1 /* 2 * Audio FIFO 3 * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 /** 23 * @file 24 * Audio FIFO Buffer 25 */ 26 27 #ifndef AVUTIL_AUDIO_FIFO_H 28 #define AVUTIL_AUDIO_FIFO_H 29 30 #include "avutil.h" 31 #include "fifo.h" 32 #include "samplefmt.h" 33 34 /** 35 * @addtogroup lavu_audio 36 * @{ 37 * 38 * @defgroup lavu_audiofifo Audio FIFO Buffer 39 * @{ 40 */ 41 42 /** 43 * Context for an Audio FIFO Buffer. 44 * 45 * - Operates at the sample level rather than the byte level. 46 * - Supports multiple channels with either planar or packed sample format. 47 * - Automatic reallocation when writing to a full buffer. 48 */ 49 typedef struct AVAudioFifo AVAudioFifo; 50 51 /** 52 * Free an AVAudioFifo. 53 * 54 * @param af AVAudioFifo to free 55 */ 56 void av_audio_fifo_free(AVAudioFifo *af); 57 58 /** 59 * Allocate an AVAudioFifo. 60 * 61 * @param sample_fmt sample format 62 * @param channels number of channels 63 * @param nb_samples initial allocation size, in samples 64 * @return newly allocated AVAudioFifo, or NULL on error 65 */ 66 AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels, 67 int nb_samples); 68 69 /** 70 * Reallocate an AVAudioFifo. 71 * 72 * @param af AVAudioFifo to reallocate 73 * @param nb_samples new allocation size, in samples 74 * @return 0 if OK, or negative AVERROR code on failure 75 */ 76 av_warn_unused_result 77 int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples); 78 79 /** 80 * Write data to an AVAudioFifo. 81 * 82 * The AVAudioFifo will be reallocated automatically if the available space 83 * is less than nb_samples. 84 * 85 * @see enum AVSampleFormat 86 * The documentation for AVSampleFormat describes the data layout. 87 * 88 * @param af AVAudioFifo to write to 89 * @param data audio data plane pointers 90 * @param nb_samples number of samples to write 91 * @return number of samples actually written, or negative AVERROR 92 * code on failure. If successful, the number of samples 93 * actually written will always be nb_samples. 94 */ 95 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples); 96 97 /** 98 * Peek data from an AVAudioFifo. 99 * 100 * @see enum AVSampleFormat 101 * The documentation for AVSampleFormat describes the data layout. 102 * 103 * @param af AVAudioFifo to read from 104 * @param data audio data plane pointers 105 * @param nb_samples number of samples to peek 106 * @return number of samples actually peek, or negative AVERROR code 107 * on failure. The number of samples actually peek will not 108 * be greater than nb_samples, and will only be less than 109 * nb_samples if av_audio_fifo_size is less than nb_samples. 110 */ 111 int av_audio_fifo_peek(AVAudioFifo *af, void **data, int nb_samples); 112 113 /** 114 * Peek data from an AVAudioFifo. 115 * 116 * @see enum AVSampleFormat 117 * The documentation for AVSampleFormat describes the data layout. 118 * 119 * @param af AVAudioFifo to read from 120 * @param data audio data plane pointers 121 * @param nb_samples number of samples to peek 122 * @param offset offset from current read position 123 * @return number of samples actually peek, or negative AVERROR code 124 * on failure. The number of samples actually peek will not 125 * be greater than nb_samples, and will only be less than 126 * nb_samples if av_audio_fifo_size is less than nb_samples. 127 */ 128 int av_audio_fifo_peek_at(AVAudioFifo *af, void **data, int nb_samples, int offset); 129 130 /** 131 * Read data from an AVAudioFifo. 132 * 133 * @see enum AVSampleFormat 134 * The documentation for AVSampleFormat describes the data layout. 135 * 136 * @param af AVAudioFifo to read from 137 * @param data audio data plane pointers 138 * @param nb_samples number of samples to read 139 * @return number of samples actually read, or negative AVERROR code 140 * on failure. The number of samples actually read will not 141 * be greater than nb_samples, and will only be less than 142 * nb_samples if av_audio_fifo_size is less than nb_samples. 143 */ 144 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples); 145 146 /** 147 * Drain data from an AVAudioFifo. 148 * 149 * Removes the data without reading it. 150 * 151 * @param af AVAudioFifo to drain 152 * @param nb_samples number of samples to drain 153 * @return 0 if OK, or negative AVERROR code on failure 154 */ 155 int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples); 156 157 /** 158 * Reset the AVAudioFifo buffer. 159 * 160 * This empties all data in the buffer. 161 * 162 * @param af AVAudioFifo to reset 163 */ 164 void av_audio_fifo_reset(AVAudioFifo *af); 165 166 /** 167 * Get the current number of samples in the AVAudioFifo available for reading. 168 * 169 * @param af the AVAudioFifo to query 170 * @return number of samples available for reading 171 */ 172 int av_audio_fifo_size(AVAudioFifo *af); 173 174 /** 175 * Get the current number of samples in the AVAudioFifo available for writing. 176 * 177 * @param af the AVAudioFifo to query 178 * @return number of samples available for writing 179 */ 180 int av_audio_fifo_space(AVAudioFifo *af); 181 182 /** 183 * @} 184 * @} 185 */ 186 187 #endif /* AVUTIL_AUDIO_FIFO_H */ 188