Add support for s16 format to the linear resampler.

miniaudio.h

@@ -4278,6 +4278,18 @@ static MA_INLINE float ma_mix_f32_fast(float x, float y, float a)
     /*return x + (y - x)*a;*/
 }
 
+static MA_INLINE ma_int32 ma_mix_s32_fast(ma_int32 x, ma_int32 y, float a)
+{
+    ma_int32 r0 = (y - x);
+    ma_int32 r1 = (ma_int32)(r0*a);
+    return x + r1;
+}
+
+static MA_INLINE ma_int32 ma_mix_s16_fast(ma_int32 x, ma_int32 y, float a)
+{
+    return (ma_int16)ma_mix_s32_fast(x, y, a);
+}
+
 #if defined(MA_SUPPORT_SSE2)
 static MA_INLINE __m128 ma_mix_f32_fast__sse2(__m128 x, __m128 y, __m128 a)
 {

research/ma_lpf.h

@@ -119,8 +119,8 @@ ma_result ma_biquad_init(const ma_biquad_config* pConfig, ma_biquad* pBQ)
         return MA_INVALID_ARGS; /* Division by zero. */
     }
 
-    /* Currently only supporting f32, but support for other formats will be added later. */
-    if (pConfig->format != ma_format_f32) {
+    /* Currently only supporting f32 and s16, but support for other formats will be added later. */
+    if (pConfig->format != ma_format_f32 && pConfig->format != ma_format_s16) {
         return MA_INVALID_ARGS;
     }
 
@@ -243,7 +243,7 @@ ma_result ma_lpf_init(const ma_lpf_config* pConfig, ma_lpf* pLPF)
     bqConfig.b1 = (double)( 1 - c);
     bqConfig.b2 = (double)((1 - c) / 2);
 
-    bqConfig.format = pConfig->format;
+    bqConfig.format   = pConfig->format;
     bqConfig.channels = pConfig->channels;
 
     result = ma_biquad_init(&bqConfig, &pLPF->bq);