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uzzaw
Editing MPEG2 Files in Real-Time
on Apr 29, 2004 at 5:22:29 pm

I'm a newbie, but I have been doing some research on the web and I have a question about editing mpeg2 files in real-time.

(1) I have had discussions with others that capturing straight to mpeg2 would kind of defeat the purpose of using a PC. He stated that you would want to capture to AVI, then edit the AVI, then render the mpeg2 and the reason you wouldn't want to capture straight to mpeg2 is you can typically only edit every 15 frames instead of being able to go to an exact frame. Can you only edit every 15 frames or so?

(2) Also he mentioned that if you make changes to the mpeg2 or AVI you have to render it when you're finished editing. Which I beleive is true, but with real-time capturing to mpeg2 it won't take as long. Correct?

Thanks,
Rob



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Kenneth Daves
Re: Editing MPEG2 Files in Real-Time
on Apr 29, 2004 at 7:36:19 pm

Some programs let you edit Mpeg at I frames and will re-render only the edited sections (titles and filters, for example) of Mpeg as long as the output settings match the original settings. It saves time, but is less versatile.


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uzzaw
Re: Editing MPEG2 Files in Real-Time
on Apr 29, 2004 at 7:58:55 pm

So if I was using the Matrox software bundle or the Canopus Storm do they allow you to edit individual frames?


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Kenneth Daves
Re: Editing MPEG2 Files in Real-Time
on Apr 30, 2004 at 12:43:44 am

Both of those are way out of my league. However, I do think that using either of those two products for editing standard Mpeg IBP files would be like going fishing in a battleship.


What kind of editing do you plan on doing?


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uzzaw
Re: Editing MPEG2 Files in Real-Time
on Apr 30, 2004 at 5:24:11 am

I'm into the hobby of sports tape collecting. I'm trying to get the best quality version of different games I'm intersted in. Most or all of my edits are removing commercials. I currently have a Panasonic E80HS standalone DVD recorder which works fine, but I would like to build a computer system to enhance colors, fix audio problems, etc. (i.e. things my standalone dvd recorder isn't capable of).

A lot of collectors I talk to go the avi render to mpeg2 route and I was wondering why they didn't go strait to the mpeg2. And one persons response was the questions I asked above. I just wanted to check with others to get some additional insight.

Rob

P.S. Forgive me, but what does IBP stand for when you said, "Mpeg IBP files"


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Kenneth Daves
Re: Editing MPEG2 Files in Real-Time
on Apr 30, 2004 at 12:32:03 pm

The key to editing Mpeg without losing quality is to not have to re-encode it. You can trim out unwanted parts of the video and edit the audio in a Mpeg file without re-encoding the video, but color correcting the video would require re-encoding all the color-corrected parts of the video, which will result in a significant loss of quality. You should either do your color correction while capturing the Mpeg or capture as AVI.

Mpeg IBP is a standard Mpeg compression algorithm. I don’t mean to be rude, but you can find out about it by searching the internet. If I tried to explain it, it would be the blind misleading the blind.


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uzzaw
Re: Editing MPEG2 Files in Real-Time
on Apr 30, 2004 at 3:36:50 pm

Thanks! I understand exactly what you me when you are talking about correcting before capturing. I have another question about retaining the quality, forgive my ignorance, but when you render from avi to mpeg2 is there quality loss and if so is it noticable?

Thanks for all of your help you have really answered my questions.

Rob


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Kenneth Daves
Re: Editing MPEG2 Files in Real-Time
on May 1, 2004 at 2:50:26 am

There is a loss in quality but I have trouble telling the difference.


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