It's all about the codec
I get asked a lot of DVD related questions so I've decided to post part of an email I got from a co-worker.
The question was kind of generic but it had to do with DVD ripping/burning/encoding.
Copy of the email below:
His Question:
_____________________________________________
From: [Unamed Co-worker]
Sent: Wednesday, December 21, 2005 12:43 PM
To: Jeff Estes
Subject: question
Jeff- I have looked everywhere for the answer to this question and I can't find a clear cut answer.I am wondering what the difference is between 120 Minutes of video on a regular 4.6GB dvdr as apposed to the actual 4.6GB of space available.Is Video burned to a DVDR different than burning raw data? Is it possible to fit more than 120 minutes on one dvd? I would really like to know…Here is my situation just for example…I have all three seasons of a tv show downloaded. (Its around 78 Episodes)Now, I have dual layer DVDs that I know I would be able to fit more data on and those are what 240 Minutes I would guess)Now each season is roughtly 4.6 GB of space, and of course each season is around 26 episodes at around 20 Minuts or so a piece.Is it possible to squeeze each season on a 4.6 DVD or better yet a 8.5 Dual layer? (What I really want to know is the difference between data vs. actually video/data.Also, these videos are Audio Video Interlaced format…Any info would be much appreicated..thanks![Co-worker hidden to protect his identity]
My Answer:
It's all about the codec's. Most commercial DVD's are created to completely consume the available space on a given DVD. The more space you have the less compression you have to use. The less compression involved then the less "loss" you have. You can fit as much information on a DVD as you'd like. It all comes down to the codec you decide to use when encoding your video feed.
(FYI you never want to recompress encoded video that's already been run through another codec)
For example if you have a raw uncompressed AVI file you can then turn it into (use a codec) whatever format you want QuickTime, Windows Movie, DIVA, FLAC, MPEG 2,4 etc.
It's generally a bad idea to take one compressed file and recompress it. Think about making photo copies of photocopied material. It gets worse as you continue to rip new copies.
The VOB and IFO files that you find on commercial produced DVD's are generally MPEG2 formatted movies. They are already compressed or Re-mastered. Programs like DVD Shrink and DVD Decrypter know this and just squeeze a little more space out of the MPEG2 video to get it to fit on smaller media.
I hope this answers your questions.
Jeffery Estes
The question was kind of generic but it had to do with DVD ripping/burning/encoding.
Copy of the email below:
His Question:
_____________________________________________
From: [Unamed Co-worker]
Sent: Wednesday, December 21, 2005 12:43 PM
To: Jeff Estes
Subject: question
Jeff- I have looked everywhere for the answer to this question and I can't find a clear cut answer.I am wondering what the difference is between 120 Minutes of video on a regular 4.6GB dvdr as apposed to the actual 4.6GB of space available.Is Video burned to a DVDR different than burning raw data? Is it possible to fit more than 120 minutes on one dvd? I would really like to know…Here is my situation just for example…I have all three seasons of a tv show downloaded. (Its around 78 Episodes)Now, I have dual layer DVDs that I know I would be able to fit more data on and those are what 240 Minutes I would guess)Now each season is roughtly 4.6 GB of space, and of course each season is around 26 episodes at around 20 Minuts or so a piece.Is it possible to squeeze each season on a 4.6 DVD or better yet a 8.5 Dual layer? (What I really want to know is the difference between data vs. actually video/data.Also, these videos are Audio Video Interlaced format…Any info would be much appreicated..thanks![Co-worker hidden to protect his identity]
My Answer:
It's all about the codec's. Most commercial DVD's are created to completely consume the available space on a given DVD. The more space you have the less compression you have to use. The less compression involved then the less "loss" you have. You can fit as much information on a DVD as you'd like. It all comes down to the codec you decide to use when encoding your video feed.
(FYI you never want to recompress encoded video that's already been run through another codec)
For example if you have a raw uncompressed AVI file you can then turn it into (use a codec) whatever format you want QuickTime, Windows Movie, DIVA, FLAC, MPEG 2,4 etc.
It's generally a bad idea to take one compressed file and recompress it. Think about making photo copies of photocopied material. It gets worse as you continue to rip new copies.
The VOB and IFO files that you find on commercial produced DVD's are generally MPEG2 formatted movies. They are already compressed or Re-mastered. Programs like DVD Shrink and DVD Decrypter know this and just squeeze a little more space out of the MPEG2 video to get it to fit on smaller media.
I hope this answers your questions.
Jeffery Estes
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