BASS MIDI

BASS_MIDI_StreamCreateEvents

Creates a sample stream from a sequence of MIDI events.

HSTREAM BASS_MIDI_StreamCreateEvents(
    BASS_MIDI_EVENT *events,
    DWORD ppqn,
    DWORD flags,
    DWORD freq
);

Parameters

events

Pointer to an array containing the event sequence to play.

ppqn

The Pulses Per Quarter Note, or ticks per beat.

flags

A combination of these flags.

BASS_SAMPLE_8BITS	Use 8-bit resolution. If neither this or the BASS_SAMPLE_FLOAT flags are specified, then the sample data will be 16-bit.
BASS_SAMPLE_FLOAT	Use 32-bit floating-point sample data. See Floating-point channels for more info.
BASS_SAMPLE_MONO	Decode/play the MIDI in mono (uses less CPU than stereo). This flag is automatically applied if BASS_DEVICE_MONO was specified when calling BASS_Init.
BASS_SAMPLE_SOFTWARE	Force the stream to not use hardware mixing.
BASS_SAMPLE_3D	Enable 3D functionality. This requires that the BASS_DEVICE_3D flag was specified when calling BASS_Init. 3D channels must also be mono, so BASS_SAMPLE_MONO is automatically applied. The SPEAKER flags cannot be used together with this flag.
BASS_SAMPLE_LOOP	Loop the events. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_SAMPLE_FX	Enable the old implementation of DirectX 8 effects. See the DX8 effect implementations section for details. Use BASS_ChannelSetFX to add effects to the stream.
BASS_STREAM_AUTOFREE	Automatically free the stream when playback ends.
BASS_STREAM_DECODE	Decode/render the sample data, without playing it. Use BASS_ChannelGetData to retrieve decoded sample data. The BASS_SAMPLE_3D, BASS_STREAM_AUTOFREE and SPEAKER flags cannot be used together with this flag. The BASS_SAMPLE_SOFTWARE and BASS_SAMPLE_FX flags are also ignored.
BASS_SPEAKER_xxx	Speaker assignment flags. The BASS_SAMPLE_MONO flag is automatically applied when using a mono speaker assignment flag.
BASS_MIDI_DECAYEND	Let the sound decay naturally (including reverb) instead of stopping abruptly at the end of the events, including when looping. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_MIDI_DECAYSEEK	Let the old sound decay naturally (including reverb) when changing the position, including looping. This flag can be toggled at any time using BASS_ChannelFlags, but it should generally only be used in BASS_ChannelSetPosition calls to have it applied to particular position changes, eg. custom loops.
BASS_MIDI_NOFX	Disable reverb and chorus processing, saving some CPU time. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_MIDI_NOSYSRESET	Ignore system reset events (MIDI_EVENT_SYSTEM) when the system mode is unchanged. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_MIDI_NOTEOFF1	Only release the oldest instance upon a note off event (MIDI_EVENT_NOTE with velocity=0) when there are overlapping instances of the note. Otherwise all instances are released. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_MIDI_SINCINTER	Use sinc interpolated sample mixing. This increases the sound quality, but also requires more CPU. Otherwise linear interpolation is used. The sinc interpolation uses 8 points by default, but 16 point sinc interpolation is also available via the BASS_ATTRIB_MIDI_SRC attribute.

freq

Sample rate to render/play the MIDI stream at... 0 = the rate specified in the BASS_Init call, 1 = the device's current output rate (or the BASS_Init rate if that is not available).

Return value

If successful, the new stream's handle is returned, else 0 is returned. Use BASS_ErrorGetCode to get the error code.

Error codes

BASS_ERROR_INIT	BASS_Init has not been successfully called.
BASS_ERROR_NOTAVAIL	Only decoding channels (BASS_STREAM_DECODE) are allowed when using the "no sound" device. The BASS_STREAM_AUTOFREE flag is also unavailable to decoding channels.
BASS_ERROR_ILLPARAM	ppqn cannot be 0.
BASS_ERROR_ILLTYPE	The event sequence contains invalid event type(s).
BASS_ERROR_POSITION	The events must be in chronological order (within each track).
BASS_ERROR_FORMAT	The sample format is not supported by the device/drivers. If the stream is more than stereo or the BASS_SAMPLE_FLOAT flag is used, it could be that they are not supported.
BASS_ERROR_SPEAKER	The specified SPEAKER flags are invalid. The device/drivers do not support them or 3D functionality is enabled.
BASS_ERROR_MEM	There is insufficient memory.
BASS_ERROR_NO3D	Could not initialize 3D support.
BASS_ERROR_UNKNOWN	Some other mystery problem!

Remarks

This function creates a 16 channel MIDI stream to play a predefined sequence of MIDI events. Any of the standard MIDI events listed in the BASS_MIDI_StreamEvent section can be used, but the MIDI_EVENT_SYSTEMEX and the "non-MIDI" events (eg. MIDI_EVENT_MIXLEVEL) events are not available and will be rejected. The sequence should end with a MIDI_EVENT_END event. Multiple tracks are possible via the MIDI_EVENT_END_TRACK event, which signals the end of a track; the next event will be in a new track.

The event sequence is copied, so the events array does not need to persist beyond the function call.

Soundfonts provide the sounds that are used to render a MIDI stream. A default soundfont configuration is applied initially to the new MIDI stream, which can subsequently be overridden using BASS_MIDI_StreamSetFonts.

Platform-specific

Away from Windows, all mixing is done in software (by BASS), so the BASS_SAMPLE_SOFTWARE flag is unnecessary. The BASS_SAMPLE_FX flag is also ignored. On Android and iOS, sinc interpolation requires a NEON-supporting CPU; the BASS_MIDI_SINCINTER flag will otherwise be ignored. Sinc interpolation is not available on Windows CE.

Example

Play a middle C note (key 60) on a violin every 2 seconds.

BASS_MIDI_EVENT events[]={
    {MIDI_EVENT_TEMPO, 500000, 0, 0}, // set the tempo to 0.5 seconds per quarter note
    {MIDI_EVENT_PROGRAM, 40, 0, 0}, // select the violin preset
    {MIDI_EVENT_NOTE, MAKEWORD(60, 100), 0, 0}, // press the key
    {MIDI_EVENT_NOTE, 60, 0, 200}, // release the key after 200 ticks
    {MIDI_EVENT_END, 0, 0, 400} // end after 400 ticks
};
HSTREAM stream=BASS_MIDI_StreamCreateEvents(events, 100, BASS_SAMPLE_LOOP, 0); // create a looping stream from the events
BASS_ChannelPlay(stream, 0); // start playing it