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John Rolfano, DNxHD and Mac question
Joe:
I gave the film file to someone with a Mac to convert. Again, I compiled my Sony Vegas timelined movie with the DNxHD codec used to compile and followed your instructions on your web page. I went over the top and compiled with the highest setting of 4444 listed as an option. The film was,for the most part, shot on a Canon 5D Mark III, but also on a Mark II and a T3i.
Their Mac didn’t have the DNxHD codec so I downloaded the codec for the Mac from the link supplied on the web page you offered in your instructional web page.
What I’m told is the codec, after being loaded on a Mac, won’t play back the movie on a Mac. This includes Quicktime, VLC player and MPEG Streamclip. I’m told they can hear audio, but that’s it. And he’s tried it on both his home and work Macs. I’m able to play back the video on my PC, a quad core processor 2.5ghz, 8 megs ram. Granted, choppy at times, but I only want the file to serve as a master to convert to ProRes HQ.
Is it a certain version of OX 10 that is required for the codec, for example? Is there hardware, which may be older, somehow obsolste? I know he has an older version of his Mac OS 10 because I gave him a hard drive that was formatted on exFAT and his Mac wouldn’t recognize it. To fix this, I was able to put the PC made DNxHD movie file on a Mac formatted external drive and gave it to him.
Is it because I compiled in 4444 highest setting, perhaps?
Thanks for your help.
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10 Replies
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Sorry I spelled your name wrong. Waiting in line at the airport.
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No worries… I answered your other post. Your friend’s Mac is over 7 years old and may be the problem why nothing works. That’s the equivalent of someone still running Windows XP today and expecting modern cameras and codecs to work with it. Find someone with a modern computer to work with or get them to upgrade their OS X.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
It could be your 4444 encoding. And that’s almost certainly not needed. If you recall the notation for color subsampling, it’s nearly always three numbers: 4:2:2, 4:4:4, 4:2:0, 4:1:1. The reason is that this is setting the ratio of Luma samples to Cr and Cb samples in a pair of digital scan lines… 4:4:4 means you’re not tossing out any color samples.
When you’re talking 4:4:4:4, that means you’re also including an alpha channel… one additional 8 or 10-bit channel of information. This is usually meant to be transparency, and as I recall, DNxHD allows this to be rendering uncompressed, even while doing the usual JPEG-like intraframe compression on the YCrCb components.
In short — unless you’re using the alpha channel, this will make your DNxHD files large, perhaps even huge, compared to just 4:4:4 or 4:2:2… or it’ll make them lower quality, since some of the bit-budget is needed for the alpha channel (I think that’s how DNxHD does it — fixed bit rate, but it’s been awhile). I do not know if that could also be a compatibility issue… I know Vegas handles transparency, but only if you ask nicely, otherwise it’s ignored. But it’s possible the older Mac software is confused about that.
-Dave
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The 444 setting is overkill given the source cameras you list. They all generate 4:2:0. If you are using an external recorder connected to the 5Dmkiii via hdmi you can get 4:2:2.
The normal (for lack of a better word) DNxHD settings should be sufficient to preserve the original camera quality. Normal DNxHD is 4:2:2.
Nothing “wrong” with 4:4:4. Just probably overkill.
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You CANNOT use DNxHD w/ Alpha at all. Avid’s Alpha is back-as()sward encoded. The resulting file is useless in anything except Avid software. If you need Alpha, stick with QT Animation or QT PNG.
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Don’t know… I always use uncompressed files for alpha channel stuff. It remains the case that 4:4:4:4 is probably not what he wants.
-Dave
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[Tyson Onaga] “You CANNOT use DNxHD w/ Alpha at all. Avid’s Alpha is back-as()sward encoded. The resulting file is useless in anything except Avid software.”
Yea, that’s really important to remember. Avid’s alpha is the opposite of what everyone else uses and is useless in most programs. I’ve never been able to the the alpha channel recognized from a DNxHD file.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thank you all for your help.
I just got back in town yesterday.
I don’t need an alpha channel.
So, may I ask what the best quality, recommended render would be for a film shot on a 5D Mark III without overkill?
I’m going to try both rendering a new file, and ask my editor friend about the age of his Mac, his workplace Mac, and see if it is indeed hardware and/or OS related.
Thanks again.
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I am told by my friend with a Mac that his is pre Snow Leopard, and his system at work has Snow Leopard.
In both cases, the result is the same.
It can’t read the video, only audio playback.
Any other ideas?
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[Michael Gibrall] “…and his system at work has Snow Leopard.”
Did he install the Avid DNxHD codec on his system at work? I hate to have to ask but it’s important that he installed the codec at work and didn’t just try and play the file without it.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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