[FFmpeg-trac] #2373(avfilter:new): hqdn3d produces banding

FFmpeg trac at avcodec.org
Mon Mar 18 19:02:09 CET 2013

#2373: hqdn3d produces banding
             Reporter:  sun       |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avfilter  |                  Version:  git-master
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
 Summary of the bug: the temporal denoiser of the hqdn3d filter produces
 banding. This is mostly noticeable on fine gradients with low luma value
 and some noise. Seems that the filter tries to clamp a pixel's value over
 the time.
 How to reproduce:
 I have uploaded a short example raw file that will show banding in the
 thicker parts of the tree. There is not much noise, but this shows that
 some gradients get destroyed by the filter.


 % ffmpeg -i input -vcodec dnxhd -acodec copy -vb 120000k -vf
 hqdn3d=0:0:8:8 output
 ffmpeg version N-37943-gc87c2d0
 built on N-37943-gc87c2d0

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2373>
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