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FFmpeg/libavcodec/4xm.c

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  1. /*

  2.  * 4XM codec

  3.  * Copyright (c) 2003 Michael Niedermayer

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

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

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

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * 4XM codec.

  25.  */

  26. 

  27. #include <inttypes.h>

  28. 

  29. #include "libavutil/avassert.h"

  30. #include "libavutil/frame.h"

  31. #include "libavutil/imgutils.h"

  32. #include "libavutil/intreadwrite.h"

  33. #include "avcodec.h"

  34. #include "bytestream.h"

  35. #include "dsputil.h"

  36. #include "get_bits.h"

  37. #include "internal.h"

  38. 

  39. 

  40. #define BLOCK_TYPE_VLC_BITS 5

  41. #define ACDC_VLC_BITS 9

  42. 

  43. #define CFRAME_BUFFER_COUNT 100

  44. 

  45. static const uint8_t block_type_tab[2][4][8][2] = {

  46.     {

  47.         {    // { 8, 4, 2 } x { 8, 4, 2}

  48.             { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 30, 5 }, { 31, 5 }, { 0, 0 }

  49.         }, { // { 8, 4 } x 1

  50.             { 0, 1 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  51.         }, { // 1 x { 8, 4 }

  52.             { 0, 1 }, { 2, 2 }, { 0, 0 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  53.         }, { // 1 x 2, 2 x 1

  54.             { 0, 1 }, { 0, 0 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }

  55.         }

  56.     }, {

  57.         {   // { 8, 4, 2 } x { 8, 4, 2}

  58.             { 1, 2 }, { 4, 3 }, { 5, 3 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  59.         }, {// { 8, 4 } x 1

  60.             { 1, 2 }, { 0, 0 }, { 2, 2 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  61.         }, {// 1 x { 8, 4 }

  62.             { 1, 2 }, { 2, 2 }, { 0, 0 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  63.         }, {// 1 x 2, 2 x 1

  64.             { 1, 2 }, { 0, 0 }, { 0, 0 }, { 0, 2 }, { 2, 2 }, { 6, 3 }, { 7, 3 }

  65.       }

  66.     }

  67. };

  68. 

  69. static const uint8_t size2index[4][4] = {

  70.     { -1, 3, 1, 1 },

  71.     {  3, 0, 0, 0 },

  72.     {  2, 0, 0, 0 },

  73.     {  2, 0, 0, 0 },

  74. };

  75. 

  76. static const int8_t mv[256][2] = {

  77.     {   0,   0 }, {   0,  -1 }, {  -1,   0 }, {   1,   0 }, {   0,   1 }, {  -1,  -1 }, {   1,  -1 }, {  -1,   1 },

  78.     {   1,   1 }, {   0,  -2 }, {  -2,   0 }, {   2,   0 }, {   0,   2 }, {  -1,  -2 }, {   1,  -2 }, {  -2,  -1 },

  79.     {   2,  -1 }, {  -2,   1 }, {   2,   1 }, {  -1,   2 }, {   1,   2 }, {  -2,  -2 }, {   2,  -2 }, {  -2,   2 },

  80.     {   2,   2 }, {   0,  -3 }, {  -3,   0 }, {   3,   0 }, {   0,   3 }, {  -1,  -3 }, {   1,  -3 }, {  -3,  -1 },

  81.     {   3,  -1 }, {  -3,   1 }, {   3,   1 }, {  -1,   3 }, {   1,   3 }, {  -2,  -3 }, {   2,  -3 }, {  -3,  -2 },

  82.     {   3,  -2 }, {  -3,   2 }, {   3,   2 }, {  -2,   3 }, {   2,   3 }, {   0,  -4 }, {  -4,   0 }, {   4,   0 },

  83.     {   0,   4 }, {  -1,  -4 }, {   1,  -4 }, {  -4,  -1 }, {   4,  -1 }, {   4,   1 }, {  -1,   4 }, {   1,   4 },

  84.     {  -3,  -3 }, {  -3,   3 }, {   3,   3 }, {  -2,  -4 }, {  -4,  -2 }, {   4,  -2 }, {  -4,   2 }, {  -2,   4 },

  85.     {   2,   4 }, {  -3,  -4 }, {   3,  -4 }, {   4,  -3 }, {  -5,   0 }, {  -4,   3 }, {  -3,   4 }, {   3,   4 },

  86.     {  -1,  -5 }, {  -5,  -1 }, {  -5,   1 }, {  -1,   5 }, {  -2,  -5 }, {   2,  -5 }, {   5,  -2 }, {   5,   2 },

  87.     {  -4,  -4 }, {  -4,   4 }, {  -3,  -5 }, {  -5,  -3 }, {  -5,   3 }, {   3,   5 }, {  -6,   0 }, {   0,   6 },

  88.     {  -6,  -1 }, {  -6,   1 }, {   1,   6 }, {   2,  -6 }, {  -6,   2 }, {   2,   6 }, {  -5,  -4 }, {   5,   4 },

  89.     {   4,   5 }, {  -6,  -3 }, {   6,   3 }, {  -7,   0 }, {  -1,  -7 }, {   5,  -5 }, {  -7,   1 }, {  -1,   7 },

  90.     {   4,  -6 }, {   6,   4 }, {  -2,  -7 }, {  -7,   2 }, {  -3,  -7 }, {   7,  -3 }, {   3,   7 }, {   6,  -5 },

  91.     {   0,  -8 }, {  -1,  -8 }, {  -7,  -4 }, {  -8,   1 }, {   4,   7 }, {   2,  -8 }, {  -2,   8 }, {   6,   6 },

  92.     {  -8,   3 }, {   5,  -7 }, {  -5,   7 }, {   8,  -4 }, {   0,  -9 }, {  -9,  -1 }, {   1,   9 }, {   7,  -6 },

  93.     {  -7,   6 }, {  -5,  -8 }, {  -5,   8 }, {  -9,   3 }, {   9,  -4 }, {   7,  -7 }, {   8,  -6 }, {   6,   8 },

  94.     {  10,   1 }, { -10,   2 }, {   9,  -5 }, {  10,  -3 }, {  -8,  -7 }, { -10,  -4 }, {   6,  -9 }, { -11,   0 },

  95.     {  11,   1 }, { -11,  -2 }, {  -2,  11 }, {   7,  -9 }, {  -7,   9 }, {  10,   6 }, {  -4,  11 }, {   8,  -9 },

  96.     {   8,   9 }, {   5,  11 }, {   7, -10 }, {  12,  -3 }, {  11,   6 }, {  -9,  -9 }, {   8,  10 }, {   5,  12 },

  97.     { -11,   7 }, {  13,   2 }, {   6, -12 }, {  10,   9 }, { -11,   8 }, {  -7,  12 }, {   0,  14 }, {  14,  -2 },

  98.     {  -9,  11 }, {  -6,  13 }, { -14,  -4 }, {  -5, -14 }, {   5,  14 }, { -15,  -1 }, { -14,  -6 }, {   3, -15 },

  99.     {  11, -11 }, {  -7,  14 }, {  -5,  15 }, {   8, -14 }, {  15,   6 }, {   3,  16 }, {   7, -15 }, { -16,   5 },

  100.     {   0,  17 }, { -16,  -6 }, { -10,  14 }, { -16,   7 }, {  12,  13 }, { -16,   8 }, { -17,   6 }, { -18,   3 },

  101.     {  -7,  17 }, {  15,  11 }, {  16,  10 }, {   2, -19 }, {   3, -19 }, { -11, -16 }, { -18,   8 }, { -19,  -6 },

  102.     {   2, -20 }, { -17, -11 }, { -10, -18 }, {   8,  19 }, { -21,  -1 }, { -20,   7 }, {  -4,  21 }, {  21,   5 },

  103.     {  15,  16 }, {   2, -22 }, { -10, -20 }, { -22,   5 }, {  20, -11 }, {  -7, -22 }, { -12,  20 }, {  23,  -5 },

  104.     {  13, -20 }, {  24,  -2 }, { -15,  19 }, { -11,  22 }, {  16,  19 }, {  23, -10 }, { -18, -18 }, {  -9, -24 },

  105.     {  24, -10 }, {  -3,  26 }, { -23,  13 }, { -18, -20 }, {  17,  21 }, {  -4,  27 }, {  27,   6 }, {   1, -28 },

  106.     { -11,  26 }, { -17, -23 }, {   7,  28 }, {  11, -27 }, {  29,   5 }, { -23, -19 }, { -28, -11 }, { -21,  22 },

  107.     { -30,   7 }, { -17,  26 }, { -27,  16 }, {  13,  29 }, {  19, -26 }, {  10, -31 }, { -14, -30 }, {  20, -27 },

  108.     { -29,  18 }, { -16, -31 }, { -28, -22 }, {  21, -30 }, { -25,  28 }, {  26, -29 }, {  25, -32 }, { -32, -32 }

  109. };

  110. 

  111. /* This is simply the scaled down elementwise product of the standard JPEG

  112.  * quantizer table and the AAN premul table. */

  113. static const uint8_t dequant_table[64] = {

  114.     16, 15, 13, 19, 24, 31, 28, 17,

  115.     17, 23, 25, 31, 36, 63, 45, 21,

  116.     18, 24, 27, 37, 52, 59, 49, 20,

  117.     16, 28, 34, 40, 60, 80, 51, 20,

  118.     18, 31, 48, 66, 68, 86, 56, 21,

  119.     19, 38, 56, 59, 64, 64, 48, 20,

  120.     27, 48, 55, 55, 56, 51, 35, 15,

  121.     20, 35, 34, 32, 31, 22, 15,  8,

  122. };

  123. 

  124. static VLC block_type_vlc[2][4];

  125. 

  126. 

  127. typedef struct CFrameBuffer {

  128.     unsigned int allocated_size;

  129.     unsigned int size;

  130.     int id;

  131.     uint8_t *data;

  132. } CFrameBuffer;

  133. 

  134. typedef struct FourXContext {

  135.     AVCodecContext *avctx;

  136.     DSPContext dsp;

  137.     uint16_t *frame_buffer;

  138.     uint16_t *last_frame_buffer;

  139.     GetBitContext pre_gb;          ///< ac/dc prefix

  140.     GetBitContext gb;

  141.     GetByteContext g;

  142.     GetByteContext g2;

  143.     int mv[256];

  144.     VLC pre_vlc;

  145.     int last_dc;

  146.     DECLARE_ALIGNED(16, int16_t, block)[6][64];

  147.     void *bitstream_buffer;

  148.     unsigned int bitstream_buffer_size;

  149.     int version;

  150.     CFrameBuffer cfrm[CFRAME_BUFFER_COUNT];

  151. } FourXContext;

  152. 

  153. 

  154. #define FIX_1_082392200  70936

  155. #define FIX_1_414213562  92682

  156. #define FIX_1_847759065 121095

  157. #define FIX_2_613125930 171254

  158. 

  159. #define MULTIPLY(var, const) (((var) * (const)) >> 16)

  160. 

  161. static void idct(int16_t block[64])

  162. {

  163.     int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;

  164.     int tmp10, tmp11, tmp12, tmp13;

  165.     int z5, z10, z11, z12, z13;

  166.     int i;

  167.     int temp[64];

  168. 

  169.     for (i = 0; i < 8; i++) {

  170.         tmp10 = block[8 * 0 + i] + block[8 * 4 + i];

  171.         tmp11 = block[8 * 0 + i] - block[8 * 4 + i];

  172. 

  173.         tmp13 = block[8 * 2 + i] + block[8 * 6 + i];

  174.         tmp12 = MULTIPLY(block[8 * 2 + i] - block[8 * 6 + i], FIX_1_414213562) - tmp13;

  175. 

  176.         tmp0 = tmp10 + tmp13;

  177.         tmp3 = tmp10 - tmp13;

  178.         tmp1 = tmp11 + tmp12;

  179.         tmp2 = tmp11 - tmp12;

  180. 

  181.         z13 = block[8 * 5 + i] + block[8 * 3 + i];

  182.         z10 = block[8 * 5 + i] - block[8 * 3 + i];

  183.         z11 = block[8 * 1 + i] + block[8 * 7 + i];

  184.         z12 = block[8 * 1 + i] - block[8 * 7 + i];

  185. 

  186.         tmp7  =          z11 + z13;

  187.         tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);

  188. 

  189.         z5    = MULTIPLY(z10 + z12, FIX_1_847759065);

  190.         tmp10 = MULTIPLY(z12,  FIX_1_082392200) - z5;

  191.         tmp12 = MULTIPLY(z10, -FIX_2_613125930) + z5;

  192. 

  193.         tmp6 = tmp12 - tmp7;

  194.         tmp5 = tmp11 - tmp6;

  195.         tmp4 = tmp10 + tmp5;

  196. 

  197.         temp[8 * 0 + i] = tmp0 + tmp7;

  198.         temp[8 * 7 + i] = tmp0 - tmp7;

  199.         temp[8 * 1 + i] = tmp1 + tmp6;

  200.         temp[8 * 6 + i] = tmp1 - tmp6;

  201.         temp[8 * 2 + i] = tmp2 + tmp5;

  202.         temp[8 * 5 + i] = tmp2 - tmp5;

  203.         temp[8 * 4 + i] = tmp3 + tmp4;

  204.         temp[8 * 3 + i] = tmp3 - tmp4;

  205.     }

  206. 

  207.     for (i = 0; i < 8 * 8; i += 8) {

  208.         tmp10 = temp[0 + i] + temp[4 + i];

  209.         tmp11 = temp[0 + i] - temp[4 + i];

  210. 

  211.         tmp13 = temp[2 + i] + temp[6 + i];

  212.         tmp12 = MULTIPLY(temp[2 + i] - temp[6 + i], FIX_1_414213562) - tmp13;

  213. 

  214.         tmp0 = tmp10 + tmp13;

  215.         tmp3 = tmp10 - tmp13;

  216.         tmp1 = tmp11 + tmp12;

  217.         tmp2 = tmp11 - tmp12;

  218. 

  219.         z13 = temp[5 + i] + temp[3 + i];

  220.         z10 = temp[5 + i] - temp[3 + i];

  221.         z11 = temp[1 + i] + temp[7 + i];

  222.         z12 = temp[1 + i] - temp[7 + i];

  223. 

  224.         tmp7  = z11 + z13;

  225.         tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);

  226. 

  227.         z5    = MULTIPLY(z10 + z12, FIX_1_847759065);

  228.         tmp10 = MULTIPLY(z12,  FIX_1_082392200) - z5;

  229.         tmp12 = MULTIPLY(z10, -FIX_2_613125930) + z5;

  230. 

  231.         tmp6 = tmp12 - tmp7;

  232.         tmp5 = tmp11 - tmp6;

  233.         tmp4 = tmp10 + tmp5;

  234. 

  235.         block[0 + i] = (tmp0 + tmp7) >> 6;

  236.         block[7 + i] = (tmp0 - tmp7) >> 6;

  237.         block[1 + i] = (tmp1 + tmp6) >> 6;

  238.         block[6 + i] = (tmp1 - tmp6) >> 6;

  239.         block[2 + i] = (tmp2 + tmp5) >> 6;

  240.         block[5 + i] = (tmp2 - tmp5) >> 6;

  241.         block[4 + i] = (tmp3 + tmp4) >> 6;

  242.         block[3 + i] = (tmp3 - tmp4) >> 6;

  243.     }

  244. }

  245. 

  246. static av_cold void init_vlcs(FourXContext *f)

  247. {

  248.     static VLC_TYPE table[2][4][32][2];

  249.     int i, j;

  250. 

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

  252.         for (j = 0; j < 4; j++) {

  253.             block_type_vlc[i][j].table           = table[i][j];

  254.             block_type_vlc[i][j].table_allocated = 32;

  255.             init_vlc(&block_type_vlc[i][j], BLOCK_TYPE_VLC_BITS, 7,

  256.                      &block_type_tab[i][j][0][1], 2, 1,

  257.                      &block_type_tab[i][j][0][0], 2, 1,

  258.                      INIT_VLC_USE_NEW_STATIC);

  259.         }

  260.     }

  261. }

  262. 

  263. static void init_mv(FourXContext *f, int linesize)

  264. {

  265.     int i;

  266. 

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

  268.         if (f->version > 1)

  269.             f->mv[i] = mv[i][0] + mv[i][1] * linesize / 2;

  270.         else

  271.             f->mv[i] = (i & 15) - 8 + ((i >> 4) - 8) * linesize / 2;

  272.     }

  273. }

  274. 

  275. #if HAVE_BIGENDIAN

  276. #define LE_CENTRIC_MUL(dst, src, scale, dc)             \

  277.     {                                                   \

  278.         unsigned tmpval = AV_RN32(src);                 \

  279.         tmpval = (tmpval << 16) | (tmpval >> 16);       \

  280.         tmpval = tmpval * (scale) + (dc);               \

  281.         tmpval = (tmpval << 16) | (tmpval >> 16);       \

  282.         AV_WN32A(dst, tmpval);                          \

  283.     }

  284. #else

  285. #define LE_CENTRIC_MUL(dst, src, scale, dc)              \

  286.     {                                                    \

  287.         unsigned tmpval = AV_RN32(src) * (scale) + (dc); \

  288.         AV_WN32A(dst, tmpval);                           \

  289.     }

  290. #endif

  291. 

  292. static inline void mcdc(uint16_t *dst, const uint16_t *src, int log2w,

  293.                         int h, int stride, int scale, unsigned dc)

  294. {

  295.     int i;

  296.     dc *= 0x10001;

  297. 

  298.     switch (log2w) {

  299.     case 0:

  300.         for (i = 0; i < h; i++) {

  301.             dst[0] = scale * src[0] + dc;

  302.             if (scale)

  303.                 src += stride;

  304.             dst += stride;

  305.         }

  306.         break;

  307.     case 1:

  308.         for (i = 0; i < h; i++) {

  309.             LE_CENTRIC_MUL(dst, src, scale, dc);

  310.             if (scale)

  311.                 src += stride;

  312.             dst += stride;

  313.         }

  314.         break;

  315.     case 2:

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

  317.             LE_CENTRIC_MUL(dst, src, scale, dc);

  318.             LE_CENTRIC_MUL(dst + 2, src + 2, scale, dc);

  319.             if (scale)

  320.                 src += stride;

  321.             dst += stride;

  322.         }

  323.         break;

  324.     case 3:

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

  326.             LE_CENTRIC_MUL(dst,     src,     scale, dc);

  327.             LE_CENTRIC_MUL(dst + 2, src + 2, scale, dc);

  328.             LE_CENTRIC_MUL(dst + 4, src + 4, scale, dc);

  329.             LE_CENTRIC_MUL(dst + 6, src + 6, scale, dc);

  330.             if (scale)

  331.                 src += stride;

  332.             dst += stride;

  333.         }

  334.         break;

  335.     default:

  336.         av_assert0(0);

  337.     }

  338. }

  339. 

  340. static int decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src,

  341.                           int log2w, int log2h, int stride)

  342. {

  343.     const int index = size2index[log2h][log2w];

  344.     const int h     = 1 << log2h;

  345.     int code        = get_vlc2(&f->gb,

  346.                                block_type_vlc[1 - (f->version > 1)][index].table,

  347.                                BLOCK_TYPE_VLC_BITS, 1);

  348.     uint16_t *start = f->last_frame_buffer;

  349.     uint16_t *end   = start + stride * (f->avctx->height - h + 1) - (1 << log2w);

  350.     int ret;

  351.     int scale   = 1;

  352.     unsigned dc = 0;

  353. 

  354.     av_assert0(code >= 0 && code <= 6 && log2w >= 0);

  355. 

  356.     if (code == 1) {

  357.         log2h--;

  358.         if ((ret = decode_p_block(f, dst, src, log2w, log2h, stride)) < 0)

  359.             return ret;

  360.         return decode_p_block(f, dst + (stride << log2h),

  361.                               src + (stride << log2h),

  362.                               log2w, log2h, stride);

  363.     } else if (code == 2) {

  364.         log2w--;

  365.         if ((ret = decode_p_block(f, dst , src, log2w, log2h, stride)) < 0)

  366.             return ret;

  367.         return decode_p_block(f, dst + (1 << log2w),

  368.                               src + (1 << log2w),

  369.                               log2w, log2h, stride);

  370.     } else if (code == 6) {

  371.         if (bytestream2_get_bytes_left(&f->g2) < 4) {

  372.             av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");

  373.             return AVERROR_INVALIDDATA;

  374.         }

  375.         if (log2w) {

  376.             dst[0]      = bytestream2_get_le16u(&f->g2);

  377.             dst[1]      = bytestream2_get_le16u(&f->g2);

  378.         } else {

  379.             dst[0]      = bytestream2_get_le16u(&f->g2);

  380.             dst[stride] = bytestream2_get_le16u(&f->g2);

  381.         }

  382.         return 0;

  383.     }

  384. 

  385.     if ((code&3)==0 && bytestream2_get_bytes_left(&f->g) < 1) {

  386.         av_log(f->avctx, AV_LOG_ERROR, "bytestream overread\n");

  387.         return AVERROR_INVALIDDATA;

  388.     }

  389. 

  390.     if (code == 0) {

  391.         src  += f->mv[bytestream2_get_byte(&f->g)];

  392.     } else if (code == 3 && f->version >= 2) {

  393.         return 0;

  394.     } else if (code == 4) {

  395.         src  += f->mv[bytestream2_get_byte(&f->g)];

  396.         if (bytestream2_get_bytes_left(&f->g2) < 2){

  397.             av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");

  398.             return AVERROR_INVALIDDATA;

  399.         }

  400.         dc    = bytestream2_get_le16(&f->g2);

  401.     } else if (code == 5) {

  402.         if (bytestream2_get_bytes_left(&f->g2) < 2){

  403.             av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");

  404.             return AVERROR_INVALIDDATA;

  405.         }

  406.         av_assert0(start <= src && src <= end);

  407.         scale = 0;

  408.         dc    = bytestream2_get_le16(&f->g2);

  409.     }

  410. 

  411.     if (start > src || src > end) {

  412.         av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n");

  413.         return AVERROR_INVALIDDATA;

  414.     }

  415. 

  416.     mcdc(dst, src, log2w, h, stride, scale, dc);

  417. 

  418.     return 0;

  419. }

  420. 

  421. static int decode_p_frame(FourXContext *f, const uint8_t *buf, int length)

  422. {

  423.     int x, y;

  424.     const int width  = f->avctx->width;

  425.     const int height = f->avctx->height;

  426.     uint16_t *dst    = f->frame_buffer;

  427.     uint16_t *src;

  428.     unsigned int bitstream_size, bytestream_size, wordstream_size, extra,

  429.                  bytestream_offset, wordstream_offset;

  430.     int ret;

  431. 

  432.     src = f->last_frame_buffer;

  433. 

  434.     if (f->version > 1) {

  435.         extra           = 20;

  436.         if (length < extra)

  437.             return AVERROR_INVALIDDATA;

  438.         bitstream_size  = AV_RL32(buf + 8);

  439.         wordstream_size = AV_RL32(buf + 12);

  440.         bytestream_size = AV_RL32(buf + 16);

  441.     } else {

  442.         extra           = 0;

  443.         bitstream_size  = AV_RL16(buf - 4);

  444.         wordstream_size = AV_RL16(buf - 2);

  445.         bytestream_size = FFMAX(length - bitstream_size - wordstream_size, 0);

  446.     }

  447. 

  448.     if (bitstream_size > length || bitstream_size >= INT_MAX/8 ||

  449.         bytestream_size > length - bitstream_size ||

  450.         wordstream_size > length - bytestream_size - bitstream_size ||

  451.         extra > length - bytestream_size - bitstream_size - wordstream_size) {

  452.         av_log(f->avctx, AV_LOG_ERROR, "lengths %d %d %d %d\n", bitstream_size, bytestream_size, wordstream_size,

  453.         bitstream_size+ bytestream_size+ wordstream_size - length);

  454.         return AVERROR_INVALIDDATA;

  455.     }

  456. 

  457.     av_fast_padded_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size,

  458.                           bitstream_size);

  459.     if (!f->bitstream_buffer)

  460.         return AVERROR(ENOMEM);

  461.     f->dsp.bswap_buf(f->bitstream_buffer, (const uint32_t*)(buf + extra),

  462.                      bitstream_size / 4);

  463.     init_get_bits(&f->gb, f->bitstream_buffer, 8 * bitstream_size);

  464. 

  465.     wordstream_offset = extra + bitstream_size;

  466.     bytestream_offset = extra + bitstream_size + wordstream_size;

  467.     bytestream2_init(&f->g2, buf + wordstream_offset,

  468.                      length - wordstream_offset);

  469.     bytestream2_init(&f->g, buf + bytestream_offset,

  470.                      length - bytestream_offset);

  471. 

  472.     init_mv(f, width * 2);

  473. 

  474.     for (y = 0; y < height; y += 8) {

  475.         for (x = 0; x < width; x += 8)

  476.             if ((ret = decode_p_block(f, dst + x, src + x, 3, 3, width)) < 0)

  477.                 return ret;

  478.         src += 8 * width;

  479.         dst += 8 * width;

  480.     }

  481. 

  482.     return 0;

  483. }

  484. 

  485. /**

  486.  * decode block and dequantize.

  487.  * Note this is almost identical to MJPEG.

  488.  */

  489. static int decode_i_block(FourXContext *f, int16_t *block)

  490. {

  491.     int code, i, j, level, val;

  492. 

  493.     if (get_bits_left(&f->gb) < 2){

  494.         av_log(f->avctx, AV_LOG_ERROR, "%d bits left before decode_i_block()\n", get_bits_left(&f->gb));

  495.         return -1;

  496.     }

  497. 

  498.     /* DC coef */

  499.     val = get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3);

  500.     if (val >> 4) {

  501.         av_log(f->avctx, AV_LOG_ERROR, "error dc run != 0\n");

  502.         return AVERROR_INVALIDDATA;

  503.     }

  504. 

  505.     if (val)

  506.         val = get_xbits(&f->gb, val);

  507. 

  508.     val        = val * dequant_table[0] + f->last_dc;

  509.     f->last_dc = block[0] = val;

  510.     /* AC coefs */

  511.     i = 1;

  512.     for (;;) {

  513.         code = get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3);

  514. 

  515.         /* EOB */

  516.         if (code == 0)

  517.             break;

  518.         if (code == 0xf0) {

  519.             i += 16;

  520.         } else {

  521.             if (code & 0xf) {

  522.                 level = get_xbits(&f->gb, code & 0xf);

  523.             } else {

  524.                 av_log(f->avctx, AV_LOG_ERROR, "0 coeff\n");

  525.                 return AVERROR_INVALIDDATA;

  526.             }

  527.             i    += code >> 4;

  528.             if (i >= 64) {

  529.                 av_log(f->avctx, AV_LOG_ERROR, "run %d oveflow\n", i);

  530.                 return 0;

  531.             }

  532. 

  533.             j = ff_zigzag_direct[i];

  534.             block[j] = level * dequant_table[j];

  535.             i++;

  536.             if (i >= 64)

  537.                 break;

  538.         }

  539.     }

  540. 

  541.     return 0;

  542. }

  543. 

  544. static inline void idct_put(FourXContext *f, int x, int y)

  545. {

  546.     int16_t (*block)[64] = f->block;

  547.     int stride           = f->avctx->width;

  548.     int i;

  549.     uint16_t *dst = f->frame_buffer + y * stride + x;

  550. 

  551.     for (i = 0; i < 4; i++) {

  552.         block[i][0] += 0x80 * 8 * 8;

  553.         idct(block[i]);

  554.     }

  555. 

  556.     if (!(f->avctx->flags & CODEC_FLAG_GRAY)) {

  557.         for (i = 4; i < 6; i++)

  558.             idct(block[i]);

  559.     }

  560. 

  561.     /* Note transform is:

  562.      * y  = ( 1b + 4g + 2r) / 14

  563.      * cb = ( 3b - 2g - 1r) / 14

  564.      * cr = (-1b - 4g + 5r) / 14 */

  565.     for (y = 0; y < 8; y++) {

  566.         for (x = 0; x < 8; x++) {

  567.             int16_t *temp = block[(x >> 2) + 2 * (y >> 2)] +

  568.                             2 * (x & 3) + 2 * 8 * (y & 3); // FIXME optimize

  569.             int cb = block[4][x + 8 * y];

  570.             int cr = block[5][x + 8 * y];

  571.             int cg = (cb + cr) >> 1;

  572.             int y;

  573. 

  574.             cb += cb;

  575. 

  576.             y               = temp[0];

  577.             dst[0]          = ((y + cb) >> 3) + (((y - cg) & 0xFC) << 3) + (((y + cr) & 0xF8) << 8);

  578.             y               = temp[1];

  579.             dst[1]          = ((y + cb) >> 3) + (((y - cg) & 0xFC) << 3) + (((y + cr) & 0xF8) << 8);

  580.             y               = temp[8];

  581.             dst[stride]     = ((y + cb) >> 3) + (((y - cg) & 0xFC) << 3) + (((y + cr) & 0xF8) << 8);

  582.             y               = temp[9];

  583.             dst[1 + stride] = ((y + cb) >> 3) + (((y - cg) & 0xFC) << 3) + (((y + cr) & 0xF8) << 8);

  584.             dst            += 2;

  585.         }

  586.         dst += 2 * stride - 2 * 8;

  587.     }

  588. }

  589. 

  590. static int decode_i_mb(FourXContext *f)

  591. {

  592.     int ret;

  593.     int i;

  594. 

  595.     f->dsp.clear_blocks(f->block[0]);

  596. 

  597.     for (i = 0; i < 6; i++)

  598.         if ((ret = decode_i_block(f, f->block[i])) < 0)

  599.             return ret;

  600. 

  601.     return 0;

  602. }

  603. 

  604. static const uint8_t *read_huffman_tables(FourXContext *f,

  605.                                           const uint8_t * const buf,

  606.                                           int buf_size)

  607. {

  608.     int frequency[512] = { 0 };

  609.     uint8_t flag[512];

  610.     int up[512];

  611.     uint8_t len_tab[257];

  612.     int bits_tab[257];

  613.     int start, end;

  614.     const uint8_t *ptr = buf;

  615.     const uint8_t *ptr_end = buf + buf_size;

  616.     int j;

  617. 

  618.     memset(up, -1, sizeof(up));

  619. 

  620.     start = *ptr++;

  621.     end   = *ptr++;

  622.     for (;;) {

  623.         int i;

  624. 

  625.         if (ptr_end - ptr < FFMAX(end - start + 1, 0) + 1) {

  626.             av_log(f->avctx, AV_LOG_ERROR, "invalid data in read_huffman_tables\n");

  627.             return NULL;

  628.         }

  629. 

  630.         for (i = start; i <= end; i++)

  631.             frequency[i] = *ptr++;

  632.         start = *ptr++;

  633.         if (start == 0)

  634.             break;

  635. 

  636.         end = *ptr++;

  637.     }

  638.     frequency[256] = 1;

  639. 

  640.     while ((ptr - buf) & 3)

  641.         ptr++; // 4byte align

  642. 

  643.     if (ptr > ptr_end) {

  644.         av_log(f->avctx, AV_LOG_ERROR, "ptr overflow in read_huffman_tables\n");

  645.         return NULL;

  646.     }

  647. 

  648.     for (j = 257; j < 512; j++) {

  649.         int min_freq[2] = { 256 * 256, 256 * 256 };

  650.         int smallest[2] = { 0, 0 };

  651.         int i;

  652.         for (i = 0; i < j; i++) {

  653.             if (frequency[i] == 0)

  654.                 continue;

  655.             if (frequency[i] < min_freq[1]) {

  656.                 if (frequency[i] < min_freq[0]) {

  657.                     min_freq[1] = min_freq[0];

  658.                     smallest[1] = smallest[0];

  659.                     min_freq[0] = frequency[i];

  660.                     smallest[0] = i;

  661.                 } else {

  662.                     min_freq[1] = frequency[i];

  663.                     smallest[1] = i;

  664.                 }

  665.             }

  666.         }

  667.         if (min_freq[1] == 256 * 256)

  668.             break;

  669. 

  670.         frequency[j]           = min_freq[0] + min_freq[1];

  671.         flag[smallest[0]]      = 0;

  672.         flag[smallest[1]]      = 1;

  673.         up[smallest[0]]        =

  674.         up[smallest[1]]        = j;

  675.         frequency[smallest[0]] = frequency[smallest[1]] = 0;

  676.     }

  677. 

  678.     for (j = 0; j < 257; j++) {

  679.         int node, len = 0, bits = 0;

  680. 

  681.         for (node = j; up[node] != -1; node = up[node]) {

  682.             bits += flag[node] << len;

  683.             len++;

  684.             if (len > 31)

  685.                 // can this happen at all ?

  686.                 av_log(f->avctx, AV_LOG_ERROR,

  687.                        "vlc length overflow\n");

  688.         }

  689. 

  690.         bits_tab[j] = bits;

  691.         len_tab[j]  = len;

  692.     }

  693. 

  694.     if (init_vlc(&f->pre_vlc, ACDC_VLC_BITS, 257, len_tab, 1, 1,

  695.                  bits_tab, 4, 4, 0))

  696.         return NULL;

  697. 

  698.     return ptr;

  699. }

  700. 

  701. static int mix(int c0, int c1)

  702. {

  703.     int blue  =  2 * (c0 & 0x001F) + (c1 & 0x001F);

  704.     int green = (2 * (c0 & 0x03E0) + (c1 & 0x03E0)) >> 5;

  705.     int red   =  2 * (c0 >> 10)    + (c1 >> 10);

  706.     return red / 3 * 1024 + green / 3 * 32 + blue / 3;

  707. }

  708. 

  709. static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length)

  710. {

  711.     int x, y, x2, y2;

  712.     const int width  = f->avctx->width;

  713.     const int height = f->avctx->height;

  714.     const int mbs    = (FFALIGN(width, 16) >> 4) * (FFALIGN(height, 16) >> 4);

  715.     uint16_t *dst    = f->frame_buffer;

  716.     const uint8_t *buf_end = buf + length;

  717.     GetByteContext g3;

  718. 

  719.     if (length < mbs * 8) {

  720.         av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");

  721.         return AVERROR_INVALIDDATA;

  722.     }

  723.     bytestream2_init(&g3, buf, length);

  724. 

  725.     for (y = 0; y < height; y += 16) {

  726.         for (x = 0; x < width; x += 16) {

  727.             unsigned int color[4] = { 0 }, bits;

  728.             if (buf_end - buf < 8)

  729.                 return -1;

  730.             // warning following is purely guessed ...

  731.             color[0] = bytestream2_get_le16u(&g3);

  732.             color[1] = bytestream2_get_le16u(&g3);

  733. 

  734.             if (color[0] & 0x8000)

  735.                 av_log(f->avctx, AV_LOG_ERROR, "unk bit 1\n");

  736.             if (color[1] & 0x8000)

  737.                 av_log(f->avctx, AV_LOG_ERROR, "unk bit 2\n");

  738. 

  739.             color[2] = mix(color[0], color[1]);

  740.             color[3] = mix(color[1], color[0]);

  741. 

  742.             bits = bytestream2_get_le32u(&g3);

  743.             for (y2 = 0; y2 < 16; y2++) {

  744.                 for (x2 = 0; x2 < 16; x2++) {

  745.                     int index = 2 * (x2 >> 2) + 8 * (y2 >> 2);

  746.                     dst[y2 * width + x2] = color[(bits >> index) & 3];

  747.                 }

  748.             }

  749.             dst += 16;

  750.         }

  751.         dst += 16 * width - x;

  752.     }

  753. 

  754.     return 0;

  755. }

  756. 

  757. static int decode_i_frame(FourXContext *f, const uint8_t *buf, int length)

  758. {

  759.     int x, y, ret;

  760.     const int width  = f->avctx->width;

  761.     const int height = f->avctx->height;

  762.     const unsigned int bitstream_size = AV_RL32(buf);

  763.     unsigned int prestream_size;

  764.     const uint8_t *prestream;

  765. 

  766.     if (bitstream_size > (1 << 26))

  767.         return AVERROR_INVALIDDATA;

  768. 

  769.     if (length < bitstream_size + 12) {

  770.         av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");

  771.         return AVERROR_INVALIDDATA;

  772.     }

  773. 

  774.     prestream_size = 4 * AV_RL32(buf + bitstream_size + 4);

  775.     prestream      =             buf + bitstream_size + 12;

  776. 

  777.     if (prestream_size + bitstream_size + 12 != length

  778.         || prestream_size > (1 << 26)) {

  779.         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %d %d\n",

  780.                prestream_size, bitstream_size, length);

  781.         return AVERROR_INVALIDDATA;

  782.     }

  783. 

  784.     prestream = read_huffman_tables(f, prestream, prestream_size);

  785.     if (!prestream) {

  786.         av_log(f->avctx, AV_LOG_ERROR, "Error reading Huffman tables.\n");

  787.         return AVERROR_INVALIDDATA;

  788.     }

  789. 

  790.     av_assert0(prestream <= buf + length);

  791. 

  792.     init_get_bits(&f->gb, buf + 4, 8 * bitstream_size);

  793. 

  794.     prestream_size = length + buf - prestream;

  795. 

  796.     av_fast_padded_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size,

  797.                           prestream_size);

  798.     if (!f->bitstream_buffer)

  799.         return AVERROR(ENOMEM);

  800.     f->dsp.bswap_buf(f->bitstream_buffer, (const uint32_t*)prestream,

  801.                      prestream_size / 4);

  802.     init_get_bits(&f->pre_gb, f->bitstream_buffer, 8 * prestream_size);

  803. 

  804.     f->last_dc = 0 * 128 * 8 * 8;

  805. 

  806.     for (y = 0; y < height; y += 16) {

  807.         for (x = 0; x < width; x += 16) {

  808.             if ((ret = decode_i_mb(f)) < 0)

  809.                 return ret;

  810. 

  811.             idct_put(f, x, y);

  812.         }

  813.     }

  814. 

  815.     if (get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3) != 256)

  816.         av_log(f->avctx, AV_LOG_ERROR, "end mismatch\n");

  817. 

  818.     return 0;

  819. }

  820. 

  821. static int decode_frame(AVCodecContext *avctx, void *data,

  822.                         int *got_frame, AVPacket *avpkt)

  823. {

  824.     const uint8_t *buf    = avpkt->data;

  825.     int buf_size          = avpkt->size;

  826.     FourXContext *const f = avctx->priv_data;

  827.     AVFrame *picture      = data;

  828.     int i, frame_4cc, frame_size, ret;

  829. 

  830.     if (buf_size < 20)

  831.         return AVERROR_INVALIDDATA;

  832. 

  833.     av_assert0(avctx->width % 16 == 0 && avctx->height % 16 == 0);

  834. 

  835.     if (buf_size < AV_RL32(buf + 4) + 8) {

  836.         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %"PRIu32"\n",

  837.                buf_size, AV_RL32(buf + 4));

  838.         return AVERROR_INVALIDDATA;

  839.     }

  840. 

  841.     frame_4cc = AV_RL32(buf);

  842. 

  843.     if (frame_4cc == AV_RL32("cfrm")) {

  844.         int free_index       = -1;

  845.         int id, whole_size;

  846.         const int data_size  = buf_size - 20;

  847.         CFrameBuffer *cfrm;

  848. 

  849.         if (f->version <= 1) {

  850.             av_log(f->avctx, AV_LOG_ERROR, "cfrm in version %d\n", f->version);

  851.             return AVERROR_INVALIDDATA;

  852.         }

  853. 

  854.         id         = AV_RL32(buf + 12);

  855.         whole_size = AV_RL32(buf + 16);

  856. 

  857.         if (data_size < 0 || whole_size < 0) {

  858.             av_log(f->avctx, AV_LOG_ERROR, "sizes invalid\n");

  859.             return AVERROR_INVALIDDATA;

  860.         }

  861. 

  862.         for (i = 0; i < CFRAME_BUFFER_COUNT; i++)

  863.             if (f->cfrm[i].id && f->cfrm[i].id < avctx->frame_number)

  864.                 av_log(f->avctx, AV_LOG_ERROR, "lost c frame %d\n",

  865.                        f->cfrm[i].id);

  866. 

  867.         for (i = 0; i < CFRAME_BUFFER_COUNT; i++) {

  868.             if (f->cfrm[i].id == id)

  869.                 break;

  870.             if (f->cfrm[i].size == 0)

  871.                 free_index = i;

  872.         }

  873. 

  874.         if (i >= CFRAME_BUFFER_COUNT) {

  875.             i             = free_index;

  876.             f->cfrm[i].id = id;

  877.         }

  878.         cfrm = &f->cfrm[i];

  879. 

  880.         if (data_size > UINT_MAX -  cfrm->size - FF_INPUT_BUFFER_PADDING_SIZE)

  881.             return AVERROR_INVALIDDATA;

  882. 

  883.         cfrm->data = av_fast_realloc(cfrm->data, &cfrm->allocated_size,

  884.                                      cfrm->size + data_size + FF_INPUT_BUFFER_PADDING_SIZE);

  885.         // explicit check needed as memcpy below might not catch a NULL

  886.         if (!cfrm->data) {

  887.             av_log(f->avctx, AV_LOG_ERROR, "realloc failure\n");

  888.             return AVERROR(ENOMEM);

  889.         }

  890. 

  891.         memcpy(cfrm->data + cfrm->size, buf + 20, data_size);

  892.         cfrm->size += data_size;

  893. 

  894.         if (cfrm->size >= whole_size) {

  895.             buf        = cfrm->data;

  896.             frame_size = cfrm->size;

  897. 

  898.             if (id != avctx->frame_number)

  899.                 av_log(f->avctx, AV_LOG_ERROR, "cframe id mismatch %d %d\n",

  900.                        id, avctx->frame_number);

  901. 

  902.             if (f->version <= 1)

  903.                 return AVERROR_INVALIDDATA;

  904. 

  905.             cfrm->size = cfrm->id = 0;

  906.             frame_4cc  = AV_RL32("pfrm");

  907.         } else

  908.             return buf_size;

  909.     } else {

  910.         buf        = buf      + 12;

  911.         frame_size = buf_size - 12;

  912.     }

  913. 

  914.     if ((ret = ff_get_buffer(avctx, picture, 0)) < 0)

  915.         return ret;

  916. 

  917.     if (frame_4cc == AV_RL32("ifr2")) {

  918.         picture->pict_type = AV_PICTURE_TYPE_I;

  919.         if ((ret = decode_i2_frame(f, buf - 4, frame_size + 4)) < 0) {

  920.             av_log(f->avctx, AV_LOG_ERROR, "decode i2 frame failed\n");

  921.             return ret;

  922.         }

  923.     } else if (frame_4cc == AV_RL32("ifrm")) {

  924.         picture->pict_type = AV_PICTURE_TYPE_I;

  925.         if ((ret = decode_i_frame(f, buf, frame_size)) < 0) {

  926.             av_log(f->avctx, AV_LOG_ERROR, "decode i frame failed\n");

  927.             return ret;

  928.         }

  929.     } else if (frame_4cc == AV_RL32("pfrm") || frame_4cc == AV_RL32("pfr2")) {

  930.         picture->pict_type = AV_PICTURE_TYPE_P;

  931.         if ((ret = decode_p_frame(f, buf, frame_size)) < 0) {

  932.             av_log(f->avctx, AV_LOG_ERROR, "decode p frame failed\n");

  933.             return ret;

  934.         }

  935.     } else if (frame_4cc == AV_RL32("snd_")) {

  936.         av_log(avctx, AV_LOG_ERROR, "ignoring snd_ chunk length:%d\n",

  937.                buf_size);

  938.     } else {

  939.         av_log(avctx, AV_LOG_ERROR, "ignoring unknown chunk length:%d\n",

  940.                buf_size);

  941.     }

  942. 

  943.     picture->key_frame = picture->pict_type == AV_PICTURE_TYPE_I;

  944. 

  945.     av_image_copy_plane(picture->data[0], picture->linesize[0],

  946.                         (const uint8_t*)f->frame_buffer,  avctx->width * 2,

  947.                         avctx->width * 2, avctx->height);

  948.     FFSWAP(uint16_t *, f->frame_buffer, f->last_frame_buffer);

  949. 

  950.     *got_frame = 1;

  951. 

  952.     emms_c();

  953. 

  954.     return buf_size;

  955. }

  956. 

  957. static av_cold int decode_end(AVCodecContext *avctx)

  958. {

  959.     FourXContext * const f = avctx->priv_data;

  960.     int i;

  961. 

  962.     av_freep(&f->frame_buffer);

  963.     av_freep(&f->last_frame_buffer);

  964.     av_freep(&f->bitstream_buffer);

  965.     f->bitstream_buffer_size = 0;

  966.     for (i = 0; i < CFRAME_BUFFER_COUNT; i++) {

  967.         av_freep(&f->cfrm[i].data);

  968.         f->cfrm[i].allocated_size = 0;

  969.     }

  970.     ff_free_vlc(&f->pre_vlc);

  971. 

  972.     return 0;

  973. }

  974. 

  975. static av_cold int decode_init(AVCodecContext *avctx)

  976. {

  977.     FourXContext * const f = avctx->priv_data;

  978.     int ret;

  979. 

  980.     if (avctx->extradata_size != 4 || !avctx->extradata) {

  981.         av_log(avctx, AV_LOG_ERROR, "extradata wrong or missing\n");

  982.         return AVERROR_INVALIDDATA;

  983.     }

  984.     if((avctx->width % 16) || (avctx->height % 16)) {

  985.         av_log(avctx, AV_LOG_ERROR, "unsupported width/height\n");

  986.         return AVERROR_INVALIDDATA;

  987.     }

  988. 

  989.     ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);

  990.     if (ret < 0)

  991.         return ret;

  992. 

  993.     f->frame_buffer      = av_mallocz(avctx->width * avctx->height * 2);

  994.     f->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);

  995.     if (!f->frame_buffer || !f->last_frame_buffer) {

  996.         decode_end(avctx);

  997.         return AVERROR(ENOMEM);

  998.     }

  999. 

  1000.     f->version = AV_RL32(avctx->extradata) >> 16;

  1001.     ff_dsputil_init(&f->dsp, avctx);

  1002.     f->avctx = avctx;

  1003.     init_vlcs(f);

  1004. 

  1005.     if (f->version > 2)

  1006.         avctx->pix_fmt = AV_PIX_FMT_RGB565;

  1007.     else

  1008.         avctx->pix_fmt = AV_PIX_FMT_BGR555;

  1009. 

  1010.     return 0;

  1011. }

  1012. 

  1013. AVCodec ff_fourxm_decoder = {

  1014.     .name           = "4xm",

  1015.     .long_name      = NULL_IF_CONFIG_SMALL("4X Movie"),

  1016.     .type           = AVMEDIA_TYPE_VIDEO,

  1017.     .id             = AV_CODEC_ID_4XM,

  1018.     .priv_data_size = sizeof(FourXContext),

  1019.     .init           = decode_init,

  1020.     .close          = decode_end,

  1021.     .decode         = decode_frame,

  1022.     .capabilities   = CODEC_CAP_DR1,

  1023. };