[FFmpeg-cvslog] ffmpeg: document avi special case

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sun Feb  5 05:14:26 2012 +0100| [982783ac49c1a1f0739cad9cf0ec8a7b5d427e62] | committer: Michael Niedermayer

ffmpeg: document avi special case

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=982783ac49c1a1f0739cad9cf0ec8a7b5d427e62
---

 ffmpeg.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/ffmpeg.c b/ffmpeg.c
index e83da34..3241bcb 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -2448,6 +2448,11 @@ static int transcode_init(OutputFile *output_files, int nb_output_files,
             codec->extradata_size= icodec->extradata_size;
 
             codec->time_base = ist->st->time_base;
+            /*
+             * Avi is a special case here because it supports variable fps but
+             * having the fps and timebase differe significantly adds quite some
+             * overhead
+             */
             if(!strcmp(oc->oformat->name, "avi")) {
                 if (   copy_tb<0 && av_q2d(icodec->time_base)*icodec->ticks_per_frame > 2*av_q2d(ist->st->time_base)
                                  && av_q2d(ist->st->time_base) < 1.0/500