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lpc10codec.cpp
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Linux-Unix program

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Visual C++

lpc10codec.cpp：Code Content
  1. /***************************************************************************
  2.  *                                                                         *
  3.  *   This program is free software; you can redistribute it and/or modify  *
  4.  *   it under the terms of the GNU General Public License as published by  *
  5.  *   the Free Software Foundation; either version 2 of the License, or     *
  6.  *   (at your option) any later version.                                   *
  7.  *                                                                         *
  8.  *   copyright            : (C) 2002 by Zhang Yong                         *
  9.  *   email                : z-yong163@163.com                              *
  10.  ***************************************************************************/
  12. #include "lpc10codec.h"
  13. #include <malloc.h>
  14. #include <memory.h>
  16. #define LPC10_BYTES_IN_COMPRESSED_FRAME
  17. ((LPC10_BITS_IN_COMPRESSED_FRAME >> 3) + !!(LPC10_BITS_IN_COMPRESSED_FRAME & 7))
  20. Lpc10Codec::Lpc10Codec()
  21. {
  22. encodeState = create_lpc10_encoder_state();
  23. decodeState = create_lpc10_decoder_state();
  24. }
  26. Lpc10Codec::~Lpc10Codec()
  27. {
  28. free(encodeState);
  29. free(decodeState);
  30. }
  32. int Lpc10Codec::encode(const char *in, char *out, int n)
  33. {
  34. float speech[LPC10_SAMPLES_PER_FRAME];
  35. INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];
  36. short *data = (short *) in;
  37. n /= sizeof(short);
  39. int i = n % LPC10_SAMPLES_PER_FRAME;
  40. if (i) {
  41. i = LPC10_SAMPLES_PER_FRAME - i;
  42. while (i-- > 0)
  43. data[n++] = 0;
  44. }
  46. char *p = out;
  47. n /= LPC10_SAMPLES_PER_FRAME;
  48. memset(out, 0, n * LPC10_BYTES_IN_COMPRESSED_FRAME);
  50. while (n-- > 0) {
  51. for (i = 0; i < LPC10_SAMPLES_PER_FRAME; ++i)
  52. speech[i] = data[i] / 32768.0f;
  54. lpc10_encode(speech, bits, encodeState);
  56. for (i = 0; i < LPC10_BITS_IN_COMPRESSED_FRAME; ++i)
  57. p[i >> 3] |= (!!bits[i] << (i & 7));
  59. p += LPC10_BYTES_IN_COMPRESSED_FRAME;
  60. data += LPC10_SAMPLES_PER_FRAME;
  61. }
  63. return (p - out);
  64. }
  66. int Lpc10Codec::decode(const char *in, char *out, int n)
  67. {
  68. float speech[LPC10_SAMPLES_PER_FRAME];
  69. INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];
  70. short *data = (short *) out;
  72. n /= LPC10_BYTES_IN_COMPRESSED_FRAME;
  73. while (n-- > 0) {
  74. for (int i = 0; i < LPC10_BITS_IN_COMPRESSED_FRAME; ++i)
  75. bits[i] = !!(in[i >> 3] & (1 << (i & 7)));
  77. lpc10_decode(bits, speech, decodeState);
  79. for (i = 0; i < LPC10_SAMPLES_PER_FRAME; ++i)
  80. *data++ = (short) (speech[i] * 32768);
  82. in += LPC10_BYTES_IN_COMPRESSED_FRAME;
  83. }
  85. return ((char *) data - out);
  86. }