[FFmpeg-cvslog] avcodec: try to document timebase a bit more

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Mar  5 13:29:16 2016 +0100| [da904faaa546afb7dfae9e7633028469a2670937] | committer: Michael Niedermayer

avcodec: try to document timebase a bit more

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=da904faaa546afb7dfae9e7633028469a2670937
---

 libavcodec/avcodec.h |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index e249e65..d676c57 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1669,7 +1669,15 @@ typedef struct AVCodecContext {
      * timebase should be 1/framerate and timestamp increments should be
      * identically 1.
      * This often, but not always is the inverse of the frame rate or field rate
-     * for video.
+     * for video. 1/time_base is not the average frame rate if the frame rate is not
+     * constant.
+     *
+     * Like containers, elementary streams also can store timestamps, 1/time_base
+     * is the unit in which these timestamps are specified.
+     * As example of such codec time base see ISO/IEC 14496-2:2001(E)
+     * vop_time_increment_resolution and fixed_vop_rate
+     * (fixed_vop_rate == 0 implies that it is different from the framerate)
+     *
      * - encoding: MUST be set by user.
      * - decoding: the use of this field for decoding is deprecated.
      *             Use framerate instead.