scale in mixing to prevent excessive gain

src/twn_audio.c

@@ -366,9 +366,11 @@ static void audio_mixin_streams(const AudioChannel *channel,
     for (size_t s = 0; s < frames; ++s) {
         /* left channel */
         sa[s * 2 + 0] += (float)(sb[s * 2 + 0] * channel->volume * left_panning);
+        sa[s * 2 + 0] *= 1 / (float)M_2_SQRTPI;
 
         /* right channel */
         sa[s * 2 + 1] += (float)(sb[s * 2 + 1] * channel->volume * right_panning);
+        sa[s * 2 + 1] *= 1 / (float)M_2_SQRTPI;
     }
 }