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ffmpeg-4.2.2/libavutil/tx.h 2.69 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #ifndef AVUTIL_TX_H
  #define AVUTIL_TX_H
  
  #include <stdint.h>
  #include <stddef.h>
  
  typedef struct AVTXContext AVTXContext;
  
  typedef struct AVComplexFloat {
      float re, im;
  } AVComplexFloat;
  
  enum AVTXType {
      /**
       * Standard complex to complex FFT with sample data type AVComplexFloat.
       * Scaling currently unsupported
       */
      AV_TX_FLOAT_FFT = 0,
      /**
       * Standard MDCT with sample data type of float and a scale type of
       * float. Length is the frame size, not the window size (which is 2x frame)
       */
      AV_TX_FLOAT_MDCT = 1,
  };
  
  /**
   * Function pointer to a function to perform the transform.
   *
   * @note Using a different context than the one allocated during av_tx_init()
   * is not allowed.
   *
   * @param s the transform context
   * @param out the output array
   * @param in the input array
   * @param stride the input or output stride (depending on transform direction)
   * in bytes, currently implemented for all MDCT transforms
   */
  typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
  
  /**
   * Initialize a transform context with the given configuration
   * Currently power of two lengths from 4 to 131072 are supported, along with
   * any length decomposable to a power of two and either 3, 5 or 15.
   *
   * @param ctx the context to allocate, will be NULL on error
   * @param tx pointer to the transform function pointer to set
   * @param type type the type of transform
   * @param inv whether to do an inverse or a forward transform
   * @param len the size of the transform in samples
   * @param scale pointer to the value to scale the output if supported by type
   * @param flags currently unused
   *
   * @return 0 on success, negative error code on failure
   */
  int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
                 int inv, int len, const void *scale, uint64_t flags);
  
  /**
   * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
   */
  void av_tx_uninit(AVTXContext **ctx);
  
  #endif /* AVUTIL_TX_H */