how to make the 4:2:2 movie with the silence pictures function?

Started by ass5001, September 03, 2012, 02:31:50 AM

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ass5001

how to make the 4:2:2 movie with the silence pictures function?
thanx! ::)

ass5001


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deleted.account

I'd also like to know a bit more about the .422. I've looked at the wiki, used the couple of tools to create jpegs/pngs which don't appear very optimum.

So .422's are uncompressed raw YCC, but what about pixel format? Planar or interleaved, what I'd like to do is open them in Avisynth, but trying raw import plugins like rawsource or sashimi with any YCC pixel formats results in errors.

Silent pic was simple mode. Image size assumed was the 17--x9-- whatever exact dims are.

Cheers



deleted.account

Ok, thanks again A1ex that was one of the formats I'd tried as it appears to be the usual for raw generally, will look into it further.

ass5001

so...
who the hell cares what's the 4:2:2...
still the question,
how to make the silent pictures into 24fps movie and beat the RED Scarlet down?
HELP ::)

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deleted.account

I've had problems getting a correct frame via Avisynth, so asked the Doom9 community for help, they found a solution and suggest that the silent pic may not be being written correctly as it uses signed integer rathet than unsigned?

Any dev comment regarding this? I know tools exist that give a usable image from silent pic but...

1%

Did they elaborate? Not hard to change signed ints to unsigned. I haven't even looked at silent pic funciton so not sure.

deleted.account

I'm new to the silent pic feature so its probably already well known but it appears the raw yuv is JFIF that is chroma over full 8bit range, along with the luma and part of JFIF is that chroma is stored +- 128 centered about 0.

http://www.jpeg.org/public/jfif.pdf

Where as Rec BT 709 chroma is stored over limited range 16 - 240 so in avisynth shifting the chroma to 16 - 240 range which is what is assumed the output would be if unsigned.

Comment by um3k at Doom9:
QuoteStrangely, the chroma is offset and wrapped. My guess is that whatever program made it used a signed integer when it should have used unsigned.

My response:

QuoteWrapped? The mt_lut seems to be shifting the chroma? Is the source in that case JFIF? Where chroma is full range and I think described as centred at 0 +128 & - 127? If that makes any sense.

um3k:

QuoteI'm having trouble finding a reference for JFIF chroma storage, but if I understand your post correctly, that could indeed be the case, and would make sense in the context of a (primarily) still camera. Regardless, a modulo addition works quite nicely to fix it.

http://forum.doom9.org/showthread.php?t=165831

What is maybe interesting is if you were able to change to unsigned whether chroma in the raw yuv would then be stored rec709 and if firmware more up stream still fed it full range as if JFIF then full chroma rec709 + full luma would be xvYCC extended gamut.

http://www.sony.net/SonyInfo/technology/technology/theme/xvycc_01.html

I believe the Digic3 & 4 supports xvYCC anyway, somewhere.

JFIF is a bit of a ugly YCC format and poynton is quite critical.

http://books.google.co.uk/books?id=dSCEGFt47NkC&pg=PA175&lpg=PA175&dq=chroma%2BJFIF%2Bvideo&source=bl&ots=OL4zeJ7Vyr&sig=aoNstetOv-HN7PpZ3i-dOj2JxVs&hl=en#v=onepage&q=chroma%2BJFIF%2Bvideo&f=false