HD to SD conversion

[Tuik]

Hello,

I have many movies come from bluray in 720p or 1080p and i'd like to backup them into smaller files with xvid encoding. This backup smaller files are to be seen in SD televisions so the resolution of the final file should be 720x(proportional height). Of course, i want the max quality possible and the loss of detail to be minimal.

At this point i have already created one small script which i think satisfies my requirements... I used this options due the reading i've done here


Loadplugin("C:\Program Files (x86)\AviSynth 2.5\plugins\FFMS2.dll")
Import("C:\Program Files (X86)\AviSynth 2.5\plugins\Seesaw.avs")

FFmpegSource2("video.mkv")

#Crop(0,80,1280,544)

Spline36Resize(720,304)

SeeSaw(NRlimit=2, NRlimit2=1, Sstr=2.2, Szp=100, Slimit=-3, Sdamplo=10, Spower=6, sootheT=30, SdampHi=40)



Now, because i'm newbie at this, i don't know if this is a good combination and, although i've reached acceptable results so far, i would like to know your opinion about the best way to convert hd source in a sd one with the best detail and sharpness possible without much noise and jaggies.

Thanks for your opinions

[7ekno]

SeeSaw not needed, you are resizing from a relatively clean source ...

Spline36Resize is considered a "neutral" resizing (with regard to blur / sharpening) ...

If you want more sharpening in the final output, simply resize with Spline64Resize or Lanczos4 ...

If you want more bluring in the final output, simply resize with Bilinear ...

7ek

[stax76]

There is some things you can do for speedup, using DGDecNV for decoding, cropping and resizing for instance (assuming you have a Nvidia card and buy a DGDecNV license).

[Guest]

I have many movies come from bluray in 720p or 1080p Where are you getting these movies?

Other posters, please refrain from answering until this is clarified.

[Tuik]

They are backup's i made long time ago from my blurays. And now i'd like to convert them all again to xvid in SD. I aprecciate your help.

[Guest]

Start again from your source disks for maximum quality.

[Tuik]

Yes, but i still have my question...

Is this script good for downsizing keeping the detail and sharpeness?

With the original disk which is heavier the script is like this:


Loadplugin("C:\Program Files (x86)\AviSynth 2.5\plugins\FFMS2.dll")
Import("C:\Program Files (X86)\AviSynth 2.5\plugins\Seesaw.avs")

FFmpegSource2("video.m2ts)

#Crop(0,80,1280,544) #If Needed

Spline36Resize(720,304)

SeeSaw(NRlimit=2, NRlimit2=1, Sstr=2.2, Szp=100, Slimit=-3, Sdamplo=10, Spower=6, sootheT=30, SdampHi=40)




What do you suggest?

[wonkey_monkey]

so the resolution of the final file should be 720x(proportional height).

Not necessarily... standard def television doesn't really have a resolution in that sense. How were you planning on playing these files back?

David

[Tuik]

Not necessarily... standard def television doesn't really have a resolution in that sense. How were you planning on playing these files back?

David

Really? I always assumed that standard PAL resolution was 720x576.... could you explain me better?

The files are to be played on a standard standalone dvd player which reads divx/xvid.

Thanks for the help

[IanB]

A lot of standalone dvd player which reads divx/xvid assume the pixels are square so 720x544 (4:3), 720x400 (16:9) & 720x304 (2.35:1) are the appropriate size.

One of the players I have treats 720x576 and 704x576 xvids specially in that it does not adjust the PAR, i.e. straight through 1 for 1. But for 720x572 it assumes square pixels and pillar boxes the image as 699x572 (5:4), bah humbug!

The player a friend has actually reads the aspect flags in the xvid stream inside the .avi container which is usually good but does occasionally cause problems when I borrow his disks.

Experiment with your player and display setup to see what does and does not work well. Check all the boundary sizes like 320x240, 352x240, 352x288, 352x480, 352x576, 704x480, 704x576, 720x480, 720x576, 768x576 & 1024x576 for irregular behaviour.

Also I tend to use Spline16Resize as it has less passband ripple when downsizing.

[Blue_MiSfit]

@IanB

How did you measure the passband ripple for spline16? I'm very interested in learning more about these sorts of things.

~MiSfit

[IanB]

By eyeball :-...
Wide=704 # 624
High=400 # 352
A=Spline16Resize(Wide/2, High, 0, 0, Width()/2.0, 0) # Left half
B=Spline36Resize(Wide/2, High, Width()/2.0, 0, 0, 0) # Right half
StackHorizontal(A, B)

[thetoof]

Tuik, don't forget colormatrix to convert from rec 701 to rec 601 (different matrix for HD and SD iirc)

[Tuik]

Thanks ;)

thetoof, what it's that of colormatrix? I really don't what it means....

[thetoof]

HD is encoded using different coefficients than SD; the encoder usually assumes that HD = rec.709 (typo before) and SD = rec.601, so if you don't properly convert them it messes up your colors. See colormatrix docs for more info. Plugin and guide - http://web.missouri.edu/~kes25c/

[Tuik]

Thanks... Another thing, the sharpener is after or before the resizer? Is this sharpener and its settings good for what i want?

Once more, thanks for help ;)

[thetoof]

Sharpening while going from HD to SD would be overkill, in general (as 7ekno said).

A resizer I like to attain great sharpness with minimal artifacts is when downscaling good sources is automttap3 (part of sssharp by *.mp4 guy). One way to use it would be spline36 to 2x the destination resolution and then 0.5 downscale with automttap3.