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