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01-25-2018, 04:09 AM
jeffpeck jeffpeck is offline
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Ok, I am capturing VHS tapes from a DAC-100 Firewire/DV converter to a Macbook Pro.

I have found that QuickTime provides the simplest interface for capturing, by simply selecting "New Movie Recording" and selecting the input device.

I select "Maximum" quality, which produces a "Apple ProRes 4444" encoded video.

It looks good to me, but I don't know much about different codecs and what sort of things to look for to determine if it's the "best" quality.

I am thinking though: The DAC-100 is producing DV output, which is compressed. It is then being compressed AGAIN when capturing as Apple ProRes 4444. Right?

Would there be any advantage to trying to make sure that it is captured as DV? And if so, what software can I use? (How does iMovie store/capture video?)

I'm not sure if I'm asking the right question, so please educate me!

To be clear though, everything looks good at this point in my setup. I just want to check if there is any additional improvements that I can make by changing something about the capture software.
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  #2  
01-25-2018, 04:47 AM
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lordsmurf lordsmurf is offline
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The obligatory: DV is never an optimal compression for NTSC, due to 4:1:1 color loss. However, for Mac, it's really the only decent solution. Given all the worse Mac choices, DV isn't so bad. This is why video was always a Windows world, for everything from capture to authoring.

But you know all this, mostly rhetorical for future thread readers.

Now, with that out of the way...

The DAC-100 is a nice box, essentially the same as the Canopus ADVC-100, but a few $$ less (both when new, and usually used). It often gave less problems than the Canopus, too. It hardware encodes to DV 4:1:1 internally, and passes that encode to the computer over Firewire.

You're having a thought exercise that applies to all video...

You can usually expand 4:1:1 to 4:2:2 or even 4:4:4/4:4:4:4 (FYI: overkill) with no quality loss. It's no different than encoding a lossy codec like MPEG or H.264 back to a lossless codec. I'd not exceed the "lossy" (but not really) ProRes422. ProRes 4444 is just ridiculous here.

The only advantage of DV as DV is 13gb/hour, instead of the huge files from ProRes. Then again, ProRes is semi-lossy, so not as large as lossless (30-40gb/hour), at about 20-25gb/hour for ProRes422. If there are for permanent archives, sure, smaller is better (without compromising quality). But if temporary working files, I wouldn't cry over 5-10gb/hour.

Your Mac setup is much newer than mine, so can't advise to closely on it. Things have changed quite a bit (on Mac) in the past 5+ years. It doesn't have the legacy compatibility like Windows does software-wise (noting that Windows XP>10 legacy hardware/video is not great). So some options and placements are vastly different now.

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  #3  
01-25-2018, 03:59 PM
jeffpeck jeffpeck is offline
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Thanks! I will have to see if there is a way to save the QuickTime file as ProRes422. I suppose I could capture at the "Maximum" ProRes 4444 quality and then use additional software to export as ProRes422 to save space. (A quick google seems to suggest that this might only be possible with Adobe Premier of Final Cut Pro, and this is not a freely available codec. Hrm...)

At least I can be confident that by using the default ProRes 4444, I will not be increasing the loss from compression.

QuickTime seems to only have "Maximum" quality which produces ProRes 4444 and "High" quality, which produces MPEG (I think).

I will have to check into what iMovie does.

I should add, I'm doing this on a 2010 Macbook Pro running Yosemite (10.10, released in 2014). It has the firewire port, which is an advantage over doing this on a newer Thunderbolt 3 Mac, which would require 3 separate dongles. So, if you have any knowledge on software that applied around 5+ years ago, it may still be applicable here.
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  #4  
01-26-2018, 01:29 AM
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lordsmurf lordsmurf is offline
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My Mac Mini is from 2010/2011, but the hardware age isn't the issue. I still use OS X 10.6 that came with it, and all the new software of the day (FCP, Avid, DVDSP, etc).

The newer OS are what has forced some older software to cease functioning. That's why I've never upgraded it. (It's not used for online anything, and has firewall in place to essentially block most all traffic in/out. So updates not a concern. I have a Windows 10 tablet and Linux desktop if I want to do anything online, like post here.)

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  #5  
01-26-2018, 09:16 AM
hodgey hodgey is offline
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I've used IMovie 7 on OSX El capitan on an older macbook to capture from DV, and it does store the captured DV data directly. I'm not sure about what it does when exporting, but the raw captured data was available in the iMovie library folder.

Adding to what LS said, another impracticality with proRes for DV footage is that prores uses 10-bit colour as opposed to 8-bit colour as used in DV and most common video formats. This makes sense for modern HD video, but it it is a bit overkill for DV, and can be impractical if you want to use Avisynth and similar for processing the captured video, as it's not very well supported.

Another alternative if it's not used for anything else is to put a different OS (some version of windows or linux) on it, or you could even run linux from a USB stick and capture using dvgrab (though you would need an external hard-drive in that case as only OS X is able to write to the OS X filesystem.

Last edited by hodgey; 01-26-2018 at 09:51 AM. Reason: Added extra line
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