What to do about getting uncompressed codecs when shooting slow motion?

[Mads Nybo jørgensen]

Hey Tim,

With regard to shooting MP4, that depends on quite a few factors.
1) Where will your final master be used – if OnLine only, the audience might be more forgiving, as opposed to cinema where the picture might start breaking up or show artefacts in the projection.
2) What lens and imaging chip does your prosumer camera use?
3) MP4 does not need to be heavily compressed – it depends on the camera, and the codec + speed of cards. The higher bitrate in MBPS, the better quality.
4) Most importantly: Do you know how much the production wishes to slow down the video? And, have you planned out the shots?

I would suggest that you investigate whether you can attach an external recorder (normally via HDMI – Atomos or similar). You might be able to get one that can record “straight” from the imaging chip to a ProRes format.

You could also ask around for a hire for that particular shoot.

Phantom has a list of Rental Partners on their website:
https://www.phantomhighspeed.com/contactus/findyourphantom/rentalpartners

Oh, don’t forget to match your lights “flicker”, to that of the camera shutter shooting the slo-mo…

My day job is as a video editor – in other words, don’t trust me, except that I have experience in fixing slo-mo video when it went wrong.

Hope this helps.

Atb
Mads

[Craig Seeman]

Sony FX Cameras can shoot 4k 120fps or 1080 240fps using Intraframe (not Long GOP) H.264 10 bit 4:2:2. H.264 isn’t necessarily heavily compressed. This setting is close to Apple ProRes quality levels. Neither is truly “uncompressed” but certainly close enough for very high-end post-production.

See this on XAVC I vs ProRes.

https://www.xdcam-user.com/2021/01/xavc-i-v-proreshq-multi-generation-test/

[Craig Seeman]

Perhaps I should also mention that the Blackmagic Ursa Mini Pro 12k shoot 4k super 16 at 240fps in Blackmagic Raw.

Also there’s the FreeFly Wave which can shoot over 400fps in 4k using its Raw codec. Starting at about $12,000 its much less expensive than a Phantom.

https://freeflysystems.com/wave

[Ben Balser]

H264 (which is mp4) has come a long way, been advanced, and is perfectly good for use in productions, and as said before, depends on the camera. Manufacturers have great flexibility in implimenting H264, and most do a great job. We use it all the time for television broadcast and web use, and it looks great. I shoot slow motion on my iPhone 14 Pro Max, no one has ever seen the final production and said, “Hey, that looks like an iPhone.” Nope, what I hear is, “that’s great slow motion, what did you shoot it with?”

[Tim Gallaher]

Hi Mads,

Thanks for the detailed reply. It’s been a super busy week at work, thus my delay in responding. To answer your questions:

1) Final master will be shown both online and projected in small halls for art performances.

2) Haven’t bought a slow motion camera yet as I kept hoping one would come out that output to something other than H264.

3) Thanks for this. I didn’t know that. Do you know the full range of MBPS for H264 to give me an idea of it’s upper range?

4) It’s my project, and I’d like 240fps in 1080p. I’d like to shoot several projects in slow motion of various natural phenomena, such as water flowing in streams, sunlight patters in water, wind blowing through tree branches, etc.

That’s a good idea about an external recorder. I’ll research that. And this will all be shot outside in sunlight, so flicker shouldn’t be a problem.

Thanks again, your input is very helpful.

Best,

Tim

[Tim Gallaher]

Thanks Craig, this is very helpful. I’ll check out Sony FX cameras.

[Tim Gallaher]

Thanks Ben. Really good to know. What about longevity though? Doesn’t H264 shot on an iPhone degrade much faster over time than something less compressed? I hate the idea of working on a project only to find it degrading in just a handful of years.

[Mads Nybo jørgensen]

Hey Tim,

No problem, we are all busy – and it is always nice to hear back on replies to posts.

3) In theory you can go as high as you like with H264. I’ve just checked in Premiere Pro, which will in CBR (and VBR) allow you to go to 50 Mbps – your bigger problem with that, is whether the playback device to screen can handle it…

4) Many years ago I worked on some the first Digital HD slomo, DOP’ed and Directed by Michael Brennan. It was a football getting kicked, and weirdly enough (hope Michael won’t mind me mentioning this 🙂) the shot got unintentionally better because of rain and issues with lights.
There was an article written on it, which I haven’t found.
But Michael have later won an award:
https://definitionmagazine.com/features/gtc-member-michael-brennan-wins-for-best-risk-shot-at-golden-eye-festival/
The take-away is that the closer to the subject you get, the better the slow-motion will work – unless you intentionally want large images with little movement in.

Question:
Why are you limiting yourself to 240fps in 1080p?
Is it a financial restraint, or just that you already have the kit?
If concerned about future proofing, I would suggest going 4K.
If done right, you might even find some additional “funding” through Pond 5 and other stock websites.
You should also consider doing some tests where you shoot interlaced, as that will give you more options on the rate of slow-motion + you can always export it in progressive mode.

Project sounds interesting – looking forward to seeing it when it goes online.

Atb
Mads

[Paul Carlin]

FiLMiCPro allows you to shoot 4K 60fps using ProRes on an iPhone 13+. However, it records 4:2:0 Rec709 (no Log), so you will loose color definition.

That said, You should look into shooting with what you have, and then running it through Topaz AI to upscale and clean it up. Very inexpensive AI driven software. Topaz labs dot com.

[Eric Kornblum]

Hiya Tim,
As others here have mentioned, MP4 spans a broad range of quality levels depending on the bit depth (8 bit vs 10 bit), chroma subsampling (4:2:2 vs 4:2:0), and data rate.

8 bit 4:2:0 is pretty common as a final delivery format, so in theory if you shot everything framed, exposed, and white balanced perfectly in-camera, and you didn’t want to have creative flexibility in terms of color correction/grading or moving/scaling the video in your edit, you could actually shoot that way. But that’s theory 🙂

In reality, I’d suggest you’re really going to want to record using a 10 bit 4:2:2 codec (or better), as any footage (regardless of codec) will quickly start degrading once you start color grading/correcting, moving/resizing, etc.

As far as data rate, what you’ll want/need will depend on how much detail there is in your scene and how much movement there is. As a reference point, Sony’s FX30 (the lowest $1800 entry point to their cinema line) will do 1080p240, 10 bit 4:2:2 at 50 mbps (using an IPB codec) or at 222 mbps (using an all I-frame codec).

And as others here have mentioned, if future-proofing is a big concern, you may want to consider shooting at 4k (or UHD) instead of 1080p (HD). But of course this can bump you up into a higher price bracket not just for the camera, but also for the memory cards, storage space, processing power, etc…

Sounds like a fun/interesting project. Best wishes for it!