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losing quality re-rendering
when i edit a wedding i break it up into 3 clips…..1) is the pre-cermony, 2) ceremony and 3) reception…..I render each section after completed with mpeg2 and ac-3 audio….when i’m finished with all three clips I render them together again with mpeg2 and ac-3…..My question is do i lose noticable quality when i render the 3 clips individually using mpeg2 and ac-3? Then again when finished with all three clips, render again in mpeg2 with ac3? Should I be using something different to render them individually before the final render? Which would be the best process to follow? Thanks, Gary
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5 Replies
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You’re taking a 4:1:1 signal and converting that to a 4:2:0 signal. Then you’re taking that 4:2:0 siganl and re-converting it so yes, you’re definitely losing quality.
Adam Wilt’s site has some good pictures as well as explanations about 4:1:1 and 4:2:0.2 ways to maintain quality.
The first is to render out each section as an avi and then bring them back in for the final edit. This will involve some recompression but, if you’re not doing anything other than joining the 3 clips, it will be minimal.The other option is to open 2 copies of Vegas. Call #1 “final edit”. In the second copy, load in “pre-ceremony” and do a copy-paste into #1. Then open up “ceremony” and “reception” respectively and repeat. Now save and do your final render. With this option, no rendering is necessary until you’re ready for the final one.
Mike
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Gary, definitely change your procedure to using DV-AVI as the intermediate renders. Then you can start your final project and add these DV-AVI files to the timeline and render THAT to MPEG2.
Recompressing MPEG2 is NOT a good formula for quality.
Edward Troxel
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[Gary & Yvonne] “Which would be the best process to follow?”
I’d recommend taking advantage of nested .veg files in Vegas 6 and assemble the segments in a master project so you don’t have an intermediate render at all.
BTW, re-rendering Mpeg files has been discussed here MANY times including a couple of days ago.
Gary Kleiner
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yeah re-rendering mpeg2 is just about the worst kind
of thing you can do to make your footage un-pretty.many years ago, before I worked in production
and didn’t know better, a student film I edited
had been mpeg1 compressed over about 4 or 5 times.It looked awful. I learned a hard lesson that day.
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If you have titles and other generated media it is best NOT to render to AVI then reload and encode to MPEG-2. Rather encode to MPEG-2 directly from the timeline. You’ll get better quality on the generated media since it is represented in 4:4:4 color space within Vegas. If you render to AVI if is converted to 4:1:1 or 4:2:0 depending on whether you use PAL or NTSC. I.e., you are throwing away some of the color if you render to AVI first.
Good luck.
Dennis
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