post processing decoder options

davexnet · 21st December 2008, 07:37

Hello, in the Divx decoder options you can, for example, turn off the post-processing
"automatic deblocker".

If you do this and open a poorer quality Divx file in Virtualdub you can sure see the difference.
The macro blocks are not softened at all.

If you then re-encode this video, you're re-encoding this non-softened version.
the output is different - it's almost as if you had a different source file.

In general, if you need to re-encode a file like this, should this kind of post-processing
be left on, or are there circumstances where turning it off is better?

LoRd_MuldeR · 23rd December 2008, 15:58

Depends on your personal preferences

For MPEG-4 ASP the deblocking post-processor is fully optional. You will get reduced blocking at the cost of reduced details/sharpness, if deblocking is enabled.

Decide whether this is what you want or not...

davexnet · 24th December 2008, 06:24

What you say makes sense. The reason I mentioned it are twofold:

1) I never realized it was a factor. (I guess I never looked at the decoder options before - or if I did,
I assumed it only affected dshow playback in the media player)

2) I've never seen any post, discussion or anything about the relevance of this option, as it pertains
to re-encoding.

Dark Shikari · 24th December 2008, 06:26

If you're re-encoding, you might as well spend time and use a better deblocker.

I'm a fan of dfttest, though its obnoxiously slow.

21st December 2008, 07:37	#1 \| Link
davexnet Registered User Join Date: Feb 2002 Posts: 145	post processing decoder options Hello, in the Divx decoder options you can, for example, turn off the post-processing "automatic deblocker". If you do this and open a poorer quality Divx file in Virtualdub you can sure see the difference. The macro blocks are not softened at all. If you then re-encode this video, you're re-encoding this non-softened version. the output is different - it's almost as if you had a different source file. In general, if you need to re-encode a file like this, should this kind of post-processing be left on, or are there circumstances where turning it off is better?

23rd December 2008, 15:58	#2 \| Link
LoRd_MuldeR Software Developer Join Date: Jun 2005 Location: Last House on Slunk Street Posts: 13,275	Depends on your personal preferences For MPEG-4 ASP the deblocking post-processor is fully optional. You will get reduced blocking at the cost of reduced details/sharpness, if deblocking is enabled. Decide whether this is what you want or not... __________________ Go to https://standforukraine.com/ to find legitimate Ukrainian Charities 🇺🇦✊

24th December 2008, 06:26	#4 \| Link
Dark Shikari x264 developer Join Date: Sep 2005 Posts: 8,666	If you're re-encoding, you might as well spend time and use a better deblocker. I'm a fan of dfttest, though its obnoxiously slow. __________________ Follow x264 development progress \| akupenguin quotes \| x264 git status ffmpeg and x264-related consulting/coding contracts \| Doom10

24th December 2008, 06:24	#3 \| Link
davexnet Registered User Join Date: Feb 2002 Posts: 145	What you say makes sense. The reason I mentioned it are twofold: 1) I never realized it was a factor. (I guess I never looked at the decoder options before - or if I did, I assumed it only affected dshow playback in the media player) 2) I've never seen any post, discussion or anything about the relevance of this option, as it pertains to re-encoding.