• Compression Techniques

  Adaptive quantization

  Posted by Stan Juznitok on June 28, 2011 at 12:52 pm

  Hi,

  Is there a way to control adaptive quantization parameters from FFMPEG?
  There are few of tehm that can be reached from x264 itself, as described in:
  https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping

  but how to control them from FFMPEG command line?

  Thanks!

  Michael Rampe replied 15 years, 1 month ago 2 Members · 3 Replies
• 3 Replies

• 

  Michael Rampe

  July 4, 2011 at 10:55 pm

  [Stan Juznitok] “There are few of tehm that can be reached from x264 itself, as described in:
  https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping“

  This lists all of the options…..
  Which ones specifically are you after?

  Michael
• 

  Stan Juznitok

  July 7, 2011 at 3:30 pm

  For example, there is:
  –aq-strength (x264) — control the strength of adaptive quantization

  Is there a way to control the adaptive quantization from the FFMEPG itself? I’m trying to get more details about the parameters that have a high influence on the resulting bitrates when x264 compression is done, and I guess the quantization has dominant role in it. Adaptive quantization seems to have the influence on the resulting bitrates, but what is the algorithm or logic that decides on this adaptivity?

  Thank you!
• 

  Michael Rampe

  July 7, 2011 at 9:47 pm

  [Stan Juznitok] “Is there a way to control the adaptive quantization from the FFMEPG itself?”

  Yes. Quite recently, there is the added option to control x264 settings direct from FFmpeg.

  Your example would require:
  “-x264opts aq-strength=1”
  ….as an extra command line option.

  Example:
  $ ffmpeg -i tilt_shift_3.mov -vcodec libx264 -preset slow -x264opts aq-strength=1 -crf 6 tilt_shift_3h.mp4

  If this does not work for you, upgrade your FFmpeg install.
  Hope this helps.

  Michael

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