You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

146 lines
3.8KB

  1. /*
  2. * Winnov WNV1 codec
  3. * Copyright (c) 2005 Konstantin Shishkov
  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 wnv1.c
  24. * Winnov WNV1 codec.
  25. */
  26. #include "avcodec.h"
  27. #include "bitstream.h"
  28. typedef struct WNV1Context{
  29. AVCodecContext *avctx;
  30. AVFrame pic;
  31. int shift;
  32. GetBitContext gb;
  33. } WNV1Context;
  34. static uint16_t code_tab[16][2]={
  35. {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
  36. {0x000,1},
  37. {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
  38. };
  39. #define CODE_VLC_BITS 9
  40. static VLC code_vlc;
  41. /* returns modified base_value */
  42. static inline int wnv1_get_code(WNV1Context *w, int base_value)
  43. {
  44. int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
  45. if(v==15)
  46. return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
  47. else
  48. return base_value + ((v - 7)<<w->shift);
  49. }
  50. static int decode_frame(AVCodecContext *avctx,
  51. void *data, int *data_size,
  52. uint8_t *buf, int buf_size)
  53. {
  54. WNV1Context * const l = avctx->priv_data;
  55. AVFrame * const p= (AVFrame*)&l->pic;
  56. unsigned char *Y,*U,*V;
  57. int i, j;
  58. int prev_y = 0, prev_u = 0, prev_v = 0;
  59. if(p->data[0])
  60. avctx->release_buffer(avctx, p);
  61. p->reference = 0;
  62. if(avctx->get_buffer(avctx, p) < 0){
  63. av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  64. return -1;
  65. }
  66. p->key_frame = 1;
  67. for(i=8; i<buf_size; i++)
  68. buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
  69. init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
  70. if (buf[2] >> 4 == 6)
  71. l->shift = 2;
  72. else {
  73. l->shift = 8 - (buf[2] >> 4);
  74. if (l->shift > 4) {
  75. av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
  76. l->shift = 4;
  77. }
  78. if (l->shift < 1) {
  79. av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
  80. l->shift = 1;
  81. }
  82. }
  83. Y = p->data[0];
  84. U = p->data[1];
  85. V = p->data[2];
  86. for (j = 0; j < avctx->height; j++) {
  87. for (i = 0; i < avctx->width / 2; i++) {
  88. Y[i * 2] = wnv1_get_code(l, prev_y);
  89. prev_u = U[i] = wnv1_get_code(l, prev_u);
  90. prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
  91. prev_v = V[i] = wnv1_get_code(l, prev_v);
  92. }
  93. Y += p->linesize[0];
  94. U += p->linesize[1];
  95. V += p->linesize[2];
  96. }
  97. *data_size = sizeof(AVFrame);
  98. *(AVFrame*)data = l->pic;
  99. return buf_size;
  100. }
  101. static int decode_init(AVCodecContext *avctx){
  102. WNV1Context * const l = avctx->priv_data;
  103. l->avctx = avctx;
  104. avctx->pix_fmt = PIX_FMT_YUV422P;
  105. if(!code_vlc.table){
  106. init_vlc(&code_vlc, CODE_VLC_BITS, 16,
  107. &code_tab[0][1], 4, 2,
  108. &code_tab[0][0], 4, 2, 1);
  109. }
  110. return 0;
  111. }
  112. AVCodec wnv1_decoder = {
  113. "wnv1",
  114. CODEC_TYPE_VIDEO,
  115. CODEC_ID_WNV1,
  116. sizeof(WNV1Context),
  117. decode_init,
  118. NULL,
  119. NULL,
  120. decode_frame,
  121. CODEC_CAP_DR1,
  122. };