tx.h 4.0 KB

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  1. /*
  2. * This file is part of FFmpeg.
  3. *
  4. * FFmpeg is free software; you can redistribute it and/or
  5. * modify it under the terms of the GNU Lesser General Public
  6. * License as published by the Free Software Foundation; either
  7. * version 2.1 of the License, or (at your option) any later version.
  8. *
  9. * FFmpeg is distributed in the hope that it will be useful,
  10. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12. * Lesser General Public License for more details.
  13. *
  14. * You should have received a copy of the GNU Lesser General Public
  15. * License along with FFmpeg; if not, write to the Free Software
  16. * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17. */
  18. #ifndef AVUTIL_TX_H
  19. #define AVUTIL_TX_H
  20. #include <stdint.h>
  21. #include <stddef.h>
  22. typedef struct AVTXContext AVTXContext;
  23. typedef struct AVComplexFloat {
  24. float re, im;
  25. } AVComplexFloat;
  26. typedef struct AVComplexDouble {
  27. double re, im;
  28. } AVComplexDouble;
  29. typedef struct AVComplexInt32 {
  30. int32_t re, im;
  31. } AVComplexInt32;
  32. enum AVTXType {
  33. /**
  34. * Standard complex to complex FFT with sample data type AVComplexFloat.
  35. * Output is not 1/len normalized. Scaling currently unsupported.
  36. * The stride parameter is ignored.
  37. */
  38. AV_TX_FLOAT_FFT = 0,
  39. /**
  40. * Standard MDCT with sample data type of float and a scale type of
  41. * float. Length is the frame size, not the window size (which is 2x frame)
  42. * For forward transforms, the stride specifies the spacing between each
  43. * sample in the output array in bytes. The input must be a flat array.
  44. * For inverse transforms, the stride specifies the spacing between each
  45. * sample in the input array in bytes. The output will be a flat array.
  46. * Stride must be a non-zero multiple of sizeof(float).
  47. */
  48. AV_TX_FLOAT_MDCT = 1,
  49. /**
  50. * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
  51. */
  52. AV_TX_DOUBLE_FFT = 2,
  53. /**
  54. * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
  55. * Stride must be a non-zero multiple of sizeof(double).
  56. */
  57. AV_TX_DOUBLE_MDCT = 3,
  58. /**
  59. * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
  60. */
  61. AV_TX_INT32_FFT = 4,
  62. /**
  63. * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
  64. * Only scale values less than or equal to 1.0 are supported.
  65. * Stride must be a non-zero multiple of sizeof(int32_t).
  66. */
  67. AV_TX_INT32_MDCT = 5,
  68. };
  69. /**
  70. * Function pointer to a function to perform the transform.
  71. *
  72. * @note Using a different context than the one allocated during av_tx_init()
  73. * is not allowed.
  74. *
  75. * @param s the transform context
  76. * @param out the output array
  77. * @param in the input array
  78. * @param stride the input or output stride in bytes
  79. *
  80. * The out and in arrays must be aligned to the maximum required by the CPU
  81. * architecture.
  82. * The stride must follow the constraints the transform type has specified.
  83. */
  84. typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
  85. /**
  86. * Initialize a transform context with the given configuration
  87. * Currently power of two lengths from 2 to 131072 are supported, along with
  88. * any length decomposable to a power of two and either 3, 5 or 15.
  89. *
  90. * @param ctx the context to allocate, will be NULL on error
  91. * @param tx pointer to the transform function pointer to set
  92. * @param type type the type of transform
  93. * @param inv whether to do an inverse or a forward transform
  94. * @param len the size of the transform in samples
  95. * @param scale pointer to the value to scale the output if supported by type
  96. * @param flags currently unused
  97. *
  98. * @return 0 on success, negative error code on failure
  99. */
  100. int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
  101. int inv, int len, const void *scale, uint64_t flags);
  102. /**
  103. * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
  104. */
  105. void av_tx_uninit(AVTXContext **ctx);
  106. #endif /* AVUTIL_TX_H */