New shooters and editors can typically get hung up on which codec and knowledge charge they need to use, and certainly, selecting the unsuitable setting can damage your day. For those who simply flip up all of the settings to their most, an SD card can out of the blue cease recording, or a extra succesful recording medium can replenish faster than anticipated.
However it doesn’t matter what the codec, decision or body charge in use, it’s the information charge that defines how a lot cupboard space a clip takes up. Let’s take a deep dive.
Megabits or MegaBytes?
Once you see a quantity quoted, like “100Mbps”, it’s simple to suppose meaning “100 MegaBytes per second” — however it doesn’t. The lowercase “b” means “bits” whereas an uppercase “B” would imply “Bytes”, they usually’re completely different by an element of 8. (To keep away from confusion, QuickTime Participant makes use of “Mbit/s” however you’ll see Mbps within the menus of most cameras).
Nonetheless it’s written, that 100Mbps is definitely ~12.5 MegaBytes per second. I choose to jot down Mbps or MB/s to make a extra apparent distinction between bits and Bytes.
Codecs matter
Many codecs and containers are utilized by in the present day’s cameras, and on the whole, you possibly can solely optimize for 2 of those three traits: ease of playback, picture high quality, and small file sizes.
- For those who select ProRes 422 or HQ, you’ll get bigger file sizes which are simple to work with and look nice.
- For those who select H.264 Lengthy-GOP you’ll get smaller file sizes which are simple to work with on most computer systems and look fairly good.
HEVC might be more durable to work with on computer systems with out {hardware} acceleration, however this codec makes smaller recordsdata than H.264 on the identical file dimension. Since all fashionable Macs have ProRes, HEVC and H.264 acceleration inbuilt, most traditional video recordsdata play again easily. This isn’t the case for all these codecs on a Home windows PC, as a result of {hardware} encoding varies relying on whether or not it’s coming from the CPU or GPU, on the drivers, and in case your software program can make the most of it.
Knowledge charges are generally decided by the codec, and generally not. ProRes makes use of a set knowledge charge for every taste (Proxy, LT, 422, HQ, 4444, and many others.) so you recognize kind of how large a file can be if you recognize the decision, body charge, and codec.
ProRes defines knowledge charges for supported resolutions and body charges — right here’s the White Paper
H.264 and HEVC are extra versatile. A knowledge charge that’s too low will typically produce blocky, artifact-ridden photos, however intelligent encoding strategies can get loads out of a bit. On an iPhone, all these numbers are fairly low. In Closing Reduce Digital camera or the Digital camera app, the HEVC knowledge charge is round 25Mbps in UHD, although when you use the Blackmagic Digital camera app, you possibly can dial in one in every of 4 knowledge charges from 17Mbps to 54Mbps. It’s exhausting to identify a high quality distinction between the highest three knowledge charges, however the lowest does begin to lose a bit element. Usually, the extra element in a shot, and the extra it modifications, the extra knowledge it wants. Sending the background out of focus ought to depart extra knowledge for the in-focus areas to look good.
Blackmagic Digital camera provides flexibility in HEVC and H.264 knowledge charge
RAW recordsdata (in many alternative codecs) are likely to have very excessive knowledge charges and are often more durable to work with, however the high quality and suppleness of those codecs is well worth the sacrifice for a lot of professionals. If you’d like the flexibleness to push a picture within the grade, you possibly can’t beat RAW.
Sure, the ProRes RAW knowledge charge actually is about 20 instances bigger than common HEVC
Digital camera producers determine the codecs and knowledge charge mixtures that their cameras will provide, and digital camera operators determine which of them greatest swimsuit their wants. Anticipate a digital camera to make bigger recordsdata than a cellphone, although.
Lastly, when you shoot on a contemporary Blackmagic digital camera you then’ll encounter BRAW, in quite a lot of compression strengths — run your individual exams when you can.
Different specs matter too
Along with the codec, different components can decide the ultimate knowledge charge. Capturing in 10-bit moderately than 8-bit would require extra space, as will taking pictures in 4:2:2 moderately than 4:2:0, or All-I as an alternative of Lengthy-GOP. To elucidate these components:
- 8-bit information every channel within the picture with one in every of 256 completely different values, whereas 10-bit makes use of 1024. Whereas 10-bit provides smoother gradients, particularly when recording in Log, it’s not properly supported in H.264, and on some cameras, you could have to make use of HEVC. You too can report with extra constancy if you want — ProRes RAW can use 16-bit.
- 4:2:0 information one colour pixel for each 4 luminance pixels, whereas 4:2:2 information one colour pixel for each 2 luminance pixels. For those who plan to paint grade, 4:2:2 has twice as a lot colour decision as 4:2:0, however RAW does even higher. Capturing at the next decision than you intend to ship makes this issue much less necessary.
- All-Intra (or All-I) information a collection of full nonetheless frames, whereas Lengthy-GOP describes frames when it comes to how completely different a body is from a close-by body up to now or future. Some shooters choose to shoot All-I, however I’ve discovered it fully pointless. Your mileage might differ, however for me, the information charge is far larger, the picture high quality isn’t, and the recordsdata are a lot more durable to work with.
It’s true that Lengthy-GOP recordsdata used to trigger points, however bear in mind — when you’re on a contemporary Mac with a contemporary NLE, it’s {hardware} accelerated and Lengthy-GOP shouldn’t be an issue. Check earlier than you triple your knowledge charge by following previous recommendation.
Knowledge charge throughout seize is necessary
Don’t simply select the very best knowledge charge attainable, as a result of your media might not be capable to deal with it. The quantity proven on an SD or different media card is often a most learn velocity, however when you’re recording, that’s irrelevant. Generally you may see a second quantity, a most write velocity, however that’s not a lot use both. To keep away from dropping frames, it is advisable know the minimal write velocity, and that’s not often printed on the cardboard. The UHS Velocity Class give some very primary requirements, however not way more than that.
SD playing cards don’t all the time publicise their minimal write velocity
Usually, it’s solely older media requirements like SD which may have points with excessive knowledge charges. For those who can, utilizing a sooner media card like CF Specific Sort B will keep away from any seize issues and likewise prevent time throughout offloading — the learn speeds are a lot, a lot larger.
Once you crank up all of the settings, recording in ProRes RAW HQ or some taste of All-I, you’ll be pushing the information charge up into many a whole lot of Mbps and even into Gbps territory. On a CF Specific Sort B card or direct to an SSD, your most important drawback is the quantity of house it takes up. However on an SD card, it’ll begin dropping frames properly earlier than it will get full.
Of word, an exterior SSD is required for ProRes RAW on an iPhone 17 Professional. I believe it’s probably that the storage in an iPhone might generally have a minimal write velocity decrease than is usually required by ProRes RAW HQ. Nicely, it’s that, or lingering authorized restrictions from RED’s patent claims over inner RAW recording.
To keep away from dropping frames, it’s necessary to decide on a setting with an information charge that your media can deal with for the whole deliberate size of the shoot, with a buffer for security. Some gadgets will get slower over time, as they warmth up or get full, so it’s important to learn the specs of any media you intend to report to, and do the maths.
Knowledge charge throughout enhancing and archiving
After all, a decrease knowledge charge additionally comes with the good thing about taking much less house, however that’s largely a profit for transferring, storing and archiving that knowledge later. On the highest knowledge charges, you’ll want to make use of sooner media than SD playing cards, and when you’re recording in a demanding format, be sure that your SSD is designed for a excessive steady write velocity — many are usually not.
ProRes RAW HQ in open gate (4224×3024) on an iPhone 17 Professional Max can require as a lot as 1.2Gbps, however it’s a bit exhausting to foretell precisely — the information charge is variable. 1.2Gbps is 150MB/s, and it provides up quick — one hour is over 500GB. As quickly as you begin taking pictures on a number of cameras or for a number of hours, it is advisable start thinking about how a lot storage goes to price, and even how lengthy it’s going to take to repeat that footage.
This shiny sky has been boosted approach an excessive amount of — ProRes RAW (left) is simply usable, ProRes HQ (center) is streaky, and HEVC (proper) is a blocky mess (click on for full dimension)
Clearly, on the most important jobs this turns into the DIT’s drawback. The precedence is, and needs to be, the very best picture at any price. On an all-day occasion with one or two shooters, for an output that’ll solely see minor corrections utilized? Dial the information charge down and save the house. ProRes is ideal for filmmaking and demanding shoots, however typically an excessive amount of for longer occasions.
By shifting to a extra compressed format, you’ll quit some grading flexibility, however it’s not all the time an issue. If there’s an expert colorist concerned, crank it up. For those who’re assured that you would be able to set the white steadiness and expose appropriately on set, a extra compressed codec might be simply wonderful.
Excessive knowledge charges have been the explanation I moved away from the Blackmagic Cinema Digital camera to a Lumix GH5 a few years in the past. On the time, I may shoot 1080p in ProRes at round 130Mbps on the BMCC, or UHD in H.264 at 100Mbps on the Lumix GH5. 4 instances the decision, smaller file sizes, alternative made. On these earlier BM cameras, there have been no reasonably compressed, suitable codecs, although in the present day extra compressed BRAW choices can be found.
What I shoot in the present day
My Lumix GH7 has many (maybe too many) choices for knowledge charge and determination, however you may make sense of the mess by saving your favourite settings below “My Record”. As a substitute of biking by numerous choices, you simply add your favorite mixtures to the listing. This additionally makes it simple to leap between mixtures solely present in particular containers — and there are a number of.
Just some of the in depth mixtures of information charge, body charge and determination on the GH7 — right here’s the total listing
My typical decisions are:
- Open Gate 5760×4320 4:2:0 10-bit at 200Mbps for interviews and anything I would need to reframe. Large decision, comparatively low knowledge charge, nice more often than not.
- UHD 4:2:2 10-bit at 150Mbps after I want 4K and I’m going to be handing the footage off to somebody who needs to paint grade however not reframe.
- UHD 4:2:0 10-bit at 72Mbps (MP4 container solely) for occasions the place I would need to reframe, however the cameras aren’t shifting a lot, the frames aren’t advanced, and colour correction received’t be excessive.
- ProRes RAW 5728×3024, full sensor knowledge, 16-bit at as much as 2.3Gbps (however perhaps just one.6Gbps) for essentially the most demanding initiatives.
Whereas I like having the choice of ProRes, I don’t typically have to shoot in ProRes. For those who shoot a number of longer occasions like I do, there’s actual worth in understanding that you just undoubtedly received’t run out of media, and possibly received’t even have to swap playing cards. If I shot ProRes I’d be going by terabytes every shoot day, and I wouldn’t be capable to report to CF + SD playing cards concurrently for security.
Picture high quality isn’t all the time the one necessary issue. In case your recordsdata are going to finish up on-line, at a decrease decision than you’re taking pictures in, contemplate all of the variables earlier than simply cranking every little thing up.
Seize ≠ supply
The info charge you seize in isn’t related to the information charge you export in. As a substitute, each compression step simply must be excessive sufficient to keep away from introducing artifacts. After you add to a supply platform, it will likely be recompressed once more, and viewers can be proven a file with a fair decrease knowledge charge.
A shooter on a GH7 may report at 150–200Mbps within the HEVC codec, export a UHD HEVC at 40-50Mbps, and that is likely to be seen by many viewers as a smaller 1080p at simply 2.5Mbps. (Even when the unique footage got here from an iPhone capturing UHD at 25Mbps, the primary UHD HEVC export ought to nonetheless be at 40-50Mbps.)
On the “Excessive High quality – Adaptive Excessive Bitrate” choices in Premiere, or the “Laptop” choice in Closing Reduce Professional, you’ll be exporting a file that’s properly above what any of your viewers will ever see. YouTube or Vimeo will compress it closely into quite a lot of completely different resolutions and codecs, all far decrease high quality than the one you despatched, and there’s nothing you are able to do about it. Capturing in the next high quality format helps with colour correction, however it all will get mashed right into a small pipe finally.
Since you don’t management the ultimate output, and most platforms set the output knowledge charge as little as their prospects will tolerate, you merely must keep away from photos that look dangerous in low-data charge 4:2:0, together with:
- Crimson textual content on a black background — 4:2:0 will damage this mixture each time
- Confetti cannons — every little thing modifications each body, and compression falls aside
- Tremendous-detailed pictures, like a drone flying by a leafless forest with every little thing in focus — an excessive amount of element means the image falls aside
If you’re delivering on-line, to YouTube or one other comparable platform, you actually don’t want to fret a lot about what you add. You possibly can add ProRes, you possibly can add a top quality HEVC file, you possibly can add H.264 when you like. For SDR output, H.264 8-bit can be wonderful, although you’ll need to soar to HEVC (and ideally 10-bit) for HDR output.
So who does have to care about output? Anybody following a spec sheet. Sending a TVC to air in Australia? You’re in all probability sending ProRes with Adstream’s specs, and since ProRes defines its personal knowledge charges per decision and body charge, it’s all out of your palms. Identical with any bigger streamers — simply observe the specs.
Sending an advert to broadcast TV in Australia? A few of the particulars you’ll want
Additionally, anybody pushing bizarre boundaries, producing twin 5K @ 50fps stereoscopic movies for the Apple Imaginative and prescient Professional, then… sure, you’ll need to run some experiments with excessive and really excessive knowledge charges to seek out the best steadiness. Apple’s Compressor and Adobe Media Encoder each provide many controls with a deal with skilled encoding wants.
The final group that should fear about knowledge charge is anybody producing video recordsdata to be shared on to purchasers. For those who’re creating coaching movies to be despatched to employees and performed from an inner server, you in all probability shouldn’t be creating 20Mbps 1080p movies. If a retailer has a 100Mbps web connection, and 50 employees at that retailer are despatched a video to look at, you’ve simply saturated their bandwidth many instances over.
As a substitute, get that knowledge charge all the way down to 2Mbps or so, in all probability with Handbrake, as a result of it produces recordsdata that look good at low knowledge charges. Need extra management? Shutter Encoder is your buddy. However once more, chances are you’ll not want it.
Conclusion
A fast abstract, then:
- Shoot the very best picture your digital camera provides, however provided that you don’t must compromise an excessive amount of on file dimension.
- All-I isn’t all the time the only option.
- Know the boundaries of your media, and decide the very best compromise that received’t drop frames or replenish too many playing cards or drives too rapidly.
- Check your decisions earlier than you commit. Issues change.
- iPhone default knowledge charges are on the low facet, however they nonetheless look fairly good.
- Working with a colorist? RAW when you can.
- Comply with specs you probably have them, or prime quality presets when you don’t.
- It’ll look higher in your laptop than it ever will once more.
Disagreement is welcome within the feedback.
