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View Full Version : Help needed: a quick compressibility test Xvid 1300+ to 800/700 MB


jeffy
13th March 2007, 14:10
I need your help, again :)

I have a noisy SD capture in MPEG-2, about 42 mins, about 2.5 GB.
Then I use Xvid 1.2.-127, Dec 8, 2006 (as supplied with AutoGK 2.40) with VirtualDubMod 1.5.10.2, build 2542, Xvid all settings default, target quantizer=2, threads=2, single pass. The trouble is, the capture is noisy. So I play with DegrainMedian here and there and the result with TQ2 is about 1350 MB, resolution 720x576, 25 fps. Sometimes when the captures are not noisy, I'll get about 800 MB, which is okay for me.

I am willing to go down to 640x480, 25 fps, about 700-800 MB, single pass, but I do want to get it also from the 1350 MB AVI, not only from the original MPEG-2 file. I know that each recompression is not good quality wise, but they were noisy, so I can accept this.

The trouble is:
1) I would like to perform a quick check of the target Q2 size before doing the whole 42 mins MPEG; I know it is SelectRange (?) but don't know exactly what else I need to put into AviSynth and how long does the range have to be for it to be accurate.

2) I would like to redo the 1350 MB as described above, when messed up, into something 800 MB sized, so I would like to ask for some denoiser suggestions enabling me to do this conversion
720x576x25->640x480x25 (42 mins) (1350 MB->800 MB)

Thank you for pointers.

BigDid
13th March 2007, 22:42
I have a noisy SD capture in MPEG-2, about 42 mins, about 2.5 GB.
... So I play with DegrainMedian here and there and the result with TQ2 is about 1350 MB, resolution 720x576, 25 fps.
...
I am willing to go down to 640x480, 25 fps, about 700-800 MB, single pass, but I do want to get it also from the 1350 MB AVI, not only from the original MPEG-2 file.
Hi,

Interesting challenge. Let's say you have pre-processed your capture.

I know that each recompression is not good quality wise, but they were noisy, so I can accept this.
Noisy how bad?
Unless you have used a lossless codec (Huffyuv, Lagarith...) or a near-lossless CQM like Sharktooth V3EHR: http://forum.doom9.org/showthread.php?p=552539#post552539
, you have losses and what is gone is gone.

1) I would like to perform a quick check of the target Q2 size before doing the whole 42 mins MPEG; I know it is SelectRange (?) but don't know exactly what else I need to put into AviSynth and how long does the range have to be for it to be accurate.
For PAL you can use SelectRangeEvery(300,15), for NTSC (280,14) for a 5% comptest
or try the "enc" tool from jonny: http://forum.doom9.org/showthread.php?p=292871#post292871


2) I would like to redo the 1350 MB as described above, when messed up, into something 800 MB sized, so I would like to ask for some denoiser suggestions enabling me to do this conversion
720x576x25->640x480x25 (42 mins) (1350 MB->800 MB)
Some hints:
- Spresso() from Didée: http://forum.doom9.org/showthread.php?p=743559#post743559
- denoisers/degrainers with strong params: fast but blurry like degrainmedian(), slow but accurate like fft3dfilter(); for real slow but really effective script see RemovenoiseMC() and RemoveHighNoiseMC(): http://forum.doom9.org/showthread.php?p=814426#post814426
- resizer that soften/blurs like bicubic/bilinear
- a soft/compressible to very compressible CQM like H263/Jawor1cd/V3ULR...

What is unusual is that doing a target/1pass is not caring about size so, caring about size is going 2 pass ...
Would you care to share more?

Did

jeffy
13th March 2007, 23:06
What is unusual is that doing a target/1pass is not caring about size so, caring about size is going 2 pass ...
Would you care to share more?

Did

Thank you for a long and VALUABLE input!
I don't care if TQ=2 encode is smaller than approx. 1 GB for 45 mins.
Then I do care :D and will do a bitrate based single pass instead (800 MB - 1 GB / 45 mins). If not satisfied, I will start over :D

jeffy
13th March 2007, 23:16
I have also tried DeBlockQED(), Lanczos4Resize(640,480) with 1350 MB avi, chosen the bitrate for it to be 800 MB and didn't turn out that bad :)

henryho_hk
19th March 2007, 02:23
It seems DeBlockQED() is not for denoising. If you have a fast display card (really fast ones), try also fft3dGPU.