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loss of detail

Started by rabbit, March 19, 2012, 03:32:45 AM

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I have been trying to convert an mpeg-2 file to mpeg4-avc using both Avidemux and Handbrake. I noticed that almost regardless of the compression settings there seems to be a significant loss of detail from the Avidemux conversions. This seems odd considering both applications use x264 and that the loss of detail is so great.

I have since noticed that this loss of detail is apparent even when opening the source mpeg-2 file in Avidemux and viewing the still image within the Avidemux window - prior to any attempt at conversion. If I open the mpeg-2 file in Avidemux and VLC without pressing play on either and view the image of the first frame of the movie, the image displayed in VLC is more detailed than that displayed in Avidemux. Somehow Avidemux is losing the image detail from the source prior to conversion.

Anyone have any idea what might be causing this?


Phil T.  :)


Be careful with this, because image in the first instance of VLC is always better.


But if I create an mpeg4-avc file with Avidemux, and then look at it in VLC, it still has the lost detail.


post processing is activated by default for mpeg2
Try disabling it



I am having the same issue. I am trying to convert an old home video DVD (interlaced) I made to AVC and spent hours tweaking any encoder setting that had something to do with sharpness. Even CRF0 was blurry!

I am using yadif deinterlacer to turn it in to 50fps progressive scan.

So can I just clarify, by turning off post-processing of the mpeg2 file do you mean hit F4 and uncheck Horizontal Deblocking and Vertical Deblocking?

I've tried that but it doesn't seem to help. Particularly my hair is quite detailed in the original mpeg2 but just comes out as coloured bands in the AVC version.



If possible upgrade to Avidemux-2.5.6, and also try the 2.6 branch.
I will pull up a couple of MPEG-2s I have and run it through myself.


March 25, 2012, 11:13:10 PM #6 Last Edit: March 25, 2012, 11:14:47 PM by rabbit
Quote from: mean on March 19, 2012, 12:41:43 PM
post processing is activated by default for mpeg2
Try disabling it

That was it. Turned off horizontal and vertical de-blocking and the problem went away.




I'm VERY interested.
Does the post-processing have an effect on Avidemux window only, or on encoded video as well?