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# 6.1 Constants

This section describes all constants used in MIDAS initialization and configuration. They are grouped according to the `enum` used to define them.

## 2.1.1 MIDASdsoundModes

    enum MIDASdsoundModes

### Description

These constants are used to describe different MIDAS DirectSound usage modes. By default MIDAS does not use DirectSound at all, and DirectSound usage can be enabled by setting MIDAS_OPTION_DSOUND_MODE. Note that MIDAS_OPTION_DSOUND_HWND needs to be set when using DirectSound. A complete discussion of using DirectSound with MIDAS is available at MIDAS Programmer's Guide.

### Values

MIDAS_DSOUND_DISABLED
  DirectSound usage is disabled
MIDAS_DSOUND_STREAM
  DirectSound is used in stream mode - MIDAS will play to a DirectSound stream buffer. DirectSound usage is disabled if DirectSound runs in emulation mode.
MIDAS_DSOUND_PRIMARY
  DirectSound is used in primary buffer mode if possible - MIDAS will play directly to DirectSound primary buffer. If primary buffer is not available for writing, this mode behaves like MIDAS_DSOUND_STREAM.
MIDAS_DSOUND_FORCE_STREAM
  Behaves like MIDAS_DSOUND_STREAM, except that DirectSound is used always, even in emulation mode.

## 2.1.2 MIDASfilterModes

    enum MIDASfilterModes

### Description

These constants are used to describe different MIDAS output filter modes. By default, no output filter is enabled, but most programs can benefit from using a slight output filter (MIDAS_FILTER_LESS), unless all sounds are played exactly at the mixing frequency or an integer part of it. Programs using low mixing rates, 22kHz or below, might sound better with more filtering -- it is usually a good idea to check the sound quality with different filters, and use the one that sounds best.

The filter mode can be set by changing the option MIDAS_OPTION_FILTER_MODE with the function MIDASsetOption.

### Values

MIDAS_FILTER_NONE
  No filtering
MIDAS_FILTER_LESS
  Some filtering
MIDAS_FILTER_MORE
  More filtering

## 2.1.3 MIDASmodes

    enum MIDASmodes

### Description

These constants are used to describe different MIDAS output modes. They are used with the function MIDASsetOption, when changing the setting MIDAS_OPTION_OUTPUTMODE.

### Values

MIDAS_MODE_8BIT_MONO
  8-bit mono output
MIDAS_MODE_16BIT_MONO
  16-bit mono output
MIDAS_MODE_8BIT_STEREO
  8-bit stereo output
MIDAS_MODE_16BIT_STEREO
  16-bit stereo output

## 2.1.4 MIDASoptions

    enum MIDASoptions

### Description

These constants are used with the function MIDASsetOption to change different MIDAS configuration options.

### Values

MIDAS_OPTION_MIXRATE
  Output mixing rate
MIDAS_OPTION_OUTPUTMODE
  Output mode, see `enum` MIDASmodes
MIDAS_OPTION_MIXBUFLEN
  Mixing buffer length, in milliseconds
MIDAS_OPTION_MIXBUFBLOCKS
  The number of blocks the buffer should be divided into
MIDAS_OPTION_DSOUND_MODE
  DirectSound mode to use, see `enum` MIDASdsoundModes
MIDAS_OPTION_DSOUND_HWND
  Window handle for DirectSound support. The window handle is used by DirectSound to determine which window has the focus. The window handle has to be set when using DirectSound.
MIDAS_OPTION_DSOUND_OBJECT
  The DirectSound object that should be used. Setting this option forces DirectSound support on.
MIDAS_OPTION_DSOUND_BUFLEN
  Output buffer length fot DirectSound, in milliseconds. This option is used instead of MIDAS_OPTION_MIXBUFLEN when using DirectSound without emulation.
MIDAS_OPTION_FILTER_MODE
  Output filter mode, see `enum` MIDASfilterModes.

Next: 6.2 Data types Up: 2 Configurationinitialization and Previous: 2 Configurationinitialization and