[FFmpeg-trac] #2592(FFmpeg:new): Bug with b-frames?

FFmpeg trac at avcodec.org
Mon May 20 19:40:02 CEST 2013


#2592: Bug with b-frames?
-----------------------------------+--------------------------------------
             Reporter:  microchip  |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  FFmpeg     |                  Version:  git-master
             Keywords:             |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
-----------------------------------+--------------------------------------
 Hi,

 I pulled ffmpeg from git today and started to encode to mpeg2video with 2
 b-frames in 2-pass mode. I noticed that the git version behaves
 differently than the 1.2.1 version of ffmpeg. I looked at the passlog file
 and noticed that all type:3 entries have in:0 and out:0. In 1.2.1, the
 type:3 entries have entries > 0. My command line for both git and 1.2.1
 version is identical and is as follows:


 {{{
 /usr/local/bin/ffmpeg -i /home/neutrino/file2dvd/Con_Air/tmp30017.avi -f
 dvd -c:v mpeg2video -vf scale=720:368,pad=720:480:0:56,setdar=16/9
 -sws_flags spline -aspect 16:9 -mbd 2 -precmp 2 -cmp 2 -subcmp 2 -trellis
 2 -dia_size -1 -last_pred 4 -flags +mv0 -mpv_flags +cbp_rd -bf 2 -dc 11
 -preme 2 -mv0_threshold 0 -bidir_refine 2 -g 18 -r 24000/1001 -b:v 4653k
 -c:a ac3 -b:a 192k -ar 48000 -passlogfile
 /home/neutrino/file2dvd/Con_Air/Con_Air -pass 1 -y /dev/null
 }}}

 The second pass is identical but with -pass 2 option. I also noticed that
 when using the git version, during the second pass, the bitrate seems very
 low compared to the first pass. This is not the case when using the 1.2.1
 version of ffmpeg.

 Both ffmpeg's are compiled with the following options;

 {{{
 ./configure --enable-shared --enable-gpl --enable-version3 --enable-
 libx264 --enable-libxvid --enable-libmp3lame --enable-avresample
 }}}

 I am attatching 2 log files, one from ffmpeg 1.2.1 and one from the git
 version.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2592>
FFmpeg <http://ffmpeg.org>
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