Help Resizing 720p » 480p

[Enkidu]

I want to resize a 720p video ( Anime ) to 480p, but the output gets pixelated ( some kind of blocks ).
Can anyone help me with this?
What i did was, simply change the height and width values ( 1280x720 » 848x480 DAR 1.767 )


Ps : I'm using meGUI

[jagabo]

Use more bitrate?

[Enkidu]

The source (1280x720) Overall bitrate is 1808kbps, and i'm using 1000kbps(848x480). Is that the problem ?
Btw, the source is h264, and i'm using lanczos4 (sharp) to resize.

[poisondeathray]

Does the source have problems already ? like noise or macroblocking ?

Try using a higher bitrate as suggested , or use some denoising filters to lower your bitrate requirement , or use a softer resize (sharp, detailed content will require more bitrate)

What encoding settings ?

Why the arbitrary 1000kbps ? Do you need a specific filesize ?

[Enkidu]

No problems with the source. ( see the attachments )
My encoding settings are :

program --preset fast --pass 2 --bitrate 1000 --stats ".stats" --deblock 2:2 --bframes 6 --b-adapt 2 --b-pyramid strict --ref 8 --qpstep 7 --ipratio 1.0 --pbratio 1.0 --ratetol 2.0 --rc-lookahead 40 --aq-strength 1.5 --merange 32 --me umh --direct temporal --nr 500 --subme 7 --partitions all --psy-rd 0.80:0 --output "output" "input"

I don't want a file bigger than 250/280mb. Only bigger if it's really necessary.
Any recommendation for the denoising filter ?

Ps: I'm not using ffdshowdecoder on encode

[poisondeathray]

This looks like corruption , or you disabled deblocking (in the decoder), or a weightp error

What software and decoder are you using for playback and to take screenshots ?

Did you disable deblocking in the decoder ?

What happens if you play the output file in another player eg. mpchc, smplayer ?

Where does the "blocking" occur? every frame? or only on dark scenes ?

[jagabo]

Those are encoding or decoding errors, not bitrate problems.

[Enkidu]

This screenshots were taken on VLC Player. I have CCCP as decoder.
If i play the file on mpchc i get the same quality.
The blocking is only on dark scenes, and high motion scenes. (sometimes but very rare on bright scenes)

Ps: currently uninstalling all codecs, and installing only cccp and core avc

[poisondeathray]

If you are using coreavc, make sure it's v2.0 or newer, there is a documented bug with weightp that causes very similar errors to that screenshot above

What version of x264.exe ?

If you try --weightp 0 , do you still get the errors in the encode ?

For trouble shooting for now , I would reduce the qpstep (the quantizer might be making too large of a jump), and not use the nr for x264 (better filters in avisynth anyways)

If you still can't get it sorted out after sorting out your codecs/decoders , post a sample of the source, smallest possible that can replicate those errors with your given settings

[Enkidu]

I will try with that settings and tell you the results.
Can i use this denoising filter instead of the x264 nr ? #DeGrainMedian(limitY=2,limitUV=3,mode=1)
I'm using MEgui 3.0.5

[poisondeathray]

For now, during troubleshooting, I wouldn't use any denoising filter. These errors are serious , and you want to not confound your analysis with other variables. Once you get it sorted out, then you could tweak your settings/filters. I didn't mention above, but it could also be hardware issue. I've seen this corruption with a bad memory stick , and unstable overclock before too. If your system is overclocked, reset to default for now.

What version of x264.exe are you using? If it's not current update it from x264.nl

Also post your avs script

If you can, encoding only small sections that consistenly give you reproducible errors , so you don't waste time. You could use Trim() in your script for example, to encode a section , until you figure out what's going on

I'm using MEgui 3.0.5

Use something newer. 0.3.5.6 is current as of today . Your x264.exe version might be outdated as well - there are frequent releases that fix lots of issues.

[jagabo]

If you're using DXVA decoding be sure to use DXVA compatible settings when you encode.

[Enkidu]

Problem is solved .

This was the changes i made :

1 - Update x264
2 - weightp 0
3 - qpstep 4

My Avs script :

DirectShowSource("D:\Azureus\[Zero-Raws] Seikimatsu Occult Gakuin - 01 RAW (TX 1280x720 x264 AAC).mkv", fps=23.976, audio=false, convertfps=true)
#deinterlace
#crop
Spline36Resize(848,480) # Spline36 (Neutral)
#denoise

My encoding settings :

program --preset fast --pass 2 --bitrate 1200 --stats ".stats" --deblock 2:2 --bframes 6 --b-adapt 2 --b-pyramid strict --ref 8 --weightp 0 --ipratio 1.0 --pbratio 1.0 --ratetol 2.0 --rc-lookahead 40 --aq-strength 1.5 --merange 32 --me umh --direct temporal --subme 7 --partitions all --psy-rd 0.80:0 --output "output" "input"



Thanks for all your help ;D