Render Questions

[Tim Cee]

Okay.....Thanks to Vasst, Jetdv.com and of course countless hours scouring the forums here at DVi, I am armed with enough basics to be a danger to myself. I have gone from learning to shoot with my Canon xha1, capture what I shot to my PC, to editing in Vegas and am close to the point of getting ready to render something I think? I have a basic question regarding what happens after I render my test project to whatever format or output decided.
Once rendered does it destroy or otherwise degrade the project? I come from Still Photography where you save a copy of your raw image as an original, save a lossles or tiff file copy of your edited image then make copies of whatever size and output. In Vegas Can my project for example be rendered from the timeline first for let's say Vimeo, then use the same project for a Windows avi, then use the same project again to make a dvd? Does the project degrade after rendering? Am I missing something? I have a basic understanding of batch rendering in Vegas but feel I may be missing something here. Could use some input, Thanks in advance.

[Perrone Ford]

Rendering is the equivalent of a "Save Copy". It is totally non-destructive.

[Tim Cee]

Thanks Perrone, I appreciate the help. I am glad to hear that.

[Tom Roper]

The project does not degrade. As long as you render from the project, there is no additional degrading except for the render itself, which is unfortunately a copy with a generational loss.

Rendering is not a save copy. It is a re-encoding of the video, a generational loss. It is the equivalent in your still camera of saving a raw file as a .jpg.

The exception that Perrone is probably referring to is when you render files that are already in a lossless format, like AVI, or cineform intermediate. But if you render mpeg-2, or AVC, or WMV, or any compressed format, it's lossy.

"Smart rendering" on the other hand, is a more lossless process applicable to simple cuts/adds/splices editing for compressed formats like mpeg-2, where otherwise no color correction is applied. With smart rendering, only a few frames around the edit point are re-encoded.

Vegas can smart render HDV by the way.

[Perrone Ford]

Tom, my analogy to it being equivalent to a "save copy" was only in reference to it being non-destructive. Of course you are right, there is generational loss, as well as other kinds of losses happening as well including detail, chroma, and perhaps luma and resolution as well.

So it could be the equivalent of going from RAW to TIFF or RAW to JPG, or RAW to GIF depending on what render is being done. However the "RAW" image is untouched in our render scenario, and that is all I was trying to convey.

[Edward Troxel]

It also depends on several factors, though. For example, starting with DV-AVI rendering to DV-AVI with NO EFFECTS will be an exact copy. There are other smart rendering formats as well. When you start adding effects, every frame must be rendered. When you render to a different format, every frame must be rendered. In those cases there will be a generational loss. But there could also be color information changes as well. So it's a much more difficult question than a simple response can answer.

[Tim Cee]

Thanks for the help everybody. So if I understand you all correctly the rendering process is not what will degrade the project, the effects added to the project is what causes the degradation?

[Perrone Ford]

Originally Posted by Tim Cee

Thanks for the help everybody. So if I understand you all correctly the rendering process is not what will degrade the project, the effects added to the project is what causes the degradation?

Tim,

You are confusing us. When you talk about "the project" are you talking about your original source material in the timeline, or are you talking about the rendered file? They are not the same. Your original files will remain untouched. The rendered file will show differences depending on how it's encoded. And depending on how it's encoded, it may well show degradation with NO effects.

If you open a RAW still and save it as a JPG without touching anything, you'll lose quality. Same scenario here. You still have the RAW file, and here you still have the source material.

[Tim Cee]

Hey Perrone, sorry about the confusion. I am at the rendering part of the Vasst Series of Tutorial DVD's and having trouble understanding it so that was the reason for my question. I will try to rephrase it below. I aplolgize for my lack of the vernacular thus far but I am trying.
Okay, I drag some of my captured HD clips down on the time line then do my transistions and titles and what not's. I am calling that work I do my project. Each time I close that work in progress it saves it with the edits or changes i just made, I get that. Then later I get back to it and make some more editing changes or add ins or something. Okay, Now I feel I am done with the project and want to (render?) it. Now here is where the question comes in. Let's say I want to take that project from the time line and make a clip to share with DVi on Vimeo. I do that and all is good, I understand how that works. But then let's say next I want to take that same project from the time line a few days later and make a windows media clip of it to watch on my PC. Then let's say a few days later I want to take that same project again from the time line and make a DVD to watch at home. Does this project degrade after each render? Sorry everyone for the confusion and my lack of skills but I am working at this feverishly.
Thanks for the help everyone.

[Perrone Ford]

Originally Posted by Tim Cee

...But then let's say next I want to take that same project from the time line a few days later and make a windows media clip of it to watch on my PC. Then let's say a few days later I want to take that same project again from the time line and make a DVD to watch at home. Does this project degrade after each render? Sorry everyone for the confusion and my lack of skills but I am working at this feverishly.
Thanks for the help everyone.

I think I understand, and the answer is no. Rendering is not destructive to your process. You can render different versions indefinitely.

What we typically do is to create a "Master" render when we finish our projects in a very high quality format. Then when we want to make copies later, we use that Master to do so. This is often much faster than forcing the computer to recalculate all the transitions, etc., every time we want a new copy. Some people erase the originals once the master file is created. Some keep the original materials in case they want to edit differently, make different titles, etc.

Does this help?

[Mike Kujbida]

Originally Posted by Tim Cee

Does this project degrade after each render?

No it doesn't.
The only way for it to degrade would be for you to render (encode, to be precise) to one format, then take that encoded file and re-encode it to another format.
As long as you encode from the original timeline, the only quality loss (degradation) you'll see is the conversion to a different format (for example, DVD).
Think of it as photocopying.
If you take an original document and copy it, the copy looks OK.
Try copying the copied document though and odds are that you'll notice a quality loss compared to the original copy.
Copy the original document again and it looks OK.
Hope this helps to "clear the pixels", as it were :-)

[J.K. Ahn]

Tim, if I can add my explanation:

You have your source material, the files created by your camcorder.

You have transferred these onto your computer and then dragged them into a timeline in Vegas. you have then saved the Vegas project.

The Vegas files do not contain any video, they just point to your source material instead. What they do contain are details of where various source files are on your hard drives, where you have placed them on your timeline, and any edits you have made (colour changes, transitions etc). Basically the project files detail what you have done with the video source files rather than the video itself.

Rendering creates a video clip based on the source video files and the project data which tells the rendering process what should be done with that video.

So as long as you keep your source material, you can use the project files to render out to a number of different formats.There won't be any quality loss in the way that you are meaning.

If you use Adobe Lightroom for processing your raw's, then the project files are analogous to the changes you make in lightroom (e.g. white balance, cropping) being written to a physical file instead of being kept within Lightroom's memory. Exporting the image to a JPG would be the equivalent of rendering.



I hope my expanded version of what others have said already helps your understanding. I'm also fairly new to video editing so I appreciate confusion!!


JK

[Edward Troxel]

As long as you're starting with the same source files, you'll always be starting with the same quality. You can open the project as many times as you like as often as you like and render to a different format. You'll always be going back to the original files so you'll be starting with the same quality each time.

Now... If you took the original and rendered it to WMV. Then took the WMV and rendered it to MPEG. Then took the MPEG2 and rendered it to DV. Then took the DV and rendered it to HDV - the final file would be horribly reduced in quality. Go back to the original project and render straight to HDV and you'll be back to your original quality.

[Tim Cee]

I get it now. Thanks you guys for the help. As I said I was right at the render part of my Vasst tutorials and stuck on the wrong concept but have a better understanding now thanks to all of you. Thanks again.
Tim