BASS.NET API for the Un4seen BASS Audio LibraryBassMidiBASS_MIDI_StreamCreate Method BASS.NET API for the Un4seen BASS Audio Library
Creates a sample stream to render real-time MIDI events.

Namespace: Un4seen.Bass.AddOn.Midi
Assembly: Bass.Net (in Bass.Net.dll) Version: 2.4.12.0
Syntax

[DllImportAttribute("bassmidi.dll", CharSet = CharSet.Unicode)]
public static int BASS_MIDI_StreamCreate(
	int channels,
	BASSFlag flags,
	int freq
)

Parameters

channels
Type: SystemInt32
The number of MIDI channels: 1 (min) - 128 (max).
flags
Type: Un4seen.BassBASSFlag
Any combination of these flags (see BASSFlag):
BASS_SAMPLE_8BITSUse 8-bit resolution. If neither this or the BASS_SAMPLE_FLOAT flags are specified, then the sample data will be 16-bit.
BASS_SAMPLE_FLOATUse 32-bit floating-point sample data. WDM drivers or the BASS_STREAM_DECODE flag are required to use this flag in Windows. See Floating-point channels for more info.
BASS_SAMPLE_MONODecode/play the stream (MP3/MP2/MP1 only) in mono, reducing the CPU usage (if it was originally stereo). This flag is automatically applied if BASS_DEVICE_MONO was specified when calling BASS_Init(Int32, Int32, BASSInit, IntPtr).
BASS_SAMPLE_SOFTWAREForce the stream to not use hardware mixing.
BASS_SAMPLE_3DUse 3D functionality. This is ignored if BASS_DEVICE_3D wasn't specified when calling BASS_Init(Int32, Int32, BASSInit, IntPtr). 3D streams must be mono. The SPEAKER flags can not be used together with this flag.
BASS_SAMPLE_LOOPLoop the file. This flag can be toggled at any time using BASS_ChannelFlags(Int32, BASSFlag, BASSFlag). This flag is ignored when streaming in blocks (BASS_STREAM_BLOCK).
BASS_SAMPLE_FXRequires DirectX 8 or above: Enable the old implementation of DirectX 8 effects. See the DX8 effect implementations section for details. Use BASS_ChannelSetFX(Int32, BASSFXType, Int32) to add effects to the stream.
BASS_STREAM_AUTOFREEAutomatically free the stream when it ends. This allows you to stream a file and forget about it, as BASS will automatically free the stream's resources when it has reached the end or when BASS_ChannelStop(Int32) (or BASS_Stop) is called.
BASS_STREAM_DECODEDecode the sample data, without outputting it. Use BASS_ChannelGetData(Int32, IntPtr, Int32) to retrieve decoded sample data. The BASS_SAMPLE_SOFTWARE, BASS_SAMPLE_3D, BASS_SAMPLE_FX, BASS_STREAM_AUTOFREE and SPEAKER flags can not be used together with this flag.
BASS_SPEAKER_xxxSpeaker assignment flags.
BASS_MIDI_NOFXDisable reverb and chorus processing, saving some CPU time. This flag can be toggled at any time using BASS_ChannelFlags(Int32, BASSFlag, BASSFlag).
BASS_MIDI_NOSYSRESETIgnore system reset events (MIDI_EVENT_SYSTEM) when the system mode is unchanged. This flag can be toggled at any time using BASS_ChannelFlags(Int32, BASSFlag, BASSFlag).
BASS_MIDI_NOTEOFF1Only 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(Int32, BASSFlag, BASSFlag).
BASS_MIDI_SINCINTERUse sinc interpolated sample mixing. This increases the sound quality, but also requires more CPU. Otherwise linear interpolation is used.
freq
Type: SystemInt32
Sample rate (in Hz) to render/play the MIDI at (0 = the rate specified in the BASS_Init(Int32, Int32, BASSInit, IntPtr) call; 1 = the device's current output rate or the BASS_Init rate if that is not available).

Return Value

Type: Int32
If successful, the new stream's handle is returned, else 0 is returned. Use BASS_ErrorGetCode to get the error code.
Remarks

This function creates a stream solely for real-time MIDI events. As it's not based on any file, the stream has no predetermined length and is never-ending. Seeking isn't possible, but it is possible to reset everything, including playback buffer, by calling BASS_ChannelPlay(Int32, Boolean) (restart = ) or BASS_ChannelSetPosition(Int32, Int64, BASSMode) (pos = 0).

MIDI events are applied using the BASS_MIDI_StreamEvent(Int32, Int32, BASSMIDIEvent, Int32) function. If the stream is being played (it's not a decoding channel), then there will be some delay in the effect of the events being heard. This latency can be reduced by making use of the BASS_CONFIG_BUFFER and BASS_CONFIG_UPDATEPERIOD options.

If a stream has 16 MIDI channels, then channel 10 defaults to percussion/drums and the rest melodic, otherwise they are all melodic. That can be changed using BASS_MIDI_StreamEvent(Int32, Int32, BASSMIDIEvent, Int32) and the MIDI_EVENT_DRUMS event.

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 overriden using BASS_MIDI_StreamSetFonts(Int32, BASS_MIDI_FONT, Int32).

To play a MIDI file, use BASS_MIDI_StreamCreateFile(String, Int64, Int64, BASSFlag, Int32).

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.

ERROR CODEDescription
BASS_ERROR_INITBASS_Init(Int32, Int32, BASSInit, IntPtr) has not been successfully called.
BASS_ERROR_NOTAVAILOnly 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_ILLPARAMchannels is not valid.
BASS_ERROR_FORMATThe 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_SPEAKERThe specified SPEAKER flags are invalid. The device/drivers do not support them, they are attempting to assign a stereo stream to a mono speaker or 3D functionality is enabled.
BASS_ERROR_MEMThere is insufficient memory.
BASS_ERROR_NO3DCould not initialize 3D support.
BASS_ERROR_UNKNOWNSome other mystery problem!

See Also

Reference