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 libavdevice/alsa-audio.h
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 "libavformat/avformat.h"
36
37/* XXX: we make the assumption that the soundcard accepts this format */
38/* XXX: find better solution with "preinit" method, needed also in
39        other formats */
40#ifdef WORDS_BIGENDIAN
41#define DEFAULT_CODEC_ID CODEC_ID_PCM_S16BE
42#else
43#define DEFAULT_CODEC_ID CODEC_ID_PCM_S16LE
44#endif
45
46typedef struct {
47    snd_pcm_t *h;
48    int frame_size;  ///< preferred size for reads and writes
49    int period_size; ///< bytes per sample * channels
50} AlsaData;
51
52/**
53 * Opens an ALSA PCM.
54 *
55 * @param s media file handle
56 * @param mode either SND_PCM_STREAM_CAPTURE or SND_PCM_STREAM_PLAYBACK
57 * @param sample_rate in: requested sample rate;
58 *                    out: actually selected sample rate
59 * @param channels number of channels
60 * @param codec_id in: requested CodecID or CODEC_ID_NONE;
61 *                 out: actually selected CodecID, changed only if
62 *                 CODEC_ID_NONE was requested
63 *
64 * @return 0 if OK, AVERROR_xxx on error
65 */
66int ff_alsa_open(AVFormatContext *s, int mode, unsigned int *sample_rate,
67                 int channels, int *codec_id);
68
69/**
70 * Closes the ALSA PCM.
71 *
72 * @param s1 media file handle
73 *
74 * @return 0
75 */
76int ff_alsa_close(AVFormatContext *s1);
77
78/**
79 * Tries to recover from ALSA buffer underrun.
80 *
81 * @param s1 media file handle
82 * @param err error code reported by the previous ALSA call
83 *
84 * @return 0 if OK, AVERROR_xxx on error
85 */
86int ff_alsa_xrun_recover(AVFormatContext *s1, int err);
87
88#endif /* AVDEVICE_ALSA_AUDIO_H */
89