[MPlayer-users] Horrible Compression Artifacts in High MotionScenes

Nico Sabbi nsabbi at email.it
Mon Oct 3 17:58:33 CEST 2005


Kichigai Mentat wrote:

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> Hello. I'm attempting to compress a video with the following command  
> line:
>
> mencoder INPUT -o OUTPUT -nosound -ovc lavc -lavcopts  
> vcodec=mpeg4:vpass=3:aspect=16/9:idct=8:trell:vmax_b_frames=0:vqmax=31:v 
> hq:v4mv:vrc_eq=tex:vfdct=5:dia=-1:vbitrate=1200:vrc_minrate=650:vrc_maxr 
> ate=2500:vrc_buf_size=1835 -vf  
> crop=720:464:0:8,filmdint=dint_thres=256,pp=lb -ofps 29.976
>


> My guess was with that kind of a bitrate, there would be enough  
> information to compensate for high-motion scenes (which this video is  
> full of). Instead, the result was that virtually all high-motion  
> scenes are flooded with compression artifacts. Scenes with repetitive  
> motion (the same background repeating) or even as simple as following  
> someone running comes out with blocking everywhere. Low motion scenes  
> are crystal clear, but high-motion scenes (which make up the bulk of  
> the video) do not, even after three or four passes. Any ideas on  
> what's going on, or how to fix it?
>
my advice is to add :sc_threshold=N (usually I use -1500) to enable 
lavc's scene change detection


 
 
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