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#91 | |
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Join Date: Jun 2009
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Quote:
I mean, if there is any kind of limitation lack of accuracy is due to a poor design of the application. If well designed, on PLAY a system my have problem to make a perfect reading in RT, but that is just a matter of processing power. On stand-by the scope should make a perfect reading, I don't know about other NLEs, but I think that the VideoScope in FC is OK (full scan). rafael |
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#92 | |
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Quote:
But I don't see an Aperture Mode problem or mismatch in the colorbars that Piotr posted. The frame sizes are identical, there is no border around one but not the other, and the bars are exactly the same width. Actually, in all the posts I've seen by Piotr comparing EX and nano images, I haven't seen a size disparity. Since Aperture Mode changes can only affect image size (by cropping or changing the pixel aspect ratio) I never considered Aperture Mode with the nano as being an issue. But Piotr is not using FCP, so maybe that's why you are seeing issues that we seem not to be. BTW, have you tried opening the file in QT Pro and manually changing the Aperture Mode? Perhaps CD can add a firmware choice to change the Aperture Mode used by the nano? IIUC, it's just a flag in the QT wrapper that doesn't affect how the image is recorded; it's strictly for playback. Thanks and good luck, Peter
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Avid Media Composer 3.1.3. Boris Red and Continuum Complete. Vegas 8.0c. TMPGEnc Xpress Pro 4.0 Last edited by Peter Moretti; November 22nd, 2010 at 08:02 PM. |
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#93 |
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Hi Peter,
Yes, I shot too fast without realizing that Piotr was working with MXF files. However I think that in the background of the issue brought by Piotr could be some similar "displaying related" reason. - The issue that the Piotr's pics shows (Post 33) is exactly what FC shows when comparing the same clip with different Presentation/Aperture. - I don't think that Presentation/Aperture is something exclusive of QT. That feature has been set to address certain needs when displaying file-based digital Video on a computer. Somehow, MXF files have to address the same "needs". All this told from my absolute lack of knowledge on MXF files and the fact that I can't try to dig more inside that technology with my Mac. We will keep trying to put together the pieces of our puzzles :-) Cheers, rafael |
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#94 |
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I can completely understand why you would think from just looking at the scopes that the problem is an Aperture Mode issue; as I'm sure that's very similar to the way an Aperture Mode discrepancy looks.
If I were CD, IMHO, I'd be hesitant to make an all out change to the Aperture Mode from Classic to Production, but including an option to change it would be nice. BTW, have you tried changing the Aperture Mode manually in QT Pro? It's under: Window... Show Movie Properties... Conform aperture to. Good luck and I really hope this gets resolved for you. B/c the differences can be relatively minor, thus potentially passing before many sets of eyes before someone spots it. But when that happens, all hell can break loose. (I imagine there hasn't been much of an uproar over this b/c MXF is being widely used.) Take care.
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#95 |
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Join Date: Nov 2008
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A comment and a request.
If you want to go to the horses mouth, click here for the Apple tech note on the functionality of, and how Macintoshes react to, the aperture setting. Also note that Google is your friend; entering "macintosh aperture mode quicktime" brought it up as the first choice. It does not go into detail about whether the aperture mode is a flag in the quicktime header, or an atom in the data, or even whether it's Apple specific. I suspect it's in the quicktime header, but I haven't done the detective work to verify my suspicion. I also don't know if CD is embedding pixel aspect ratio or not, but that's one of the functions of the aperture mode fields. The edge cropping flag is one of the others. If CD decides it's worthwhile to implement the aperture mode info in one or more of their file formats (mov, mpg, mxf), then the discussion becomes "what should it be set to, or should it be a user menu selection". That was the comment; the request is for a moderator to separate out all these extraneous discussions from this thread, the nanoFlash Public Beta 1.6.226 Firmware Comments thread, and for everyone to PLEASE try to stop hijacking threads, (to which I guess I'm now also guilty of), particularly ones as important as this one. Billy |
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#96 |
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Dear Billy,
Thank you for posting the link. I have read it. Based on what I read, I have a few questions: 1. It only mentions SD video. Does this make any difference for HD video? It does not indicate that HD video will be changed at all. 2. We may have choosen "Classic" so that our files work with only versions of Quicktime Player and newer versions. I do not know the answer, but I do not know what will happen if we choose Production and this prevents older versions of Quicktime Player from working. This would have to be something for us to consider.
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#97 |
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Note that the aperture setting does NOT change the way the video is recorded at all, it's just a little information that the playback or editing system can choose to implement or ignore.
The cropping aspects were mostly due to the crap on the right and left of the frame that DV cameras invariably put out. The pixel aspect ratio was there for cameras that didn't use square pixels (DV again, mostly), so the aspect ratio didn't get changed on playback. (Actual pixels versus displayed pixels). As far as I know, this is only relevant in SD. Whether it was meant to apply to HiDef or not I don't know, but at least on Macintoshes, it does seem to have an effect on playback of HiDef images today, (even if it's not supposed to). In early days, before "aperture" and prosumer HD camcorders, there was a setting called "hi quality". DV format video suffered when it was turned off, though I always attributed it to course de-interlacing rather than alteration of the pixel aspect ratio (it may have been both). Back then almost nothing was shot in progressive, and this was an easy way for Apple to get rid of the interlace artifacts when played back on the (progressive scan) computer. They de-interlaced when "high quality" was turned off. Of course, they threw away half the vertical resolution that way... Billy ps From my reading of the tech note, it looks like older versions of Quicktime Player will ignore the aperture setting, so that probably shouldn't effect your decision. Newer versions of Quicktime can be told to ignore the setting embedded in the video and use whatever you tell them. In any case, more research is needed, particularly with regard to how non-Apple systems react to the "aperture" info. (What an inappropriate name to call what this setting does). |
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#98 |
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Join Date: Jun 2009
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Hi Dan, Billy and Peter,
At the end of the day I don't think the "Aperture" is any big issue. I think that is enough that the people is aware of this act, in the improbable case that somebody want to mix the same picture coming from SxS and NANO. So I don't think of the need of changing nothing on the NANO files. Billy, you are right that, up to the Apple notes, the "Presentation" is to address some issues of DV, but the fact is that that setting is in available for every QT movie, and can change the properties of the movie. I guess that the NANO-QT files just keeps the same "Presentation" option than the original standard SONY XDCAM HD 422. Cheers, Rafael PS: Just to add that I found that difference when I was trying to reproduce the Piotr tests about SxS vs NANO noise. I saw that I could never fully match both pictures. it was always like a "1 frame" off-set but impossible to correct by trimming in any direction. |
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#99 |
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I just want to add, with Billy's permission ;), that there are HD formats that don't use square pixels. Some are HDV, XDCAM (not 4:2:2) and XDCAM EX SP. These formats should all benefit from using "Production" over "Classic" Aperture Mode settings.
I am surprised that there is a Classic vs Production difference w/ nano files, but of course it's possible and seeing some frame grabs would be nice. BTW, Aperture Mode has been part of QT since 7.1, so I think the vast majority of nano users will be using a version of QT that takes advantage of the setting. And like Billy said, I'd be very surprised if the older versions of QT don't just ignore any Aperture Mode setting. HTH.
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Avid Media Composer 3.1.3. Boris Red and Continuum Complete. Vegas 8.0c. TMPGEnc Xpress Pro 4.0 Last edited by Peter Moretti; November 23rd, 2010 at 08:34 PM. |
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#100 |
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Does Programmer's Guide to Video Systems - Lurker's Guide - lurkertech.com answer your question? In brief, the clean aperture takes 16 pixels off the left edge, 16 pixels off the right, 9 pixels off the top and 9 pixels off the bottom in HD, both 1080 and 720. That preserves the 16:9 ratio.
As Billy pointed out, the full frame (production aperture) is in the file, it is just that video players are supposed to cut those edges off. Editors are supposed to use the full production aperture. This gives them some flack at the edges for things like sharpening and softening filters which need the values of the surrounding pixels to work. That way the contents of the clean aperture can be filtered properly and the final viewer never sees those edges that could not be filtered properly. Theoretically, computer players will probably show the full frame and video (non-computer) hardware will only display the clean aperture. I'm no Martha Stewart, but it's a good thing. |
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#101 |
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Dear Friends,
Billy, Peter and Adam, I appreciate your assistance. If the consensus is that this applies to HD and "Production" would be a worthwhile change, then we will, of course, consider the change. I hope everyone understands that we have to be conservative. We can cause a lot of problems for ourselves and others if we make a change and it causes unexpected problems. I will bring this up with our engineers. I also want everyone to know that this, at this time, seems like a safe change. After all, this is used by the Sony EX cameras, and I have not heard of any problem with it. While in an ideal world we could have an option for everything, having lots of options adds to the complexity of the system, and it intimidates new users. For every new option, there are many that do not understand the option and it creates confusion and uncertainty. Thus, it would be my choice to investigate this change the make it. After all, this "Aperture" function is not widely known, nor intuitive even to experts.
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#102 |
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Dear Adam,
Others have suggested that we use "Production". Is this your recommendation as well?
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#103 |
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Yes, I would go with Production since that is what you are actually saving into the files.
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#104 |
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Dan,
If you want to play it most conservatively, you might want to test if changing to Production makes any difference to those users who are having problems. That can pretty easily be done by changing the Aperture setting in Quicktime Pro and saving the file. Here's a step-by-step: Open the file in QT Pro, choose Window, Show Movie Properties and click on the Presentation tab. There is check box called "Conform aperture to:" and next to it is a pulldown menu with the four different Aperture Mode choices. Choose "Production Aperture" and save the file. That should do the same thing as changing the Aperture Mode that the nano writes. This way those users can test to see if the Aperture setting change makes any difference. But of course if you think it really isn't necessary to test this way, then I would imagine that a change to Production would not cause any problems. What I do find odd is that Aperture Mode is causing a mismatch between the EX and nano files. B/c square pixel files (which XDCAM 422 uses) should display the same using Classic or Production, AFAIK. (That's b/c Production does not crop the edges, it only adjusts for pixel aspect ratios that are not 1:1.) Best of luck with all this :)
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#105 |
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Dear Adam and Peter,
We will investigate this. Right now, based on the document that I read, for HD, I am guessing that changing to Production will not make any difference. But, we need to run some tests. We welcome others insterested in this to run their own tests, using the procedure provided above and report their results. Our employee who would normally run this test is out sick, so we will have a delay before we can test it.
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