[Qemu-devel] Re: [PATCH] audio: split sample conversion and volumemixing

[malc]

On Tue, 11 Jan 2011, Michael Walle wrote:

> 
> Hi Wolfgang,
> 
> > The fixed point path for scaling in mixeng_volume() seems to be under by
> > a factor of two, IMHO. The right shift should be by 31, not 32. (Because
> > the volume, which I assume is a signed 32 bit integer, can be 0.5 at
> > most).
> I must admit i just copied the shift from the original define. But the volume 
> and the samples are signed 64bit values.
> 
> @malc: any comments on this?

I don't understand the problem, the result of multiplication is converted
from 32.32 fixed point to integer by shifting right by 32.. It escapes me
how 31 fits here.

> 
> > Does the code work with FLOAT_MIXENG undefined?
> At least for my input voice, it works with integer arithmetic. 
> 
> 

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