Hi,
>
> I'm working on an embedded ARM board running Linux 2.4.18. The
> processor is a Hynix 7201 based on ARM720T core, running at 60MHz (25
> BogoMIPS), with a Piccolo DSP.
>
> I want to change the audio volume by software, however the board
> doesnt have any hardware mixer for audio. So changing the volume via
> OSS etc. is not possible.
>
> Since I require only to playback WAV PCM files, i figure that instead
> of using a hardware mixer, i can amplify the signals inside the file
> as required, to get the required volume.
The easiest is probably to shift a number of bits left. It might not give exact amplification but should be OK.
> Can someone please point me to libraries that allow amplifications of
> signals stored in a PCM file? Please remember it has to be cross
> platform to run on the ARM, and fast since the processor isnt quite
> the heavy-duty kind.
Read file, shift, output.
For other applications/libraries see:
formatting link
/RogerL