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  1. /*
  2.  * common functions for the ATRAC family of decoders
  3.  *
  4.  * Copyright (c) 2009-2013 Maxim Poliakovski
  5.  * Copyright (c) 2009 Benjamin Larsson
  6.  *
  7.  * This file is part of FFmpeg.
  8.  *
  9.  * FFmpeg is free software; you can redistribute it and/or
  10.  * modify it under the terms of the GNU Lesser General Public
  11.  * License as published by the Free Software Foundation; either
  12.  * version 2.1 of the License, or (at your option) any later version.
  13.  *
  14.  * FFmpeg is distributed in the hope that it will be useful,
  15.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17.  * Lesser General Public License for more details.
  18.  *
  19.  * You should have received a copy of the GNU Lesser General Public
  20.  * License along with FFmpeg; if not, write to the Free Software
  21.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22.  */
  23.  
  24. /**
  25.  * @file
  26.  * ATRAC common header
  27.  */
  28.  
  29. #ifndef AVCODEC_ATRAC_H
  30. #define AVCODEC_ATRAC_H
  31.  
  32. /**
  33.  *  Gain control parameters for one subband.
  34.  */
  35. typedef struct AtracGainInfo {
  36.     int   num_points;   ///< number of gain control points
  37.     int   lev_code[7];  ///< level at corresponding control point
  38.     int   loc_code[7];  ///< location of gain control points
  39. } AtracGainInfo;
  40.  
  41. /**
  42.  *  Gain compensation context structure.
  43.  */
  44. typedef struct AtracGCContext {
  45.     float   gain_tab1[16];  ///< gain compensation level table
  46.     float   gain_tab2[31];  ///< gain compensation interpolation table
  47.     int     id2exp_offset;  ///< offset for converting level index into level exponent
  48.     int     loc_scale;      ///< scale of location code = 2^loc_scale samples
  49.     int     loc_size;       ///< size of location code in samples
  50. } AtracGCContext;
  51.  
  52. extern float ff_atrac_sf_table[64];
  53.  
  54. /**
  55.  * Generate common tables.
  56.  */
  57. void ff_atrac_generate_tables(void);
  58.  
  59. /**
  60.  *  Initialize gain compensation context.
  61.  *
  62.  * @param gctx            pointer to gain compensation context to initialize
  63.  * @param id2exp_offset   offset for converting level index into level exponent
  64.  * @param loc_scale       location size factor
  65.  */
  66. void ff_atrac_init_gain_compensation(AtracGCContext *gctx, int id2exp_offset,
  67.                                      int loc_scale);
  68.  
  69. /**
  70.  * Apply gain compensation and perform the MDCT overlapping part.
  71.  *
  72.  * @param gctx         pointer to gain compensation context
  73.  * @param in           input buffer
  74.  * @param prev         previous buffer to perform overlap against
  75.  * @param gc_now       gain control information for current frame
  76.  * @param gc_next      gain control information for next frame
  77.  * @param num_samples  number of samples to process
  78.  * @param out          output data goes here
  79.  */
  80. void ff_atrac_gain_compensation(AtracGCContext *gctx, float *in, float *prev,
  81.                                 AtracGainInfo *gc_now, AtracGainInfo *gc_next,
  82.                                 int num_samples, float *out);
  83.  
  84. /**
  85.  * Quadrature mirror synthesis filter.
  86.  *
  87.  * @param inlo      lower part of spectrum
  88.  * @param inhi      higher part of spectrum
  89.  * @param nIn       size of spectrum buffer
  90.  * @param pOut      out buffer
  91.  * @param delayBuf  delayBuf buffer
  92.  * @param temp      temp buffer
  93.  */
  94. void ff_atrac_iqmf(float *inlo, float *inhi, unsigned int nIn, float *pOut,
  95.                    float *delayBuf, float *temp);
  96.  
  97. #endif /* AVCODEC_ATRAC_H */
  98.