Re-rendering quality loss concern

everett-dale wrote on 6/9/2020, 1:38 PM

I'm creating an intro sequence that will be used in multiple videos, And depending on the video the intro may need to be time stretched to make it longer or shorter, or have an effect overlaid on it. Currently I have just edited multiple clips into a timeline and then rendered that into a video clip which in turn gets added to the beginning of all my videos. This is the only way I can figure out to make the intro into a single clip that I can manipulate in the final edit. I'm concerned that there is a quality loss in the intro because it has been rendered twice.

I've tried to just copy and past the intro edit into the finale edit, and that works but I end up with an intro that I can't Time stretch easily because it is multiple clips on separate tracks. Grouping the clips allows me to move them around as a unit, but doesn't let me add effects or transitions or to time stretch etc. as a whole. Is there a way to combine all the clips and tracks in the intro video without rendering it, or is there a way to render a video so that there is zero quality loss?

 

-everett-dale

 

Comments

3POINT wrote on 6/9/2020, 2:02 PM

I don't think that you will see a difference between a one time render and a two time render. If you can, you could use a high quality codec for your first render. Unfortunately VMS17 dropped the XAVC render output, which was a good quality codec for a first render.

j-v wrote on 6/9/2020, 2:12 PM

In the old time I did those prerenders for all kind of other projects I rendered it to Video for Windows with un uncompressed or Lagarith codec.
Don't know it the latest still is supported but uncompressed is no problem

Last changed by j-v on 6/9/2020, 2:25 PM, changed a total of 1 times.

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3POINT wrote on 6/9/2020, 3:57 PM

Today's advanced codecs are high quality which are not less than uncompressed. Depending on the resolution and compression of the used media, uncompressed makes only extreme huge files with no visable better quality.

Former user wrote on 6/9/2020, 4:01 PM

Today's advanced codecs are high quality which are not less than uncompressed. Depending on the resolution and compression of the used media, uncompressed makes only extreme huge files with no visable better quality.

It is in the eye of the beholder. You need to try different codecs to see what works for you. I used to render for large screens (30 feet or bigger) so I had to avoid compressed codecs as much as possible. If you are watching on smaller screens (phone, etc) then that is less of an issue.

Musicvid wrote on 6/9/2020, 7:41 PM

This list of software intermediates will help you choose. Only the AVI formats are truly lossless over multiple generations.

 

3POINT wrote on 6/9/2020, 11:44 PM

Does that all make sense when Everett also time stretches and wants to put an extra effect on it? Timestretching will cause already a far more visible loss due to resampling.

Musicvid wrote on 6/10/2020, 12:43 AM

If he is stretching a moving event, yes. The only sense I could read into it was that he was stretching a stationary event, where frames would not be affected, only duplicated.

everett-dale wrote on 6/10/2020, 12:37 PM

Does that all make sense when Everett also time stretches and wants to put an extra effect on it? Timestretching will cause already a far more visible loss due to resampling.

You are of course right. My concern is when looking at it from the other side of the equation. If I'm going to time stretch or add other effects, wouldn't I want the best possible quality to start with.

But after reading all the comments, I'm starting to think it might not be that huge of an issue. I come from an ancient industry (photocopying) where a copy of a copy of a copy was to be avoided at all cost! Then came digital files and each copy was (or could be) perfect. Now that I'm working with video rendering (copying) I was just surprised to see no way to avoid the copy of a copy of a copy issue rear it's ugly head from my past, especially since video is a digital file.

But as a stated a moment ago, it's starting to look like it's not the problem I thought it was.

 

Thanks to everyone who chimed in, it's greatly appreciated.

-e

Musicvid wrote on 6/10/2020, 11:08 PM

You need to research Rendering vs. Smart Rendering and Lossy vs. Lossless to learn the differences.

It's only the same game if you're careless.