Avisynth and Divx

[cd090580]

Hi,

I'm trying to convert some music videos (in vob format) recorded in my standalone dvd Recorder (TV source is analog) to Divx format to play them on a portable video player.

I've tried Dr Divx which gives good results but the crop/resize/deinterlaced included in the codec are hell damn slow.

So I'm trying with VirtualDub filters which is a lot faster (about 5 times the Dr Divx).

Now, I'm trying to do the same with avisynth script to expect a little speed improvement.

Here is my avisynth script:

video=Mpeg2Source("c:\divx\nolwen.d2v")
audio=Wavsource("c:\divx\nolwen T01 2_0ch 256Kbps 48KHz.wav")
audiodub(video,audio)
LeakKernelDeint(order=1,threshold=10,sharp=true,forcecpu=2)
Crop(18,80,-8,-84)  #new resolution 694x412
LanczosResize(384,172)

This script runs quite well, but I'd just wanted some advices about this script. Do I use good plugins or in good order in my script to achieve best quality ?

I create my d2v with DGIndex with the following settings:
->Video->IDCT Algorihtm->32 Bit MMX
->Video->YUV->RGV -> TV SCale

And for the Divx Codec (6.4.0) I use these settings:
Certification Profile: Portable
Bitrate: 800 Kbps 1 pass
Encode Mode: Balanced
Bidirectional: Disabled
Keyframes: 150
Threshold: 50 %

Noise reduction: disabled
Quantification: H263
Progressive source
Improvements: Disabled

Is it good to have a decent quality without too much macroblocks (especially in dark uniform parts of the video) ???

[jagabo]

Constant bitrate encoding will not get you the best quality. Use 2-pass variable bitrate (will take twice as long to convert), or single pass quality mode (you get the quality you ask for but you don't know the final file size).

[cd090580]

Each pass has the same speed or the analysis pass is much faster than the encoding one ?

[jagabo]

Each pass takes about the same amount of time.

[cd090580]

ok

Thanks

[cd090580]

Ok, With Divx 6.4.0 I noticed they have added a new option: Fist Pass (Fast) Which takes about 10 minutes to process a 3 min 40 s video. And the second pass runs at normal speed so this new way seems ok for me.

But now, I have another video which I can't get rid of Macroblocks even with a 2 pass. This videos use a lot of flashes, water effects and pyrotechnics.

It's final resolution is 384*164.

Here is some screens of the video:









What filters/presses can I add to try to reduced these blocks a max as I can ?

Thanks

[guns1inger]

None. These have come from the Divx encoding after avisynth has passed the video to Divx. You need to use a higher bitrate when encoding to reduce these.

[jagabo]

Some of those macroblocks may be in your MPEG source. Given the size of the sample images I'm guessing they are from the MPEG file, not the shrunken Divx file.

You can use MSU's Deblocking or Smart Deblocking filters in VirtualDub to remove macroblocks in your source.

[cd090580]

Ok I will Try these filters. Macroblock are probably in the source files (I can't see them while playing in PowerDVD). And here the jpeg compression for the screen probably increase them a lot.

[guns1inger]

You also have to remember that those images are double what you have endoded them to. If you are already in avisynth, try blockbuster, just to save you going out to virtualdub, or having to change colourspace to use the MSU filters in avisynth.

[cd090580]

Thanks,
I found a great filter ( Deblock() )provided with dgdecode.dll for avisynth. It does a very great job for the video.

One last question: I have another video capped from a vhs but the are some analog noise (poor tv quality at home).

When I do a 2 pass encode, do I need to enable the denoise in divx for the first pass ????

[guns1inger]

If you have an avisynth script, try peachsmoother for noise removal. Does wonders on VHS material.

[jagabo]

When I do a 2 pass encode, do I need to enable the denoise in divx for the first pass ????

Settings that effect the picture should be the same for both passes. It's up to you to decide whether the filter helps or hurts your video. Keep in mind that removing noise will also remove small details.

[cd090580]

If you have an avisynth script, try peachsmoother for noise removal. Does wonders on VHS material.

PeachSmoother doesn't work (SSE failed). I will try with denoiser embedded in divx codec