[FFmpeg-trac] #444(undetermined:new): x264 rev. 2074 - part of image jumping with some presets and strange bitrate dependance

FFmpeg trac at avcodec.org
Thu Sep 8 11:13:14 CEST 2011


#444: x264 rev. 2074 - part of image jumping with some presets and strange
bitrate dependance
-------------------------------------+-------------------------------------
             Reporter:  Dimon        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  mts x264     |               Blocked By:
  block jumping                      |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I have almost fully static 1920x1080p 25fps scene: dark bottom with some
 tree branches shaking within no more then 10 pixels and slow clouds
 passing by. In 30 sec of the whole scene there are couple of ~2 sec
 chunks, where bottom of the image begin to jump with ~0.2 sec period, up
 and down with visual amplitude 8-16 pixels. This happens only with "--
 preset" settings slow, slower and "harder". More "light" presets work
 pretty. Initial file is .mts, decoded through ffdshow/AviSynth. The
 command line is:

 x264 --preset slower -b 6 -r 8 --crf 18 -o file.mkv file.avs

 Players were Classic Media Player and VideLan VLC, showing the same.

 Varying -b and -r parameters doesn't help, so lack of memory for decoding
 is not very probable reason (Core Duo 2.8 GHz, 2GB RAM)

 Also, in this and close situation, with only slooowly moving and
 transforming clouds in the frame: veryfast, faster, fast, normal presets
 sequence gives growing bitrate! When visualising motion vectors in ffmpeg
 plugin, more "hard" preset shows longer vectors.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/444>
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