BASS_ChannelSlideAttribute

Slides a channel's attribute from its current value to a new value.

BOOL BASS_ChannelSlideAttribute(
    DWORD handle,
    DWORD attrib,
    float value,
    DWORD time
);

Parameters

handle

The channel handle... a HCHANNEL, HSTREAM, HMUSIC, or HRECORD.

attrib

The attribute to slide the value of. One of the following, with optional flags.

BASS_ATTRIB_FREQ	Sample rate.
BASS_ATTRIB_MUSIC_AMPLIFY	Amplification level. (HMUSIC only)
BASS_ATTRIB_MUSIC_BPM	BPM. (HMUSIC)
BASS_ATTRIB_MUSIC_PANSEP	Pan separation level. (HMUSIC)
BASS_ATTRIB_MUSIC_PSCALER	Position scaler. (HMUSIC)
BASS_ATTRIB_MUSIC_SPEED	Speed. (HMUSIC)
BASS_ATTRIB_MUSIC_VOL_CHAN	A channel volume level. (HMUSIC)
BASS_ATTRIB_MUSIC_VOL_GLOBAL	Global volume level. (HMUSIC)
BASS_ATTRIB_MUSIC_VOL_INST	An instrument/sample volume level. (HMUSIC)
BASS_ATTRIB_PAN	Panning/balance position.
BASS_ATTRIB_VOL	Volume level.
BASS_SLIDE_LOG	Flag: Slide the attribute's value logarithmically rather than linearly. This cannot be used when going from positive to negative or vice versa. An exception is when using a negative value with BASS_ATTRIB_VOL to fade-out and stop.

other attributes may be supported by add-ons, see the documentation.

value

The new attribute value. See the attribute's documentation for details on the possible values.

time

The length of time (in milliseconds) that it should take for the attribute to reach the value.

Return value

If successful, then TRUE is returned, else FALSE is returned. Use BASS_ErrorGetCode to get the error code.

Error codes

BASS_ERROR_HANDLE	handle is not a valid channel.
BASS_ERROR_ILLTYPE	attrib is not valid.
BASS_ERROR_ILLPARAM	The attribute's value cannot go from positive to negative or vice versa when the BASS_SLIDE_LOG flag is used.

some attributes may have additional error codes, see the documentation.

Remarks

This function is similar to BASS_ChannelSetAttribute, except that the attribute is ramped to the value over the specified period of time. Another difference is that the value is not pre-checked. If it is invalid, the slide will simply end early.

If an attribute is already sliding, then the old slide is stopped and replaced by the new one.

BASS_ChannelIsSliding can be used to check if an attribute is currently sliding. A BASS_SYNC_SLIDE sync can also be set via BASS_ChannelSetSync, to be triggered at the end of a slide. The sync will not be triggered in the case of an existing slide being replaced by a new one.

Attribute slides are unaffected by whether the channel is playing, paused or stopped; they carry on regardless.

Example

Fadeout a channel's volume over a period of 1 second.

BASS_ChannelSlideAttribute(channel, BASS_ATTRIB_VOL, 0, 1000);

Fadeout a channel's volume logarithmically over a period of 2 seconds.