Use the shorter channel layout description for the common case.

libavutil/audioconvert.c

@@ -51,10 +51,10 @@ static const struct {
     { "stereo",      2,  AV_CH_LAYOUT_STEREO },
     { "4.0",         4,  AV_CH_LAYOUT_4POINT0 },
     { "quad",        4,  AV_CH_LAYOUT_QUAD },
-    { "5.0",         5,  AV_CH_LAYOUT_5POINT0 },
-    { "5.0(back)",   5,  AV_CH_LAYOUT_5POINT0_BACK },
-    { "5.1",         6,  AV_CH_LAYOUT_5POINT1 },
-    { "5.1(back)",   6,  AV_CH_LAYOUT_5POINT1_BACK },
+    { "5.0(side)",   5,  AV_CH_LAYOUT_5POINT0 },
+    { "5.0",         5,  AV_CH_LAYOUT_5POINT0_BACK },
+    { "5.1(side)",   6,  AV_CH_LAYOUT_5POINT1 },
+    { "5.1",         6,  AV_CH_LAYOUT_5POINT1_BACK },
     { "5.1+downmix", 8,  AV_CH_LAYOUT_5POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
     { "7.1",         8,  AV_CH_LAYOUT_7POINT1 },
     { "7.1(wide)",   8,  AV_CH_LAYOUT_7POINT1_WIDE },