Re: [PATCH 1/2] dsound: Revised 5.1 to stereo downmix

[Andrew Eikum]

Signed-off-by: Andrew Eikum

On Tue, Apr 23, 2019 at 08:04:22PM +0200, Nikola Pavlica wrote:
> Signed-off-by: Nikola Pavlica
>
> dlls/dsound/dsound_convert.c | 24 +++++++++++-------------
>  1 file changed, 11 insertions(+), 13 deletions(-)
>
> diff --git a/dlls/dsound/dsound_convert.c b/dlls/dsound/dsound_convert.c
> index 26dbb3220a..0da9823298 100644
> --- a/dlls/dsound/dsound_convert.c
> +++ b/dlls/dsound/dsound_convert.c
> @@ -216,39 +216,37 @@ void put_stereo2surround51(const IDirectSoundBufferImpl *dsb, DWORD pos, DWORD c
>
> void put_surround512stereo(const IDirectSoundBufferImpl *dsb, DWORD pos, DWORD channel, float value)
>  {
> - /* based on pulseaudio's downmix algorithm */
> - /* based on analyzing a recording of a dsound downmix */
> switch(channel){
> - case 4: /* back left */
> -
>    value *= 0.056f; /* (1/9) / (sum of left volumes) */
> -
>
> case 4: /* surround left */
> -
>    value *= 0.24f;
>    dsb->put_aux(dsb, pos, 0, value);
>    break;
>
> case 0: /* front left */
> -
>    value *= 0.503f; /* 1 / (sum of left volumes) */
> -
>    value *= 1.0f; 
>    dsb->put_aux(dsb, pos, 0, value);
>    break;
>
> - case 5: /* back right */
> -
>    value *= 0.056f; /* (1/9) / (sum of right volumes) */
> -
>
> case 5: /* surround right */
> -
>    value *= 0.24f;
>    dsb->put_aux(dsb, pos, 1, value);
>    break;
>
> case 1: /* front right */
> -
>    value *= 0.503f; /* 1 / (sum of right volumes) */
> -
>    value *= 1.0f;
>    dsb->put_aux(dsb, pos, 1, value);
>    break;
>
> - case 2: /* front centre */
> -
>    value *= 0.252f; /* 0.5 / (sum of left/right volumes) */
> - case 2: /* centre */
> -
>    value *= 0.7;
>    dsb->put_aux(dsb, pos, 0, value);
>    dsb->put_aux(dsb, pos, 1, value);
>    break;
>
> - case 3: /* LFE */
> -
>    value *= 0.189f; /* 0.375 / (sum of left/right volumes) */
> -
>    dsb->put_aux(dsb, pos, 0, value);
> -
>    dsb->put_aux(dsb, pos, 1, value);
> - case 3:
> -
>    /* LFE is totally ignored in dsound when downmixing to 2 channels */
>    break;
> }
> }
>
> 2.21.0