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Subject: Re: Rockbox software volume control

Re: Rockbox software volume control

From: Maurus Cuelenaere <mcuelenaere_at_gmail.com>
Date: Wed, 27 Jan 2010 01:40:01 +0100

Op 26-01-10 14:04, Jeff Goode schreef:
> On 1/26/2010 02:20, Mike Giacomelli wrote:
>> > AFAICS this can be resolved by decreasing the DSP buffer size, but I'm
>> > guessing that isn't a proper solution. Perhaps this can be solved
>> in an
>> > other way that I missed, any ideas?
>> >
>>
>> My guess would be that you want to make whatever code does the DMA
>> transfer to the DAC rescale by a constant, and have that constant
>> adjusted via the volume code.
>> <http://clk.atdmt.com/GBL/go/196390706/direct/01/>
>
> What he said.
>
> Jeff
>

Thanks for the replies.

I've implemented software volume scaling by doing it right before data
gets sent off to the DMA before, but this resulted in audible 'skips'
i.e. buffer underflow.

I guess I should retry that and see whether I can get it to work properly.

The problem probably wasn't that the CPU is too slow, I guess my code
was just rather inefficient :)

-- 
Maurus Cuelenaere
Received on 2010-01-27

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