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Generation Loss in the digital world?
For the past 10 years this question comes to mind, but I’ve never remembered to ask it. Weird I know. Until now… is generation loss a factor in the digi-world? I don’t mean if you convert an HD file down to a smaller format. I mean as long as you’re trying to stay true to the source , does generation loss even need to be a concern like it was in the analog days?
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6 Replies
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I’ll also ruin my rep in the COWmunity by saying.. I kind of miss analog.
Remember drop outs in analog video. Just the anoying black lines every once in a while,but the video still played fine and you could still see it all.
Not so with blocky digital drop outs sometimes completely locking up. And you can’t look past it as easy as you could analog drop out.
Message Signature:
I don’t have any charming or witty things to put in my signature. So as Peter Griffen says, “That’s may mama!” -
Hi Vincent,
I’m also waiting to see what answer you get.
As for analog video, I miss audio: Mac MR78 and
yes, even tubes, but I don’t have a reputaion to
worry about.Rick Adams
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It depends on many factors…
Let’s say you’re working with NTSC DV compression standard-def video as an example. When you capture it from a tape, the data on your hard drive is bit-for-bit the same as what was on the tape. If you do cuts-only editing and export back to a tape, it will still be the exact same data. No generation loss whatsoever (I believe Final Cut gives the option to recompress frames… if you don’t, the original data is preserved).
If you took the same footage and added titles/effects/color correction while editing and rendered in the DV format, the footage will technically be down a generation. With DV footage, this may be quite noticeable. That’s why many people convert everything to uncompressed footage, do all effects work, and then export back to the delivery format. When you’re working uncompressed digitally, there’s theoretically no generation loss as well.
Basically, whenever there’s a format/compression change or rendering step, there’s going to be a slight loss in quality unless you’re using uncompressed/lossless all the way along.
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[Vincent Strader] “does generation loss even need to be a concern like it was in the analog days? “
No that much as with the analog, but enough to be a concern.
Degradation of the picture will depends very much of the codec you use.
The only way to avoid it would be with a fully uncompressed 444 format.
rafael -
When you’re doing NLE editing, you’re generally doing “non-destructive” editing. The footage you import, if your settings match the codec of the camera, is a bit-for bit copy of the original, just a data transfer. Likewise, when editing, what’s happening is the setting of in and out points to play back that data in a certain order. Like switching around the order of songs in an ipod playlist, you’re not moving the songs, i.e. the data, you’re moving around the markers defining the play order of that data.
As I understand it, then, if you are editing only cuts, in a non-compressed format, then yes, it is pretty much a no-loss proposition after the initial ingest and whatever compression was applied then. Once you apply transitions of any kind or layering, you are creating new frames that have to be rendered out and there you encounter theoretical losses each time, but these are very small changes and usually not noticed.
This to me is like one of those debates about angels on a pin head, because even as lossy as DV25 is, thanks to transferring via SDI, I have exported and reimported to and from tape dozens of generations and not seen as much degradation as from ONE pass of dubbing the old analog formats we used to use. Now excuse me, I have to go change the onion on my belt…
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Awesome, thanks for all those informative replies guys!
I love reading that stuff.
VinnieMessage Signature:
I don’t have any charming or witty things to put in my signature. So as Peter Griffen says, “That’s may mama!”
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