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 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 * const *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(const AVAudioFifo *af, void * const *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(const AVAudioFifo *af, void * const *data,
 128                           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 * const *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 */