I should know this, but...
 

It seems I should know this, but...
If I edit a prores sequence, render all the CC and transitions and then output the sequence as a QuickTime movie (no change or transcoding), if I use that movie in another sequence for further editing, do I lose a generation of quality?
Would it be better to use the original edited sequence pasted into the new sequence, or is the quality the exact same as the QuickTime movie?
I ask because I am working with many sequences output as stand-alone pieces, but sections of the pieces will be inserted into a bigger documentary, and using the QuickTime movies may be more efficient.

Re: I should know this, but...
 

Technically you lose a generation but unless you are using ProRes Proxy or LT you can go something like a dozen generations before you'll start seeing visible image quality loss.

Re: I should know this, but...
 

Brian,
Any time you output a standalone movie and then importing back into the project you are losing a little bit of quality compared to the original file. Sometimes this is still the best way to deal with editing issues so I would not worry if you can't see an issue. In the old days a generation was potentially a big difference but these days it is harder to see the difference unless you changed compression schemes etc.
If you just copied the media from your sequence and placed it in the new sequence you would not be losing quality but may be harder to deal with in the new edit.Helps if everything is the same frame rate and size. One reason you might not want to do this is if the projects are not being stored on the same drives and you don't want to mix them up except for the part you turned into a quicktime. There are other reasons as well you might want to use the export import route so it is a judgement call.

Re: I should know this, but...
 

Thanks for your replies.
I will have to really think about workflow... I think retaining quality is my first priority if I can keep all the projects and drives organized without exploding my little brain.
So then, if I understand this, a prores clip when rendered in the timeline with CC and FX is a generation away from the original, exporting as a QuickTime is a generation away fom the render, and then putting the QuickTime movie into another sequence and then exporting that sequence as a QuickTime movie is another generation away?
Three generations, four including the original transcode from h624 to prores. Five after transcoding for web and then the mangling compression of whatever site it goes onto...
I think I'll take up knitting...

Re: I should know this, but...
 

You're thinking of a generation incorrectly.

If a ProRes movie is placed in a ProRes sequence where no further rendering is required, there is ZERO generational loss as this is a perfect "copy" of the original (as the media will be played out from the movie file in question).

Further to generational loss - ProRes is a VERY high quality codec so any rendering of effects only incurs a minute amount of "loss", mostly for arithmetic. If the effects and colour correction don't add noise through video gain or scaling or similar calculations, there is essentially no degradation. Compared to the days of analog linear editing where output amplifiers and line loss due to copper wire, the generation loss you are considering is inconsequential.

Now... changing formats back and forth haphazardly will CERTAINLY incur loss so exporting to 5mbps h.264 and then trying to re-edit THAT in a ProRes timeline would be disastrous to quality compared to staying ProRes... which is why we use ProRes in the first place. As an Intraframe compressed codec, we don't have to worry about the artifacts incurred in interframe codecs.