audio: split sample conversion and volume mixing

Refactor the volume mixing, so it can be reused for capturing devices.
Additionally, it removes superfluous multiplications with the nominal
volume within the hardware voice code path.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: malc <av1474@comtv.ru>

1 files changed, 25 insertions, 0 deletions

diff --git a/audio/mixeng.c b/audio/mixeng.c
index 9f1d93f..4a9e8eb 100644
--- a/audio/mixeng.c
+++ b/audio/mixeng.c
@@ -333,3 +333,28 @@ void mixeng_clear (struct st_sample *buf, int len)
 {
     memset (buf, 0, len * sizeof (struct st_sample));
 }
+
+void mixeng_volume (struct st_sample *buf, int len, struct mixeng_volume *vol)
+{
+#ifdef CONFIG_MIXEMU
+    if (vol->mute) {
+        mixeng_clear (buf, len);
+        return;
+    }
+
+    while (len--) {
+#ifdef FLOAT_MIXENG
+        buf->l = buf->l * vol->l;
+        buf->r = buf->r * vol->r;
+#else
+        buf->l = (buf->l * vol->l) >> 32;
+        buf->r = (buf->r * vol->r) >> 32;
+#endif
+        buf += 1;
+    }
+#else
+    (void) buf;
+    (void) len;
+    (void) vol;
+#endif
+}