Hi,
I'm using Ulead Video Studio 6.
I succeeded in capturing from miniDV into AVI format to do editing. After that I saved the file as MPEG2 (PAL DVD) format. I then delete the AVI files as it takes up a lot of Harddisk space.
When I play this MPEG2 file using Windows Media Player 9, I'm able to drag to any time position on the seek slider. However, I realised that if I have to edit/trim this MPEG2 file, I have to re-render the whole file/clip again to save it. And this time round, when I tried playing on Windows Media Player 9, I'm unable to drag it to any time position on the seek slider. Is there some quality loss?
I read in the forums that it's better to capture direct to MPEG2 format (as compared to AVI) as it saves space and time. But I would still have to render it to MPEG2 after editing?
Editing MPEG2 Files, need to re-render
Moderator: Ken Berry
mpeg2 editing
I'd recommend capturing dv .avi's from your dv camcorder, do all your editing, and convert to mpeg2 as the final step before authoring for disc.
editing mpeg2 can be problematic because some frames rely on information from other frames that come before it, and some frames rely on information that comes from other frames before AND after it.
George
p.s. unless the mpeg file consists of only I-Frames (each frame contains all the information without needing information from other frames)
editing mpeg2 can be problematic because some frames rely on information from other frames that come before it, and some frames rely on information that comes from other frames before AND after it.
George
p.s. unless the mpeg file consists of only I-Frames (each frame contains all the information without needing information from other frames)
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jchunter_2
hocksteo,
It appears that you deleted your project assets (the edited AVI files) after creating the mpeg2 video file of your edited project. This is like writing a program, compiling it to executable form, and then deleting the source code.
BTW, it is not "better" to create an mpeg video file - it is mandatory if you want to burn your project to DVD.
As you have discovered, you can recover and reedit the information in your mpeg video file in Video Studio but you must, again, create a new video file of the edited project in order to make a new DVD that shows your edits. This new video file will render much faster than when you converted from AVI to Mpeg. The reason is that if your Project properties exactly match your mpeg file properties, no conversions are required.
As for quality loss, I ran some controlled tests that showed no visible loss of resolution whan mpeg2 video was edited and re-rendered 8 - 10 times. I will pull this info from the old forum when I get a chance, but you can find it by seraching the old forum on "Resolution Test" or "Test Pattern."
It appears that you deleted your project assets (the edited AVI files) after creating the mpeg2 video file of your edited project. This is like writing a program, compiling it to executable form, and then deleting the source code.
BTW, it is not "better" to create an mpeg video file - it is mandatory if you want to burn your project to DVD.
As you have discovered, you can recover and reedit the information in your mpeg video file in Video Studio but you must, again, create a new video file of the edited project in order to make a new DVD that shows your edits. This new video file will render much faster than when you converted from AVI to Mpeg. The reason is that if your Project properties exactly match your mpeg file properties, no conversions are required.
As for quality loss, I ran some controlled tests that showed no visible loss of resolution whan mpeg2 video was edited and re-rendered 8 - 10 times. I will pull this info from the old forum when I get a chance, but you can find it by seraching the old forum on "Resolution Test" or "Test Pattern."
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hocksteo
George,
Thanks for your recommendation to edit all in AVI then convert to MPEG2 in the final step.
I had 6 DV tapes to be convert and edit, and I'm not sure how to estimate them in terms of fitting them nicely (optimising the DVD space) into several DVDs. Therefore, I thought it'd be easier to break them into several MPEG2 files (ready for disc authoring), so that I can further fit them, i.e. cut or join them to fit disc.
jchunter_2,
It's good news to learn that the quality of MPEG2 file is not loss after 8 to 10 times of re-rendering. I find it OK too, with just a bit of jitter at the joints between MPEG2 clips/files when I re-edit it.
On a different note, do you think there's some problem with Windows Media Player 9 Series? Still unable to figure out why only after re-rendering, the MPEG2 movie cannot be dragged to a time/position in the seek slider. The first MPEG2 movie can though. Strange.
Thanks for your recommendation to edit all in AVI then convert to MPEG2 in the final step.
I had 6 DV tapes to be convert and edit, and I'm not sure how to estimate them in terms of fitting them nicely (optimising the DVD space) into several DVDs. Therefore, I thought it'd be easier to break them into several MPEG2 files (ready for disc authoring), so that I can further fit them, i.e. cut or join them to fit disc.
jchunter_2,
It's good news to learn that the quality of MPEG2 file is not loss after 8 to 10 times of re-rendering. I find it OK too, with just a bit of jitter at the joints between MPEG2 clips/files when I re-edit it.
On a different note, do you think there's some problem with Windows Media Player 9 Series? Still unable to figure out why only after re-rendering, the MPEG2 movie cannot be dragged to a time/position in the seek slider. The first MPEG2 movie can though. Strange.
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jchunter_2
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jwarner
Do you have a WMP DVD/MPEG2 decoder installed?
If not, you will get exactly those symptoms as it tries to use whatever is installed in your system to decode the MPEG.
Here's a free utility to check:
http://www.microsoft.com/downloads/deta ... laylang=en
If you don't have one, they have to be purchased. You can find them by selecting: TOOLS. PLUG-INs, DOWNLOAD PLUGINS in WMP.
It made a BIG difference when I installed a proper DVD plugin (I selected the NVIDIA one to match my video card).
If not, you will get exactly those symptoms as it tries to use whatever is installed in your system to decode the MPEG.
Here's a free utility to check:
http://www.microsoft.com/downloads/deta ... laylang=en
If you don't have one, they have to be purchased. You can find them by selecting: TOOLS. PLUG-INs, DOWNLOAD PLUGINS in WMP.
It made a BIG difference when I installed a proper DVD plugin (I selected the NVIDIA one to match my video card).
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THoff
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hocksteo
jwarner - thanks for the tip
THoff - Is it better to use CBR or VBR? I read in the VS6 user guide that using VBR is better for MPEG2 because of better compression and better quality. So I just choose PAL DVD and its default setting VBR of 6000kbps max.
The original is also VBR by the way. I convert it from AVI to MPEG using VBR and re-edit the MPEG file again and save it again also using VBR. The first file is ok with WMP but the re-edited one cannot slide to any time position.
THoff - Is it better to use CBR or VBR? I read in the VS6 user guide that using VBR is better for MPEG2 because of better compression and better quality. So I just choose PAL DVD and its default setting VBR of 6000kbps max.
The original is also VBR by the way. I convert it from AVI to MPEG using VBR and re-edit the MPEG file again and save it again also using VBR. The first file is ok with WMP but the re-edited one cannot slide to any time position.
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THoff
VBR has the potential to offer better output quality because it can shift the available encoding bandwidth around -- if a scene is simple, the unused bandwidth can be used to encode a more complex scene that follows it (within limits).
VBR encoding is obviously much more complex than CBR encoding, and the best results are achieved with multple passes. Commercial DVD encoding such as Hollywood movie releases often use 20+ passes, something that isn't practical for us simple folks.
If you aren't matching the parameters of the input video by simply selecting VBR 6000kbps, for instance, then re-rendering will be necessary even if everything else is the same. If you right-click on a file in your project, you can view the clip properties to see how it is encoded -- if you use the same settings when creating your output file and have SmartRender turned ON, then the output involves little if any rendering.
UVS will have to create a B (key) frame for the very first frame even if the first frame in the project is a P (incremental) frame, and of course titles and effects that you add cause rendering, but everything else should just be copying of existing data.
VBR encoding is obviously much more complex than CBR encoding, and the best results are achieved with multple passes. Commercial DVD encoding such as Hollywood movie releases often use 20+ passes, something that isn't practical for us simple folks.
If you aren't matching the parameters of the input video by simply selecting VBR 6000kbps, for instance, then re-rendering will be necessary even if everything else is the same. If you right-click on a file in your project, you can view the clip properties to see how it is encoded -- if you use the same settings when creating your output file and have SmartRender turned ON, then the output involves little if any rendering.
UVS will have to create a B (key) frame for the very first frame even if the first frame in the project is a P (incremental) frame, and of course titles and effects that you add cause rendering, but everything else should just be copying of existing data.