audioconvert: make av_get_channel_layout accept composite names.

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 12 insertions, 0 deletions

diff --git a/libavutil/audioconvert.h b/libavutil/audioconvert.h
index 8cef7f650a..4e0e98c9b4 100644
--- a/libavutil/audioconvert.h
+++ b/libavutil/audioconvert.h
@@ -75,6 +75,18 @@
 
 /**
  * Return a channel layout id that matches name, 0 if no match.
+ * name can be one or several of the following notations,
+ * separated by '+' or '|':
+ * - the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0,
+ *   5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix);
+ * - the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC,
+ *   SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR);
+ * - a number of channels, in decimal, optionnally followed by 'c', yielding
+ *   the default channel layout for that number of channels (@see
+ *   av_get_default_channel_layout);
+ * - a channel layout mask, in hexadecimal starting with "0x" (see the
+ *   AV_CH_* macros).
+ + Example: "stereo+FC" = "2+FC" = "2c+1c" = "0x7"
  */
 int64_t av_get_channel_layout(const char *name);