1 /* 2 * Audio FIFO 3 * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; 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 39 /** 40 * Context for an Audio FIFO Buffer. 41 * 42 * - Operates at the sample level rather than the byte level. 43 * - Supports multiple channels with either planar or packed sample format. 44 * - Automatic reallocation when writing to a full buffer. 45 */ 46 typedef struct AVAudioFifo AVAudioFifo; 47 48 /** 49 * Free an AVAudioFifo. 50 * 51 * @param af AVAudioFifo to free 52 */ 53 void av_audio_fifo_free(AVAudioFifo *af); 54 55 /** 56 * Allocate an AVAudioFifo. 57 * 58 * @param sample_fmt sample format 59 * @param channels number of channels 60 * @param nb_samples initial allocation size, in samples 61 * @return newly allocated AVAudioFifo, or NULL on error 62 */ 63 AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels, 64 int nb_samples); 65 66 /** 67 * Reallocate an AVAudioFifo. 68 * 69 * @param af AVAudioFifo to reallocate 70 * @param nb_samples new allocation size, in samples 71 * @return 0 if OK, or negative AVERROR code on failure 72 */ 73 int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples); 74 75 /** 76 * Write data to an AVAudioFifo. 77 * 78 * The AVAudioFifo will be reallocated automatically if the available space 79 * is less than nb_samples. 80 * 81 * @see enum AVSampleFormat 82 * The documentation for AVSampleFormat describes the data layout. 83 * 84 * @param af AVAudioFifo to write to 85 * @param data audio data plane pointers 86 * @param nb_samples number of samples to write 87 * @return number of samples actually written, or negative AVERROR 88 * code on failure. If successful, the number of samples 89 * actually written will always be nb_samples. 90 */ 91 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples); 92 93 /** 94 * Read data from an AVAudioFifo. 95 * 96 * @see enum AVSampleFormat 97 * The documentation for AVSampleFormat describes the data layout. 98 * 99 * @param af AVAudioFifo to read from 100 * @param data audio data plane pointers 101 * @param nb_samples number of samples to read 102 * @return number of samples actually read, or negative AVERROR code 103 * on failure. The number of samples actually read will not 104 * be greater than nb_samples, and will only be less than 105 * nb_samples if av_audio_fifo_size is less than nb_samples. 106 */ 107 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples); 108 109 /** 110 * Drain data from an AVAudioFifo. 111 * 112 * Removes the data without reading it. 113 * 114 * @param af AVAudioFifo to drain 115 * @param nb_samples number of samples to drain 116 * @return 0 if OK, or negative AVERROR code on failure 117 */ 118 int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples); 119 120 /** 121 * Reset the AVAudioFifo buffer. 122 * 123 * This empties all data in the buffer. 124 * 125 * @param af AVAudioFifo to reset 126 */ 127 void av_audio_fifo_reset(AVAudioFifo *af); 128 129 /** 130 * Get the current number of samples in the AVAudioFifo available for reading. 131 * 132 * @param af the AVAudioFifo to query 133 * @return number of samples available for reading 134 */ 135 int av_audio_fifo_size(AVAudioFifo *af); 136 137 /** 138 * Get the current number of samples in the AVAudioFifo available for writing. 139 * 140 * @param af the AVAudioFifo to query 141 * @return number of samples available for writing 142 */ 143 int av_audio_fifo_space(AVAudioFifo *af); 144 145 /** 146 * @} 147 */ 148 149 #endif /* AVUTIL_AUDIO_FIFO_H */ 150