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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 "libavutil/intreadwrite.h"

  28. #include "avcodec.h"

  29. #include "bytestream.h"

  30. #include "dsputil.h"

  31. #include "get_bits.h"

  32. 

  33. #include "libavutil/avassert.h"

  34. 

  35. #define BLOCK_TYPE_VLC_BITS 5

  36. #define ACDC_VLC_BITS 9

  37. 

  38. #define CFRAME_BUFFER_COUNT 100

  39. 

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

  41.     {

  42.         {    // { 8, 4, 2 } x { 8, 4, 2}

  43.             { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 30, 5 }, { 31, 5 }, { 0, 0 }

  44.         }, { // { 8, 4 } x 1

  45.             { 0, 1 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  46.         }, { // 1 x { 8, 4 }

  47.             { 0, 1 }, { 2, 2 }, { 0, 0 }, { 6, 3 }, { 14, 4 }, { 15, 4 }, { 0, 0 }

  48.         }, { // 1 x 2, 2 x 1

  49.             { 0, 1 }, { 0, 0 }, { 0, 0 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 }

  50.         }

  51.     }, {

  52.         {   // { 8, 4, 2 } x { 8, 4, 2}

  53.             { 1, 2 }, { 4, 3 }, { 5, 3 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  54.         }, {// { 8, 4 } x 1

  55.             { 1, 2 }, { 0, 0 }, { 2, 2 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  56.         }, {// 1 x { 8, 4 }

  57.             { 1, 2 }, { 2, 2 }, { 0, 0 }, { 0, 2 }, { 6, 3 }, { 7, 3 }, { 0, 0 }

  58.         }, {// 1 x 2, 2 x 1

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

  60.       }

  61.     }

  62. };

  63. 

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

  65.     { -1, 3, 1, 1 },

  66.     {  3, 0, 0, 0 },

  67.     {  2, 0, 0, 0 },

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

  69. };

  70. 

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

  72.     {   0,   0 }, {   0,  -1 }, {  -1,   0 }, {   1,   0 }, {   0,   1 }, {  -1,  -1 }, {   1,  -1 }, {  -1,   1 },

  73.     {   1,   1 }, {   0,  -2 }, {  -2,   0 }, {   2,   0 }, {   0,   2 }, {  -1,  -2 }, {   1,  -2 }, {  -2,  -1 },

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

  75.     {   2,   2 }, {   0,  -3 }, {  -3,   0 }, {   3,   0 }, {   0,   3 }, {  -1,  -3 }, {   1,  -3 }, {  -3,  -1 },

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

  77.     {   3,  -2 }, {  -3,   2 }, {   3,   2 }, {  -2,   3 }, {   2,   3 }, {   0,  -4 }, {  -4,   0 }, {   4,   0 },

  78.     {   0,   4 }, {  -1,  -4 }, {   1,  -4 }, {  -4,  -1 }, {   4,  -1 }, {   4,   1 }, {  -1,   4 }, {   1,   4 },

  79.     {  -3,  -3 }, {  -3,   3 }, {   3,   3 }, {  -2,  -4 }, {  -4,  -2 }, {   4,  -2 }, {  -4,   2 }, {  -2,   4 },

  80.     {   2,   4 }, {  -3,  -4 }, {   3,  -4 }, {   4,  -3 }, {  -5,   0 }, {  -4,   3 }, {  -3,   4 }, {   3,   4 },

  81.     {  -1,  -5 }, {  -5,  -1 }, {  -5,   1 }, {  -1,   5 }, {  -2,  -5 }, {   2,  -5 }, {   5,  -2 }, {   5,   2 },

  82.     {  -4,  -4 }, {  -4,   4 }, {  -3,  -5 }, {  -5,  -3 }, {  -5,   3 }, {   3,   5 }, {  -6,   0 }, {   0,   6 },

  83.     {  -6,  -1 }, {  -6,   1 }, {   1,   6 }, {   2,  -6 }, {  -6,   2 }, {   2,   6 }, {  -5,  -4 }, {   5,   4 },

  84.     {   4,   5 }, {  -6,  -3 }, {   6,   3 }, {  -7,   0 }, {  -1,  -7 }, {   5,  -5 }, {  -7,   1 }, {  -1,   7 },

  85.     {   4,  -6 }, {   6,   4 }, {  -2,  -7 }, {  -7,   2 }, {  -3,  -7 }, {   7,  -3 }, {   3,   7 }, {   6,  -5 },

  86.     {   0,  -8 }, {  -1,  -8 }, {  -7,  -4 }, {  -8,   1 }, {   4,   7 }, {   2,  -8 }, {  -2,   8 }, {   6,   6 },

  87.     {  -8,   3 }, {   5,  -7 }, {  -5,   7 }, {   8,  -4 }, {   0,  -9 }, {  -9,  -1 }, {   1,   9 }, {   7,  -6 },

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

  89.     {  10,   1 }, { -10,   2 }, {   9,  -5 }, {  10,  -3 }, {  -8,  -7 }, { -10,  -4 }, {   6,  -9 }, { -11,   0 },

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

  91.     {   8,   9 }, {   5,  11 }, {   7, -10 }, {  12,  -3 }, {  11,   6 }, {  -9,  -9 }, {   8,  10 }, {   5,  12 },

  92.     { -11,   7 }, {  13,   2 }, {   6, -12 }, {  10,   9 }, { -11,   8 }, {  -7,  12 }, {   0,  14 }, {  14,  -2 },

  93.     {  -9,  11 }, {  -6,  13 }, { -14,  -4 }, {  -5, -14 }, {   5,  14 }, { -15,  -1 }, { -14,  -6 }, {   3, -15 },

  94.     {  11, -11 }, {  -7,  14 }, {  -5,  15 }, {   8, -14 }, {  15,   6 }, {   3,  16 }, {   7, -15 }, { -16,   5 },

  95.     {   0,  17 }, { -16,  -6 }, { -10,  14 }, { -16,   7 }, {  12,  13 }, { -16,   8 }, { -17,   6 }, { -18,   3 },

  96.     {  -7,  17 }, {  15,  11 }, {  16,  10 }, {   2, -19 }, {   3, -19 }, { -11, -16 }, { -18,   8 }, { -19,  -6 },

  97.     {   2, -20 }, { -17, -11 }, { -10, -18 }, {   8,  19 }, { -21,  -1 }, { -20,   7 }, {  -4,  21 }, {  21,   5 },

  98.     {  15,  16 }, {   2, -22 }, { -10, -20 }, { -22,   5 }, {  20, -11 }, {  -7, -22 }, { -12,  20 }, {  23,  -5 },

  99.     {  13, -20 }, {  24,  -2 }, { -15,  19 }, { -11,  22 }, {  16,  19 }, {  23, -10 }, { -18, -18 }, {  -9, -24 },

  100.     {  24, -10 }, {  -3,  26 }, { -23,  13 }, { -18, -20 }, {  17,  21 }, {  -4,  27 }, {  27,   6 }, {   1, -28 },

  101.     { -11,  26 }, { -17, -23 }, {   7,  28 }, {  11, -27 }, {  29,   5 }, { -23, -19 }, { -28, -11 }, { -21,  22 },

  102.     { -30,   7 }, { -17,  26 }, { -27,  16 }, {  13,  29 }, {  19, -26 }, {  10, -31 }, { -14, -30 }, {  20, -27 },

  103.     { -29,  18 }, { -16, -31 }, { -28, -22 }, {  21, -30 }, { -25,  28 }, {  26, -29 }, {  25, -32 }, { -32, -32 }

  104. };

  105. 

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

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

  108. static const uint8_t dequant_table[64] = {

  109.     16, 15, 13, 19, 24, 31, 28, 17,

  110.     17, 23, 25, 31, 36, 63, 45, 21,

  111.     18, 24, 27, 37, 52, 59, 49, 20,

  112.     16, 28, 34, 40, 60, 80, 51, 20,

  113.     18, 31, 48, 66, 68, 86, 56, 21,

  114.     19, 38, 56, 59, 64, 64, 48, 20,

  115.     27, 48, 55, 55, 56, 51, 35, 15,

  116.     20, 35, 34, 32, 31, 22, 15,  8,

  117. };

  118. 

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

  120. 

  121. 

  122. typedef struct CFrameBuffer {

  123.     unsigned int allocated_size;

  124.     unsigned int size;

  125.     int id;

  126.     uint8_t *data;

  127. } CFrameBuffer;

  128. 

  129. typedef struct FourXContext {

  130.     AVCodecContext *avctx;

  131.     DSPContext dsp;

  132.     AVFrame current_picture, last_picture;

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

  134.     GetBitContext gb;

  135.     GetByteContext g;

  136.     GetByteContext g2;

  137.     int mv[256];

  138.     VLC pre_vlc;

  139.     int last_dc;

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

  141.     void *bitstream_buffer;

  142.     unsigned int bitstream_buffer_size;

  143.     int version;

  144.     CFrameBuffer cfrm[CFRAME_BUFFER_COUNT];

  145. } FourXContext;

  146. 

  147. 

  148. #define FIX_1_082392200  70936

  149. #define FIX_1_414213562  92682

  150. #define FIX_1_847759065 121095

  151. #define FIX_2_613125930 171254

  152. 

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

  154. 

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

  156. {

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

  158.     int tmp10, tmp11, tmp12, tmp13;

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

  160.     int i;

  161.     int temp[64];

  162. 

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

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

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

  166. 

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

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

  169. 

  170.         tmp0 = tmp10 + tmp13;

  171.         tmp3 = tmp10 - tmp13;

  172.         tmp1 = tmp11 + tmp12;

  173.         tmp2 = tmp11 - tmp12;

  174. 

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

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

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

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

  179. 

  180.         tmp7  =          z11 + z13;

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

  182. 

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

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

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

  186. 

  187.         tmp6 = tmp12 - tmp7;

  188.         tmp5 = tmp11 - tmp6;

  189.         tmp4 = tmp10 + tmp5;

  190. 

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

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

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

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

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

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

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

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

  199.     }

  200. 

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

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

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

  204. 

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

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

  207. 

  208.         tmp0 = tmp10 + tmp13;

  209.         tmp3 = tmp10 - tmp13;

  210.         tmp1 = tmp11 + tmp12;

  211.         tmp2 = tmp11 - tmp12;

  212. 

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

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

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

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

  217. 

  218.         tmp7  = z11 + z13;

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

  220. 

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

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

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

  224. 

  225.         tmp6 = tmp12 - tmp7;

  226.         tmp5 = tmp11 - tmp6;

  227.         tmp4 = tmp10 + tmp5;

  228. 

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

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

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

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

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

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

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

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

  237.     }

  238. }

  239. 

  240. static av_cold void init_vlcs(FourXContext *f)

  241. {

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

  243.     int i, j;

  244. 

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

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

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

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

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

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

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

  252.                      INIT_VLC_USE_NEW_STATIC);

  253.         }

  254.     }

  255. }

  256. 

  257. static void init_mv(FourXContext *f)

  258. {

  259.     int i;

  260. 

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

  262.         if (f->version > 1)

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

  264.         else

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

  266.     }

  267. }

  268. 

  269. #if HAVE_BIGENDIAN

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

  271.     {                                                   \

  272.         unsigned tmpval = AV_RN32(src);                 \

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

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

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

  276.         AV_WN32A(dst, tmpval);                          \

  277.     }

  278. #else

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

  280.     {                                                    \

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

  282.         AV_WN32A(dst, tmpval);                           \

  283.     }

  284. #endif

  285. 

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

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

  288. {

  289.     int i;

  290.     dc *= 0x10001;

  291. 

  292.     switch (log2w) {

  293.     case 0:

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

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

  296.             if (scale)

  297.                 src += stride;

  298.             dst += stride;

  299.         }

  300.         break;

  301.     case 1:

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

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

  304.             if (scale)

  305.                 src += stride;

  306.             dst += stride;

  307.         }

  308.         break;

  309.     case 2:

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

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

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

  313.             if (scale)

  314.                 src += stride;

  315.             dst += stride;

  316.         }

  317.         break;

  318.     case 3:

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

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

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

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

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

  324.             if (scale)

  325.                 src += stride;

  326.             dst += stride;

  327.         }

  328.         break;

  329.     default:

  330.         av_assert2(0);

  331.     }

  332. }

  333. 

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

  335.                            int log2w, int log2h, int stride)

  336. {

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

  338.     const int h     = 1 << log2h;

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

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

  341.                                BLOCK_TYPE_VLC_BITS, 1);

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

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

  344. 

  345.     av_assert2(code >= 0 && code <= 6);

  346. 

  347.     if (code == 0) {

  348.         if (f->g.buffer_end - f->g.buffer < 1) {

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

  350.             return;

  351.         }

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

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

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

  355.             return;

  356.         }

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

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

  359.         log2h--;

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

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

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

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

  364.         log2w--;

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

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

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

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

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

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

  371.         if (f->g.buffer_end - f->g.buffer < 1) {

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

  373.             return;

  374.         }

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

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

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

  378.             return;

  379.         }

  380.         if (f->g2.buffer_end - f->g2.buffer < 1){

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

  382.             return;

  383.         }

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

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

  386.         if (f->g2.buffer_end - f->g2.buffer < 1) {

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

  388.             return;

  389.         }

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

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

  392.         if (f->g2.buffer_end - f->g2.buffer < 2) {

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

  394.             return;

  395.         }

  396.         if (log2w) {

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

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

  399.         } else {

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

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

  402.         }

  403.     }

  404. }

  405. 

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

  407. {

  408.     int x, y;

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

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

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

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

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

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

  415.                  bytestream_offset, wordstream_offset;

  416. 

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

  418.         extra           = 20;

  419.         if (length < extra)

  420.             return -1;

  421.         bitstream_size  = AV_RL32(buf + 8);

  422.         wordstream_size = AV_RL32(buf + 12);

  423.         bytestream_size = AV_RL32(buf + 16);

  424.     } else {

  425.         extra           = 0;

  426.         bitstream_size  = AV_RL16(buf - 4);

  427.         wordstream_size = AV_RL16(buf - 2);

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

  429.     }

  430. 

  431.     if (bitstream_size > length ||

  432.         bytestream_size > length - bitstream_size ||

  433.         wordstream_size > length - bytestream_size - bitstream_size ||

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

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

  436.         bitstream_size+ bytestream_size+ wordstream_size - length);

  437.         return -1;

  438.     }

  439. 

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

  441.                    bitstream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  442.     if (!f->bitstream_buffer)

  443.         return AVERROR(ENOMEM);

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

  445.                      bitstream_size / 4);

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

  447.            0, FF_INPUT_BUFFER_PADDING_SIZE);

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

  449. 

  450.     wordstream_offset = extra + bitstream_size;

  451.     bytestream_offset = extra + bitstream_size + wordstream_size;

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

  453.                      length - wordstream_offset);

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

  455.                      length - bytestream_offset);

  456. 

  457.     init_mv(f);

  458. 

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

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

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

  462.         src += 8 * stride;

  463.         dst += 8 * stride;

  464.     }

  465. 

  466.     return 0;

  467. }

  468. 

  469. /**

  470.  * decode block and dequantize.

  471.  * Note this is almost identical to MJPEG.

  472.  */

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

  474. {

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

  476. 

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

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

  479.         return -1;

  480.     }

  481. 

  482.     /* DC coef */

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

  484.     if (val >> 4)

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

  486. 

  487.     if (val)

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

  489. 

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

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

  492.     /* AC coefs */

  493.     i = 1;

  494.     for (;;) {

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

  496. 

  497.         /* EOB */

  498.         if (code == 0)

  499.             break;

  500.         if (code == 0xf0) {

  501.             i += 16;

  502.         } else {

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

  504.             i    += code >> 4;

  505.             if (i >= 64) {

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

  507.                 return 0;

  508.             }

  509. 

  510.             j = ff_zigzag_direct[i];

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

  512.             i++;

  513.             if (i >= 64)

  514.                 break;

  515.         }

  516.     }

  517. 

  518.     return 0;

  519. }

  520. 

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

  522. {

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

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

  525.     int i;

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

  527. 

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

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

  530.         idct(block[i]);

  531.     }

  532. 

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

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

  535.             idct(block[i]);

  536.     }

  537. 

  538.     /* Note transform is:

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

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

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

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

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

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

  545.                             2 * (x & 3) + 2 * 8 * (y & 3); // FIXME optimize

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

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

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

  549.             int y;

  550. 

  551.             cb += cb;

  552. 

  553.             y               = temp[0];

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

  555.             y               = temp[1];

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

  557.             y               = temp[8];

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

  559.             y               = temp[9];

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

  561.             dst            += 2;

  562.         }

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

  564.     }

  565. }

  566. 

  567. static int decode_i_mb(FourXContext *f)

  568. {

  569.     int i;

  570. 

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

  572. 

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

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

  575.             return -1;

  576. 

  577.     return 0;

  578. }

  579. 

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

  581.                                           const uint8_t * const buf, int buf_size)

  582. {

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

  584.     uint8_t flag[512];

  585.     int up[512];

  586.     uint8_t len_tab[257];

  587.     int bits_tab[257];

  588.     int start, end;

  589.     const uint8_t *ptr = buf;

  590.     const uint8_t *ptr_end = buf + buf_size;

  591.     int j;

  592. 

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

  594. 

  595.     start = *ptr++;

  596.     end   = *ptr++;

  597.     for (;;) {

  598.         int i;

  599. 

  600.         if (start <= end && ptr_end - ptr < end - start + 1 + 1)

  601.             return NULL;

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

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

  604.         start = *ptr++;

  605.         if (start == 0)

  606.             break;

  607. 

  608.         end = *ptr++;

  609.     }

  610.     frequency[256] = 1;

  611. 

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

  613.         ptr++; // 4byte align

  614. 

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

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

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

  618.         int i;

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

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

  621.                 continue;

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

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

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

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

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

  627.                     smallest[0] = i;

  628.                 } else {

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

  630.                     smallest[1] = i;

  631.                 }

  632.             }

  633.         }

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

  635.             break;

  636. 

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

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

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

  640.         up[smallest[0]]        =

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

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

  643.     }

  644. 

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

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

  647. 

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

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

  650.             len++;

  651.             if (len > 31)

  652.                 // can this happen at all ?

  653.                 av_log(f->avctx, AV_LOG_ERROR,

  654.                        "vlc length overflow\n");

  655.         }

  656. 

  657.         bits_tab[j] = bits;

  658.         len_tab[j]  = len;

  659.     }

  660. 

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

  662.                  bits_tab, 4, 4, 0))

  663.         return NULL;

  664. 

  665.     return ptr;

  666. }

  667. 

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

  669. {

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

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

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

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

  674. }

  675. 

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

  677. {

  678.     int x, y, x2, y2;

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

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

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

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

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

  684.     const uint8_t *buf_end = buf + length;

  685.     GetByteContext g3;

  686. 

  687.     if (length < mbs * 8) {

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

  689.         return AVERROR_INVALIDDATA;

  690.     }

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

  692. 

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

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

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

  696.             if (buf_end - buf < 8)

  697.                 return -1;

  698.             // warning following is purely guessed ...

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

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

  701. 

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

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

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

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

  706. 

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

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

  709. 

  710.             bits = bytestream2_get_le32u(&g3);

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

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

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

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

  715.                 }

  716.             }

  717.             dst += 16;

  718.         }

  719.         dst += 16 * stride - x;

  720.     }

  721. 

  722.     return 0;

  723. }

  724. 

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

  726. {

  727.     int x, y;

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

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

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

  731.     unsigned int prestream_size;

  732.     const uint8_t *prestream;

  733. 

  734.     if (bitstream_size > (1<<26) || length < bitstream_size + 12) {

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

  736.         return AVERROR_INVALIDDATA;

  737.     }

  738. 

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

  740.     prestream      =             buf + bitstream_size + 12;

  741. 

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

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

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

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

  746.                prestream_size, bitstream_size, length);

  747.         return -1;

  748.     }

  749. 

  750.     prestream = read_huffman_tables(f, prestream, buf + length - prestream);

  751.     if (!prestream)

  752.         return -1;

  753. 

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

  755. 

  756.     prestream_size = length + buf - prestream;

  757. 

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

  759.                    prestream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  760.     if (!f->bitstream_buffer)

  761.         return AVERROR(ENOMEM);

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

  763.                      prestream_size / 4);

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

  765.            0, FF_INPUT_BUFFER_PADDING_SIZE);

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

  767. 

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

  769. 

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

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

  772.             if (decode_i_mb(f) < 0)

  773.                 return -1;

  774. 

  775.             idct_put(f, x, y);

  776.         }

  777.     }

  778. 

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

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

  781. 

  782.     return 0;

  783. }

  784. 

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

  786.                         int *data_size, AVPacket *avpkt)

  787. {

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

  789.     int buf_size          = avpkt->size;

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

  791.     AVFrame *picture      = data;

  792.     AVFrame *p, temp;

  793.     int i, frame_4cc, frame_size;

  794. 

  795.     if (buf_size < 12)

  796.         return AVERROR_INVALIDDATA;

  797.     frame_4cc = AV_RL32(buf);

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

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

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

  801. 

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

  803.         int free_index       = -1;

  804.         const int data_size  = buf_size - 20;

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

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

  807.         CFrameBuffer *cfrm;

  808. 

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

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

  811.             return AVERROR_INVALIDDATA;

  812.         }

  813. 

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

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

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

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

  818. 

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

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

  821.                 break;

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

  823.                 free_index = i;

  824.         }

  825. 

  826.         if (i >= CFRAME_BUFFER_COUNT) {

  827.             i             = free_index;

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

  829.         }

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

  831. 

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

  833.             return AVERROR_INVALIDDATA;

  834. 

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

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

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

  838.         if (!cfrm->data) {

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

  840.             return -1;

  841.         }

  842. 

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

  844.         cfrm->size += data_size;

  845. 

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

  847.             buf        = cfrm->data;

  848.             frame_size = cfrm->size;

  849. 

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

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

  852.                        id, avctx->frame_number);

  853. 

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

  855.             frame_4cc  = AV_RL32("pfrm");

  856.         } else

  857.             return buf_size;

  858.     } else {

  859.         buf        = buf      + 12;

  860.         frame_size = buf_size - 12;

  861.     }

  862. 

  863.     temp               = f->current_picture;

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

  865.     f->last_picture    = temp;

  866. 

  867.     p                  = &f->current_picture;

  868.     avctx->coded_frame = p;

  869. 

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

  871.     avctx->flags |= CODEC_FLAG_EMU_EDGE;

  872. 

  873.     p->reference= 3;

  874.     if (avctx->reget_buffer(avctx, p) < 0) {

  875.         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

  876.         return -1;

  877.     }

  878. 

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

  880.         p->pict_type= AV_PICTURE_TYPE_I;

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

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

  883.             return -1;

  884.         }

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

  886.         p->pict_type= AV_PICTURE_TYPE_I;

  887.         if (decode_i_frame(f, buf, frame_size) < 0) {

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

  889.             return -1;

  890.         }

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

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

  893.             f->last_picture.reference = 3;

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

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

  896.                 return -1;

  897.             }

  898.         }

  899. 

  900.         p->pict_type = AV_PICTURE_TYPE_P;

  901.         if (decode_p_frame(f, buf, frame_size) < 0) {

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

  903.             return -1;

  904.         }

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

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

  907.                buf_size);

  908.     } else {

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

  910.                buf_size);

  911.     }

  912. 

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

  914. 

  915.     *picture   = *p;

  916.     *data_size = sizeof(AVPicture);

  917. 

  918.     emms_c();

  919. 

  920.     return buf_size;

  921. }

  922. 

  923. 

  924. static av_cold void common_init(AVCodecContext *avctx)

  925. {

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

  927. 

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

  929. 

  930.     f->avctx = avctx;

  931. }

  932. 

  933. static av_cold int decode_init(AVCodecContext *avctx)

  934. {

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

  936. 

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

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

  939.         return 1;

  940.     }

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

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

  943.         return AVERROR_INVALIDDATA;

  944.     }

  945. 

  946.     avcodec_get_frame_defaults(&f->current_picture);

  947.     avcodec_get_frame_defaults(&f->last_picture);

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

  949.     common_init(avctx);

  950.     init_vlcs(f);

  951. 

  952.     if (f->version > 2)

  953.         avctx->pix_fmt = PIX_FMT_RGB565;

  954.     else

  955.         avctx->pix_fmt = PIX_FMT_BGR555;

  956. 

  957.     return 0;

  958. }

  959. 

  960. 

  961. static av_cold int decode_end(AVCodecContext *avctx)

  962. {

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

  964.     int i;

  965. 

  966.     av_freep(&f->bitstream_buffer);

  967.     f->bitstream_buffer_size = 0;

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

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

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

  971.     }

  972.     ff_free_vlc(&f->pre_vlc);

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

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

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

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

  977. 

  978.     return 0;

  979. }

  980. 

  981. AVCodec ff_fourxm_decoder = {

  982.     .name           = "4xm",

  983.     .type           = AVMEDIA_TYPE_VIDEO,

  984.     .id             = AV_CODEC_ID_4XM,

  985.     .priv_data_size = sizeof(FourXContext),

  986.     .init           = decode_init,

  987.     .close          = decode_end,

  988.     .decode         = decode_frame,

  989.     .capabilities   = CODEC_CAP_DR1,

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

  991. };