26 Oct
2009
26 Oct
'09
7:38 a.m.
Well if the audio was clipped, there would probably be some audible
distortion.
Perhaps if a code fragment was posted we could give a more informed
opinion.
Victor
On 26 Oct 2009, at 09:08, Jörn Nettingsmeier wrote:
On 10/26/2009 07:33 AM, Drip Stone wrote:
Hi everybody,
I have a question regarding amplifying a PCM frame. For each frame, I
get a float number, and multiply this number by 2, and then output
frames to alsa one by one using function snd_pcm_writei. But the wav
file sounds the same to me, nothing gets amplified. Could anyone
explain
this to me? I appreciate your help!
you should hear an amplification by roughly 6dB... what might happen
is
this: your file already has a peak at 1.0f. after your operation, it
will peak at 2.0f, which your DAC can't handle. so the file will
have to
be clamped between -1.0f and 1.0f, effectively undoing your gain
operation. just a guess.
or you might be expecting the wrong thing... times two doesn't feel
"twice as loud". then again, +6dB is quite audible in any case.
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