Splitting A ProRes File - Without Re-Encoding?

[tupp]

By the way, since you are just copying, you might not need the extra codecs.

[M Carter]

19 hours ago, Axel said:

 

You probably read the book DV Rebel's Guide by Stu Maschwitz. He said in order to maintain quality you should never recompress. I think it was an own chapter with capital letters:

NO RECOMPRESSION

Therefore he recommended to use DV (an intraframe codec as well) only as acquisition codec and to encode to *uncompressed* immediately before any further changes were made (referring to changes to the pixels, not simple cuts).

That was in 2006. Now ProRes is not uncompressed and it's lossy, though 'visually lossless'. Surely after some generations compression artifacts will show, I don't know when. I don't worry about generations though if I stabilize and denoise my clips and re-import them before making the Resolve-roundtrip (don't have Studio and don't have the Neat plugin for Resolve). 

With interframe codecs, the image is always completely recompressed. So-called 'smart rendering' isn't smart. Depending on the data rates and the profiles, you will *see* compression artifacts not later than in the third generation, sometimes in the second. This could be called 'visually lossy'.

But the OP is talking ProRes. It's awesome that a book from the 480p DV era (1990?? 2000?) says "don't recompress', but I'll tell you from years of working with ProRes, stop worrying. You can compress it again and again and you won't see any artifacts.

Every week I stabilize a ProRes clip, render it, then retime that render at several different speeds. I'll do a couple versions with the variable diffusion plugin, and I'll render a master edit to ProRes. You can run it through your system many times and it holds up like a mofo. 

Show me a third or fourth generation ProRes clip with "artifacts" that aren't caused by pushing the footage too hard (artifacts you'd see in the first go-round). I very, very rarely denoise ProRes (maybe for a night shoot as 1200 iso). The first thing I do is convert whatever camera format comes in the door to ProRes. You can beat the daylights out of it and my system cuts it like butter, 1080 or 4k or whatever you got. 

All of the conjecture on this thread is fine if you're in an H264 world. I run a ProRes shop and I have zero worries about generational loss in a reasonable (or even a "kinda pushing it") workflow.

[User]

5 hours ago, M Carter said:

You can run it through your system many times and it holds up like a mofo. 

The first thing I do is convert whatever camera format comes in the door to ProRes. You can beat the daylights out of it and my system cuts it like butter, 1080 or 4k or whatever you got. 

I run a ProRes shop and I have zero worries about generational loss in a reasonable (or even a "kinda pushing it") workflow.

Finally the real deal! Thanks again M Carter, love the no nonsense approach.

[Axel]

Well, I am glad you mentioned my poor English, but that was exactly what I was trying to tell you. ProRes isn't known for being a particularly effective codec, it's famous for it's robustness (other word for that?). It made uncompressed obsolete. Don't worry about recompression.

[User]

2 minutes ago, Axel said:

Well, I am glad you mentioned my poor English, but that was exactly what I was trying to tell you. ProRes isn't known for being a particularly effective codec, it's famous for it's robustness (other word for that?). It made uncompressed obsolete. Don't worry about recompression.

No worries on the English lesson Axel ;), I appreciate your participation here. But in your latest comment here: "ProRes isn't known for being a particularly effective codec, it's famous for it's robustness." I'd have to question your words again because as I've come to know it ProRes is and has been an incredibly effective codec. That's why it because what it has in the world today. Maybe you mean something other than the word 'effective'? Class leading? Innovative? Ground breaking? Anyways.

[Axel]

ProRes is a flavour of mpeg2, a very old codec that is not very intelligent/effective in terms of compression. H.264 allows for much smaller file sizes to store the same quality. More so H265. But these codecs fall apart very quickly once you change anything. For delivery, i.e. to upload to Youtube or to stream for broadcast, they may be better. But they are not good for editing, let alone grading or compositing.

[M Carter]

8 hours ago, Axel said:

ProRes is a flavour of mpeg2, a very old codec that is not very intelligent/effective in terms of compression. H.264 allows for much smaller file sizes to store the same quality. More so H265. But these codecs fall apart very quickly once you change anything. For delivery, i.e. to upload to Youtube or to stream for broadcast, they may be better. But they are not good for editing, let alone grading or compositing.

I don't think anyone thinks of ProRes as a delivery codec. It may not be the most efficient codec around as far as file size, but I assume it's striking a compromise between file size and efficiency. And it's crazy efficient in the NLE workflow - you can very easily edit 1080 on a pre-intel PPC mac all day.

If it's news to anyone that prores is an editing codec and H264 is a delivery codec, they probably have some studying to do. (And yes, I'm aware people edit with H264, but I don't think it's optimal).