_MEMSOUND
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The _MEMSOUND function returns a _MEM value referring to a sound's raw data in memory using a designated sound handle created by the _SNDOPEN function.
Syntax
- soundBlock = _MEMSOUND[(soundHandle&, channel%)]
Parameters
- The soundBlock _MEM type variable holds the read-only elements .OFFSET, .SIZE, .ELEMENTSIZE, and .SOUND.
- .ELEMENTSIZE will contain the number of bytes-per-sample the audio contains. Usually returns 2 (16-bit audio).
- .SOUND will contain the same handle value as returned by the _SNDOPEN function.
- The second parameter channel% must be 1 (left channel/mono) or 2 (right channel, for stereo files).
Description
- Use the function to access raw sound data in memory for direct access.
- Sound handle values and the memory used must still be freed using _SNDCLOSE when no longer required.
- If .SIZE returns 0, that means the data could not be accessed. It may happen if you try to access the right channel in a mono file, for example.
Availability
- QB64 1.5 and up (QB64 Team)
- QBPE 0.5 and up (QB64 Phoenix Edition)
Examples
Example 1: Checking that a sound file is stereo.
song& = _SNDOPEN("song.wav") 'replace song.wav with a sound file you have IF song& = 0 THEN PRINT "Load failed.": END DIM leftchannel AS _MEM, rightchannel AS _MEM leftchannel = _MEMSOUND(song&, 1) rightchannel = _MEMSOUND(song&, 2) IF rightchannel.SIZE > 0 THEN PRINT "This file is STEREO" IF rightchannel.SIZE = 0 AND leftchannel.SIZE > 0 THEN PRINT "This file is MONO" ELSEIF rightchannel.SIZE = 0 AND leftchannel.SIZE = 0 THEN PRINT "An error occurred." END IF _SNDCLOSE song& 'closing the sound releases the mem blocks |
Example 2: Plotting a sound's waves.
SCREEN _NEWIMAGE(800, 327, 32) song& = _SNDOPEN("drums.ogg") 'replace drums.ogg with a sound file you have IF song& = 0 THEN PRINT "Load failed.": END DIM leftchannel AS _MEM leftchannel = _MEMSOUND(song&, 1) IF leftchannel.SIZE = 0 THEN PRINT "An error occurred." END END IF DIM i AS _OFFSET i = 0 DO _MEMGET leftchannel, leftchannel.OFFSET + i, a% 'get sound data LOCATE 1, 1: PRINT i; "/"; leftchannel.SIZE LINE (x, _HEIGHT / 2)-STEP(0, a% / 100), _RGB32(0, 111, 0) 'plot wave x = x + 1 IF x > _WIDTH THEN x = 0 LINE (0, 0)-(_WIDTH, _HEIGHT), _RGB32(0, 120), BF 'fade out screen END IF i = i + 2 IF i + 2 > leftchannel.SIZE THEN EXIT DO _LIMIT 500 LOOP _SNDCLOSE song& 'closing the sound releases the mem blocks |