libavutil/audio_fifo.h

   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.
  89  */
  90 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples);
  91
  92 /**
  93  * Read data from an AVAudioFifo.
  94  *
  95  * @see enum AVSampleFormat
  96  * The documentation for AVSampleFormat describes the data layout.
  97  *
  98  * @param af          AVAudioFifo to read from
  99  * @param data        audio data plane pointers
 100  * @param nb_samples  number of samples to read
 101  * @return            number of samples actually read, or negative AVERROR code
 102  *                    on failure.
 103  */
 104 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples);
 105
 106 /**
 107  * Drain data from an AVAudioFifo.
 108  *
 109  * Removes the data without reading it.
 110  *
 111  * @param af          AVAudioFifo to drain
 112  * @param nb_samples  number of samples to drain
 113  * @return            0 if OK, or negative AVERROR code on failure
 114  */
 115 int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples);
 116
 117 /**
 118  * Reset the AVAudioFifo buffer.
 119  *
 120  * This empties all data in the buffer.
 121  *
 122  * @param af  AVAudioFifo to reset
 123  */
 124 void av_audio_fifo_reset(AVAudioFifo *af);
 125
 126 /**
 127  * Get the current number of samples in the AVAudioFifo available for reading.
 128  *
 129  * @param af  the AVAudioFifo to query
 130  * @return    number of samples available for reading
 131  */
 132 int av_audio_fifo_size(AVAudioFifo *af);
 133
 134 /**
 135  * Get the current number of samples in the AVAudioFifo available for writing.
 136  *
 137  * @param af  the AVAudioFifo to query
 138  * @return    number of samples available for writing
 139  */
 140 int av_audio_fifo_space(AVAudioFifo *af);
 141
 142 /**
 143  * @}
 144  */
 145
 146 #endif /* AVUTIL_AUDIO_FIFO_H */