[pulseaudio-discuss] [PATCH 2/3] volume: Print a warning when volume is clipped in pa_sw_volume_multiply/divide()

[Tanu Kaskinen]

On Fri, 2017-04-28 at 11:13 +0200, Georg Chini wrote:
> When the volume exceeds PA_VOLUME_MAX in pa_sw_volume_multiply() or
> pa_sw_volume_divide(), volume settings are insanely high and the
> user should be notified about it.
> 
> This patch adds volume clamping to pa_sw_volume_divide() and prints
> a warning when the volume is clipped in both functions.
> ---
>  src/pulse/volume.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/src/pulse/volume.c b/src/pulse/volume.c
> index 1667b940..73e78370 100644
> --- a/src/pulse/volume.c
> +++ b/src/pulse/volume.c
> @@ -199,16 +199,23 @@ pa_volume_t pa_cvolume_min_mask(const pa_cvolume *a, const pa_channel_map *cm, p
>  }
>  
>  pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b) {
> +    uint64_t result;
>  
>      pa_return_val_if_fail(PA_VOLUME_IS_VALID(a), PA_VOLUME_INVALID);
>      pa_return_val_if_fail(PA_VOLUME_IS_VALID(b), PA_VOLUME_INVALID);
>  
>      /* cbrt((a/PA_VOLUME_NORM)^3*(b/PA_VOLUME_NORM)^3)*PA_VOLUME_NORM = a*b/PA_VOLUME_NORM */
>  
> -    return (pa_volume_t) PA_CLAMP_VOLUME((((uint64_t) a * (uint64_t) b + (uint64_t) PA_VOLUME_NORM / 2ULL) / (uint64_t) PA_VOLUME_NORM));
> +    result = ((uint64_t) a * (uint64_t) b + (uint64_t) PA_VOLUME_NORM / 2ULL) / (uint64_t) PA_VOLUME_NORM;
> +
> +    if (result > (uint64_t)PA_VOLUME_MAX)
> +        pa_log_warn("pa_sw_volume_multiply: Volume exceeds maximum allowed value and will be clipped. Please check your volume settings");
> +
> +    return (pa_volume_t) PA_CLAMP_VOLUME(result);
>  }
>  
>  pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) {
> +    uint64_t result;
>  
>      pa_return_val_if_fail(PA_VOLUME_IS_VALID(a), PA_VOLUME_INVALID);
>      pa_return_val_if_fail(PA_VOLUME_IS_VALID(b), PA_VOLUME_INVALID);
> @@ -216,7 +223,12 @@ pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) {
>      if (b <= PA_VOLUME_MUTED)
>          return 0;
>  
> -    return (pa_volume_t) (((uint64_t) a * (uint64_t) PA_VOLUME_NORM + (uint64_t) b / 2ULL) / (uint64_t) b);
> +    result = ((uint64_t) a * (uint64_t) PA_VOLUME_NORM + (uint64_t) b / 2ULL) / (uint64_t) b;
> +
> +    if (result > (uint64_t)PA_VOLUME_MAX)
> +        pa_log_warn("pa_sw_volume_divide: Volume exceeds maximum allowed value and will be clipped. Please check your volume settings");
> +
> +    return (pa_volume_t) PA_CLAMP_VOLUME(result);
>  }
>  
>  /* Amplitude, not power */

Looks good to me.

-- 
Tanu

https://www.patreon.com/tanuk