lavu: Move preprocessor macros in a separate file

[ffmpeg] / libavresample / audio_mix.c

diff --git a/libavresample/audio_mix.c b/libavresample/audio_mix.c
index 096bcf3d660f5db8bd398176895f021bc2a1775f..073609e7eec8e19c899e2bb955af736b0e9fe1f4 100644 (file)
--- a/libavresample/audio_mix.c
+++ b/libavresample/audio_mix.c
@@ -201,23 +201,23 @@ static void mix_1_to_2_fltp_flt_c(float **samples, float **matrix, int len,
 
     while (len > 4) {
         v = *src++;
-        *dst0++ = v * m1;
-        *dst1++ = v * m0;
+        *dst0++ = v * m0;
+        *dst1++ = v * m1;
         v = *src++;
-        *dst0++ = v * m1;
-        *dst1++ = v * m0;
+        *dst0++ = v * m0;
+        *dst1++ = v * m1;
         v = *src++;
-        *dst0++ = v * m1;
-        *dst1++ = v * m0;
+        *dst0++ = v * m0;
+        *dst1++ = v * m1;
         v = *src++;
-        *dst0++ = v * m1;
-        *dst1++ = v * m0;
+        *dst0++ = v * m0;
+        *dst1++ = v * m1;
         len -= 4;
     }
     while (len > 0) {
         v = *src++;
-        *dst0++ = v * m1;
-        *dst1++ = v * m0;
+        *dst0++ = v * m0;
+        *dst1++ = v * m1;
         len--;
     }
 }
@@ -282,7 +282,7 @@ static void mix_2_to_6_fltp_flt_c(float **samples, float **matrix, int len,
     }
 }
 
-static int mix_function_init(AudioMix *am)
+static av_cold int mix_function_init(AudioMix *am)
 {
     am->func_descr = am->func_descr_generic = "n/a";
     am->mix = am->mix_generic = NULL;
@@ -572,11 +572,22 @@ static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
         int skip = 1;
 
         for (o = 0; o < am->out_channels; o++) {
+            int i0;
             if ((o != i && matrix[o * stride + i] != 0.0) ||
                 (o == i && matrix[o * stride + i] != 1.0)) {
                 skip = 0;
                 break;
             }
+            /* if the input contributes fully to the output, also check that no
+               other inputs contribute to this output */
+            if (o == i) {
+                for (i0 = 0; i0 < am->in_channels; i0++) {
+                    if (i0 != i && matrix[o * stride + i0] != 0.0) {
+                        skip = 0;
+                        break;
+                    }
+                }
+            }
         }
         if (skip) {
             am->input_skip[i] = 1;
@@ -607,6 +618,7 @@ static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
        corresponding input channel */
     for (o = 0; o < FFMIN(am->in_channels, am->out_channels); o++) {
         int skip = 1;
+        int o0;
 
         for (i = 0; i < am->in_channels; i++) {
             if ((o != i && matrix[o * stride + i] != 0.0) ||
@@ -615,6 +627,15 @@ static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
                 break;
             }
         }
+        /* check if the corresponding input channel makes a contribution to
+           any other output channel */
+        i = o;
+        for (o0 = 0; o0 < am->out_channels; o0++) {
+            if (o0 != i && matrix[o0 * stride + i] != 0.0) {
+                skip = 0;
+                break;
+            }
+        }
         if (skip) {
             am->output_skip[o] = 1;
             am->out_matrix_channels--;