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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 libavcodec/4xm.c

  24.  * 4XM codec.

  25.  */

  26. 

  27. #include "libavutil/intreadwrite.h"

  28. #include "avcodec.h"

  29. #include "dsputil.h"

  30. #include "get_bits.h"

  31. #include "bytestream.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}x1

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

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

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

  49.   },{ //1x2, 2x1

  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}x1

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

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

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

  59.   },{//1x2, 2x1

  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 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.     const uint8_t *bytestream;

  136.     const uint16_t *wordstream;

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

  157.     int tmp10, tmp11, tmp12, tmp13;

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

  159.     int i;

  160.     int temp[64];

  161. 

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

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

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

  165. 

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

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

  168. 

  169.         tmp0 = tmp10 + tmp13;

  170.         tmp3 = tmp10 - tmp13;

  171.         tmp1 = tmp11 + tmp12;

  172.         tmp2 = tmp11 - tmp12;

  173. 

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

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

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

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

  178. 

  179.         tmp7  =          z11 + z13;

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

  181. 

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

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

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

  185. 

  186.         tmp6 = tmp12 - tmp7;

  187.         tmp5 = tmp11 - tmp6;

  188.         tmp4 = tmp10 + tmp5;

  189. 

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

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

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

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

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

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

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

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

  198.     }

  199. 

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

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

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

  203. 

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

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

  206. 

  207.         tmp0 = tmp10 + tmp13;

  208.         tmp3 = tmp10 - tmp13;

  209.         tmp1 = tmp11 + tmp12;

  210.         tmp2 = tmp11 - tmp12;

  211. 

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

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

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

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

  216. 

  217.         tmp7 = z11 + z13;

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

  219. 

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

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

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

  223. 

  224.         tmp6 = tmp12 - tmp7;

  225.         tmp5 = tmp11 - tmp6;

  226.         tmp4 = tmp10 + tmp5;

  227. 

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

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

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

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

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

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

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

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

  236.     }

  237. }

  238. 

  239. static av_cold void init_vlcs(FourXContext *f){

  240.     static VLC_TYPE table[8][32][2];

  241.     int i;

  242. 

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

  244.         block_type_vlc[0][i].table= table[i];

  245.         block_type_vlc[0][i].table_allocated= 32;

  246.         init_vlc(&block_type_vlc[0][i], BLOCK_TYPE_VLC_BITS, 7,

  247.                  &block_type_tab[0][i][0][1], 2, 1,

  248.                  &block_type_tab[0][i][0][0], 2, 1, INIT_VLC_USE_NEW_STATIC);

  249.     }

  250. }

  251. 

  252. static void init_mv(FourXContext *f){

  253.     int i;

  254. 

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

  256.         if(f->version>1)

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

  258.         else

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

  260.     }

  261. }

  262. 

  263. static inline void mcdc(uint16_t *dst, uint16_t *src, int log2w, int h, int stride, int scale, int dc){

  264.    int i;

  265.    dc*= 0x10001;

  266. 

  267.    switch(log2w){

  268.    case 0:

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

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

  271.             if(scale) src += stride;

  272.             dst += stride;

  273.         }

  274.         break;

  275.     case 1:

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

  277.             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;

  278.             if(scale) src += stride;

  279.             dst += stride;

  280.         }

  281.         break;

  282.     case 2:

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

  284.             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;

  285.             ((uint32_t*)dst)[1] = scale*((uint32_t*)src)[1] + dc;

  286.             if(scale) src += stride;

  287.             dst += stride;

  288.         }

  289.         break;

  290.     case 3:

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

  292.             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;

  293.             ((uint32_t*)dst)[1] = scale*((uint32_t*)src)[1] + dc;

  294.             ((uint32_t*)dst)[2] = scale*((uint32_t*)src)[2] + dc;

  295.             ((uint32_t*)dst)[3] = scale*((uint32_t*)src)[3] + dc;

  296.             if(scale) src += stride;

  297.             dst += stride;

  298.         }

  299.         break;

  300.     default: assert(0);

  301.     }

  302. }

  303. 

  304. static void decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src, int log2w, int log2h, int stride){

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

  306.     const int h= 1<<log2h;

  307.     int code= get_vlc2(&f->gb, block_type_vlc[1-(f->version>1)][index].table, BLOCK_TYPE_VLC_BITS, 1);

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

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

  310. 

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

  312. 

  313.     if(code == 0){

  314.         src += f->mv[ *f->bytestream++ ];

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

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

  317.             return;

  318.         }

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

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

  321.         log2h--;

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

  323.         decode_p_block(f, dst + (stride<<log2h), src + (stride<<log2h), log2w, log2h, stride);

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

  325.         log2w--;

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

  327.         decode_p_block(f, dst + (1<<log2w), src + (1<<log2w), log2w, log2h, stride);

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

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

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

  331.         src += f->mv[ *f->bytestream++ ];

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

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

  334.             return;

  335.         }

  336.         mcdc(dst, src, log2w, h, stride, 1, le2me_16(*f->wordstream++));

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

  338.         mcdc(dst, src, log2w, h, stride, 0, le2me_16(*f->wordstream++));

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

  340.         if(log2w){

  341.             dst[0] = le2me_16(*f->wordstream++);

  342.             dst[1] = le2me_16(*f->wordstream++);

  343.         }else{

  344.             dst[0     ] = le2me_16(*f->wordstream++);

  345.             dst[stride] = le2me_16(*f->wordstream++);

  346.         }

  347.     }

  348. }

  349. 

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

  351.     int x, y;

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

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

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

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

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

  357.     unsigned int bitstream_size, bytestream_size, wordstream_size, extra;

  358. 

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

  360.         extra=20;

  361.         bitstream_size= AV_RL32(buf+8);

  362.         wordstream_size= AV_RL32(buf+12);

  363.         bytestream_size= AV_RL32(buf+16);

  364.     }else{

  365.         extra=0;

  366.         bitstream_size = AV_RL16(buf-4);

  367.         wordstream_size= AV_RL16(buf-2);

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

  369.     }

  370. 

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

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

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

  374.        || wordstream_size > (1<<26)

  375.        ){

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

  377.         bitstream_size+ bytestream_size+ wordstream_size - length);

  378.         return -1;

  379.     }

  380. 

  381.     av_fast_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size, bitstream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  382.     if (!f->bitstream_buffer)

  383.         return AVERROR(ENOMEM);

  384.     f->dsp.bswap_buf(f->bitstream_buffer, (const uint32_t*)(buf + extra), bitstream_size/4);

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

  386. 

  387.     f->wordstream= (const uint16_t*)(buf + extra + bitstream_size);

  388.     f->bytestream= buf + extra + bitstream_size + wordstream_size;

  389. 

  390.     init_mv(f);

  391. 

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

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

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

  395.         }

  396.         src += 8*stride;

  397.         dst += 8*stride;

  398.     }

  399. 

  400.     if(   bitstream_size != (get_bits_count(&f->gb)+31)/32*4

  401.        || (((const char*)f->wordstream - (const char*)buf + 2)&~2) != extra + bitstream_size + wordstream_size

  402.        || (((const char*)f->bytestream - (const char*)buf + 3)&~3) != extra + bitstream_size + wordstream_size + bytestream_size)

  403.         av_log(f->avctx, AV_LOG_ERROR, " %d %td %td bytes left\n",

  404.             bitstream_size - (get_bits_count(&f->gb)+31)/32*4,

  405.             -(((const char*)f->bytestream - (const char*)buf + 3)&~3) + (extra + bitstream_size + wordstream_size + bytestream_size),

  406.             -(((const char*)f->wordstream - (const char*)buf + 2)&~2) + (extra + bitstream_size + wordstream_size)

  407.         );

  408. 

  409.     return 0;

  410. }

  411. 

  412. /**

  413.  * decode block and dequantize.

  414.  * Note this is almost identical to MJPEG.

  415.  */

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

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

  418. 

  419.     /* DC coef */

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

  421.     if (val>>4){

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

  423.     }

  424. 

  425.     if(val)

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

  427. 

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

  429.     f->last_dc =

  430.     block[0] = val;

  431.     /* AC coefs */

  432.     i = 1;

  433.     for(;;) {

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

  435. 

  436.         /* EOB */

  437.         if (code == 0)

  438.             break;

  439.         if (code == 0xf0) {

  440.             i += 16;

  441.         } else {

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

  443.             i += code >> 4;

  444.             if (i >= 64) {

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

  446.                 return 0;

  447.             }

  448. 

  449.             j= ff_zigzag_direct[i];

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

  451.             i++;

  452.             if (i >= 64)

  453.                 break;

  454.         }

  455.     }

  456. 

  457.     return 0;

  458. }

  459. 

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

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

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

  463.     int i;

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

  465. 

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

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

  468.         idct(block[i]);

  469.     }

  470. 

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

  472.         for(i=4; i<6; i++) idct(block[i]);

  473.     }

  474. 

  475. /* Note transform is:

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

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

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

  479. */

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

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

  482.             DCTELEM *temp= block[(x>>2) + 2*(y>>2)] + 2*(x&3) + 2*8*(y&3); //FIXME optimize

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

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

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

  486.             int y;

  487. 

  488.             cb+=cb;

  489. 

  490.             y = temp[0];

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

  492.             y = temp[1];

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

  494.             y = temp[8];

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

  496.             y = temp[9];

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

  498.             dst += 2;

  499.         }

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

  501.     }

  502. }

  503. 

  504. static int decode_i_mb(FourXContext *f){

  505.     int i;

  506. 

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

  508. 

  509.     for(i=0; i<6; i++){

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

  511.             return -1;

  512.     }

  513. 

  514.     return 0;

  515. }

  516. 

  517. static const uint8_t *read_huffman_tables(FourXContext *f, const uint8_t * const buf){

  518.     int frequency[512];

  519.     uint8_t flag[512];

  520.     int up[512];

  521.     uint8_t len_tab[257];

  522.     int bits_tab[257];

  523.     int start, end;

  524.     const uint8_t *ptr= buf;

  525.     int j;

  526. 

  527.     memset(frequency, 0, sizeof(frequency));

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

  529. 

  530.     start= *ptr++;

  531.     end= *ptr++;

  532.     for(;;){

  533.         int i;

  534. 

  535.         for(i=start; i<=end; i++){

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

  537.         }

  538.         start= *ptr++;

  539.         if(start==0) break;

  540. 

  541.         end= *ptr++;

  542.     }

  543.     frequency[256]=1;

  544. 

  545.     while((ptr - buf)&3) ptr++; // 4byte align

  546. 

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

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

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

  550.         int i;

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

  552.             if(frequency[i] == 0) continue;

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

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

  555.                     min_freq[1]= min_freq[0]; smallest[1]= smallest[0];

  556.                     min_freq[0]= frequency[i];smallest[0]= i;

  557.                 }else{

  558.                     min_freq[1]= frequency[i];smallest[1]= i;

  559.                 }

  560.             }

  561.         }

  562.         if(min_freq[1] == 256*256) break;

  563. 

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

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

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

  567.         up[ smallest[0] ]=

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

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

  570.     }

  571. 

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

  573.         int node;

  574.         int len=0;

  575.         int bits=0;

  576. 

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

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

  579.             len++;

  580.             if(len > 31) av_log(f->avctx, AV_LOG_ERROR, "vlc length overflow\n"); //can this happen at all ?

  581.         }

  582. 

  583.         bits_tab[j]= bits;

  584.         len_tab[j]= len;

  585.     }

  586. 

  587.     init_vlc(&f->pre_vlc, ACDC_VLC_BITS, 257,

  588.              len_tab , 1, 1,

  589.              bits_tab, 4, 4, 0);

  590. 

  591.     return ptr;

  592. }

  593. 

  594. static int mix(int c0, int c1){

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

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

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

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

  599. }

  600. 

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

  602.     int x, y, x2, y2;

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

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

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

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

  607. 

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

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

  610.             unsigned int color[4], bits;

  611.             memset(color, 0, sizeof(color));

  612. //warning following is purely guessed ...

  613.             color[0]= bytestream_get_le16(&buf);

  614.             color[1]= bytestream_get_le16(&buf);

  615. 

  616.             if(color[0]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 1\n");

  617.             if(color[1]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 2\n");

  618. 

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

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

  621. 

  622.             bits= bytestream_get_le32(&buf);

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

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

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

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

  627.                 }

  628.             }

  629.             dst+=16;

  630.         }

  631.         dst += 16*stride - width;

  632.     }

  633. 

  634.     return 0;

  635. }

  636. 

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

  638.     int x, y;

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

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

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

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

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

  644.     const int token_count av_unused = AV_RL32(buf + bitstream_size + 8);

  645.     unsigned int prestream_size= 4*AV_RL32(buf + bitstream_size + 4);

  646.     const uint8_t *prestream= buf + bitstream_size + 12;

  647. 

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

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

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

  651.         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %d %d\n", prestream_size, bitstream_size, length);

  652.         return -1;

  653.     }

  654. 

  655.     prestream= read_huffman_tables(f, prestream);

  656. 

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

  658. 

  659.     prestream_size= length + buf - prestream;

  660. 

  661.     av_fast_malloc(&f->bitstream_buffer, &f->bitstream_buffer_size, prestream_size + FF_INPUT_BUFFER_PADDING_SIZE);

  662.     if (!f->bitstream_buffer)

  663.         return AVERROR(ENOMEM);

  664.     f->dsp.bswap_buf(f->bitstream_buffer, (const uint32_t*)prestream, prestream_size/4);

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

  666. 

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

  668. 

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

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

  671.             if(decode_i_mb(f) < 0)

  672.                 return -1;

  673. 

  674.             idct_put(f, x, y);

  675.         }

  676.         dst += 16*stride;

  677.     }

  678. 

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

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

  681. 

  682.     return 0;

  683. }

  684. 

  685. static int decode_frame(AVCodecContext *avctx,

  686.                         void *data, int *data_size,

  687.                         AVPacket *avpkt)

  688. {

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

  690.     int buf_size = avpkt->size;

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

  692.     AVFrame *picture = data;

  693.     AVFrame *p, temp;

  694.     int i, frame_4cc, frame_size;

  695. 

  696.     frame_4cc= AV_RL32(buf);

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

  698.         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %d\n", buf_size, AV_RL32(buf+4));

  699.     }

  700. 

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

  702.         int free_index=-1;

  703.         const int data_size= buf_size - 20;

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

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

  706.         CFrameBuffer *cfrm;

  707. 

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

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

  710.                 av_log(f->avctx, AV_LOG_ERROR, "lost c frame %d\n", f->cfrm[i].id);

  711.         }

  712. 

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

  714.             if(f->cfrm[i].id   == id) break;

  715.             if(f->cfrm[i].size == 0 ) free_index= i;

  716.         }

  717. 

  718.         if(i>=CFRAME_BUFFER_COUNT){

  719.             i= free_index;

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

  721.         }

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

  723. 

  724.         cfrm->data= av_fast_realloc(cfrm->data, &cfrm->allocated_size, cfrm->size + data_size + FF_INPUT_BUFFER_PADDING_SIZE);

  725.         if(!cfrm->data){ //explicit check needed as memcpy below might not catch a NULL

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

  727.             return -1;

  728.         }

  729. 

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

  731.         cfrm->size += data_size;

  732. 

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

  734.             buf= cfrm->data;

  735.             frame_size= cfrm->size;

  736. 

  737.             if(id != avctx->frame_number){

  738.                 av_log(f->avctx, AV_LOG_ERROR, "cframe id mismatch %d %d\n", id, avctx->frame_number);

  739.             }

  740. 

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

  742.             frame_4cc= AV_RL32("pfrm");

  743.         }else

  744.             return buf_size;

  745.     }else{

  746.         buf= buf + 12;

  747.         frame_size= buf_size - 12;

  748.     }

  749. 

  750.     temp= f->current_picture;

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

  752.     f->last_picture= temp;

  753. 

  754.     p= &f->current_picture;

  755.     avctx->coded_frame= p;

  756. 

  757.     avctx->flags |= CODEC_FLAG_EMU_EDGE; // alternatively we would have to use our own buffer management

  758. 

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

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

  761. 

  762.     p->reference= 1;

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

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

  765.         return -1;

  766.     }

  767. 

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

  769.         p->pict_type= FF_I_TYPE;

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

  771.             return -1;

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

  773.         p->pict_type= FF_I_TYPE;

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

  775.             return -1;

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

  777.         p->pict_type= FF_P_TYPE;

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

  779.             return -1;

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

  781.         av_log(avctx, AV_LOG_ERROR, "ignoring snd_ chunk length:%d\n", buf_size);

  782.     }else{

  783.         av_log(avctx, AV_LOG_ERROR, "ignoring unknown chunk length:%d\n", buf_size);

  784.     }

  785. 

  786.     p->key_frame= p->pict_type == FF_I_TYPE;

  787. 

  788.     *picture= *p;

  789.     *data_size = sizeof(AVPicture);

  790. 

  791.     emms_c();

  792. 

  793.     return buf_size;

  794. }

  795. 

  796. 

  797. static av_cold void common_init(AVCodecContext *avctx){

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

  799. 

  800.     dsputil_init(&f->dsp, avctx);

  801. 

  802.     f->avctx= avctx;

  803. }

  804. 

  805. static av_cold int decode_init(AVCodecContext *avctx){

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

  807. 

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

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

  810.         return 1;

  811.     }

  812. 

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

  814.     common_init(avctx);

  815.     init_vlcs(f);

  816. 

  817.     if(f->version>2) avctx->pix_fmt= PIX_FMT_RGB565;

  818.     else             avctx->pix_fmt= PIX_FMT_RGB555;

  819. 

  820.     return 0;

  821. }

  822. 

  823. 

  824. static av_cold int decode_end(AVCodecContext *avctx){

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

  826.     int i;

  827. 

  828.     av_freep(&f->bitstream_buffer);

  829.     f->bitstream_buffer_size=0;

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

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

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

  833.     }

  834.     free_vlc(&f->pre_vlc);

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

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

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

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

  839. 

  840.     return 0;

  841. }

  842. 

  843. AVCodec fourxm_decoder = {

  844.     "4xm",

  845.     CODEC_TYPE_VIDEO,

  846.     CODEC_ID_4XM,

  847.     sizeof(FourXContext),

  848.     decode_init,

  849.     NULL,

  850.     decode_end,

  851.     decode_frame,

  852.     CODEC_CAP_DR1,

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

  854. };