Anything to be gained by converting internal H.264 to ProRes or DNxHD?

[FUBARFilms]

I've heard conflicting things about converting your footage to a more robust codec before applying effects and finishing off projects. My computer handles the native footage quite easily so it's not a performance issue for me but by converting to a better codec is there any actual quality to be gained for grading, etc. or is the footage whatever it is out of the camera regardless?

 

[Thomas Smet]

I've heard conflicting things about converting your footage to a more robust codec before applying effects and finishing off projects. My computer handles the native footage quite easily so it's not a performance issue for me but by converting to a better codec is there any actual quality to be gained for grading, etc. or is the footage whatever it is out of the camera regardless?

Nope.

Well at least with a decent NLE it will not gain you anything at all. A program like FCPX and Adobe Premiere work in a 32bit float color space so basically every frame of your video is converted to 32bit uncompressed on the fly during editing. All that work is done for you and the only thing you lose is actually having the physical file sucking up space on your storage.

What you do gain is system performance because that conversion on the fly doesn't need to take place. While you may think your system performs fine it can always get better. I personally am a fan of converting to ProRes because the material scrubs/skims like a hot knife through butter on a hot summers day. I like the fluidity of working that way as a personal preference. In the end the videos I deliver to a client are no better or worse. It's just the ride is sweet.

The same is even true if you down convert to HD. If you toss 4k material into a HD project and your system can handle it then it is best to just let the NLE do the work because it is basically converting every frame to uncompressed (not ProRes but massively larger) RGB on the fly as you edit. I can edit 4k GH4 material in a HD project in FCPX on my 2012 iMac with no problems. I am really getting frames even better than if they were converted to ProRes4444 HD frames because ProRes is still image compression. Think of ProRes like jpeg photos vs raw photos. Yeah the skimming (scrubbing) when I do this is a bit jerky but it gets the job done. A solution that works for me is to let FCPX create proxies of all the project material. It happens in the background pretty quick and I can instantly switch back and forth between native and proxy depending on what I'm doing. If I rapidly just skimming and trimming I use proxy. When visual quality matters for color and layering graphics I switch back to native.

The only time I would suggest converting to a format like ProRes is if you are down converting 4k to HD and need to use the material in other programs for FX work. This way you have consistency across the programs and know the quality of the material will stay equal across those programs. If performance is a desire as well then converting is a solid method to increasing system performance. For HD projects I tend to convert to ProRes just to beef up the performance of FCPX. Proxy works well but since I have drives fast enough for ProRes I keep it that way so I can move the clips between Motion, Fusion and After Effects as needed.

 

[FUBARFilms]

Ah i see, that's good to know. However, what if I am sending to Resolve to grade? Same thing?

 

[Dermot]

re-rendering , and therefore re-compressing the camera orignal to ProRez for gradeing works well in most situations, Resolve is not a fan of long GoP of any flavor.

the place where it's sub-optimal is when you have to grade a h.264 into a scene shot on Alexa and the deliverable is a theatre screen.. then you need every little bit of information possiable, and i render uncompresed 16float caches from the tiny h.264's... ouch.... but when you need the last little bit at the edge, that's how to get there from here

i ask for h.264's to be rendered into DNxHD @ 175/8bit, and the camera orignals standing by incase i need to access them

 

[Thomas Smet]

Like I said if you do have to send to another application then yes go ahead and convert because you create consistency across the applications and not every application will handle the H264 the same way. I'm speaking of a strictly FCPX or Premiere workflow. If you have the space and the time then go ahead and convert. Even on a 12 core Mac Pro ProRes will perform better than H264. Not to say H264 performs badly, just that ProRes will always perform better. If the extra zippiness is important is really up to you.

For HD projects I always convert because I'm weird about zippiness. For 4k projects I leave it as H264 and create proxies if need be. I would love to convert 4k as well but don't have the drive space/speed to do that right now.