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>
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/libavutil/audioconvert.h b/libavutil/audioconvert.h
index 2b0c9cdea9..35a1a087f6 100644
--- a/libavutil/audioconvert.h
+++ b/libavutil/audioconvert.h
@@ -106,7 +106,21 @@
  */
 
 /**
- * Return a channel layout id that matches name, 0 if no match.
+ * Return a channel layout id that matches name, or 0 if no match is found.
+ *
+ * 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, optionally 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"
  */
 uint64_t av_get_channel_layout(const char *name);