mcs/class/System/System.Media/AudioDevice.cs

   1
   2 #if NET_2_0
   3 using System;
   4 using System.IO;
   5 using System.Runtime.InteropServices;
   6
   7 namespace Mono.Audio {
   8
   9         /* these are the values used by alsa */
  10 #if PUBLIC_API
  11         public
  12 #else
  13         internal
  14 #endif
  15         enum AudioFormat {
  16                 S8,
  17                 U8,
  18                 S16_LE,
  19                 S16_BE,
  20                 U16_LE,
  21                 U16_BE,
  22                 S24_LE,
  23                 S24_BE,
  24                 U24_LE,
  25                 U24_BE,
  26                 S32_LE,
  27                 S32_BE,
  28                 U32_LE,
  29                 U32_BE,
  30                 FLOAT_LE,
  31                 FLOAT_BE,
  32                 FLOAT64_LE,
  33                 FLOAT64_BE,
  34                 IEC958_SUBFRAME_LE,
  35                 IEC958_SUBFRAME_BE,
  36                 MU_LAW,
  37                 A_LAW,
  38                 IMA_ADPCM,
  39                 MPEG,
  40                 GSM
  41         }
  42
  43 #if PUBLIC_API
  44         public
  45 #else
  46         internal
  47 #endif
  48         class AudioDevice {
  49
  50                 static AudioDevice TryAlsa (string name) {
  51                         AudioDevice dev;
  52                         try {
  53                                 dev = new AlsaDevice (name);
  54                                 return dev;
  55                         } catch {
  56                                 return null;
  57                         }
  58                 }
  59
  60                 public static AudioDevice CreateDevice (string name) {
  61                         AudioDevice dev;
  62
  63                         dev = TryAlsa (name);
  64                         /* if no option is found, return a silent device */
  65                         if (dev == null)
  66                                 dev = new AudioDevice ();
  67                         return dev;
  68                 }
  69
  70                 public virtual bool SetFormat (AudioFormat format, int channels, int rate) {
  71                         return true;
  72                 }
  73
  74                 public virtual int PlaySample (byte[] buffer, int num_frames) {
  75                         return num_frames;
  76                 }
  77
  78                 public virtual void Wait () {
  79                 }
  80         }
  81
  82         class AlsaDevice: AudioDevice, IDisposable {
  83                 IntPtr handle;
  84
  85                 [DllImport ("libasound.so.2")]
  86                 static extern int snd_pcm_open (ref IntPtr handle, string pcm_name, int stream, int mode);
  87
  88                 [DllImport ("libasound.so.2")]
  89                 static extern int snd_pcm_close (IntPtr handle);
  90
  91                 [DllImport ("libasound.so.2")]
  92                 static extern int snd_pcm_drain (IntPtr handle);
  93
  94                 [DllImport ("libasound.so.2")]
  95                 static extern int snd_pcm_writei (IntPtr handle, byte[] buf, int size);
  96
  97                 [DllImport ("libasound.so.2")]
  98                 static extern int snd_pcm_set_params (IntPtr handle, int format, int access, int channels, int rate, int soft_resample, int latency);
  99
 100                 public AlsaDevice (string name) {
 101                         if (name == null)
 102                                 name = "default";
 103                         int err = snd_pcm_open (ref handle, name, 0, 0);
 104                         if (err < 0)
 105                                 throw new Exception ("no open " + err);
 106                 }
 107
 108                 ~AlsaDevice () {
 109                         Dispose (false);
 110                 }
 111
 112                 public void Dispose () {
 113                         Dispose (true);
 114                         GC.SuppressFinalize (this);
 115                 }
 116
 117                 protected virtual void Dispose (bool disposing) {
 118                         if (disposing) {
 119
 120                         }
 121                         if (handle != IntPtr.Zero)
 122                                 snd_pcm_close (handle);
 123                         handle = IntPtr.Zero;
 124                 }
 125
 126                 public override bool SetFormat (AudioFormat format, int channels, int rate) {
 127                         int err = snd_pcm_set_params (handle, (int)format, 3, channels, rate, 1, 500000);
 128                         return err == 0;
 129                 }
 130
 131                 public override int PlaySample (byte[] buffer, int num_frames) {
 132                         int frames = snd_pcm_writei (handle, buffer, num_frames);
 133                         return frames;
 134                 }
 135
 136                 public override void Wait () {
 137                         snd_pcm_drain (handle);
 138                 }
 139         }
 140
 141 }
 142 #endif
 143