Are 2-pass MPEG2 files smaller? at DVinfo.net

William Hohauser · April 9th, 2007, 09:56 AM

I am working on a project that's busting the capacity of a 4.7 DVD. A dual layer disc is out of the budget for duplication. The margin is very slim and I am trying to avoid more compression if possible. The question is: Will a 2-pass encode have a different size than a 1-pass encode? Which way, larger or smaller? Or is it completely unpredictable?

Thanks for any advice.

Chris Harris · April 9th, 2007, 12:18 PM

A 2 pass encode will in theory, give you greater quality at the same filesize. If you are trying to squeeze the most out of a 4.7 DVD, I'd definitely go for a two pass encode.

Mark Sloan · April 9th, 2007, 07:30 PM

So from what Chris said means... reduce your bit rate and use 2 pass to get just as good quality. You are sacrificing speed of encoding for better quality at a lower bit rate.

William Hohauser · April 9th, 2007, 09:04 PM

It's compressing overnight. 720p HDV to 16:9 SD Mpeg2, 2 pass. Takes some time on my 2 generations ago G5.

Grant Harrington · April 9th, 2007, 10:29 PM

Quote:

Originally Posted by William Hohauser

I am working on a project that's busting the capacity of a 4.7 DVD. A dual layer disc is out of the budget for duplication. The margin is very slim and I am trying to avoid more compression if possible.

Thanks for any advice.

Sounds like you are already compressing, but for future projects, you could try the BitBudget guide at http://www.recipe4dvd.com/ It will help you balance quality and quantity.

There is a link on the left hand side of the site to download a PDF and an Excel worksheet that will crunch to optimum numbers for you.

Grant

William Hohauser · April 10th, 2007, 12:15 PM

Quote:

Originally Posted by Grant Harrington

Sounds like you are already compressing, but for future projects, you could try the BitBudget guide at http://www.recipe4dvd.com/ It will help you balance quality and quantity.

There is a link on the left hand side of the site to download a PDF and an Excel worksheet that will crunch to optimum numbers for you.

Grant

That's a very neat spreadsheet, thanks. Thanks to everyone's suggestions, they all helped.

The file came out the exact same size as a 1-pass. Another problem came up which I'll describe in a separate topic.

April 9th, 2007, 09:56 AM	#1
William Hohauser Inner Circle Join Date: Dec 2005 Location: New York City Posts: 2,650	Are 2-pass MPEG2 files smaller? I am working on a project that's busting the capacity of a 4.7 DVD. A dual layer disc is out of the budget for duplication. The margin is very slim and I am trying to avoid more compression if possible. The question is: Will a 2-pass encode have a different size than a 1-pass encode? Which way, larger or smaller? Or is it completely unpredictable? Thanks for any advice. __________________ William Hohauser - New York City Producer/Edit/Camera/Animation

April 9th, 2007, 09:04 PM	#4
William Hohauser Inner Circle Join Date: Dec 2005 Location: New York City Posts: 2,650	It's compressing overnight. 720p HDV to 16:9 SD Mpeg2, 2 pass. Takes some time on my 2 generations ago G5. __________________ William Hohauser - New York City Producer/Edit/Camera/Animation

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April 9th, 2007, 12:18 PM	#2
Chris Harris Major Player Join Date: Mar 2006 Location: San Francisco, California Posts: 487	A 2 pass encode will in theory, give you greater quality at the same filesize. If you are trying to squeeze the most out of a 4.7 DVD, I'd definitely go for a two pass encode.

April 9th, 2007, 07:30 PM	#3
Mark Sloan Major Player Join Date: Jun 2002 Location: Venice, CA Posts: 346	So from what Chris said means... reduce your bit rate and use 2 pass to get just as good quality. You are sacrificing speed of encoding for better quality at a lower bit rate.