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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 "blockdsp.h"

  35. #include "bswapdsp.h"

  36. #include "bytestream.h"

  37. #include "get_bits.h"

  38. #include "internal.h"

  39. 

  40. 

  41. #define BLOCK_TYPE_VLC_BITS 5

  42. #define ACDC_VLC_BITS 9

  43. 

  44. #define CFRAME_BUFFER_COUNT 100

  45. 

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

  47.     {

  48.         {    // { 8, 4, 2 } x { 8, 4, 2}

  49.             { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 30, 5 }, { 31, 5 }, { 0, 0 }

  50.         }, { // { 8, 4 } x 1

  51.             { 0, 1 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  52.         }, { // 1 x { 8, 4 }

  53.             { 0, 1 }, { 2, 2 }, { 0, 0 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  54.         }, { // 1 x 2, 2 x 1

  55.             { 0, 1 }, { 0, 0 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }

  56.         }

  57.     }, {

  58.         {   // { 8, 4, 2 } x { 8, 4, 2}

  59.             { 1, 2 }, { 4, 3 }, { 5, 3 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  60.         }, {// { 8, 4 } x 1

  61.             { 1, 2 }, { 0, 0 }, { 2, 2 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  62.         }, {// 1 x { 8, 4 }

  63.             { 1, 2 }, { 2, 2 }, { 0, 0 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  64.         }, {// 1 x 2, 2 x 1

  65.             { 1, 2 }, { 0, 0 }, { 0, 0 }, { 0, 2 }, { 2, 2 }, { 6, 3 }, { 7, 3 }

  66.       }

  67.     }

  68. };

  69. 

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

  71.     { -1, 3, 1, 1 },

  72.     {  3, 0, 0, 0 },

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

  74.     {  2, 0, 0, 0 },

  75. };

  76. 

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

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

  79.     {   1,   1 }, {   0,  -2 }, {  -2,   0 }, {   2,   0 }, {   0,   2 }, {  -1,  -2 }, {   1,  -2 }, {  -2,  -1 },

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

  81.     {   2,   2 }, {   0,  -3 }, {  -3,   0 }, {   3,   0 }, {   0,   3 }, {  -1,  -3 }, {   1,  -3 }, {  -3,  -1 },

  82.     {   3,  -1 }, {  -3,   1 }, {   3,   1 }, {  -1,   3 }, {   1,   3 }, {  -2,  -3 }, {   2,  -3 }, {  -3,  -2 },

  83.     {   3,  -2 }, {  -3,   2 }, {   3,   2 }, {  -2,   3 }, {   2,   3 }, {   0,  -4 }, {  -4,   0 }, {   4,   0 },

  84.     {   0,   4 }, {  -1,  -4 }, {   1,  -4 }, {  -4,  -1 }, {   4,  -1 }, {   4,   1 }, {  -1,   4 }, {   1,   4 },

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

  86.     {   2,   4 }, {  -3,  -4 }, {   3,  -4 }, {   4,  -3 }, {  -5,   0 }, {  -4,   3 }, {  -3,   4 }, {   3,   4 },

  87.     {  -1,  -5 }, {  -5,  -1 }, {  -5,   1 }, {  -1,   5 }, {  -2,  -5 }, {   2,  -5 }, {   5,  -2 }, {   5,   2 },

  88.     {  -4,  -4 }, {  -4,   4 }, {  -3,  -5 }, {  -5,  -3 }, {  -5,   3 }, {   3,   5 }, {  -6,   0 }, {   0,   6 },

  89.     {  -6,  -1 }, {  -6,   1 }, {   1,   6 }, {   2,  -6 }, {  -6,   2 }, {   2,   6 }, {  -5,  -4 }, {   5,   4 },

  90.     {   4,   5 }, {  -6,  -3 }, {   6,   3 }, {  -7,   0 }, {  -1,  -7 }, {   5,  -5 }, {  -7,   1 }, {  -1,   7 },

  91.     {   4,  -6 }, {   6,   4 }, {  -2,  -7 }, {  -7,   2 }, {  -3,  -7 }, {   7,  -3 }, {   3,   7 }, {   6,  -5 },

  92.     {   0,  -8 }, {  -1,  -8 }, {  -7,  -4 }, {  -8,   1 }, {   4,   7 }, {   2,  -8 }, {  -2,   8 }, {   6,   6 },

  93.     {  -8,   3 }, {   5,  -7 }, {  -5,   7 }, {   8,  -4 }, {   0,  -9 }, {  -9,  -1 }, {   1,   9 }, {   7,  -6 },

  94.     {  -7,   6 }, {  -5,  -8 }, {  -5,   8 }, {  -9,   3 }, {   9,  -4 }, {   7,  -7 }, {   8,  -6 }, {   6,   8 },

  95.     {  10,   1 }, { -10,   2 }, {   9,  -5 }, {  10,  -3 }, {  -8,  -7 }, { -10,  -4 }, {   6,  -9 }, { -11,   0 },

  96.     {  11,   1 }, { -11,  -2 }, {  -2,  11 }, {   7,  -9 }, {  -7,   9 }, {  10,   6 }, {  -4,  11 }, {   8,  -9 },

  97.     {   8,   9 }, {   5,  11 }, {   7, -10 }, {  12,  -3 }, {  11,   6 }, {  -9,  -9 }, {   8,  10 }, {   5,  12 },

  98.     { -11,   7 }, {  13,   2 }, {   6, -12 }, {  10,   9 }, { -11,   8 }, {  -7,  12 }, {   0,  14 }, {  14,  -2 },

  99.     {  -9,  11 }, {  -6,  13 }, { -14,  -4 }, {  -5, -14 }, {   5,  14 }, { -15,  -1 }, { -14,  -6 }, {   3, -15 },

  100.     {  11, -11 }, {  -7,  14 }, {  -5,  15 }, {   8, -14 }, {  15,   6 }, {   3,  16 }, {   7, -15 }, { -16,   5 },

  101.     {   0,  17 }, { -16,  -6 }, { -10,  14 }, { -16,   7 }, {  12,  13 }, { -16,   8 }, { -17,   6 }, { -18,   3 },

  102.     {  -7,  17 }, {  15,  11 }, {  16,  10 }, {   2, -19 }, {   3, -19 }, { -11, -16 }, { -18,   8 }, { -19,  -6 },

  103.     {   2, -20 }, { -17, -11 }, { -10, -18 }, {   8,  19 }, { -21,  -1 }, { -20,   7 }, {  -4,  21 }, {  21,   5 },

  104.     {  15,  16 }, {   2, -22 }, { -10, -20 }, { -22,   5 }, {  20, -11 }, {  -7, -22 }, { -12,  20 }, {  23,  -5 },

  105.     {  13, -20 }, {  24,  -2 }, { -15,  19 }, { -11,  22 }, {  16,  19 }, {  23, -10 }, { -18, -18 }, {  -9, -24 },

  106.     {  24, -10 }, {  -3,  26 }, { -23,  13 }, { -18, -20 }, {  17,  21 }, {  -4,  27 }, {  27,   6 }, {   1, -28 },

  107.     { -11,  26 }, { -17, -23 }, {   7,  28 }, {  11, -27 }, {  29,   5 }, { -23, -19 }, { -28, -11 }, { -21,  22 },

  108.     { -30,   7 }, { -17,  26 }, { -27,  16 }, {  13,  29 }, {  19, -26 }, {  10, -31 }, { -14, -30 }, {  20, -27 },

  109.     { -29,  18 }, { -16, -31 }, { -28, -22 }, {  21, -30 }, { -25,  28 }, {  26, -29 }, {  25, -32 }, { -32, -32 }

  110. };

  111. 

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

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

  114. static const uint8_t dequant_table[64] = {

  115.     16, 15, 13, 19, 24, 31, 28, 17,

  116.     17, 23, 25, 31, 36, 63, 45, 21,

  117.     18, 24, 27, 37, 52, 59, 49, 20,

  118.     16, 28, 34, 40, 60, 80, 51, 20,

  119.     18, 31, 48, 66, 68, 86, 56, 21,

  120.     19, 38, 56, 59, 64, 64, 48, 20,

  121.     27, 48, 55, 55, 56, 51, 35, 15,

  122.     20, 35, 34, 32, 31, 22, 15,  8,

  123. };

  124. 

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

  126. 

  127. 

  128. typedef struct CFrameBuffer {

  129.     unsigned int allocated_size;

  130.     unsigned int size;

  131.     int id;

  132.     uint8_t *data;

  133. } CFrameBuffer;

  134. 

  135. typedef struct FourXContext {

  136.     AVCodecContext *avctx;

  137.     BlockDSPContext bdsp;

  138.     BswapDSPContext bbdsp;

  139.     uint16_t *frame_buffer;

  140.     uint16_t *last_frame_buffer;

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

  142.     GetBitContext gb;

  143.     GetByteContext g;

  144.     GetByteContext g2;

  145.     int mv[256];

  146.     VLC pre_vlc;

  147.     int last_dc;

  148.     DECLARE_ALIGNED(32, int16_t, block)[6][64];

  149.     void *bitstream_buffer;

  150.     unsigned int bitstream_buffer_size;

  151.     int version;

  152.     CFrameBuffer cfrm[CFRAME_BUFFER_COUNT];

  153. } FourXContext;

  154. 

  155. 

  156. #define FIX_1_082392200  70936

  157. #define FIX_1_414213562  92682

  158. #define FIX_1_847759065 121095

  159. #define FIX_2_613125930 171254

  160. 

  161. #define MULTIPLY(var, const) ((int)((var) * (unsigned)(const)) >> 16)

  162. 

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

  164. {

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

  166.     int tmp10, tmp11, tmp12, tmp13;

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

  168.     int i;

  169.     int temp[64];

  170. 

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

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

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

  174. 

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

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

  177. 

  178.         tmp0 = tmp10 + tmp13;

  179.         tmp3 = tmp10 - tmp13;

  180.         tmp1 = tmp11 + tmp12;

  181.         tmp2 = tmp11 - tmp12;

  182. 

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

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

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

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

  187. 

  188.         tmp7  =          z11 + z13;

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

  190. 

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

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

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

  194. 

  195.         tmp6 = tmp12 - tmp7;

  196.         tmp5 = tmp11 - tmp6;

  197.         tmp4 = tmp10 + tmp5;

  198. 

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

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

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

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

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

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

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

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

  207.     }

  208. 

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

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

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

  212. 

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

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

  215. 

  216.         tmp0 = tmp10 + tmp13;

  217.         tmp3 = tmp10 - tmp13;

  218.         tmp1 = tmp11 + tmp12;

  219.         tmp2 = tmp11 - tmp12;

  220. 

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

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

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

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

  225. 

  226.         tmp7  = z11 + z13;

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

  228. 

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

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

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

  232. 

  233.         tmp6 = tmp12 - tmp7;

  234.         tmp5 = tmp11 - tmp6;

  235.         tmp4 = tmp10 + tmp5;

  236. 

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

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

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

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

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

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

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

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

  245.     }

  246. }

  247. 

  248. static av_cold void init_vlcs(FourXContext *f)

  249. {

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

  251.     int i, j;

  252. 

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

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

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

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

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

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

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

  260.                      INIT_VLC_USE_NEW_STATIC);

  261.         }

  262.     }

  263. }

  264. 

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

  266. {

  267.     int i;

  268. 

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

  270.         if (f->version > 1)

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

  272.         else

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

  274.     }

  275. }

  276. 

  277. #if HAVE_BIGENDIAN

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

  279.     {                                                   \

  280.         unsigned tmpval = AV_RN32(src);                 \

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

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

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

  284.         AV_WN32A(dst, tmpval);                          \

  285.     }

  286. #else

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

  288.     {                                                    \

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

  290.         AV_WN32A(dst, tmpval);                           \

  291.     }

  292. #endif

  293. 

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

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

  296. {

  297.     int i;

  298.     dc *= 0x10001;

  299. 

  300.     switch (log2w) {

  301.     case 0:

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

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

  304.             if (scale)

  305.                 src += stride;

  306.             dst += stride;

  307.         }

  308.         break;

  309.     case 1:

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

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

  312.             if (scale)

  313.                 src += stride;

  314.             dst += stride;

  315.         }

  316.         break;

  317.     case 2:

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

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

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

  321.             if (scale)

  322.                 src += stride;

  323.             dst += stride;

  324.         }

  325.         break;

  326.     case 3:

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

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

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

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

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

  332.             if (scale)

  333.                 src += stride;

  334.             dst += stride;

  335.         }

  336.         break;

  337.     default:

  338.         av_assert0(0);

  339.     }

  340. }

  341. 

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

  343.                           int log2w, int log2h, int stride)

  344. {

  345.     int index, h, code, ret, scale = 1;

  346.     uint16_t *start, *end;

  347.     unsigned dc = 0;

  348. 

  349.     av_assert0(log2w >= 0 && log2h >= 0);

  350. 

  351.     index = size2index[log2h][log2w];

  352.     av_assert0(index >= 0);

  353. 

  354.     if (get_bits_left(&f->gb) < 1)

  355.         return AVERROR_INVALIDDATA;

  356.     h     = 1 << log2h;

  357.     code  = get_vlc2(&f->gb, block_type_vlc[1 - (f->version > 1)][index].table,

  358.                      BLOCK_TYPE_VLC_BITS, 1);

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

  360. 

  361.     start = f->last_frame_buffer;

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

  363. 

  364.     if (code == 1) {

  365.         log2h--;

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

  367.             return ret;

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

  369.                               src + (stride << log2h),

  370.                               log2w, log2h, stride);

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

  372.         log2w--;

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

  374.             return ret;

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

  376.                               src + (1 << log2w),

  377.                               log2w, log2h, stride);

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

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

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

  381.             return AVERROR_INVALIDDATA;

  382.         }

  383.         if (log2w) {

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

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

  386.         } else {

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

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

  389.         }

  390.         return 0;

  391.     }

  392. 

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

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

  395.         return AVERROR_INVALIDDATA;

  396.     }

  397. 

  398.     if (code == 0) {

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

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

  401.         return 0;

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

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

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

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

  406.             return AVERROR_INVALIDDATA;

  407.         }

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

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

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

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

  412.             return AVERROR_INVALIDDATA;

  413.         }

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

  415.         scale = 0;

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

  417.     }

  418. 

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

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

  421.         return AVERROR_INVALIDDATA;

  422.     }

  423. 

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

  425. 

  426.     return 0;

  427. }

  428. 

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

  430. {

  431.     int x, y;

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

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

  434.     uint16_t *dst    = f->frame_buffer;

  435.     uint16_t *src;

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

  437.                  bytestream_offset, wordstream_offset;

  438.     int ret;

  439. 

  440.     src = f->last_frame_buffer;

  441. 

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

  443.         extra           = 20;

  444.         if (length < extra)

  445.             return AVERROR_INVALIDDATA;

  446.         bitstream_size  = AV_RL32(buf + 8);

  447.         wordstream_size = AV_RL32(buf + 12);

  448.         bytestream_size = AV_RL32(buf + 16);

  449.     } else {

  450.         extra           = 0;

  451.         bitstream_size  = AV_RL16(buf - 4);

  452.         wordstream_size = AV_RL16(buf - 2);

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

  454.     }

  455. 

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

  457.         bytestream_size > length - bitstream_size ||

  458.         wordstream_size > length - bytestream_size - bitstream_size ||

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

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

  461.         bitstream_size+ bytestream_size+ wordstream_size - length);

  462.         return AVERROR_INVALIDDATA;

  463.     }

  464. 

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

  466.                           bitstream_size);

  467.     if (!f->bitstream_buffer)

  468.         return AVERROR(ENOMEM);

  469.     f->bbdsp.bswap_buf(f->bitstream_buffer, (const uint32_t *) (buf + extra),

  470.                        bitstream_size / 4);

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

  472. 

  473.     wordstream_offset = extra + bitstream_size;

  474.     bytestream_offset = extra + bitstream_size + wordstream_size;

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

  476.                      length - wordstream_offset);

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

  478.                      length - bytestream_offset);

  479. 

  480.     init_mv(f, width * 2);

  481. 

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

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

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

  485.                 return ret;

  486.         src += 8 * width;

  487.         dst += 8 * width;

  488.     }

  489. 

  490.     return 0;

  491. }

  492. 

  493. /**

  494.  * decode block and dequantize.

  495.  * Note this is almost identical to MJPEG.

  496.  */

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

  498. {

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

  500. 

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

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

  503.         return AVERROR_INVALIDDATA;

  504.     }

  505. 

  506.     /* DC coef */

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

  508.     if (val >> 4) {

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

  510.         return AVERROR_INVALIDDATA;

  511.     }

  512. 

  513.     if (val)

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

  515. 

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

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

  518.     /* AC coefs */

  519.     i = 1;

  520.     for (;;) {

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

  522. 

  523.         /* EOB */

  524.         if (code == 0)

  525.             break;

  526.         if (code == 0xf0) {

  527.             i += 16;

  528.         } else {

  529.             if (code & 0xf) {

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

  531.             } else {

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

  533.                 return AVERROR_INVALIDDATA;

  534.             }

  535.             i    += code >> 4;

  536.             if (i >= 64) {

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

  538.                 return 0;

  539.             }

  540. 

  541.             j = ff_zigzag_direct[i];

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

  543.             i++;

  544.             if (i >= 64)

  545.                 break;

  546.         }

  547.     }

  548. 

  549.     return 0;

  550. }

  551. 

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

  553. {

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

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

  556.     int i;

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

  558. 

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

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

  561.         idct(block[i]);

  562.     }

  563. 

  564.     if (!(f->avctx->flags & AV_CODEC_FLAG_GRAY)) {

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

  566.             idct(block[i]);

  567.     }

  568. 

  569.     /* Note transform is:

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

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

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

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

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

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

  576.                             2 * (x & 3) + 2 * 8 * (y & 3); // FIXME optimize

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

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

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

  580.             int y;

  581. 

  582.             cb += cb;

  583. 

  584.             y               = temp[0];

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

  586.             y               = temp[1];

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

  588.             y               = temp[8];

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

  590.             y               = temp[9];

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

  592.             dst            += 2;

  593.         }

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

  595.     }

  596. }

  597. 

  598. static int decode_i_mb(FourXContext *f)

  599. {

  600.     int ret;

  601.     int i;

  602. 

  603.     f->bdsp.clear_blocks(f->block[0]);

  604. 

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

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

  607.             return ret;

  608. 

  609.     return 0;

  610. }

  611. 

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

  613.                                           const uint8_t * const buf,

  614.                                           int buf_size)

  615. {

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

  617.     uint8_t flag[512];

  618.     int up[512];

  619.     uint8_t len_tab[257];

  620.     int bits_tab[257];

  621.     int start, end;

  622.     const uint8_t *ptr = buf;

  623.     const uint8_t *ptr_end = buf + buf_size;

  624.     int j;

  625. 

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

  627. 

  628.     start = *ptr++;

  629.     end   = *ptr++;

  630.     for (;;) {

  631.         int i;

  632. 

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

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

  635.             return NULL;

  636.         }

  637. 

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

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

  640.         start = *ptr++;

  641.         if (start == 0)

  642.             break;

  643. 

  644.         end = *ptr++;

  645.     }

  646.     frequency[256] = 1;

  647. 

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

  649.         ptr++; // 4byte align

  650. 

  651.     if (ptr > ptr_end) {

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

  653.         return NULL;

  654.     }

  655. 

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

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

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

  659.         int i;

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

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

  662.                 continue;

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

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

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

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

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

  668.                     smallest[0] = i;

  669.                 } else {

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

  671.                     smallest[1] = i;

  672.                 }

  673.             }

  674.         }

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

  676.             break;

  677. 

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

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

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

  681.         up[smallest[0]]        =

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

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

  684.     }

  685. 

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

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

  688. 

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

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

  691.             len++;

  692.             if (len > 31)

  693.                 // can this happen at all ?

  694.                 av_log(f->avctx, AV_LOG_ERROR,

  695.                        "vlc length overflow\n");

  696.         }

  697. 

  698.         bits_tab[j] = bits;

  699.         len_tab[j]  = len;

  700.     }

  701. 

  702.     ff_free_vlc(&f->pre_vlc);

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

  704.                  bits_tab, 4, 4, 0))

  705.         return NULL;

  706. 

  707.     return ptr;

  708. }

  709. 

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

  711. {

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

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

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

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

  716. }

  717. 

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

  719. {

  720.     int x, y, x2, y2;

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

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

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

  724.     uint16_t *dst    = f->frame_buffer;

  725.     const uint8_t *buf_end = buf + length;

  726.     GetByteContext g3;

  727. 

  728.     if (length < mbs * 8) {

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

  730.         return AVERROR_INVALIDDATA;

  731.     }

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

  733. 

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

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

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

  737.             if (buf_end - buf < 8)

  738.                 return AVERROR_INVALIDDATA;

  739.             // warning following is purely guessed ...

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

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

  742. 

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

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

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

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

  747. 

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

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

  750. 

  751.             bits = bytestream2_get_le32u(&g3);

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

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

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

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

  756.                 }

  757.             }

  758.             dst += 16;

  759.         }

  760.         dst += 16 * width - x;

  761.     }

  762. 

  763.     return 0;

  764. }

  765. 

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

  767. {

  768.     int x, y, ret;

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

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

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

  772.     unsigned int prestream_size;

  773.     const uint8_t *prestream;

  774. 

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

  776.         return AVERROR_INVALIDDATA;

  777. 

  778.     if (length < bitstream_size + 12) {

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

  780.         return AVERROR_INVALIDDATA;

  781.     }

  782. 

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

  784.     prestream      =             buf + bitstream_size + 12;

  785. 

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

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

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

  789.                prestream_size, bitstream_size, length);

  790.         return AVERROR_INVALIDDATA;

  791.     }

  792. 

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

  794.     if (!prestream) {

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

  796.         return AVERROR_INVALIDDATA;

  797.     }

  798. 

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

  800. 

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

  802. 

  803.     prestream_size = length + buf - prestream;

  804. 

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

  806.                           prestream_size);

  807.     if (!f->bitstream_buffer)

  808.         return AVERROR(ENOMEM);

  809.     f->bbdsp.bswap_buf(f->bitstream_buffer, (const uint32_t *) prestream,

  810.                        prestream_size / 4);

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

  812. 

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

  814. 

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

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

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

  818.                 return ret;

  819. 

  820.             idct_put(f, x, y);

  821.         }

  822.     }

  823. 

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

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

  826. 

  827.     return 0;

  828. }

  829. 

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

  831.                         int *got_frame, AVPacket *avpkt)

  832. {

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

  834.     int buf_size          = avpkt->size;

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

  836.     AVFrame *picture      = data;

  837.     int i, frame_4cc, frame_size, ret;

  838. 

  839.     if (buf_size < 20)

  840.         return AVERROR_INVALIDDATA;

  841. 

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

  843. 

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

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

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

  847.         return AVERROR_INVALIDDATA;

  848.     }

  849. 

  850.     frame_4cc = AV_RL32(buf);

  851. 

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

  853.         int free_index       = -1;

  854.         int id, whole_size;

  855.         const int data_size  = buf_size - 20;

  856.         CFrameBuffer *cfrm;

  857. 

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

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

  860.             return AVERROR_INVALIDDATA;

  861.         }

  862. 

  863.         id         = AV_RL32(buf + 12);

  864.         whole_size = AV_RL32(buf + 16);

  865. 

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

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

  868.             return AVERROR_INVALIDDATA;

  869.         }

  870. 

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

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

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

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

  875. 

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

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

  878.                 break;

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

  880.                 free_index = i;

  881.         }

  882. 

  883.         if (i >= CFRAME_BUFFER_COUNT) {

  884.             i             = free_index;

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

  886.         }

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

  888. 

  889.         if (data_size > UINT_MAX -  cfrm->size - AV_INPUT_BUFFER_PADDING_SIZE)

  890.             return AVERROR_INVALIDDATA;

  891. 

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

  893.                                      cfrm->size + data_size + AV_INPUT_BUFFER_PADDING_SIZE);

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

  895.         if (!cfrm->data) {

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

  897.             return AVERROR(ENOMEM);

  898.         }

  899. 

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

  901.         cfrm->size += data_size;

  902. 

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

  904.             buf        = cfrm->data;

  905.             frame_size = cfrm->size;

  906. 

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

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

  909.                        id, avctx->frame_number);

  910. 

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

  912.                 return AVERROR_INVALIDDATA;

  913. 

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

  915.             frame_4cc  = AV_RL32("pfrm");

  916.         } else

  917.             return buf_size;

  918.     } else {

  919.         buf        = buf      + 12;

  920.         frame_size = buf_size - 12;

  921.     }

  922. 

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

  924.         return ret;

  925. 

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

  927.         picture->pict_type = AV_PICTURE_TYPE_I;

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

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

  930.             return ret;

  931.         }

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

  933.         picture->pict_type = AV_PICTURE_TYPE_I;

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

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

  936.             return ret;

  937.         }

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

  939.         picture->pict_type = AV_PICTURE_TYPE_P;

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

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

  942.             return ret;

  943.         }

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

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

  946.                buf_size);

  947.     } else {

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

  949.                buf_size);

  950.     }

  951. 

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

  953. 

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

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

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

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

  958. 

  959.     *got_frame = 1;

  960. 

  961.     emms_c();

  962. 

  963.     return buf_size;

  964. }

  965. 

  966. static av_cold int decode_end(AVCodecContext *avctx)

  967. {

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

  969.     int i;

  970. 

  971.     av_freep(&f->frame_buffer);

  972.     av_freep(&f->last_frame_buffer);

  973.     av_freep(&f->bitstream_buffer);

  974.     f->bitstream_buffer_size = 0;

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

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

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

  978.     }

  979.     ff_free_vlc(&f->pre_vlc);

  980. 

  981.     return 0;

  982. }

  983. 

  984. static av_cold int decode_init(AVCodecContext *avctx)

  985. {

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

  987.     int ret;

  988. 

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

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

  991.         return AVERROR_INVALIDDATA;

  992.     }

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

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

  995.         return AVERROR_INVALIDDATA;

  996.     }

  997. 

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

  999.     if (ret < 0)

  1000.         return ret;

  1001. 

  1002.     f->frame_buffer      = av_mallocz(avctx->width * avctx->height * 2);

  1003.     f->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);

  1004.     if (!f->frame_buffer || !f->last_frame_buffer) {

  1005.         decode_end(avctx);

  1006.         return AVERROR(ENOMEM);

  1007.     }

  1008. 

  1009.     f->version = AV_RL32(avctx->extradata) >> 16;

  1010.     ff_blockdsp_init(&f->bdsp, avctx);

  1011.     ff_bswapdsp_init(&f->bbdsp);

  1012.     f->avctx = avctx;

  1013.     init_vlcs(f);

  1014. 

  1015.     if (f->version > 2)

  1016.         avctx->pix_fmt = AV_PIX_FMT_RGB565;

  1017.     else

  1018.         avctx->pix_fmt = AV_PIX_FMT_BGR555;

  1019. 

  1020.     return 0;

  1021. }

  1022. 

  1023. AVCodec ff_fourxm_decoder = {

  1024.     .name           = "4xm",

  1025.     .long_name      = NULL_IF_CONFIG_SMALL("4X Movie"),

  1026.     .type           = AVMEDIA_TYPE_VIDEO,

  1027.     .id             = AV_CODEC_ID_4XM,

  1028.     .priv_data_size = sizeof(FourXContext),

  1029.     .init           = decode_init,

  1030.     .close          = decode_end,

  1031.     .decode         = decode_frame,

  1032.     .capabilities   = AV_CODEC_CAP_DR1,

  1033. };