1 files changed, 50 insertions, 13 deletions

diff --git a/src/mixer.c b/src/mixer.c
index 3fc1ac9..ba40215 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -7,7 +7,7 @@
 #include <xas/audio.h>
 #include <xas/mixer.h>
 
-static void mixer_apply_int16_t_mono(int16_t *dest,
+static void mixer_apply_mono_to_mono(int16_t *dest,
                                      int16_t *src,
                                      size_t count,
                                      float bias_l,
@@ -19,16 +19,41 @@ static void mixer_apply_int16_t_mono(int16_t *dest,
     }
 }
 
-static void mixer_apply_int16_t_stereo(int16_t *dest,
+static void mixer_apply_mono_to_stereo(int16_t *dest,
                                        int16_t *src,
                                        size_t count,
                                        float bias_l,
                                        float bias_r) {
     size_t i;
 
-    for (i=0; i<2*count; i+=2) {
-        dest[i]   += (int16_t)roundf(src[i]   * bias_l);
-        dest[i+1] += (int16_t)roundf(src[i+1] * bias_r);
+    for (i=0; i<count; i++) {
+        dest[i]   += src[i];
+        dest[i+1] += src[i];
+    }
+}
+
+static void mixer_apply_stereo_to_stereo(int16_t *dest,
+                                         int16_t *src,
+                                         size_t count,
+                                         float bias_l,
+                                         float bias_r) {
+    size_t i;
+
+    for (i=0; i<count; i++) {
+        dest[i]   += src[i];
+        dest[i+1] += src[i+1];
+    }
+}
+
+static void mixer_apply_stereo_to_mono(int16_t *dest,
+                                       int16_t *src,
+                                       size_t count,
+                                       float bias_l,
+                                       float bias_r) {
+    size_t i;
+
+    for (i=0; i<count; i++) {
+        dest[i] += (src[i] + src[i+1]) / 2;
     }
 }
 
@@ -40,24 +65,34 @@ static ssize_t mixer_fill(xas_mixer *mixer,
 
     xas_mixer_input *input = mixer->inputs;
 
-    void (*mixer_apply)(int16_t *,
-                        int16_t *,
-                        size_t,
-                        float,
-                        float) = (output->channels == 2)?
-        mixer_apply_int16_t_stereo:
-        mixer_apply_int16_t_mono;
-
     memset(mixer->buf,
            '\0',
            output->sample_size * output->channels * output->buffer_size);
 
     while (input) {
+        void (*mixer_apply)(int16_t *,
+                            int16_t *,
+                            size_t,
+                            float,
+                            float);
+
         xas_mixer_input *next = input->next;
         int16_t *buf;
 
         ssize_t readlen;
 
+        if (output->channels == 2 && input->stream->channels == 2) {
+            mixer_apply = mixer_apply_stereo_to_stereo;
+        } else if (output->channels == 2 && input->stream->channels == 1) {
+            mixer_apply = mixer_apply_mono_to_stereo;
+        } else if (output->channels == 1 && input->stream->channels == 1) {
+            mixer_apply = mixer_apply_mono_to_mono;
+        } else if (output->channels == 1 && input->stream->channels == 2) {
+            mixer_apply = mixer_apply_stereo_to_mono;
+        } else {
+            goto error_invalid_input;
+        }
+
         if ((readlen = xas_audio_stream_read(input->stream,
                                                (void **)&buf,
                                                count)) < 0) {
@@ -83,6 +118,7 @@ static ssize_t mixer_fill(xas_mixer *mixer,
 
     return total;
 
+error_invalid_input:
 error_audio_read_stream:
     return -1;
 }
@@ -140,6 +176,7 @@ void xas_mixer_destroy(xas_mixer *mixer) {
 
     xas_audio_stream_destroy(mixer->output);
 
+    free(mixer->buf);
     free(mixer);
 }