No luck with smart render... thoughts?

somegeek · Post by **somegeek** » Mon Nov 06, 2006 9:20 am

If you take a video file - edit it to cut out clips and save as a project file vs render into a new single file... will burning that project to a DVD require a render?

somegeek

somegeek · Post by **somegeek** » Mon Nov 06, 2006 9:40 am

Post by **Ron P.** » Mon Nov 06, 2006 12:51 pm

Of course it will require rendering. A VSP is not a video file, it is a set of instructions, telling where the clips are located on your system, and everything that has been done to them.

If your clips are DV, then you will have to render to DVD compatible MPEG2.

somegeek · Post by **somegeek** » Mon Nov 06, 2006 4:47 pm

This is a previously captured HDV tape that was down converted for DVD. I created a project that cuts out about a 3rd of the content on the down converted file. More of a sanity check I guess if the program needs to render again.

If I set the quality at 100% will any quality be lost on the render?

Post by **Ken Berry** » Mon Nov 06, 2006 9:52 pm

Mpeg-2 by its very nature is a lossy format -- each rendering entails some loss in quality, though how much and whether it is perceptible to the naked eye is the subject of considerable debate. If the initial file was high quality, with only minimal editing done to it, and you keep the bitrate high, I would tend to think that there would be minimal loss of quality, and probably none that you would notice.

sjj1805 · Post by **sjj1805** » Tue Nov 07, 2006 1:23 am

Firstly you need to understand the term "Smart Render"
This applies to a VIDEO file. When you make alterations to the VIDEO file it MUST be rendered. If a VIDEO file remains unchanged it does not need to be rendered but instead simply copied as is. This is termed stream copy.

If you turn on Smart Render then those unchanged parts will stream copy and so save time. Only the parts that have changed will be rendered again.

Now the next thing you need to understand is PROJECT FILE.
This is NOT a VIDEO it is a list of instructions.

When you place a video onto your editor timeline and make cuts, joins, add titles alter music and so on, the video on your hard drive remains unchanged.
The video editor knows what needs to be done but has not yet done so until you RENDER your video (with or without smart render turned on)

You save the record of your INTENDED cuts, joins and titles and so on in a PROJECT FILE.

somegeek · Post by **somegeek** » Tue Nov 07, 2006 2:11 am

Thanks, Steve. Apprecaite it.

Just trying to get my head around this...

Say I have a 1 hour file that is DVD compliant so it won't need to be rendered again if I burn that file in whole straight to a DVD. In a new project, if I cut out a few 5 minute segments so it's now 45 minutes in my project, when I go to burn that to DVD - will that 45 minutes of data need to be rendred again into a single file?

sjj1805 · Post by **sjj1805** » Tue Nov 07, 2006 2:19 am

The final format required to create a DVD VOB file is MPEG2 but most Editing is performed using DV (avi) and so before entering the authoring stage it is wise to render to a DVD compliant MPEG2 first.

If you're source video is already a DVD compliant MPEG2 and you are only cutting things out and not putting new bits in you will find it will render quite quickly. The more you do in the way of putting things in (Titles, transitions and so on) the longer it will take to render.

jchunter · Post by **jchunter** » Wed Nov 15, 2006 5:06 pm

somegeek wrote:This is a previously captured HDV tape that was down converted for DVD. I created a project that cuts out about a 3rd of the content on the down converted file. More of a sanity check I guess if the program needs to render again.

If I set the quality at 100% will any quality be lost on the render?

1. If you re-edit your project then you must render a new video file.
2. There is NO loss of quality (compared to the original video file) when you render the edited project because you are rendering directly from the SAME source video files. That is, you are not serially re-rendering a previously rendered video file.
3. You will get the best possible standard definition, DVD-compliant video quality when you downconvert from HDV (which has much higher resolution).
4. An alternative workflow is to create a new project, place the original standard definition video file in the timeline and edit that. When you render a new video file, it will take less time than downconverting from HDV source files because it will be smart rendered. I would not be concerned about losing quality with one smart render. If you want to measure it, drop a resolution chart in the project and compare the input with the output.