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