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 */