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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 Libav.

  6.  *

  7.  * Libav 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.  * Libav 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 Libav; 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 "libavutil/intreadwrite.h"

  28. #include "avcodec.h"

  29. #include "bytestream.h"

  30. #include "dsputil.h"

  31. #include "get_bits.h"

  32. 

  33. //#undef NDEBUG

  34. //#include <assert.h>

  35. 

  36. #define BLOCK_TYPE_VLC_BITS 5

  37. #define ACDC_VLC_BITS 9

  38. 

  39. #define CFRAME_BUFFER_COUNT 100

  40. 

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

  42.     {

  43.         {    // { 8, 4, 2 } x { 8, 4, 2}

  44.             { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 30, 5 }, { 31, 5 }, { 0, 0 }

  45.         }, { // { 8, 4 } x 1

  46.             { 0, 1 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  47.         }, { // 1 x { 8, 4 }

  48.             { 0, 1 }, { 2, 2 }, { 0, 0 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  49.         }, { // 1 x 2, 2 x 1

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

  51.         }

  52.     }, {

  53.         {   // { 8, 4, 2 } x { 8, 4, 2}

  54.             { 1, 2 }, { 4, 3 }, { 5, 3 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  55.         }, {// { 8, 4 } x 1

  56.             { 1, 2 }, { 0, 0 }, { 2, 2 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  57.         }, {// 1 x { 8, 4 }

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

  59.         }, {// 1 x 2, 2 x 1

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

  61.       }

  62.     }

  63. };

  64. 

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

  66.     { -1, 3, 1, 1 },

  67.     {  3, 0, 0, 0 },

  68.     {  2, 0, 0, 0 },

  69.     {  2, 0, 0, 0 },

  70. };

  71. 

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

  73.     {   0,   0 }, {   0,  -1 }, {  -1,   0 }, {   1,   0 }, {   0,   1 }, {  -1,  -1 }, {   1,  -1 }, {  -1,   1 },

  74.     {   1,   1 }, {   0,  -2 }, {  -2,   0 }, {   2,   0 }, {   0,   2 }, {  -1,  -2 }, {   1,  -2 }, {  -2,  -1 },

  75.     {   2,  -1 }, {  -2,   1 }, {   2,   1 }, {  -1,   2 }, {   1,   2 }, {  -2,  -2 }, {   2,  -2 }, {  -2,   2 },

  76.     {   2,   2 }, {   0,  -3 }, {  -3,   0 }, {   3,   0 }, {   0,   3 }, {  -1,  -3 }, {   1,  -3 }, {  -3,  -1 },

  77.     {   3,  -1 }, {  -3,   1 }, {   3,   1 }, {  -1,   3 }, {   1,   3 }, {  -2,  -3 }, {   2,  -3 }, {  -3,  -2 },

  78.     {   3,  -2 }, {  -3,   2 }, {   3,   2 }, {  -2,   3 }, {   2,   3 }, {   0,  -4 }, {  -4,   0 }, {   4,   0 },

  79.     {   0,   4 }, {  -1,  -4 }, {   1,  -4 }, {  -4,  -1 }, {   4,  -1 }, {   4,   1 }, {  -1,   4 }, {   1,   4 },

  80.     {  -3,  -3 }, {  -3,   3 }, {   3,   3 }, {  -2,  -4 }, {  -4,  -2 }, {   4,  -2 }, {  -4,   2 }, {  -2,   4 },

  81.     {   2,   4 }, {  -3,  -4 }, {   3,  -4 }, {   4,  -3 }, {  -5,   0 }, {  -4,   3 }, {  -3,   4 }, {   3,   4 },

  82.     {  -1,  -5 }, {  -5,  -1 }, {  -5,   1 }, {  -1,   5 }, {  -2,  -5 }, {   2,  -5 }, {   5,  -2 }, {   5,   2 },

  83.     {  -4,  -4 }, {  -4,   4 }, {  -3,  -5 }, {  -5,  -3 }, {  -5,   3 }, {   3,   5 }, {  -6,   0 }, {   0,   6 },

  84.     {  -6,  -1 }, {  -6,   1 }, {   1,   6 }, {   2,  -6 }, {  -6,   2 }, {   2,   6 }, {  -5,  -4 }, {   5,   4 },

  85.     {   4,   5 }, {  -6,  -3 }, {   6,   3 }, {  -7,   0 }, {  -1,  -7 }, {   5,  -5 }, {  -7,   1 }, {  -1,   7 },

  86.     {   4,  -6 }, {   6,   4 }, {  -2,  -7 }, {  -7,   2 }, {  -3,  -7 }, {   7,  -3 }, {   3,   7 }, {   6,  -5 },

  87.     {   0,  -8 }, {  -1,  -8 }, {  -7,  -4 }, {  -8,   1 }, {   4,   7 }, {   2,  -8 }, {  -2,   8 }, {   6,   6 },

  88.     {  -8,   3 }, {   5,  -7 }, {  -5,   7 }, {   8,  -4 }, {   0,  -9 }, {  -9,  -1 }, {   1,   9 }, {   7,  -6 },

  89.     {  -7,   6 }, {  -5,  -8 }, {  -5,   8 }, {  -9,   3 }, {   9,  -4 }, {   7,  -7 }, {   8,  -6 }, {   6,   8 },

  90.     {  10,   1 }, { -10,   2 }, {   9,  -5 }, {  10,  -3 }, {  -8,  -7 }, { -10,  -4 }, {   6,  -9 }, { -11,   0 },

  91.     {  11,   1 }, { -11,  -2 }, {  -2,  11 }, {   7,  -9 }, {  -7,   9 }, {  10,   6 }, {  -4,  11 }, {   8,  -9 },

  92.     {   8,   9 }, {   5,  11 }, {   7, -10 }, {  12,  -3 }, {  11,   6 }, {  -9,  -9 }, {   8,  10 }, {   5,  12 },

  93.     { -11,   7 }, {  13,   2 }, {   6, -12 }, {  10,   9 }, { -11,   8 }, {  -7,  12 }, {   0,  14 }, {  14,  -2 },

  94.     {  -9,  11 }, {  -6,  13 }, { -14,  -4 }, {  -5, -14 }, {   5,  14 }, { -15,  -1 }, { -14,  -6 }, {   3, -15 },

  95.     {  11, -11 }, {  -7,  14 }, {  -5,  15 }, {   8, -14 }, {  15,   6 }, {   3,  16 }, {   7, -15 }, { -16,   5 },

  96.     {   0,  17 }, { -16,  -6 }, { -10,  14 }, { -16,   7 }, {  12,  13 }, { -16,   8 }, { -17,   6 }, { -18,   3 },

  97.     {  -7,  17 }, {  15,  11 }, {  16,  10 }, {   2, -19 }, {   3, -19 }, { -11, -16 }, { -18,   8 }, { -19,  -6 },

  98.     {   2, -20 }, { -17, -11 }, { -10, -18 }, {   8,  19 }, { -21,  -1 }, { -20,   7 }, {  -4,  21 }, {  21,   5 },

  99.     {  15,  16 }, {   2, -22 }, { -10, -20 }, { -22,   5 }, {  20, -11 }, {  -7, -22 }, { -12,  20 }, {  23,  -5 },

  100.     {  13, -20 }, {  24,  -2 }, { -15,  19 }, { -11,  22 }, {  16,  19 }, {  23, -10 }, { -18, -18 }, {  -9, -24 },

  101.     {  24, -10 }, {  -3,  26 }, { -23,  13 }, { -18, -20 }, {  17,  21 }, {  -4,  27 }, {  27,   6 }, {   1, -28 },

  102.     { -11,  26 }, { -17, -23 }, {   7,  28 }, {  11, -27 }, {  29,   5 }, { -23, -19 }, { -28, -11 }, { -21,  22 },

  103.     { -30,   7 }, { -17,  26 }, { -27,  16 }, {  13,  29 }, {  19, -26 }, {  10, -31 }, { -14, -30 }, {  20, -27 },

  104.     { -29,  18 }, { -16, -31 }, { -28, -22 }, {  21, -30 }, { -25,  28 }, {  26, -29 }, {  25, -32 }, { -32, -32 }

  105. };

  106. 

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

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

  109. static const uint8_t dequant_table[64] = {

  110.     16, 15, 13, 19, 24, 31, 28, 17,

  111.     17, 23, 25, 31, 36, 63, 45, 21,

  112.     18, 24, 27, 37, 52, 59, 49, 20,

  113.     16, 28, 34, 40, 60, 80, 51, 20,

  114.     18, 31, 48, 66, 68, 86, 56, 21,

  115.     19, 38, 56, 59, 64, 64, 48, 20,

  116.     27, 48, 55, 55, 56, 51, 35, 15,

  117.     20, 35, 34, 32, 31, 22, 15,  8,

  118. };

  119. 

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

  121. 

  122. 

  123. typedef struct CFrameBuffer {

  124.     unsigned int allocated_size;

  125.     unsigned int size;

  126.     int id;

  127.     uint8_t *data;

  128. } CFrameBuffer;

  129. 

  130. typedef struct FourXContext {

  131.     AVCodecContext *avctx;

  132.     DSPContext dsp;

  133.     AVFrame current_picture, last_picture;

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

  135.     GetBitContext gb;

  136.     GetByteContext g;

  137.     GetByteContext g2;

  138.     int mv[256];

  139.     VLC pre_vlc;

  140.     int last_dc;

  141.     DECLARE_ALIGNED(16, DCTELEM, block)[6][64];

  142.     void *bitstream_buffer;

  143.     unsigned int bitstream_buffer_size;

  144.     int version;

  145.     CFrameBuffer cfrm[CFRAME_BUFFER_COUNT];

  146. } FourXContext;

  147. 

  148. 

  149. #define FIX_1_082392200  70936

  150. #define FIX_1_414213562  92682

  151. #define FIX_1_847759065 121095

  152. #define FIX_2_613125930 171254

  153. 

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

  155. 

  156. static void idct(DCTELEM block[64])

  157. {

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

  159.     int tmp10, tmp11, tmp12, tmp13;

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

  161.     int i;

  162.     int temp[64];

  163. 

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

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

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

  167. 

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

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

  170. 

  171.         tmp0 = tmp10 + tmp13;

  172.         tmp3 = tmp10 - tmp13;

  173.         tmp1 = tmp11 + tmp12;

  174.         tmp2 = tmp11 - tmp12;

  175. 

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

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

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

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

  180. 

  181.         tmp7  =          z11 + z13;

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

  183. 

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

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

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

  187. 

  188.         tmp6 = tmp12 - tmp7;

  189.         tmp5 = tmp11 - tmp6;

  190.         tmp4 = tmp10 + tmp5;

  191. 

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

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

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

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

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

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

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

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

  200.     }

  201. 

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

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

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

  205. 

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

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

  208. 

  209.         tmp0 = tmp10 + tmp13;

  210.         tmp3 = tmp10 - tmp13;

  211.         tmp1 = tmp11 + tmp12;

  212.         tmp2 = tmp11 - tmp12;

  213. 

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

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

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

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

  218. 

  219.         tmp7  = z11 + z13;

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

  221. 

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

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

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

  225. 

  226.         tmp6 = tmp12 - tmp7;

  227.         tmp5 = tmp11 - tmp6;

  228.         tmp4 = tmp10 + tmp5;

  229. 

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

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

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

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

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

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

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

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

  238.     }

  239. }

  240. 

  241. static av_cold void init_vlcs(FourXContext *f)

  242. {

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

  244.     int i, j;

  245. 

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

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

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

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

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

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

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

  253.                      INIT_VLC_USE_NEW_STATIC);

  254.         }

  255.     }

  256. }

  257. 

  258. static void init_mv(FourXContext *f)

  259. {

  260.     int i;

  261. 

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

  263.         if (f->version > 1)

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

  265.         else

  266.             f->mv[i] = (i & 15) - 8 + ((i >> 4) - 8) * f->current_picture.linesize[0] / 2;

  267.     }

  268. }

  269. 

  270. #if HAVE_BIGENDIAN

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

  272.     {                                                   \

  273.         unsigned tmpval = AV_RN32(src);                 \

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

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

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

  277.         AV_WN32A(dst, tmpval);                          \

  278.     }

  279. #else

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

  281.     {                                                    \

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

  283.         AV_WN32A(dst, tmpval);                           \

  284.     }

  285. #endif

  286. 

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

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

  289. {

  290.     int i;

  291.     dc *= 0x10001;

  292. 

  293.     switch (log2w) {

  294.     case 0:

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

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

  297.             if (scale)

  298.                 src += stride;

  299.             dst += stride;

  300.         }

  301.         break;

  302.     case 1:

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

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

  305.             if (scale)

  306.                 src += stride;

  307.             dst += stride;

  308.         }

  309.         break;

  310.     case 2:

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

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

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

  314.             if (scale)

  315.                 src += stride;

  316.             dst += stride;

  317.         }

  318.         break;

  319.     case 3:

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

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

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

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

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

  325.             if (scale)

  326.                 src += stride;

  327.             dst += stride;

  328.         }

  329.         break;

  330.     default:

  331.         assert(0);

  332.     }

  333. }

  334. 

  335. static void decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src,

  336.                            int log2w, int log2h, int stride)

  337. {

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

  339.     const int h     = 1 << log2h;

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

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

  342.                                BLOCK_TYPE_VLC_BITS, 1);

  343.     uint16_t *start = (uint16_t *)f->last_picture.data[0];

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

  345. 

  346.     assert(code >= 0 && code <= 6);

  347. 

  348.     if (code == 0) {

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

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

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

  352.             return;

  353.         }

  354.         mcdc(dst, src, log2w, h, stride, 1, 0);

  355.     } else if (code == 1) {

  356.         log2h--;

  357.         decode_p_block(f, dst, src, log2w, log2h, stride);

  358.         decode_p_block(f, dst + (stride << log2h),

  359.                           src + (stride << log2h), log2w, log2h, stride);

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

  361.         log2w--;

  362.         decode_p_block(f, dst , src, log2w, log2h, stride);

  363.         decode_p_block(f, dst + (1 << log2w),

  364.                           src + (1 << log2w), log2w, log2h, stride);

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

  366.         mcdc(dst, src, log2w, h, stride, 1, 0);

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

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

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

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

  371.             return;

  372.         }

  373.         mcdc(dst, src, log2w, h, stride, 1, bytestream2_get_le16(&f->g2));

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

  375.         mcdc(dst, src, log2w, h, stride, 0, bytestream2_get_le16(&f->g2));

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

  377.         if (log2w) {

  378.             dst[0]      = bytestream2_get_le16(&f->g2);

  379.             dst[1]      = bytestream2_get_le16(&f->g2);

  380.         } else {

  381.             dst[0]      = bytestream2_get_le16(&f->g2);

  382.             dst[stride] = bytestream2_get_le16(&f->g2);

  383.         }

  384.     }

  385. }

  386. 

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

  388. {

  389.     int x, y;

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

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

  392.     uint16_t *src    = (uint16_t *)f->last_picture.data[0];

  393.     uint16_t *dst    = (uint16_t *)f->current_picture.data[0];

  394.     const int stride =             f->current_picture.linesize[0] >> 1;

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

  396.                  bytestream_offset, wordstream_offset;

  397. 

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

  399.         extra           = 20;

  400.         bitstream_size  = AV_RL32(buf + 8);

  401.         wordstream_size = AV_RL32(buf + 12);

  402.         bytestream_size = AV_RL32(buf + 16);

  403.     } else {

  404.         extra           = 0;

  405.         bitstream_size  = AV_RL16(buf - 4);

  406.         wordstream_size = AV_RL16(buf - 2);

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

  408.     }

  409. 

  410.     if (bitstream_size + bytestream_size + wordstream_size + extra != length

  411.         || bitstream_size  > (1 << 26)

  412.         || bytestream_size > (1 << 26)

  413.         || wordstream_size > (1 << 26)) {

  414.         av_log(f->avctx, AV_LOG_ERROR, "lengths %d %d %d %d\n",

  415.                bitstream_size, bytestream_size, wordstream_size,

  416.                bitstream_size + bytestream_size + wordstream_size - length);

  417.         return -1;

  418.     }

  419. 

  420.     av_fast_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size,

  421.                    bitstream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  422.     if (!f->bitstream_buffer)

  423.         return AVERROR(ENOMEM);

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

  425.                      bitstream_size / 4);

  426.     memset((uint8_t*)f->bitstream_buffer + bitstream_size,

  427.            0, FF_INPUT_BUFFER_PADDING_SIZE);

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

  429. 

  430.     wordstream_offset = extra + bitstream_size;

  431.     bytestream_offset = extra + bitstream_size + wordstream_size;

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

  433.                      length - wordstream_offset);

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

  435.                      length - bytestream_offset);

  436. 

  437.     init_mv(f);

  438. 

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

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

  441.             decode_p_block(f, dst + x, src + x, 3, 3, stride);

  442.         src += 8 * stride;

  443.         dst += 8 * stride;

  444.     }

  445. 

  446.     return 0;

  447. }

  448. 

  449. /**

  450.  * decode block and dequantize.

  451.  * Note this is almost identical to MJPEG.

  452.  */

  453. static int decode_i_block(FourXContext *f, DCTELEM *block)

  454. {

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

  456. 

  457.     /* DC coef */

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

  459.     if (val >> 4)

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

  461. 

  462.     if (val)

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

  464. 

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

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

  467.     /* AC coefs */

  468.     i = 1;

  469.     for (;;) {

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

  471. 

  472.         /* EOB */

  473.         if (code == 0)

  474.             break;

  475.         if (code == 0xf0) {

  476.             i += 16;

  477.         } else {

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

  479.             i    += code >> 4;

  480.             if (i >= 64) {

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

  482.                 return 0;

  483.             }

  484. 

  485.             j = ff_zigzag_direct[i];

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

  487.             i++;

  488.             if (i >= 64)

  489.                 break;

  490.         }

  491.     }

  492. 

  493.     return 0;

  494. }

  495. 

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

  497. {

  498.     DCTELEM (*block)[64] = f->block;

  499.     int stride           = f->current_picture.linesize[0] >> 1;

  500.     int i;

  501.     uint16_t *dst = ((uint16_t*)f->current_picture.data[0]) + y * stride + x;

  502. 

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

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

  505.         idct(block[i]);

  506.     }

  507. 

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

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

  510.             idct(block[i]);

  511.     }

  512. 

  513.     /* Note transform is:

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

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

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

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

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

  519.             DCTELEM *temp = block[(x >> 2) + 2 * (y >> 2)] +

  520.                             2 * (x & 3) + 2 * 8 * (y & 3); // FIXME optimize

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

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

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

  524.             int y;

  525. 

  526.             cb += cb;

  527. 

  528.             y               = temp[0];

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

  530.             y               = temp[1];

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

  532.             y               = temp[8];

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

  534.             y               = temp[9];

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

  536.             dst            += 2;

  537.         }

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

  539.     }

  540. }

  541. 

  542. static int decode_i_mb(FourXContext *f)

  543. {

  544.     int i;

  545. 

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

  547. 

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

  549.         if (decode_i_block(f, f->block[i]) < 0)

  550.             return -1;

  551. 

  552.     return 0;

  553. }

  554. 

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

  556.                                           const uint8_t * const buf)

  557. {

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

  559.     uint8_t flag[512];

  560.     int up[512];

  561.     uint8_t len_tab[257];

  562.     int bits_tab[257];

  563.     int start, end;

  564.     const uint8_t *ptr = buf;

  565.     int j;

  566. 

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

  568. 

  569.     start = *ptr++;

  570.     end   = *ptr++;

  571.     for (;;) {

  572.         int i;

  573. 

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

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

  576.         start = *ptr++;

  577.         if (start == 0)

  578.             break;

  579. 

  580.         end = *ptr++;

  581.     }

  582.     frequency[256] = 1;

  583. 

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

  585.         ptr++; // 4byte align

  586. 

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

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

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

  590.         int i;

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

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

  593.                 continue;

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

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

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

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

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

  599.                     smallest[0] = i;

  600.                 } else {

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

  602.                     smallest[1] = i;

  603.                 }

  604.             }

  605.         }

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

  607.             break;

  608. 

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

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

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

  612.         up[smallest[0]]        =

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

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

  615.     }

  616. 

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

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

  619. 

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

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

  622.             len++;

  623.             if (len > 31)

  624.                 // can this happen at all ?

  625.                 av_log(f->avctx, AV_LOG_ERROR,

  626.                        "vlc length overflow\n");

  627.         }

  628. 

  629.         bits_tab[j] = bits;

  630.         len_tab[j]  = len;

  631.     }

  632. 

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

  634.                  bits_tab, 4, 4, 0))

  635.         return NULL;

  636. 

  637.     return ptr;

  638. }

  639. 

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

  641. {

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

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

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

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

  646. }

  647. 

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

  649. {

  650.     int x, y, x2, y2;

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

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

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

  654.     uint16_t *dst    = (uint16_t*)f->current_picture.data[0];

  655.     const int stride =            f->current_picture.linesize[0]>>1;

  656.     GetByteContext g3;

  657. 

  658.     if (length < mbs * 8) {

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

  660.         return AVERROR_INVALIDDATA;

  661.     }

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

  663. 

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

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

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

  667.             // warning following is purely guessed ...

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

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

  670. 

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

  672.                 av_log(NULL, AV_LOG_ERROR, "unk bit 1\n");

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

  674.                 av_log(NULL, AV_LOG_ERROR, "unk bit 2\n");

  675. 

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

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

  678. 

  679.             bits = bytestream2_get_le32u(&g3);

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

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

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

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

  684.                 }

  685.             }

  686.             dst += 16;

  687.         }

  688.         dst += 16 * stride - x;

  689.     }

  690. 

  691.     return 0;

  692. }

  693. 

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

  695. {

  696.     int x, y;

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

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

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

  700.     int token_count av_unused;

  701.     unsigned int prestream_size;

  702.     const uint8_t *prestream;

  703. 

  704.     if (length < bitstream_size + 12) {

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

  706.         return AVERROR_INVALIDDATA;

  707.     }

  708. 

  709.     token_count    =     AV_RL32(buf + bitstream_size + 8);

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

  711.     prestream      =             buf + bitstream_size + 12;

  712. 

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

  714.         || bitstream_size > (1 << 26)

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

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

  717.                prestream_size, bitstream_size, length);

  718.         return -1;

  719.     }

  720. 

  721.     prestream = read_huffman_tables(f, prestream);

  722. 

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

  724. 

  725.     prestream_size = length + buf - prestream;

  726. 

  727.     av_fast_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size,

  728.                    prestream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  729.     if (!f->bitstream_buffer)

  730.         return AVERROR(ENOMEM);

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

  732.                      prestream_size / 4);

  733.     memset((uint8_t*)f->bitstream_buffer + prestream_size,

  734.            0, FF_INPUT_BUFFER_PADDING_SIZE);

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

  736. 

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

  738. 

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

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

  741.             if (decode_i_mb(f) < 0)

  742.                 return -1;

  743. 

  744.             idct_put(f, x, y);

  745.         }

  746.     }

  747. 

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

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

  750. 

  751.     return 0;

  752. }

  753. 

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

  755.                         int *data_size, AVPacket *avpkt)

  756. {

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

  758.     int buf_size          = avpkt->size;

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

  760.     AVFrame *picture      = data;

  761.     AVFrame *p, temp;

  762.     int i, frame_4cc, frame_size;

  763. 

  764.     frame_4cc = AV_RL32(buf);

  765.     if (buf_size != AV_RL32(buf + 4) + 8 || buf_size < 20)

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

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

  768. 

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

  770.         int free_index       = -1;

  771.         const int data_size  = buf_size - 20;

  772.         const int id         = AV_RL32(buf + 12);

  773.         const int whole_size = AV_RL32(buf + 16);

  774.         CFrameBuffer *cfrm;

  775. 

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

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

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

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

  780. 

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

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

  783.                 break;

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

  785.                 free_index = i;

  786.         }

  787. 

  788.         if (i >= CFRAME_BUFFER_COUNT) {

  789.             i             = free_index;

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

  791.         }

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

  793. 

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

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

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

  797.         if (!cfrm->data) {

  798.             av_log(f->avctx, AV_LOG_ERROR, "realloc falure");

  799.             return -1;

  800.         }

  801. 

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

  803.         cfrm->size += data_size;

  804. 

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

  806.             buf        = cfrm->data;

  807.             frame_size = cfrm->size;

  808. 

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

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

  811.                        id, avctx->frame_number);

  812. 

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

  814.             frame_4cc  = AV_RL32("pfrm");

  815.         } else

  816.             return buf_size;

  817.     } else {

  818.         buf        = buf      + 12;

  819.         frame_size = buf_size - 12;

  820.     }

  821. 

  822.     temp               = f->current_picture;

  823.     f->current_picture = f->last_picture;

  824.     f->last_picture    = temp;

  825. 

  826.     p                  = &f->current_picture;

  827.     avctx->coded_frame = p;

  828. 

  829.     // alternatively we would have to use our own buffer management

  830.     avctx->flags |= CODEC_FLAG_EMU_EDGE;

  831. 

  832.     if (p->data[0])

  833.         avctx->release_buffer(avctx, p);

  834. 

  835.     p->reference = 1;

  836.     if (avctx->get_buffer(avctx, p) < 0) {

  837.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  838.         return -1;

  839.     }

  840. 

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

  842.         p->pict_type = AV_PICTURE_TYPE_I;

  843.         if (decode_i2_frame(f, buf - 4, frame_size + 4) < 0)

  844.             return -1;

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

  846.         p->pict_type = AV_PICTURE_TYPE_I;

  847.         if (decode_i_frame(f, buf, frame_size) < 0)

  848.             return -1;

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

  850.         if (!f->last_picture.data[0]) {

  851.             f->last_picture.reference = 1;

  852.             if (avctx->get_buffer(avctx, &f->last_picture) < 0) {

  853.                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  854.                 return -1;

  855.             }

  856.         }

  857. 

  858.         p->pict_type = AV_PICTURE_TYPE_P;

  859.         if (decode_p_frame(f, buf, frame_size) < 0)

  860.             return -1;

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

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

  863.                buf_size);

  864.     } else {

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

  866.                buf_size);

  867.     }

  868. 

  869.     p->key_frame = p->pict_type == AV_PICTURE_TYPE_I;

  870. 

  871.     *picture   = *p;

  872.     *data_size = sizeof(AVPicture);

  873. 

  874.     emms_c();

  875. 

  876.     return buf_size;

  877. }

  878. 

  879. 

  880. static av_cold void common_init(AVCodecContext *avctx)

  881. {

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

  883. 

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

  885. 

  886.     f->avctx = avctx;

  887. }

  888. 

  889. static av_cold int decode_init(AVCodecContext *avctx)

  890. {

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

  892. 

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

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

  895.         return 1;

  896.     }

  897. 

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

  899.     common_init(avctx);

  900.     init_vlcs(f);

  901. 

  902.     if (f->version > 2)

  903.         avctx->pix_fmt = PIX_FMT_RGB565;

  904.     else

  905.         avctx->pix_fmt = PIX_FMT_BGR555;

  906. 

  907.     return 0;

  908. }

  909. 

  910. 

  911. static av_cold int decode_end(AVCodecContext *avctx)

  912. {

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

  914.     int i;

  915. 

  916.     av_freep(&f->bitstream_buffer);

  917.     f->bitstream_buffer_size = 0;

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

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

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

  921.     }

  922.     ff_free_vlc(&f->pre_vlc);

  923.     if (f->current_picture.data[0])

  924.         avctx->release_buffer(avctx, &f->current_picture);

  925.     if (f->last_picture.data[0])

  926.         avctx->release_buffer(avctx, &f->last_picture);

  927. 

  928.     return 0;

  929. }

  930. 

  931. AVCodec ff_fourxm_decoder = {

  932.     .name           = "4xm",

  933.     .type           = AVMEDIA_TYPE_VIDEO,

  934.     .id             = CODEC_ID_4XM,

  935.     .priv_data_size = sizeof(FourXContext),

  936.     .init           = decode_init,

  937.     .close          = decode_end,

  938.     .decode         = decode_frame,

  939.     .capabilities   = CODEC_CAP_DR1,

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

  941. };