Working space in After Effects

Started by ilia, August 17, 2013, 04:32:11 PM

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deleted.account

I've never seen, heard or read of 16bit Prores, where have you found that?

reddeercity

Quote from: y3llow on August 25, 2013, 01:09:51 AM
I've never seen, heard or read of 16bit Prores, where have you found that?
I have done this though Adobe Media Encoder, in the Advance setting.
here a link that talks about it from Apple Support page
http://support.apple.com/kb/HT5151

deleted.account

I see now, thanks. 16bit profile is ARGB not 4:4:4:4 at all.

andyshon

We use Rec709 (16-235) as our AE working space, then export to DPX with output space set to working space and Cineon options set to full range. This way we can grade by eye in AE, open the files in Resolve (video levels 64-960) with the AE look maintained, but still have enough latitude to make considerable adjustments in Resolve if needs be (super whites and super blacks present in the raw are maintained in the DPX even though they may be clipped by the AE grade).

I don't know if this is the proper way to work with DPXs or with broadcast levels, but it works for us. And we've also submitted these files to broadcast clients and our stock library with no reported problems (though these were timelapse sequences shot cr2 rather than ML raw).

deleted.account

If it works for you then it is all that matters, although I think you may be stretching you levels back an forth between full and broadcast possibly and that is also inferred by your mention of super blacks and whites, there won't be any in raw as its not HDR and rec709 limited range workspace will restrict the possibility also, full range rec709 workspace would allow supers, going to full range cineon if levels scaling also occurs then you've stretched levels out.

But you say it works for you, so that's good.


andyshon

If I use the full range space then whites/blacks are clipped in the DPX. If I use 16-235 then super whites are retained, if they were present in the raw file.

And I don't see where we're going back and forward? We go from the sensor space straight to rec709 16-235, and stay there. Setting Cineon to full range means it passes the working space unchanged. So our DPX has rec709 colours and gamma with black at 64 and white at 960.

andyshon

With default settings ACR puts quite a bit of data in the super black/super white portion of the signal, or if a non extended space is used for output, it clips this data.

And when I say we grade by eye in AE, I really mean in ACR.

deleted.account

Quote from: andyshon on August 25, 2013, 04:16:38 PM
If I use the full range space then whites/blacks are clipped in the DPX.

Yes, agreed because 16-235, 240 chroma is 0-255 RGB, 0-255 YCbCr doesn't fit unless converted to RGB using a slightly different calculation or a format like OpenEXR is used and a 32bit work space chosen so you can have levels below 0.0 and highlights greater than 1.0 but then apps like Resolve can't handle EXR but AE can. DPX is an odd choice though unless the recieving app requires it. For AE 16bit half float EXR is a better choice if your talking about holding onto supers.

QuoteIf I use 16-235 then super whites are retained, if they were present in the raw file.

No they don't because supers don't exist in 16-235 they live in 0-15 & 236 to 255 YCbCr. :-) There are no supers going from raw unless you specifically scale them that way into 0-255 YCbCr  and then trying to set black RGB at 16 YCC and white at 235 YCC to 255 RGB then you'll get supers but at that point you've scaled luma and chroma back and forth. :-)

raw camera space to RGB is not HDR and a typical 16bit integer pixel format or 10bit log are more than sufficient to hold more than 9 stops of camera raw? Where as your rec709 limited range by specification is typically 5 stops. So it appears you're restricting your 'latitude' and normalizing it into a limited range work space, then later dropping it into a full range cineon space to offer chance for wiggle room, seems like AEs DPX options are the problem, Resolve takes full range DPX? But AE doesn't offer it in its DPX?

QuoteAnd I don't see where we're going back and forward? We go from the sensor space straight to rec709 16-235, and stay there. Setting Cineon to full range means it passes the working space unchanged. So our DPX has rec709 colours and gamma with black at 64 and white at 960.

Well there in lies the confusion and why I mentioned scaling of levels, you say you put rec709 into full range cineon, ie: 0 - 1023 and I said then IF those levels are scaled from 16-235 ie: 64-960 to full range 0-1023 then thats not best practice but you conclude that your levels don't scale, fair enough I did say IF and possibly. :-)

andyshon

Oops. big plate of humble pie for me. This is not working how I thought it was, how i was told it would, and I'd not checked it properly divy that I am. Thanks for the warning, very timely as it happens.

I usually use essentially this workflow but exporting to DNxHD, which did seem to work. I could pull real data back into highlits or shadows in Resolve. The DPXs definitly don't work like this though. Is there a way to get a proper broadcast levels signal into a DPX from AE, or am I flogging a dead horse?

Canon raw files can contain upto 11 stops, and with some cross channel highlight reconstruction you may get a little more. In my experience a default conversion via ARC to a standard RGB space will clip some of this. And likewise if you grade for output in ARC you are likely to clip some data. But then I much prefer to do this rather than do a low contrast conversion at this point. This makes sense for us as our stuff often goes straight off for stock from AE.

deleted.account

Quote from: andyshon on August 26, 2013, 12:49:58 PM
Oops. big plate of humble pie for me. This is not working how I thought it was, how i was told it would, and I'd not checked it properly divy that I am. Thanks for the warning, very timely as it happens. I usually use essentially this workflow but exporting to DNxHD, which did seem to work. I could pull real data back into highlits or shadows in Resolve.

Not to stray into the minefield of encoding and decompressing video and 'limited' vs ' full range' handling by applications but if you used a rec709 (16-235) workspace in AE to DNxHD then there'd be no supers. If you used the non limited rec709 space you'd very possibly get a DNxHD encode with full range levels and therefore supers. But you can have a situation where a receiving codec like QT may scale levels say 16 - 235 to 0 - 255 giving you a brighter washed out appearance lifting shadows and pulling down highlights or a codec crushing the dark supers to RGB 0 (black) and compressing the highlight supers to RGB 255 (white) and stretching the levels out in between. Possibly giving the appearance of more latitude to play with.

QuoteThe DPXs definitly don't work like this though. Is there a way to get a proper broadcast levels signal into a DPX from AE, or am I flogging a dead horse?

I'd have thought your rec709 (16-235) work space dictated proper broadcast equivalent levels in DPX output. Are you not seeing that then, the part I questioned previously was outputting limited range into DPX full range, seemed like levels scaling might occur?

However is rec709 (16-235) really what you want to develop your raws into though, yes it's your final output space but you're intermediate is DPX and your outputting through Resolve?

Have you tried a wider working space in AE, exporting as full range DPX and importing into Resolve as full range, monitoring in Resolve via a rec709 display lut / calibrated monitor and encoding to rec709 video formats from there? You'll be monitoring / previewing as rec709 (16-235) so things may appear to be clipping and crushing in preview although your scopes should tell you otherwise as the 32bit work space should ensure no clipping whilst you grade and making your choices on how you compress your DR into rec709 for final encode?

QuoteCanon raw files can contain upto 11 stops, and with some cross channel highlight reconstruction you may get a little more.

Well I was being conservative when I said hold more than 9 'stops', linear encoded 16bit tif output will hold theoretically 16 stops with decent gradation which is what really matters rather than theoretical 'stops', 10bit log I'd assume much the same but it's subjective really, first how many stops are really usable re: noise, shooting ISO will affect that, then with regard to mixing from other channels that's a bit subjective too depending on the scene DR, exposure choices and color of light source(s), which channel clips first and how quickly followed by the increased noise from the multiplied weaker channels to get the white balance 'accurate'.

QuoteIn my experience a default conversion via ARC to a standard RGB space will clip some of this. And likewise if you grade for output in ARC you are likely to clip some data. But then I much prefer to do this rather than do a low contrast conversion at this point. This makes sense for us as our stuff often goes straight off for stock from AE.

There's no such thing as 'standard' RGB space :-) and it can be unbounded creating values massively bigger and smaller values than 0.0 - 1.0 display space without clipping, take ACES for example, but Canon raw is neither HDR or ACES. :-) Going back to the 32bit work space, we preview in display space 0.0 - 1.0 so we see clipping 'by eye', visually because our displays can't handle the values but the scopes will show no clipping, so it can be misleading to think data is getting clipped when in reality you can store a wide dynamic range in an intermediate file format and in a 32bit workspace but have to make choices on what to display in a limited DR output like rec709 (16-235) generally at 8bit on 6 or 8bit monitors with typically poor calibration :-)

BrotherD

 Thanks y3llow, I like the way you patiently answer questions. Is this your or one of your raw workflows from AE to Resolve?

"Have you tried a wider working space in AE, exporting as full range DPX and importing into Resolve as full range, monitoring in Resolve via a rec709 display lut / calibrated monitor and encoding to rec709 video formats from there? You'll be monitoring / previewing as rec709 (16-235) so things may appear to be clipping and crushing in preview although your scopes should tell you otherwise as the 32bit work space should ensure no clipping whilst you grade and making your choices on how you compress your DR into rec709 for final encode?"

Derrick

deleted.account

Hi, I'm new to raw video and with compressed video such as h264 out of a Canon for example I'm really happy with the appearance of it using Vision Color or Cinelook non grading picture styles, I like the combination with my old manual lenses and the idea of straight out of the camera, so I do very little grading plus I no time to devote to it.:-)

However I have used AE to Resolve for DPX simply because QT decompression in Resolve constantly crashed with the files I was feeding it so just gave upnon it.

I think though with raw, really want as few steps, as little manual intervention and minimum intermediate storage cost as possible to get what we want from raw to a 'usable' format, so I'd not use AE for the raw to intermediate stage at all.

Instead if going to Resolve due to its 'bad' Canon raw handling currently go from raw to a flat output in a flavor of 10bit 4:4:4 or if really need be 16bit tif (if Resolve can handle it) or 10bit log DPX using a batch script, dcraw and imagemagick. Like via tin2tins eyeframe.

Just using dcraw to get a flat linear RGB output to bake WB but with no camera curve applied. Rather than via ACR flattening to combat the camera curve I assume ACR adds before export, but I doon't know, never use it. :-)