QM_StartFreqMeteringSession

QM_StartFreqMeteringSession(sessionRef; movieRef; whatMix; numBands):error
	sessionRef	Longint	Frequency metering session reference
	movieRef	Longint	Movie reference
	whatMix	String4	Audio mix identifier
	numBands	Longint	Numder of bands
	error	Longint	Error result

Starts a frequency metering session for a movie.

Parameter sessionRef receives a reference number that identifies the frequency metering session. Use this reference number to retrieve band frequencies with QM_GetFreqMeteringBands, frequency levels with QM_GetFrequencyLevels, and to end the frequency metering session with QM_EndFreqMeteringSession when you are done.

Parameter movieRef specifies the movie from which you want to receive volume levels.

Parameter whatMix specifies the audio 'mix' to be used in the volume metering session. Use one of the following constants:

qm_AudioStereoMix	stmx	Stereo mix
qm_AudioMonoMix	momx	Mono mix
qm_AudioDeviceMix	dcly	Current audio device mix

Parameter numBands specifies the number of bands to be metered. QuickTime may adjust this number if it is higher than what is possible.

Related commands

QM_GetFreqMeteringBands	Returns the band frequences of the frequency metering session.
QM_GetFrequencyLevels	Retrieves the current frequency levels.
QM_EndFreqMeteringSession	Ends a frequency metering session.