Class BassFx

BassFx is a BASS addon providing several DSP functions, including tempo and pitch control.

Inheritance
Object
BassFx
Namespace: System.Dynamic.ExpandoObject
Assembly: ManagedBass.Fx.dll
Syntax
public static class BassFx : object

Properties

Version

Gets the Version of BassFx that is loaded.

Declaration
public static Version Version { get; }
Property Value
Version

Methods

BPMBeatCallbackReset(Int32)

Reset the BPM buffers.

Declaration
public static bool BPMBeatCallbackReset(int Handle)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

This function flushes the internal buffers of the BPM callback. The BPM callback is automatically reset by ChannelSetPosition(Int32, Int64, PositionFlags), except when called from a Mixtime SyncProcedure.

BPMBeatCallbackSet(Int32, BPMBeatProcedure, IntPtr)

Enable getting Beat position in seconds in real-time.

Declaration
public static bool BPMBeatCallbackSet(int Handle, BPMBeatProcedure Procedure, IntPtr User = null)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
BPMBeatProcedure Procedure

User defined function to receive the beat position values.
IntPtr User

User instance data to pass to the callback function.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

This method works on real-time (buffered) as well as on decoding channels and might also be used together with Tempo channels.

BPMBeatFree(Int32) must be called at the end to free the real-time beat position callback and resources.

Note: You should call BPMBeatCallbackReset(Int32) after you have changed the position of the stream when called from a Mixtime SyncProcedure.

BPMBeatDecodeGet(Int32, Double, Double, BassFlags, BPMBeatProcedure, IntPtr)

Enable getting Beat position in seconds of the decoded channel using a callback function.

Declaration
public static bool BPMBeatDecodeGet(int Channel, double StartSec, double EndSec, BassFlags Flags, BPMBeatProcedure Procedure, IntPtr User = null)
Parameters
Int32 Channel

Stream/music/wma/cd/any other supported add-on format using a decoding channel.
Double StartSec

Start detecting position in seconds.
Double EndSec

End detecting position in seconds (greater than 0).
BassFlags Flags

Use one of FxBpmBackground and FxFreeSource.
BPMBeatProcedure Procedure

User defined function to receive the beat position values.
IntPtr User

User instance data to pass to the callback function.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

This method works pretty much as a mix of BPMBeatCallbackSet(Int32, BPMBeatProcedure, IntPtr) and BPMDecodeGet(Int32, Double, Double, Int32, BassFlags, BPMProgressProcedure, IntPtr).

BPMBeatFree(Int32)

Free all resources used by a given handle (decode or callback beat).

Declaration
public static bool BPMBeatFree(int Handle)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

Used together with BPMBeatDecodeGet(Int32, Double, Double, BassFlags, BPMBeatProcedure, IntPtr) or BPMBeatCallbackSet(Int32, BPMBeatProcedure, IntPtr).

Note: If the FxFreeSource flag is used, this will free the source decoding channel as well. You can't set/get this flag with ChannelFlags(Int32, BassFlags, BassFlags) and .

BPMBeatGetParameters(Int32, out Single, out Single, out Single)

Gets the current beat detection parameter values.

Declaration
public static bool BPMBeatGetParameters(int Handle, out float Bandwidth, out float CenterFreq, out float Beat_rTime)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Single Bandwidth

Current bandwidth in Hz.
Single CenterFreq

Current center-frequency in Hz of the band pass filter.
Single Beat_rTime

Current beat release time in ms.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

Beat detection is using a Band Pass Filter. A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. So the Bandwidth parameter defines the range around a center-frequency to include in the beat detection algo. The CenterFreq parameter actually defines the center-frequency of the band pass filter. Once a beat is detected, the Beat_rTime parameter defines the time in ms. in which no other beat will be detected after that just detected beat. The background is, that often you have kind-of 'double beats' in a drum set. So the Beat_rTime should avoid, that a second (quickly repeated beat) beat is detected.

BPMBeatSetParameters(Int32, Single, Single, Single)

Set new values for beat detection parameters.

Declaration
public static bool BPMBeatSetParameters(int Handle, float Bandwidth, float CenterFreq, float Beat_rTime)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Single Bandwidth

Bandwidth in Hz between 0 and samplerate/2 (-1.0f = leave current, default is 10Hz).
Single CenterFreq

The center-frequency in Hz of the band pass filter between 0 and samplerate/2 (-1.0f = leave current, default is 90Hz).
Single Beat_rTime

Beat release time in ms. (-1.0f = leave current, default is 20ms).
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

Beat detection is using a Band Pass Filter. A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. So the Bandwidth parameter defines the range around a center-frequency to include in the beat detection algo. The CenterFreq parameter actually defines the center-frequency of the band pass filter. Once a beat is detected, the Beat_rTime parameter defines the time in ms. in which no other beat will be detected after that just detected beat. The background is, that often you have kind-of 'double beats' in a drum set. So the Beat_rTime should avoid, that a second (quickly repeated beat) beat is detected.

BPMCallbackReset(Int32)

Reset the BPM buffers.

Declaration
public static bool BPMCallbackReset(int Handle)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

This function flushes the internal buffers of the BPM callback. The BPM callback is automatically reset by ChannelSetPosition(Int32, Int64, PositionFlags), except when called from a Mixtime SyncProcedure.

BPMCallbackSet(Int32, BPMProcedure, Double, Int32, BassFlags, IntPtr)

Enable getting BPM value by period of time in seconds.

Declaration
public static bool BPMCallbackSet(int Handle, BPMProcedure Procedure, double Period, int MinMaxBPM, BassFlags Flags, IntPtr User = null)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
BPMProcedure Procedure

User defined function to receive the bpm value.
Double Period

Detection period in seconds.
Int32 MinMaxBPM

Set min and max bpm, LowWord=Min, HighWord=Max. 0 = defaults to 45/230.
BassFlags Flags

Use FXBpmMult2 or Default.
IntPtr User

User instance data to pass to the callback function.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

Un4seen.Bass.BASSErrorDescription
BASS_ERROR_HANDLE
BASS_ERROR_ILLPARAM
BASS_ERROR_ALREADY

BPMDecodeGet(Int32, Double, Double, Int32, BassFlags, BPMProgressProcedure, IntPtr)

Get the original BPM of a decoding channel.

Declaration
public static float BPMDecodeGet(int Channel, double StartSec, double EndSec, int MinMaxBPM, BassFlags Flags, BPMProgressProcedure Procedure, IntPtr User = null)
Parameters
Int32 Channel

Stream/music/wma/cd/any other supported add-on format using a decoding channel.
Double StartSec

Start detecting position in seconds (if less than 0 it uses the current position).
Double EndSec

End detecting position in seconds (greater than 0).
Int32 MinMaxBPM

Set min and max bpm, LowWord=Min, HighWord=Max. 0 = defaults to 45/230.
BassFlags Flags

One of FxBpmBackground, FXBpmMult2 and FxFreeSource.
BPMProgressProcedure Procedure

User defined function to receive the process in percents, use null if not in use.
IntPtr User

User instance data to pass to the callback function.
Returns
Single

If successful, the original BPM value is returned, else -1 is returned. Use LastError to get the error code.
Remarks

The BPM detection algorithm works by detecting repeating low-frequency (less than 250Hz) sound patterns and thus works mostly with most rock/pop music with bass or drum beat. The BPM detection doesn't work on pieces such as classical music without distinct, repeating bass frequency patterns. Also pieces with varying tempo, varying bass patterns or very complex bass patterns (jazz, hiphop) may produce odd BPM readings.

In cases when the bass pattern drifts a bit around a nominal beat rate (e.g. drummer is again drunken ;-), the BPM algorithm may report incorrect harmonic one-halft to one-thirdth of the correct BPM value. In such case the system could for example report BPM value of 50 or 100 instead of correct BPM value of 150.

BPMFree(Int32)

Frees all resources used by a given handle.

Declaration
public static bool BPMFree(int Handle)
Parameters
Int32 Handle

Stream/music/wma/cd/any other supported add-on format.
Returns
Boolean

If successful, true is returned, else false is returned. Use LastError to get the error code.
Remarks

Used together with BPMDecodeGet(Int32, Double, Double, Int32, BassFlags, BPMProgressProcedure, IntPtr) or BPMCallbackSet(Int32, BPMProcedure, Double, Int32, BassFlags, IntPtr). If FxFreeSource was used, this will also free the underlying decoding channel as well. You can't set/get this flag with ChannelFlags(Int32, BassFlags, BassFlags)/.

ReverseCreate(Int32, Single, BassFlags)

Creates a reversed stream from a decoding channel.

Example Create a Reverse stream.

// create decoded stream
var chan = Bass.CreateStream(FileName, Flags: BassFlags.Decode);

// create reverse stream, 2 secs decoding block
if (chan != 0)
    chan = BassFx.TempoCreate(chan, 2, BassFlags.FxFreeSource);
Declaration
public static int ReverseCreate(int Channel, float DecodingBlockLength, BassFlags Flags)
Parameters
Int32 Channel

Stream/music/wma/cd/any other supported add-on format using a decoding channel.
Single DecodingBlockLength

Length of decoding blocks in seconds. Larger blocks means less seeking overhead but larger spikes.
BassFlags Flags

A combination of these flags:

BassFlags Description
Loop Looped? Note that only complete sample loops are allowed by DirectSound (ie. you can't loop just part of a sample)
SoftwareMixing Force the sample to not use hardware mixing
Bass3D Use 3D functionality. This is ignored if Device3D wasn't specified when calling <xref:ManagedBass.Bass.Init(System.Int32,System.Int32,ManagedBass.DeviceInitFlags,System.IntPtr,System.IntPtr)>. 3D samples must be mono (use Mono)
FX Enable the old implementation of DirectX 8 effects. Use ChannelSetFX(Int32, EffectType, Int32) to add effects to the stream
AutoFree Automatically free the stream's resources when it has reached the end, or when ChannelStop(Int32) (or Stop()) is called
Decode Decode the sample data, without outputting it. Use <xref:ManagedBass.Bass.ChannelGetData(System.Int32,System.IntPtr,System.Int32)> to retrieve decoded sample data. SoftwareMixing/Bass3D/FX/AutoFree are all ignored when using this flag, as are the Speaker Assignment Flags.
SPEAKER Speaker Assignment Flags.
FxFreeSource Free the source handle as well.

Returns
Int32

If successful, the handle of the reversed stream is returned, else 0 is returned. Use LastError to get the error code.
Remarks

MODs are supported, if Prescan flag was applied to a source handle.

For better MP3/2/1 reverse playback create the source stream using the Prescan flag.

Thes ReverseDirection attribute can either be applied to the reverse channel or the underlying decoding source channel. Note, that when playing the channel reverse, the end of a reverse stream is reached at the logial beginning of the stream (this also applies to End). By default stream's position will start from the end.

ReverseGetSource(Int32)

Get the source channel handle of the reversed stream.

Declaration
public static int ReverseGetSource(int Channel)
Parameters
Int32 Channel

The handle of the reversed stream.
Returns
Int32

If successful, the handle of the source of the reversed stream is returned, else 0 is returned. Use LastError to get the error code.

TempoCreate(Int32, BassFlags)

Creates a resampling stream from a decoding channel.

Example Create a Tempo stream.

// create decoded stream
var chan = Bass.CreateStream(FileName, Flags: BassFlags.Decode);

// create a tempo stream
if (chan != 0)
    chan = BassFx.TempoCreate(chan, BassFlags.FxFreeSource);
Declaration
public static int TempoCreate(int Channel, BassFlags Flags)
Parameters
Int32 Channel

Stream/music/wma/cd/any other supported add-on format using a decoding channel (use Decode when creating the channel).
BassFlags Flags

A combination of these flags:

BassFlags Description
Loop Looped? Note that only complete sample loops are allowed by DirectSound (ie. you can't loop just part of a sample)
SoftwareMixing Force the sample to not use hardware mixing
Bass3D Use 3D functionality. This is ignored if Device3D wasn't specified when calling <xref:ManagedBass.Bass.Init(System.Int32,System.Int32,ManagedBass.DeviceInitFlags,System.IntPtr,System.IntPtr)>. 3D samples must be mono (use Mono)
FX Enable the old implementation of DirectX 8 effects. Use ChannelSetFX(Int32, EffectType, Int32) to add effects to the stream
AutoFree Automatically free the stream's resources when it has reached the end, or when ChannelStop(Int32) (or Stop()) is called
Decode Decode the sample data, without outputting it. Use <xref:ManagedBass.Bass.ChannelGetData(System.Int32,System.IntPtr,System.Int32)> to retrieve decoded sample data. SoftwareMixing/Bass3D/FX/AutoFree are all ignored when using this flag, as are the Speaker Assignment Flags.
SPEAKER Speaker Assignment Flags.
FxFreeSource Free the source handle as well.

Returns
Int32

If successful, the tempo stream handle is returned, else 0 is returned. Use LastError to get the error code.
Remarks

Multi-channels are supported.

TempoGetRateRatio(Int32)

Get the ratio of the resulting rate and source rate (the resampling ratio).

Declaration
public static float TempoGetRateRatio(int Channel)
Parameters
Int32 Channel

Tempo stream (or source channel) handle.
Returns
Single

If successful, the resampling ratio is returned, else 0 is returned. Use LastError to get the error code.

TempoGetSource(Int32)

Get the source channel handle of the reversed stream.

Declaration
public static int TempoGetSource(int Channel)
Parameters
Int32 Channel

The handle of the reversed stream.
Returns
Int32

If successful, the handle of the source of the reversed stream is returned, else 0 is returned. Use LastError to get the error code.