Retrieves the level of a mixer source channel.
DWORD BASS_Mixer_ChannelGetLevelEx( DWORD handle, float *levels, float length, DWORD flags );
|levels||An array to receive the levels.|
|length||The amount of data to inspect to calculate the level, in seconds. The maximum is 1 second. Less data than requested may be used if the full amount is not available, eg. if the source's buffer (determined by the BASS_CONFIG_MIXER_BUFFER config option) is shorter.|
|flags||A combination of these flags.|
|BASS_ERROR_HANDLE||handle is not plugged into a mixer.|
|BASS_ERROR_NOTAVAIL||The channel does not have buffering (BASS_MIXER_BUFFER) enabled.|
|BASS_ERROR_NOPLAY||The mixer is not playing.|
This function measures the level of the channel's sample data, not its level in the mixer output. It includes the effect of any DSP/FX set on the channel, but not the effect of the channel's BASS_ATTRIB_VOL or BASS_ATTRIB_PAN attributes or matrix mixing or any envelope set via BASS_Mixer_ChannelSetEnvelope.
If the mixer is being played by BASS, the returned level 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 used to get the level. The BASS_CONFIG_MIXER_BUFFER config option determines how far back the level will be available from, so it should be set high enough to cover any latency.