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 "attributes.h" 31 #include "samplefmt.h" 32 33 /** 34 * @addtogroup lavu_audio 35 * @{ 36 * 37 * @defgroup lavu_audiofifo Audio FIFO Buffer 38 * @{ 39 */ 40 41 /** 42 * Context for an Audio FIFO Buffer. 43 * 44 * - Operates at the sample level rather than the byte level. 45 * - Supports multiple channels with either planar or packed sample format. 46 * - Automatic reallocation when writing to a full buffer. 47 */ 48 typedef struct AVAudioFifo AVAudioFifo; 49 50 /** 51 * Free an AVAudioFifo. 52 * 53 * @param af AVAudioFifo to free 54 */ 55 void av_audio_fifo_free(AVAudioFifo *af); 56 57 /** 58 * Allocate an AVAudioFifo. 59 * 60 * @param sample_fmt sample format 61 * @param channels number of channels 62 * @param nb_samples initial allocation size, in samples 63 * @return newly allocated AVAudioFifo, or NULL on error 64 */ 65 AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels, 66 int nb_samples); 67 68 /** 69 * Reallocate an AVAudioFifo. 70 * 71 * @param af AVAudioFifo to reallocate 72 * @param nb_samples new allocation size, in samples 73 * @return 0 if OK, or negative AVERROR code on failure 74 */ 75 av_warn_unused_result 76 int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples); 77 78 /** 79 * Write data to an AVAudioFifo. 80 * 81 * The AVAudioFifo will be reallocated automatically if the available space 82 * is less than nb_samples. 83 * 84 * @see enum AVSampleFormat 85 * The documentation for AVSampleFormat describes the data layout. 86 * 87 * @param af AVAudioFifo to write to 88 * @param data audio data plane pointers 89 * @param nb_samples number of samples to write 90 * @return number of samples actually written, or negative AVERROR 91 * code on failure. If successful, the number of samples 92 * actually written will always be nb_samples. 93 */ 94 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples); 95 96 /** 97 * Peek data from an AVAudioFifo. 98 * 99 * @see enum AVSampleFormat 100 * The documentation for AVSampleFormat describes the data layout. 101 * 102 * @param af AVAudioFifo to read from 103 * @param data audio data plane pointers 104 * @param nb_samples number of samples to peek 105 * @return number of samples actually peek, or negative AVERROR code 106 * on failure. The number of samples actually peek will not 107 * be greater than nb_samples, and will only be less than 108 * nb_samples if av_audio_fifo_size is less than nb_samples. 109 */ 110 int av_audio_fifo_peek(AVAudioFifo *af, void **data, int nb_samples); 111 112 /** 113 * Peek data from an AVAudioFifo. 114 * 115 * @see enum AVSampleFormat 116 * The documentation for AVSampleFormat describes the data layout. 117 * 118 * @param af AVAudioFifo to read from 119 * @param data audio data plane pointers 120 * @param nb_samples number of samples to peek 121 * @param offset offset from current read position 122 * @return number of samples actually peek, or negative AVERROR code 123 * on failure. The number of samples actually peek will not 124 * be greater than nb_samples, and will only be less than 125 * nb_samples if av_audio_fifo_size is less than nb_samples. 126 */ 127 int av_audio_fifo_peek_at(AVAudioFifo *af, void **data, int nb_samples, int offset); 128 129 /** 130 * Read data from an AVAudioFifo. 131 * 132 * @see enum AVSampleFormat 133 * The documentation for AVSampleFormat describes the data layout. 134 * 135 * @param af AVAudioFifo to read from 136 * @param data audio data plane pointers 137 * @param nb_samples number of samples to read 138 * @return number of samples actually read, or negative AVERROR code 139 * on failure. The number of samples actually read will not 140 * be greater than nb_samples, and will only be less than 141 * nb_samples if av_audio_fifo_size is less than nb_samples. 142 */ 143 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples); 144 145 /** 146 * Drain data from an AVAudioFifo. 147 * 148 * Removes the data without reading it. 149 * 150 * @param af AVAudioFifo to drain 151 * @param nb_samples number of samples to drain 152 * @return 0 if OK, or negative AVERROR code on failure 153 */ 154 int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples); 155 156 /** 157 * Reset the AVAudioFifo buffer. 158 * 159 * This empties all data in the buffer. 160 * 161 * @param af AVAudioFifo to reset 162 */ 163 void av_audio_fifo_reset(AVAudioFifo *af); 164 165 /** 166 * Get the current number of samples in the AVAudioFifo available for reading. 167 * 168 * @param af the AVAudioFifo to query 169 * @return number of samples available for reading 170 */ 171 int av_audio_fifo_size(AVAudioFifo *af); 172 173 /** 174 * Get the current number of samples in the AVAudioFifo available for writing. 175 * 176 * @param af the AVAudioFifo to query 177 * @return number of samples available for writing 178 */ 179 int av_audio_fifo_space(AVAudioFifo *af); 180 181 /** 182 * @} 183 * @} 184 */ 185 186 #endif /* AVUTIL_AUDIO_FIFO_H */ 187