[FFmpeg-trac] #1882(avcodec:open): Multi-threading wmv encoder

FFmpeg trac at avcodec.org
Sat Nov 3 19:18:40 CET 2012


#1882: Multi-threading wmv encoder
-------------------------------------+-----------------------------------
             Reporter:  txspaderz    |                    Owner:
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  wmv2         |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+-----------------------------------

Comment (by txspaderz):

 Here's a tee'd output at this link (it's quite large, in a ascii format):
 http://houstondad.com/ffmpeg.log.txt


 When the process is running, it's actually switching cores (39th field of
 /proc/pid/stat shows the last executed core), here's a breakup if it
 matters:

 {{{
 root at media-center ~ # while true; do cat /proc/12514/stat | awk '{print
 $39}'; done > /home/perk/ffmpeg_cores.log
 root at media-center ~ # sort /home/perk/ffmpeg_cores.log | uniq -c | sort
 -k2 -n
  136778 0
  409369 1
  405346 2
  406885 3
 }}}



 However during the encoding time, the process is continually using only 1
 cores worth of cycles, and nothing more:

 {{{

 12514 root      20   0 91080  65m 4632 R  100  0.4  10:00.98 ffmpeg
 12514 root      20   0 91548  65m 4632 R   97  0.4  10:01.96 ffmpeg
 12514 root      20   0 90456  65m 4632 R  100  0.4  10:02.98 ffmpeg
 12514 root      20   0 90456  65m 4632 R   98  0.4  10:03.97 ffmpeg
 12514 root      20   0 90684  65m 4632 R  100  0.4  10:04.98 ffmpeg
 12514 root      20   0 90684  65m 4632 R  100  0.4  10:06.00 ffmpeg
 12514 root      20   0 90436  65m 4632 R   98  0.4  10:07.00 ffmpeg
 12514 root      20   0 90436  65m 4632 R  100  0.4  10:08.01 ffmpeg
 12514 root      20   0 90436  65m 4632 R   99  0.4  10:09.02 ffmpeg
 12514 root      20   0 90436  65m 4632 R   99  0.4  10:10.03 ffmpeg
 12514 root      20   0 90740  65m 4632 R   99  0.4  10:11.03 ffmpeg
 12514 root      20   0 91176  65m 4632 R   99  0.4  10:12.03 ffmpeg
 12514 root      20   0 91176  65m 4632 R  101  0.4  10:13.05 ffmpeg
 12514 root      20   0 91176  65m 4632 R   96  0.4  10:14.03 ffmpeg
 12514 root      20   0 91176  65m 4632 R  101  0.4  10:15.06 ffmpeg
 }}}


 Because of this, and the source files fps is 24, the encoder isn't able to
 stream in real time.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1882#comment:2>
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