[PATCH] winealsa: fix input sound distortion and heap corruption

[Andrew Eikum]

On Fri, Nov 07, 2014 at 04:06:55AM +0000, Mark Harmstone wrote:
> At present, winealsa attempts to call map_channels when a capture
> device is opened. If a microphone can be opened in either stereo or
> mono mode, and mono is requested, Wine will still return stereo
> data. Not only does this result in distorted in audio, it also very
> frequently results in heap corruption when snd_pcm_readi overruns
> the buffer allocated by the program.
> 

Thanks for fixing this.

The patch doesn't apply because it got mangled in transit:

http://source.winehq.org/patches/data/107529

The idea look OK to me, but don't we want to disable channel remapping
for _all_ capture devices? Your patch only disables it if the
application is using WAVE_FORMAT_EXTENSIBLE

I don't think we can do capture channel remapping reliably without
switching to the new ALSA channel mapping API. So it makes sense to
disable it entirely for now.

Andrew

> I don't have a copy of World of Warcraft to test this on, but this
> may also fix bug 31684. It's the same symptoms, at least.
> 
> ---
>  dlls/winealsa.drv/mmdevdrv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/dlls/winealsa.drv/mmdevdrv.c b/dlls/winealsa.drv/mmdevdrv.c
> index a4c02bf..91fba2f 100644
> --- a/dlls/winealsa.drv/mmdevdrv.c
> +++ b/dlls/winealsa.drv/mmdevdrv.c
> @@ -1164,7 +1164,7 @@ static DWORD get_channel_mask(unsigned int channels)
> 
>  static HRESULT map_channels(ACImpl *This, const WAVEFORMATEX *fmt)
>  {
> -    if(fmt->wFormatTag == WAVE_FORMAT_EXTENSIBLE || fmt->nChannels > 2){
> +    if( (This->dataflow != eCapture && fmt->wFormatTag ==
> WAVE_FORMAT_EXTENSIBLE) || fmt->nChannels > 2){
>          WAVEFORMATEXTENSIBLE *fmtex = (void*)fmt;
>          DWORD mask, flag = SPEAKER_FRONT_LEFT;
>          UINT i = 0;
> -- 
> 2.0.4
> 
>