HDMI Capture Problem SOLVED - AviSynth RULES!

Ralph.

In the code on page 33 it says between the lines "trim(1,0)" . That line does not appear in the code on page 1. What does it do?


Martin.
 
trim(1,0) cuts off the 1st frame

I think levels shift is from the way quicktime decodes DNxHD , it's not a problem on PC unless you use quicktime (viewing DNxHD through QT player on a PC exhibits the gammashift as well, but not when using other programs) . Quicktime is horrible, horrible for gamma (and other) issues even on Mac only software. h264 in MOV also has this problem. I'll look into it for a workaround. v210 shouldn't exhibit gamma or levels shift on mac or pc even through quicktime

You can see in this comparison, that the problem only occurs when using QT player. The 1st frame of your 2nd 009.mov clip is uncombed, so it makes a good comparison spot . The shots labelled "qt" in them are taken though quicktime. So "original qt.png" is the original ProRes reference picture.
http://www.mediafire.com/?7nisp9hivch4fd6


Not sure what's happening with vertical shift, or about the frame discrepancy at the end - you have to provide more details on what you did, maybe upload the clips . The script isn't perfect. It can make mistakes because the HDMI output from the GH2 isn't a perfect cadence ; the inserted fields aren't every say 25 fields all the time. It can occur at (almost) random spots . If you provide longer clips along with the simultaneous recording, the script can be tweaked. Ralph asked in the very beginning for simultaneous AVCHD recordings for this reason

Levels issue aside, the details retained in the shadow areas in the HDMI "half" is what strikes me. It's reminescent of Ralph's comparison of the fellow on the roof a dozen pages back.
 
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I 'm pretty sure that the vertical shift is from the chroma fix aspect of that script ; if you remove it or comment it out, there is no shift . Maybe Ralph or GrgurMG can have a look at it and tweak it a bit.

I used a different approach to the chroma shift a dozen or pages back, you can try that if you want. There is no shift with that method


Regarding DNxHD , apparently it's the way FCP (and quicktime) handles it
DNxHD reports RGB values to FCP not Y'CbCr. Therefore FCP applies its internal RGB interpretation which causes the gamma shift you see.
Click to expand...
http://forums.creativecow.net/thread/8/1028870#1028923

In avisynth you can access DNxHD in YCbCr, hence no shift.
 
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martinbeek said:
By the way; look at the difference in transitions between colors on the slate !! HDMI rules!


Martin
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Wow....even the noise looks good. I love how the dark areas are still detailed and not smoothed out (or pasty). When you put them side by side like this, and as good as the AVCHD is....I can see its blockiness and added compression noise loud and clear compared to the organic looking noise on the HDMI side. Wow,....what a difference. The colors look good also.

Thanks for being ourr guinea pig. This can really push me to getting the Ninja myself.

EDIT: Also, if you have not already noticed....you are getting a lot more latitude in your image from the HDMI vs AVCHD.
 
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By the way,...Cineform just confirmed with a user in another forum that the GH2 is outputting 4:2:2. FYI
 
Ian-T said:
By the way,...Cineform just confirmed with a user in another forum that the GH2 is outputting 4:2:2. FYI
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But it's not usable 4:2:2 , at least according to the tests done on Ralph's samples, and Barry's "wringer" sample. Go back about 10-20 pages, there are a bunch of tests there that are pretty indicative . You have to downsample the chroma in order to make it "usable" . It's full of aliasing. This effectively makes it 4:2:0

Can you post the link to the other forum ?
 
PDR said:
But it's not usable 4:2:2 , at least according to the tests done on Ralph's samples, and Barry's "wringer" sample. Go back about 10-20 pages, there are a bunch of tests there that are pretty indicative . You have to downsample the chroma in order to make it "usable" . It's full of aliasing. This effectively makes it 4:2:0

Can you post the link to the other forum ?
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Yes I remember Barry's statement.

The user is on HV20.com who sent a sample clip in to Cineform. Post #18 http://www.hv20.com/showthread.php?41961-WOOHOO!-Atomos-Ninja-just-arrived

But the issue remains that the HDLink is showing that it is upconverting the file. They are currently investigating.
 
Thanks for the link

Well Prores422 is ..... guess what... 422 :)

But that's just the recording format. If you examine the actual content , it's full of aliasing, you have to downsample it (it's effectively 4:2:0) . If you take a take 8-bit footage and encode it to cineform - sure it's a 10-bit recording format, but doesn't suddenly become 10-bit content.

HDLink will show that it's upconverting the file, if it decodes ProRes as 4:2:0 - there is likely a downsample somewhere along the processing chain

Now those (pretty conclusive) tests were recorded from AJA Io Pro, Intensity Pro and Nanoflash, so it's possible that Ninja is doing something different (but very unlikely IMO)
 
I see. So the fact that it shows as a ProRes 4:2:2 container says nothing about what went into it. We should get a clue by the aliasing and jagged edges that it was originally a lower chroma. It seems like another clue (IMO) would be the Cineform software trying to upconvert the footage to 4:2:2.

I think they would need to have an actual camera in hand and record the output directly to be more definitive.
 
The fact that it has jaggies and aliasing doesn't necessarily prove or disprove the original signal was higher or lower chroma subsampling. In fact I think it was 4:2:2 originally - I posted screenshots and evidence or this in the original HDMI thread, usin AEmonk's samples . If you want to see that discussion , have a look at that old thread. All 4:2:2 means is for every 4 pixels of luma there are 2 of Cb, Cr.


BUT - The problem here, is in order to make it "usuable" you have to downsample the chroma. Ralph suggested this first (ConvertToYV12) , in the beginning of this thread - that made the artifacts go away. Essentially what you are doing is downscaling, then upscaling the chroma. So if you are using the GH2 HDMI, it will effectively be 4:2:0 (you are downsizing Cb and Cr to 960x540 instead of 960 x1080)

Cineform trying to upsample the footage indicates that it "sees" the recording format at 4:2:0. It's decoding Prores422 as 420. There is no way HDLink can determine anything about the actual content - it can't distinguish between 8-bit 4:2:0 content converted to a 10-bit 422 cineform intermediate for example. It will "see" that cineform sample as 10-bit 4:2:2. Would it try upsample that? No. Even though the original content was 8-bit 4:2:0.

Now, no chroma tests specifically have been posted using the Ninja and the GH2, but I doubt the results will be any different than the Nano, AJA IoPro , or Intensity . But if we examine Martin's test clips, there is quite a bit of aliasing in Cb and Cr , simlar to all the GH2 HDMI footage
 
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Well, I've made screengrab from last Martin's file (it was progressive one), dropped into PS, converted to Lab. There were 1-pixel vertical gradations and only 2-pixel horizontal gradations in a-b channels, so it wasn't just additional resolution from luma during colorspace conversion. What's that? 4:2:2? Broken chroma? Some field differencies? Hate to ask, but could anyone shoot color resolution chart with GH2+Ninja?
BTW, is it nescessary to turn off everything on built-in LCD screen to get clean HDMI out?
 
SLoNiCK said:
Well, I've made screengrab from last Martin's file (it was progressive one), dropped into PS, converted to Lab. There were 1-pixel vertical gradations and only 2-pixel horizontal gradations in a-b channels, so it wasn't just additional resolution from luma during colorspace conversion. What's that? 4:2:2? Broken chroma? Some field differencies? Hate to ask, but could anyone shoot color resolution chart with GH2+Ninja?
BTW, is it nescessary to turn off everything on built-in LCD screen to get clean HDMI out?
Click to expand...

It is not necessary to manually clear the display information, since it will be cleaned from the HDMI signal the moment you press Record. You'll have to go into recording in order to get the correct HDMI signal anyway. The only thing you have to disable is the Highlight warning. I use two Custom settings on the mode dial on the camera; C1 with, and C2 without Highlight warning.

I only have an old Fuji film colorchart that i used during my good-old film days (s-16mm) and i don't have a fancy mcBeth card. It only shows RGB, black and 50% gray. So i gather that won't help you very much.

For Ralph and PDR, i have put the last un-altered "stutter" footage in a zip file (both AVCHD and Ninja), see link below. It's awfully dirty footage; poorly exposed at 400ASA, but nice as a worse case scenario for this test (as it turned out). I published the script that i used some posts earlier.

I had to remove older test footage from my server because i've gone through my 2GB storage limit, so some older footage in this thread is now offline.

AVCHD Cinema 24L, 1/50, nostalgic style.
ProRes 422 from Ninja, 50i.
The Ninja was started after the GH2 was put into record. I did not touch any controls on either device during the shoot.

"Raw" AVCHD and Ninja footage:
http://mediatube.marvelsfilm.com/april6.zip


The side-by-side example of AVCHD and processed AviSynth is still online: http://mediatube.marvelsfilm.com/dual_h264.mov
(Avisynth on the right; there is a hick-up around 6 secs in the Avisynth part).

Cheers!

Martin.

PS: Good news from Dave at Atomos: their techies are sure they're able to solve the green stripes problem in one of the following Ninja firmware releases!! It's (another) GH2 HDMI timing issue. Further, they now have several GH2s (also PAL) that they'll test thoroughly in the very near future. Their commitment gives me good hopes for having their techies to come up with a total GH2 solution, but that's just my wishful thinking...;-)
 
Good news from Atomos

Martin - I would suggest waiting until the firmware update before doing other tests. It may change other things besides the stripes

BTW, there are free file hosting sites available , e.g. mediafire.com, megaupload.com, sendspace.com, fileserve.com - some of them have size upload limits, but some are 1GB
 
huatao said:
Hi, I'm new here. I just read that thread from HV20.com, but isn't it talking about the canon HV20, not the panny gh2 ?

Or am I missing anything ?
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You're absolutely correct. My mistake. There are a number of folks there using the GH-2 and I didn't catch that. But now this makes me even more curious on why the HD Link is upconverting the ProRes file from that camera. PDR's explanation for the GH-2 makes sense if it in fact was the GH-2. I'm starting to now wonder if any of these consumer cameras actually output a true 4:2:2 signal over HDMI.
 
Hi, as I said I have no problems to get a from the 24P ( out 50i HDMI) a clean 25P. Please can you tell me after which seconds I should have asynchronous frames. The video I made today is about 50 sec. and I can't see any frame errors...
 
Amadeus5D2 said:
Hi, as I said I have no problems to get a from the 24P ( out 50i HDMI) a clean 25P. Please can you tell me after which seconds I should have asynchronous frames. The video I made today is about 50 sec. and I can't see any frame errors...
Click to expand...

Hello Amadeus.

Can you explain your workflow to me in a step-by-step fashion?
Can you supply a processed file?


Thanks,
Martin
 
martinbeek said:
(Avisynth on the right; there is a hick-up around 6 secs in the Avisynth part).
Click to expand...

The "stall" happens just before you went out of record on the camera. That's why I recommend stopping the HDMI capture before stopping the camera. It prevents things like this from occuring.
 
the file is uploading now and around 500MB.....done:

http://www.megaupload.com/?d=NC4PLESB

I upload the file as is so you can switch from 50i to 25P. Probably you need BM codec, I captured with the lowest BM MJPG.
The codecs comes with the drivers: http://www.blackmagic-design.com/support/software/ download e.g. latest Intensity driver Mac/Win and install to get the codecs.

The workflow is simple : camera video settings 24P, ( KIPON adapter with my 24-70 Cannon lens is fitted to GH2).

First I turned on the GH2 then I attached the HDMI cable who is connected to my Intensity shuttle. Don't press the camera rec. button..it's liveview capture, record liveview to HD with BM Media Express.

Blackmagic capture settings:

38e9b0db5c4b57def31969718e16d685.png


AE settings:

0163c37073826f12d49b03a1106a7039.png



thanks for verifying
 
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Ralph B said:
The "stall" happens just before you went out of record on the camera. That's why I recommend stopping the HDMI capture before stopping the camera. It prevents things like this from occuring.
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Mmmm.... are you sure? There are at least four seconds before scene end on the hdmi shot.
But, i'm certainly not going to question your expertise! ;-)

In the Avisynth script is mention of tweaking a certain parameter; is that still necessary, or is the standard setting sufficient?

I'll wait with further experiments until the next Ninja firmware arrives.

I have a meeting tomorrow with the service manager of Panasonic Belgium/Netherlands. Want to compare my old (december 2010) GH2 with an april 2011 model. Further i'll certainly discuss the whole HDMI saga. Not that it'll leave much of an impression i'm afraid... But the more people complain... who knows.

Thanks,

Martin Beek
 
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