(XanContext *s) {

  795. }

  796. 

  797. static int xan_decode_frame(AVCodecContext *avctx,

  798.                             void *data, int *data_size,

  799.                             uint8_t *buf, int buf_size)

  800. {

  801.     XanContext *s = avctx->priv_data;

  802.     AVPaletteControl *palette_control = (AVPaletteControl *)avctx->extradata;

  803.     int keyframe = 0;

  804. 

  805.     if (palette_control->palette_changed) {

  806.         /* load the new palette and reset the palette control */

  807.         xan_wc3_build_palette(s, palette_control->palette);

  808.         palette_control->palette_changed = 0;

  809.         keyframe = 1;

  810.     }

  811. 

  812.     if (avctx->get_buffer(avctx, &s->current_frame)) {

  813.         printf ("  Xan Video: get_buffer() failed\n");

  814.         return -1;

  815.     }

  816.     s->current_frame.reference = 3;

  817. 

  818.     s->buf = buf;

  819.     s->size = buf_size;

  820. 

  821.     if (avctx->codec->id == CODEC_ID_XAN_WC3)

  822.         xan_wc3_decode_frame(s);

  823.     else if (avctx->codec->id == CODEC_ID_XAN_WC4)

  824.         xan_wc4_decode_frame(s);

  825. 

  826.     /* release the last frame if it is allocated */

  827.     if (s->last_frame.data[0])

  828.         avctx->release_buffer(avctx, &s->last_frame);

  829. 

  830.     /* shuffle frames */

  831.     s->last_frame = s->current_frame;

  832. 

  833.     *data_size = sizeof(AVFrame);

  834.     *(AVFrame*)data = s->current_frame;

  835. 

  836.     /* always report that the buffer was completely consumed */

  837.     return buf_size;

  838. }

  839. 

  840. static int xan_decode_end(AVCodecContext *avctx)

  841. {

  842.     XanContext *s = avctx->priv_data;

  843. 

  844.     /* release the last frame */

  845.     avctx->release_buffer(avctx, &s->last_frame);

  846. 

  847.     av_free(s->buffer1);

  848.     av_free(s->buffer2);

  849. 

  850.     return 0;

  851. }

  852. 

  853. AVCodec xan_wc3_decoder = {

  854.     "xan_wc3",

  855.     CODEC_TYPE_VIDEO,

  856.     CODEC_ID_XAN_WC3,

  857.     sizeof(XanContext),

  858.     xan_decode_init,

  859.     NULL,

  860.     xan_decode_end,

  861.     xan_decode_frame,

  862.     CODEC_CAP_DR1,

  863. };

  864. 

  865. /*

  866. AVCodec xan_wc4_decoder = {

  867.     "xan_wc4",

  868.     CODEC_TYPE_VIDEO,

  869.     CODEC_ID_XAN_WC4,

  870.     sizeof(XanContext),

  871.     xan_decode_init,

  872.     NULL,

  873.     xan_decode_end,

  874.     xan_decode_frame,

  875.     CODEC_CAP_DR1,

  876. };

  877. */