filename | src/drivers/audio_alsa.c |
changeset | 669:ab344e42bca9 |
prev | 643:653b0a70f173 |
next | 697:479b8c213f61 |
author | nkeynes |
date | Mon May 12 10:00:13 2008 +0000 (15 years ago) |
permissions | -rwxr-xr-x |
last change | Cleanup most of the -Wall warnings (getting a bit sloppy...) Convert FP code to use fixed banks rather than indirect pointer (3-4% faster this way now) |
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1 /**
2 * $Id: audio_esd.c 602 2008-01-15 20:50:23Z nkeynes $
3 *
4 * The asla audio driver
5 *
6 * Copyright (c) 2008 Jonathan Muller
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program 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
16 * GNU General Public License for more details.
17 */
18 #include <stdio.h>
19 #include <unistd.h>
21 /* Use the newer ALSA API */
22 #define ALSA_PCM_NEW_HW_PARAMS_API
24 #include <alsa/asoundlib.h>
25 #include "config.h"
26 #include "aica/audio.h"
27 #include "dream.h"
30 static snd_pcm_t *_soundDevice = NULL;
31 static int frame_bytes;
34 struct lxdream_config_entry alsa_config[] = {
35 {"device", CONFIG_TYPE_FILE, "default"},
36 {NULL, CONFIG_TYPE_NONE}
37 };
40 gboolean audio_alsa_init( )
41 {
42 return TRUE;
43 }
46 gboolean audio_alsa_set_format( uint32_t rate, uint32_t format )
47 {
48 int err;
49 snd_pcm_hw_params_t *hw_params;
50 snd_pcm_sw_params_t *sw_params;
51 snd_pcm_uframes_t frames;
52 snd_pcm_uframes_t bufferSize;
53 int dir;
56 // Open the device we were told to open.
57 err = snd_pcm_open( &_soundDevice, alsa_config[0].value,
58 SND_PCM_STREAM_PLAYBACK, 0 );
60 // Check for error on open.
61 if ( err < 0 ) {
62 ERROR( "Init: cannot open audio device %s (%s)\n",
63 alsa_config[0].value, snd_strerror( err ) );
64 return FALSE;
65 } else {
66 DEBUG( "Audio device opened successfully." );
67 }
69 frame_bytes = ( 2 * ( snd_pcm_format_width( SND_PCM_FORMAT_S16_LE ) / 8 ) );
72 //snd_pcm_hw_params_alloca (&hw_params);
73 // Allocate the hardware parameter structure.
74 if ( ( err = snd_pcm_hw_params_malloc( &hw_params ) ) < 0 ) {
75 ERROR( "Init: cannot allocate hardware parameter structure (%s)\n",
76 snd_strerror( err ) );
77 return FALSE;
78 }
80 if ( ( err = snd_pcm_hw_params_any( _soundDevice, hw_params ) ) < 0 ) {
81 ERROR( "Init: cannot allocate hardware parameter structure (%s)\n",
82 snd_strerror( err ) );
83 return FALSE;
84 }
85 // Set access to RW interleaved.
86 if ( ( err = snd_pcm_hw_params_set_access( _soundDevice, hw_params,
87 SND_PCM_ACCESS_RW_INTERLEAVED ) )
88 < 0 ) {
89 ERROR( " Init: cannot set access type (%s)\n", snd_strerror( err ) );
90 return FALSE;
91 }
93 if ( ( err = snd_pcm_hw_params_set_format( _soundDevice, hw_params,
94 SND_PCM_FORMAT_S16_LE ) ) <
95 0 ) {
96 ERROR( "Init: cannot set sample format (%s)\n", snd_strerror( err ) );
97 return FALSE;
98 }
100 err = snd_pcm_hw_params_set_rate_near( _soundDevice, hw_params, &rate, 0 );
101 if ( err < 0 ) {
102 ERROR( "Init: Resampling setup failed for playback: %s\n",
103 snd_strerror( err ) );
104 return err;
105 }
106 // Set channels to stereo (2).
107 err = snd_pcm_hw_params_set_channels( _soundDevice, hw_params, 2 );
108 if ( err < 0 ) {
109 ERROR( "Init: cannot set channel count (%s)\n", snd_strerror( err ) );
110 return FALSE;
111 }
113 // frames = 4410;
114 // snd_pcm_hw_params_set_period_size_near( _soundDevice, hw_params, &frames,
115 // &dir );
117 // Apply the hardware parameters that we've set.
118 err = snd_pcm_hw_params( _soundDevice, hw_params );
119 if ( err < 0 ) {
120 DEBUG( "Init: cannot set parameters (%s)\n", snd_strerror( err ) );
121 return FALSE;
122 } else {
123 DEBUG( "Audio device parameters have been set successfully." );
124 }
126 snd_pcm_hw_params_get_period_size( hw_params, &frames, &dir );
127 DEBUG( "period size = %d\n", frames );
129 // Get the buffer size.
130 snd_pcm_hw_params_get_buffer_size( hw_params, &bufferSize );
131 DEBUG("Buffer Size = %d\n", bufferSize);
133 // If we were going to do more with our sound device we would want to store
134 // the buffer size so we know how much data we will need to fill it with.
136 //cout << "Init: Buffer size = " << bufferSize << " frames." << endl;
138 // Display the bit size of samples.
139 //cout << "Init: Significant bits for linear samples = " << snd_pcm_hw_params_get_sbits(hw_params) << endl;
141 // Free the hardware parameters now that we're done with them.
142 snd_pcm_hw_params_free( hw_params );
144 // Set the start threshold to reduce inter-buffer gaps
145 snd_pcm_sw_params_alloca( &sw_params );
146 snd_pcm_sw_params_current( _soundDevice, sw_params );
147 snd_pcm_sw_params_set_start_threshold( _soundDevice, sw_params, bufferSize/2 );
148 err = snd_pcm_sw_params( _soundDevice, sw_params );
149 if( err < 0 ) {
150 ERROR("Unable to set sw params for alsa driver: %s\n", snd_strerror(err));
151 return FALSE;
152 }
154 err = snd_pcm_prepare( _soundDevice );
155 if ( err < 0 ) {
156 ERROR( "Init: cannot prepare audio interface for use (%s)\n",
157 snd_strerror( err ) );
158 return FALSE;
159 }
160 return TRUE;
161 }
163 gboolean audio_alsa_process_buffer( audio_buffer_t buffer )
164 {
165 int err;
166 int length;
169 length = buffer->length / frame_bytes;
171 err = snd_pcm_writei( _soundDevice, buffer->data, length );
172 if( err == -EPIPE ) {
173 snd_pcm_prepare( _soundDevice );
174 } else if( err == -ESTRPIPE ) {
175 snd_pcm_resume( _soundDevice );
176 }
178 return TRUE;
179 }
182 gboolean audio_alsa_close( )
183 {
184 return TRUE;
185 }
189 struct audio_driver audio_alsa_driver = {
190 "alsa",
191 audio_alsa_init,
192 audio_alsa_set_format,
193 audio_alsa_process_buffer,
194 audio_alsa_close
195 };
.