BASSmix

BASS_Mixer_ChannelGetData

Retrieves the immediate sample data (or an FFT representation of it) of a mixer source channel.

DWORD BASS_Mixer_ChannelGetData(
    DWORD handle,
    void *buffer,
    DWORD length
);

Parameters

handle	The channel handle.
buffer	Pointer to a buffer to receive the data.
length	Number of bytes wanted, and/or the BASS_ChannelGetData flags.

Return value

If an error occurs, -1 is returned, use BASS_ErrorGetCode to get the error code. When requesting FFT data, the number of bytes read from the channel (to perform the FFT) is returned. When requesting sample data, the number of bytes written to buffer will be returned (not necessarily the same as the number of bytes read when using the BASS_DATA_FLOAT flag). When using the BASS_DATA_AVAILABLE flag, the number of bytes in the channel's buffer is returned.

Error codes

BASS_ERROR_HANDLE	handle is not plugged into a mixer.
BASS_ERROR_NOTAVAIL	The channel does not have buffering (BASS_MIXER_BUFFER) enabled.

Remarks

This function is like the standard BASS_ChannelGetData, but it gets the data from the channel's buffer instead of decoding it from the channel, which means that the mixer does not miss out on any data. In order to do this, the source channel must have buffering enabled, via the BASS_MIXER_BUFFER flag.

If the mixer is being played by BASS, the returned data will be in sync with what is currently being heard from the mixer. If another output system is being used, the BASS_ATTRIB_MIXER_LATENCY option can be used to tell the mixer what the latency is so that it can be taken account of, otherwise the channel's most recent data will be returned. The BASS_CONFIG_MIXER_BUFFER config option determines how far back data will be available from, so it should be set high enough to cover any latency.