Q I'm having problems with the QuickTime SetSoundMediaBalance (MediaSetSoundBalance) function. The documentation says the balance parameter may range from -1.0 to 1.0, but no matter what value I pass I'm not hearing much of a difference in either the left or right channel output. What's going on?
A The documentation is incorrect. The balance parameter value may range from -128 to 128. Negative values emphasize the left sound channel, while positive values emphasize the right sound channel. A value of -128 forces all output through the left channel. Similarly, a value of 128 forces all output through the right channel.
Passing a positive balance value causes the left channel to get quieter.
Passing a negative balance value causes the right channel to get quieter.
The amount it gets quieter can be seen in the following examples:
A balance value of 32 would lower the left volume by one quarter of its
current value (since 32 is a quarter of 128, the full volume setting). A
balance value of -96 would lower the right volume by 3/4 of its current
value (since 96 is 3/4 of 128).
|