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Trancoded to DN120 is bigger than source files

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Michal Oppenheim
Trancoded to DN120 is bigger than source files
on Jun 4, 2015 at 12:47:35 pm

Hallo,
I'm working with 1080/25p materials. When I transcode my AMA files or Batch import files and choose DN120, the media files size is almost three times bigger than the original media's size. How come it's bigger, if it's the minimal format that should keep the quality of the original media?
Does it still makes sense to use DN120, if the original files are much smaller?
(DN36 files are just a bit smaller, DN85 are more than twice as big.)
I also tried XDCAM HD 50Mbits, which became only a little bit bigger, and XDCAM EX 35Mbits, which became a bit smaller file size than the source.
Thanks!


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Shane Ross
Re: Trancoded to DN120 is bigger than source files
on Jun 4, 2015 at 3:52:22 pm

[Michal Oppenheim] "How come it's bigger, if it's the minimal format that should keep the quality of the original media?"

Guessing that the originals are AVCHD? Or some other highly compressed camera original format? They are bigger because the data rate is higher, and they are less "compressed." Highly compressed files like AVCHD are difficult to edit natively. Adobe does it, but only if you have a lot of RAM, fast processors, and a kick-A graphics card that enables CUDA. Because it's a difficult format...because it's highly compressed.

Now, you aren't uncompressing it...but you are converting it to a more edit friendly editing format...and edit friendly means larger file sizes. If you want you can do the offline/online workflow...convert the footage to Dnx36 or 15:1...edit, then relink to the masters and convert only what's used in the cut to higher res...if space is what you need.

XDCAM is also a compressed format, but one that Avid can edit natively. It's a little sluggish compared to Avid media (DNxHD), but I use that codec a lot and it's not that bad.

Shane
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Read my blog, Little Frog in High Def


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Michal Oppenheim
Re: Trancoded to DN120 is bigger than source files
on Jun 4, 2015 at 4:00:22 pm

Thanks a lot!
Not AVCHD, but something similar.
So what res should I use for the online, if I would like to prevent exporting with linked AMA files?
My computer is old and slow, and each export takes much longer with AMA files...
It's for a private use, but was asked to be a master resolution, same as source.


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Shane Ross
Re: Trancoded to DN120 is bigger than source files
on Jun 4, 2015 at 4:08:23 pm

DNx120 is perfectly fine for finishing.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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