add API function to perform volume adjustment on a frame of SLINEAR data

documentation cleanup


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@6874 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 19 insertions, 0 deletions

diff --git a/frame.c b/frame.c
index 5d9ddab11..7b4fa4ddf 100755
--- a/frame.c
+++ b/frame.c
@@ -1252,3 +1252,22 @@ int ast_codec_get_len(int format, int samples)
 
 	return len;
 }
+
+int ast_frame_adjust_volume(struct ast_frame *f, int adjustment)
+{
+	int count;
+	short *fdata = f->data;
+
+	if ((f->frametype != AST_FRAME_VOICE) || (f->subclass != AST_FORMAT_SLINEAR))
+		return -1;
+
+	for (count = 0; count < f->samples; count++) {
+		if (adjustment > 0) {
+			fdata[count] *= abs(adjustment);
+		} else if (adjustment < 0) {
+			fdata[count] /= abs(adjustment);
+		}
+	}
+
+	return 0;
+}