[FFmpeg-cvslog] downmix_info: clarify doxygen

[Timothy Gu]

ffmpeg | branch: master | Timothy Gu <timothygu99 at gmail.com> | Fri Jul  4 11:06:45 2014 -0700| [3679edf429ebbd9eff48e9b410ca1cef7bdf158a] | committer: Michael Niedermayer

downmix_info: clarify doxygen

Signed-off-by: Timothy Gu <timothygu99 at gmail.com>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3679edf429ebbd9eff48e9b410ca1cef7bdf158a
---

 libavutil/downmix_info.h |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavutil/downmix_info.h b/libavutil/downmix_info.h
index c369891..2fb9387 100644
--- a/libavutil/downmix_info.h
+++ b/libavutil/downmix_info.h
@@ -95,11 +95,12 @@ typedef struct AVDownmixInfo {
 /**
  * Get a frame's AV_FRAME_DATA_DOWNMIX_INFO side data for editing.
  *
- * The side data is created and added to the frame if it's absent.
+ * If the side data is absent, it is created and added to the frame.
  *
- * @param frame the frame for which the side data is to be obtained.
+ * @param frame the frame for which the side data is to be obtained or created
  *
- * @return the AVDownmixInfo structure to be edited by the caller.
+ * @return the AVDownmixInfo structure to be edited by the caller, or NULL if
+ *         the sturcture cannot be allocated.
  */
 AVDownmixInfo *av_downmix_info_update_side_data(AVFrame *frame);