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

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