Reusing previously rendered footage

[Tero Ahlfors]

[David Bowman] “Is there a degradation in final output render if I take segments of projects that have already been rendered (that is, use the rendered .mov file as a source in a new project) as compared to going back to the original source material to use in the new project?
“

If it’s H264 you’re compressing already compressed stuff and it will degrade a bunch every time you make a new version. If you use a better codec (like Prores or DNxHD/DNxHR) it will deal with generation loss better but it will also take more space.

[Jon Doughtie]

Tero hit it on the head. H.264 is good as a final delivery codec; not good for multi-generation editing.

But you also have to figure in your time, your final deliverables, and your audience. Experiment with a short segment and go through your process. You can decide whether the final quality is acceptable to you or not.

System:
Dell Precision T7600 (x2)
Win 7 64-bit
32GB RAM
Adobe CC 2015.02 (as of 6/2016)
256GB SSD system drive
4 internal media drives RAID 5
Typically cutting short form from HD MP4 and P2 MXF.

[David Bowman]

Thank you. That is very helpful.

[Duke Sweden]

If it’s just for a family end of the year treat then the quality loss is hardly worth considering. I recently took all of the videos I’ve made over the past year and made a 3 minute music video out of them, and, as I said, picture quality loss is almost non-existent to the human eye, and I use an HDTV for a monitor.

Obviously the quality would not be acceptable for broadcast, but if you’re not handing the file over to the BBC or Discovery Channel, then go with previously rendered. I say this as an amateur of course, but even the pro’s above me will kind of agree. Right?

[Tero Ahlfors]

[Duke Sweden] “I say this as an amateur of course, but even the pro’s above me will kind of agree. Right?”

If you personally don’t care about the quality and you’re not putting yourself on the line professionally then yes, I’d agree. The quality drop might not be apparent if you don’t know what to look for but the more compressed it is the more damage there will be. That’s one reason why some higher end systems (Quantel IQ, Autodesk Flame/Smoke) can/will transcode any compressed footage to an uncompressed format (like dpx sequences) when importing to stop the generation loss. It won’t make the original footage better but it won’t get worse when one is working on it.

Here’s a real life example of an extreme first generation quality loss where the original footage was the culprit: https://forums.adobe.com/thread/1907048

[Duke Sweden]

“If you personally don’t care about the quality and you’re not putting yourself on the line professionally then yes, I’d agree.”

That’s precisely the part I was asking if you agreed with. That situation, not the practice itself. Cheers.

[David Bowman]

These are all great thoughts, thanks.

I particularly like the idea of running a test and seeing the difference. I think I’ll try a side-by-side comparison. As someone mentioned above, it may be that my intended audience can’t even detect the difference, and it sure is faster to just pull in the fully rendered old videos.

Going forward I should probably find a way to just “set aside” the very best clips in a given project right after I finish with it, so that they are easy to find later. I am still sort of new to this as a hobby and haven’t really perfected my workflow.

Thanks for the advice.