[FFmpeg-devel] [PATCH] lavu/audioconvert: add av_guess_channel_layout() function

[Stefano Sabatini]

---
 doc/APIchanges           |    3 +++
 libavutil/audioconvert.c |   14 ++++++++++++++
 libavutil/audioconvert.h |    8 ++++++++
 3 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index 65d76bd..71a4bb4 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil:   2011-04-18
 
 API changes, most recent first:
 
+2011-09-xx - xxxxxxx - lavu 51.X.0
+  Add av_guess_channel_layout().
+
 2011-08-xx - xxxxxxx - lavc 53.10.0
                        lavf 53.6.0
                        lsws  2.1.0
diff --git a/libavutil/audioconvert.c b/libavutil/audioconvert.c
index 97c02f5..000c45b 100644
--- a/libavutil/audioconvert.c
+++ b/libavutil/audioconvert.c
@@ -130,3 +130,17 @@ int av_get_channel_layout_nb_channels(int64_t channel_layout)
         x &= x-1; // unset lowest set bit
     return count;
 }
+
+int64_t av_guess_channel_layout(int nb_channels)
+{
+    switch (nb_channels) {
+    case 1: return AV_CH_LAYOUT_MONO;
+    case 2: return AV_CH_LAYOUT_STEREO;
+    case 3: return AV_CH_LAYOUT_SURROUND;
+    case 4: return AV_CH_LAYOUT_QUAD;
+    case 5: return AV_CH_LAYOUT_5POINT0;
+    case 6: return AV_CH_LAYOUT_5POINT1;
+    case 8: return AV_CH_LAYOUT_7POINT1;
+    default: return 0;
+    }
+}
diff --git a/libavutil/audioconvert.h b/libavutil/audioconvert.h
index e37a2e8..2fe4808 100644
--- a/libavutil/audioconvert.h
+++ b/libavutil/audioconvert.h
@@ -92,4 +92,12 @@ void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, int6
  */
 int av_get_channel_layout_nb_channels(int64_t channel_layout);
 
+/**
+ * Guess the channel layout from the number of channels.
+ *
+ * @return channel layout mask, 0 if it cannot guess the channel
+ * layout
+ */
+int64_t av_guess_channel_layout(int nb_channels);
+
 #endif /* AVUTIL_AUDIOCONVERT_H */
-- 
1.7.2.5