ffmpeg/libavdevice/alsa-audio.h

   1 /*
   2  * ALSA input and output
   3  * Copyright (c) 2007 Luca Abeni ( lucabe72 email it )
   4  * Copyright (c) 2007 Benoit Fouet ( benoit fouet free fr )
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file
  25  * ALSA input and output: definitions and structures
  26  * @author Luca Abeni ( lucabe72 email it )
  27  * @author Benoit Fouet ( benoit fouet free fr )
  28  */
  29
  30 #ifndef AVDEVICE_ALSA_AUDIO_H
  31 #define AVDEVICE_ALSA_AUDIO_H
  32
  33 #include <alsa/asoundlib.h>
  34 #include "config.h"
  35 #include "libavutil/log.h"
  36 #include "timefilter.h"
  37 #include "avdevice.h"
  38
  39 /* XXX: we make the assumption that the soundcard accepts this format */
  40 /* XXX: find better solution with "preinit" method, needed also in
  41         other formats */
  42 #define DEFAULT_CODEC_ID AV_NE(AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE)
  43
  44 typedef void (*ff_reorder_func)(const void *, void *, int);
  45
  46 #define ALSA_BUFFER_SIZE_MAX 65536
  47
  48 typedef struct AlsaData {
  49     AVClass *class;
  50     snd_pcm_t *h;
  51     int frame_size;  ///< bytes per sample * channels
  52     int period_size; ///< preferred size for reads and writes, in frames
  53     int sample_rate; ///< sample rate set by user
  54     int channels;    ///< number of channels set by user
  55     int last_period;
  56     TimeFilter *timefilter;
  57     void (*reorder_func)(const void *, void *, int);
  58     void *reorder_buf;
  59     int reorder_buf_size; ///< in frames
  60     int64_t timestamp; ///< current timestamp, without latency applied.
  61 } AlsaData;
  62
  63 /**
  64  * Open an ALSA PCM.
  65  *
  66  * @param s media file handle
  67  * @param mode either SND_PCM_STREAM_CAPTURE or SND_PCM_STREAM_PLAYBACK
  68  * @param sample_rate in: requested sample rate;
  69  *                    out: actually selected sample rate
  70  * @param channels number of channels
  71  * @param codec_id in: requested AVCodecID or AV_CODEC_ID_NONE;
  72  *                 out: actually selected AVCodecID, changed only if
  73  *                 AV_CODEC_ID_NONE was requested
  74  *
  75  * @return 0 if OK, AVERROR_xxx on error
  76  */
  77 int ff_alsa_open(AVFormatContext *s, snd_pcm_stream_t mode,
  78                  unsigned int *sample_rate,
  79                  int channels, enum AVCodecID *codec_id);
  80
  81 /**
  82  * Close the ALSA PCM.
  83  *
  84  * @param s1 media file handle
  85  *
  86  * @return 0
  87  */
  88 int ff_alsa_close(AVFormatContext *s1);
  89
  90 /**
  91  * Try to recover from ALSA buffer underrun.
  92  *
  93  * @param s1 media file handle
  94  * @param err error code reported by the previous ALSA call
  95  *
  96  * @return 0 if OK, AVERROR_xxx on error
  97  */
  98 int ff_alsa_xrun_recover(AVFormatContext *s1, int err);
  99
 100 int ff_alsa_extend_reorder_buf(AlsaData *s, int size);
 101
 102 int ff_alsa_get_device_list(AVDeviceInfoList *device_list, snd_pcm_stream_t stream_type);
 103
 104 #endif /* AVDEVICE_ALSA_AUDIO_H */