falkTX
/
FFmpeg
mirror of https://github.com/falkTX/FFmpeg.git
1
0
Fork 0
Code Issues 0 Releases 338 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
2536 Commits
32 Branches
283MB
Tree: e4e70d2e2d
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from 'e4e70d2e2d'
${ noResults }
FFmpeg/libavcodec/xan.c

821 lines
22KB
Raw Blame History 

  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.                 ((b >> 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.                 ((b >> 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. /* advance current_x variable; reset accounting variables if current_x

  342.  * moves beyond width */

  343. #define ADVANCE_CURRENT_X() \

  344.     current_x++; \

  345.     if (current_x >= width) { \

  346.         index += line_inc; \

  347.         current_x = 0; \

  348.     }

  349. 

  350. static void inline xan_wc3_output_pixel_run(XanContext *s, 

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

  352. {

  353.     int stride;

  354.     int line_inc;

  355.     int index;

  356.     int current_x;

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

  358.     unsigned char pix;

  359.     unsigned char *palette_plane;

  360.     unsigned char *y_plane;

  361.     unsigned char *u_plane;

  362.     unsigned char *v_plane;

  363.     unsigned char *rgb_plane;

  364.     unsigned short *rgb16_plane;

  365.     unsigned short *palette16;

  366.     unsigned int *rgb32_plane;

  367.     unsigned int *palette32;

  368. 

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

  370. 

  371.     case PIX_FMT_PAL8:

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

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

  374.         line_inc = stride - width;

  375.         index = y * stride + x;

  376.         current_x = x;

  377.         while(pixel_count--) {

  378. 

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

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

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

  382. 

  383.             ADVANCE_CURRENT_X();

  384.         }

  385.         break;

  386. 

  387.     case PIX_FMT_RGB555:

  388.     case PIX_FMT_RGB565:

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

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

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

  392.         line_inc = stride - width;

  393.         index = y * stride + x;

  394.         current_x = x;

  395.         while(pixel_count--) {

  396. 

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

  398. 

  399.             ADVANCE_CURRENT_X();

  400.         }

  401.         break;

  402. 

  403.     case PIX_FMT_RGB24:

  404.     case PIX_FMT_BGR24:

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

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

  407.         line_inc = stride - width * 3;

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

  409.         current_x = x;

  410.         while(pixel_count--) {

  411.             pix = *pixel_buffer++;

  412. 

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

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

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

  416. 

  417.             ADVANCE_CURRENT_X();

  418.         }

  419.         break;

  420. 

  421.     case PIX_FMT_RGBA32:

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

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

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

  425.         line_inc = stride - width;

  426.         index = y * stride + x;

  427.         current_x = x;

  428.         while(pixel_count--) {

  429. 

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

  431. 

  432.             ADVANCE_CURRENT_X();

  433.         }

  434.         break;

  435. 

  436.     case PIX_FMT_YUV444P:

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

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

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

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

  441.         line_inc = stride - width;

  442.         index = y * stride + x;

  443.         current_x = x;

  444.         while(pixel_count--) {

  445.             pix = *pixel_buffer++;

  446. 

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

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

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

  450. 

  451.             index++;

  452.             ADVANCE_CURRENT_X();

  453.         }

  454.         break;

  455. 

  456.     default:

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

  458.         break;

  459.     }

  460. }

  461. 

  462. #define ADVANCE_CURFRAME_X() \

  463.     curframe_x++; \

  464.     if (curframe_x >= width) { \

  465.         curframe_index += line_inc; \

  466.         curframe_x = 0; \

  467.     }

  468. 

  469. #define ADVANCE_PREVFRAME_X() \

  470.     prevframe_x++; \

  471.     if (prevframe_x >= width) { \

  472.         prevframe_index += line_inc; \

  473.         prevframe_x = 0; \

  474.     }

  475. 

  476. static void inline xan_wc3_copy_pixel_run(XanContext *s, 

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

  478. {

  479.     int stride;

  480.     int line_inc;

  481.     int curframe_index, prevframe_index;

  482.     int curframe_x, prevframe_x;

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

  484.     unsigned char *palette_plane, *prev_palette_plane;

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

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

  487.     unsigned char *rgb_plane, *prev_rgb_plane;

  488.     unsigned short *rgb16_plane, *prev_rgb16_plane;

  489.     unsigned int *rgb32_plane, *prev_rgb32_plane;

  490. 

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

  492. 

  493.     case PIX_FMT_PAL8:

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

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

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

  497.         line_inc = stride - width;

  498.         curframe_index = y * stride + x;

  499.         curframe_x = x;

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

  501.         prevframe_x = x + motion_x;

  502.         while(pixel_count--) {

  503. 

  504.             palette_plane[curframe_index++] = 

  505.                 prev_palette_plane[prevframe_index++];

  506. 

  507.             ADVANCE_CURFRAME_X();

  508.             ADVANCE_PREVFRAME_X();

  509.         }

  510.         break;

  511. 

  512.     case PIX_FMT_RGB555:

  513.     case PIX_FMT_RGB565:

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

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

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

  517.         line_inc = stride - width;

  518.         curframe_index = y * stride + x;

  519.         curframe_x = x;

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

  521.         prevframe_x = x + motion_x;

  522.         while(pixel_count--) {

  523. 

  524.             rgb16_plane[curframe_index++] = 

  525.                 prev_rgb16_plane[prevframe_index++];

  526. 

  527.             ADVANCE_CURFRAME_X();

  528.             ADVANCE_PREVFRAME_X();

  529.         }

  530.         break;

  531. 

  532.     case PIX_FMT_RGB24:

  533.     case PIX_FMT_BGR24:

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

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

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

  537.         line_inc = stride - width * 3;

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

  539.         curframe_x = x;

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

  541.             (3 * (x + motion_x));

  542.         prevframe_x = x + motion_x;

  543.         while(pixel_count--) {

  544. 

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

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

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

  548. 

  549.             ADVANCE_CURFRAME_X();

  550.             ADVANCE_PREVFRAME_X();

  551.         }

  552.         break;

  553. 

  554.     case PIX_FMT_RGBA32:

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

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

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

  558.         line_inc = stride - width;

  559.         curframe_index = y * stride + x;

  560.         curframe_x = x;

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

  562.         prevframe_x = x + motion_x;

  563.         while(pixel_count--) {

  564. 

  565.             rgb32_plane[curframe_index++] = 

  566.                 prev_rgb32_plane[prevframe_index++];

  567. 

  568.             ADVANCE_CURFRAME_X();

  569.             ADVANCE_PREVFRAME_X();

  570.         }

  571.         break;

  572. 

  573.     case PIX_FMT_YUV444P:

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

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

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

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

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

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

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

  581.         line_inc = stride - width;

  582.         curframe_index = y * stride + x;

  583.         curframe_x = x;

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

  585.         prevframe_x = x + motion_x;

  586.         while(pixel_count--) {

  587. 

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

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

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

  591. 

  592.             curframe_index++;

  593.             ADVANCE_CURFRAME_X();

  594.             prevframe_index++;

  595.             ADVANCE_PREVFRAME_X();

  596.         }

  597.         break;

  598. 

  599.     default:

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

  601.         break;

  602.     }

  603. }

  604. 

  605. static void xan_wc3_decode_frame(XanContext *s) {

  606. 

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

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

  609.     int total_pixels = width * height;

  610.     unsigned char opcode;

  611.     unsigned char flag = 0;

  612.     int size = 0;

  613.     int motion_x, motion_y;

  614.     int x, y;

  615. 

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

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

  618. 

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

  620.     unsigned char *huffman_segment;

  621.     unsigned char *size_segment;

  622.     unsigned char *vector_segment;

  623.     unsigned char *imagedata_segment;

  624. 

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

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

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

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

  629. 

  630.     xan_huffman_decode(opcode_buffer, huffman_segment);

  631. 

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

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

  634.     else

  635.         imagedata_buffer = &imagedata_segment[1];

  636. 

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

  638.     x = y = 0;

  639.     while (total_pixels) {

  640. 

  641.         opcode = *opcode_buffer++;

  642.         size = 0;

  643. 

  644.         switch (opcode) {

  645. 

  646.         case 0:

  647.             flag ^= 1;

  648.             continue;

  649. 

  650.         case 1:

  651.         case 2:

  652.         case 3:

  653.         case 4:

  654.         case 5:

  655.         case 6:

  656.         case 7:

  657.         case 8:

  658.             size = opcode;

  659.             break;

  660. 

  661.         case 12:

  662.         case 13:

  663.         case 14:

  664.         case 15:

  665.         case 16:

  666.         case 17:

  667.         case 18:

  668.             size += (opcode - 10);

  669.             break;

  670. 

  671.         case 9:

  672.         case 19:

  673.             size = *size_segment++;

  674.             break;

  675. 

  676.         case 10:

  677.         case 20:

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

  679.             size_segment += 2;

  680.             break;

  681. 

  682.         case 11:

  683.         case 21:

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

  685.                 size_segment[2];

  686.             size_segment += 3;

  687.             break;

  688.         }

  689. 

  690.         if (opcode < 12) {

  691.             flag ^= 1;

  692.             if (flag) {

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

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

  695.             } else {

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

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

  698.                 imagedata_buffer += size;

  699.             }

  700.         } else {

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

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

  703.             motion_y = *vector_segment & 0xF;

  704.             vector_segment++;

  705. 

  706.             /* sign extension */

  707.             if (motion_x & 0x8)

  708.                 motion_x |= 0xFFFFFFF0;

  709.             if (motion_y & 0x8)

  710.                 motion_y |= 0xFFFFFFF0;

  711. 

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

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

  714. 

  715.             flag = 0;

  716.         }

  717. 

  718.         /* coordinate accounting */

  719.         total_pixels -= size;

  720.         while (size) {

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

  722.                 y++;

  723.                 size -= (width - x);

  724.                 x = 0;

  725.             } else {

  726.                 x += size;

  727.                 size = 0;

  728.             }

  729.         }

  730.     }

  731. 

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

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

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

  735. }

  736. 

  737. static void xan_wc4_decode_frame(XanContext *s) {

  738. }

  739. 

  740. static int xan_decode_frame(AVCodecContext *avctx,

  741.                             void *data, int *data_size,

  742.                             uint8_t *buf, int buf_size)

  743. {

  744.     XanContext *s = avctx->priv_data;

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

  746.     int keyframe = 0;

  747. 

  748.     if (palette_control->palette_changed) {

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

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

  751.         palette_control->palette_changed = 0;

  752.         keyframe = 1;

  753.     }

  754. 

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

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

  757.         return -1;

  758.     }

  759.     s->current_frame.reference = 3;

  760. 

  761.     s->buf = buf;

  762.     s->size = buf_size;

  763. 

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

  765.         xan_wc3_decode_frame(s);

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

  767.         xan_wc4_decode_frame(s);

  768. 

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

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

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

  772. 

  773.     /* shuffle frames */

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

  775. 

  776.     *data_size = sizeof(AVFrame);

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

  778. 

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

  780.     return buf_size;

  781. }

  782. 

  783. static int xan_decode_end(AVCodecContext *avctx)

  784. {

  785.     XanContext *s = avctx->priv_data;

  786. 

  787.     /* release the last frame */

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

  789. 

  790.     av_free(s->buffer1);

  791.     av_free(s->buffer2);

  792. 

  793.     return 0;

  794. }

  795. 

  796. AVCodec xan_wc3_decoder = {

  797.     "xan_wc3",

  798.     CODEC_TYPE_VIDEO,

  799.     CODEC_ID_XAN_WC3,

  800.     sizeof(XanContext),

  801.     xan_decode_init,

  802.     NULL,

  803.     xan_decode_end,

  804.     xan_decode_frame,

  805.     CODEC_CAP_DR1,

  806. };

  807. 

  808. /*

  809. AVCodec xan_wc4_decoder = {

  810.     "xan_wc4",

  811.     CODEC_TYPE_VIDEO,

  812.     CODEC_ID_XAN_WC4,

  813.     sizeof(XanContext),

  814.     xan_decode_init,

  815.     NULL,

  816.     xan_decode_end,

  817.     xan_decode_frame,

  818.     CODEC_CAP_DR1,

  819. };

  820. */