src/pcm_resample.h

   1 /*
   2  * Copyright (C) 2003-2009 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef MPD_PCM_RESAMPLE_H
  21 #define MPD_PCM_RESAMPLE_H
  22
  23 #include "pcm_buffer.h"
  24 #include "config.h"
  25
  26 #include <stdint.h>
  27 #include <stddef.h>
  28 #include <stdbool.h>
  29
  30 #ifdef HAVE_LIBSAMPLERATE
  31 #include <samplerate.h>
  32 #endif
  33
  34 /**
  35  * This object is statically allocated (within another struct), and
  36  * holds buffer allocations and the state for the resampler.
  37  */
  38 struct pcm_resample_state {
  39 #ifdef HAVE_LIBSAMPLERATE
  40         SRC_STATE *state;
  41         SRC_DATA data;
  42
  43         struct pcm_buffer in, out;
  44
  45         struct {
  46                 unsigned src_rate;
  47                 unsigned dest_rate;
  48                 uint8_t channels;
  49         } prev;
  50
  51         int error;
  52 #endif
  53
  54         struct pcm_buffer buffer;
  55 };
  56
  57 /**
  58  * Initializes a pcm_resample_state object.
  59  */
  60 void pcm_resample_init(struct pcm_resample_state *state);
  61
  62 /**
  63  * Deinitializes a pcm_resample_state object and frees allocated
  64  * memory.
  65  */
  66 void pcm_resample_deinit(struct pcm_resample_state *state);
  67
  68 /**
  69  * Resamples 16 bit PCM data.
  70  *
  71  * @param state an initialized pcm_resample_state object
  72  * @param channels the number of channels
  73  * @param src_rate the source sample rate
  74  * @param src the source PCM buffer
  75  * @param src_size the size of #src in bytes
  76  * @param dest_rate the requested destination sample rate
  77  * @param dest_size_r returns the number of bytes of the destination buffer
  78  * @return the destination buffer
  79  */
  80 const int16_t *
  81 pcm_resample_16(struct pcm_resample_state *state,
  82                 uint8_t channels,
  83                 unsigned src_rate,
  84                 const int16_t *src_buffer, size_t src_size,
  85                 unsigned dest_rate, size_t *dest_size_r,
  86                 GError **error_r);
  87
  88 /**
  89  * Resamples 32 bit PCM data.
  90  *
  91  * @param state an initialized pcm_resample_state object
  92  * @param channels the number of channels
  93  * @param src_rate the source sample rate
  94  * @param src the source PCM buffer
  95  * @param src_size the size of #src in bytes
  96  * @param dest_rate the requested destination sample rate
  97  * @param dest_size_r returns the number of bytes of the destination buffer
  98  * @return the destination buffer
  99  */
 100 const int32_t *
 101 pcm_resample_32(struct pcm_resample_state *state,
 102                 uint8_t channels,
 103                 unsigned src_rate,
 104                 const int32_t *src_buffer, size_t src_size,
 105                 unsigned dest_rate, size_t *dest_size_r,
 106                 GError **error_r);
 107
 108 /**
 109  * Resamples 24 bit PCM data.
 110  *
 111  * @param state an initialized pcm_resample_state object
 112  * @param channels the number of channels
 113  * @param src_rate the source sample rate
 114  * @param src the source PCM buffer
 115  * @param src_size the size of #src in bytes
 116  * @param dest_rate the requested destination sample rate
 117  * @param dest_size_r returns the number of bytes of the destination buffer
 118  * @return the destination buffer
 119  */
 120 static inline const int32_t *
 121 pcm_resample_24(struct pcm_resample_state *state,
 122                 uint8_t channels,
 123                 unsigned src_rate,
 124                 const int32_t *src_buffer, size_t src_size,
 125                 unsigned dest_rate, size_t *dest_size_r,
 126                 GError **error_r)
 127 {
 128         /* reuse the 32 bit code - the resampler code doesn't care if
 129            the upper 8 bits are actually used */
 130         return pcm_resample_32(state, channels,
 131                                src_rate, src_buffer, src_size,
 132                                dest_rate, dest_size_r, error_r);
 133 }
 134
 135 #endif