In Part One we looked at the meanings of full swing and studio swing, and when to use which. In this part, we’ll look at how Adobe Premiere Pro handles full swing and studio swing, and how you should go about your workflow.
No matter which corner of the earth you’re shooting from, and no matter whom you’re delivering to for whatever purpose, your workflow can only take one of nine ways to get there:
Your footage could be either full, studio or both. Your output could be either full, studio or both. Before we start looking at the specifics of each combination, let’s first understand how Adobe Premiere Pro handles video levels.
How does Adobe Premiere Pro handle full swing and studio swing?
Adobe Premiere Pro is an NLE that thrives on native editing. The overriding philosophy is: ‘Do not change customer’s footage until customer hits Render’. This means, no matter whether you shoot full or studio or both, your footage will remain as it is on origin, unless you manually transcode or render it to something else.
E.g., you could bring in PSDs from Photoshop, photos from Lightroom and footage from RAW cameras and DSLRs all into the same timeline, and Adobe Premiere Pro will not do a thing to them as far as their video levels are concerned. However, the timeline that you edit in must conform to a particular delivery standard, and this is studio swing.
In a nutshell: Your footage remains as they are on the timeline —> Your timeline conforms to studio swing.
Why is this so? Why can’t Adobe remain in full swing (pardon the pun)? That’s because Adobe Premiere Pro (like Avid, FCP and everyone else, except Sony Vegas) is an NLE from the broadcast/cinema age, and even though it can edit native 6K Red Dragon footage, it can only do so in a maximum color depth of 10-bit, within Rec. 709 guidelines. If you want to do better, you’d need to finish in After Effects or a color grading app like Speedgrade or Resolve.
How do we know that Adobe Premiere Pro operates in studio swing? Let’s find out.
How to read levels within Adobe Premiere Pro
Firstly, Adobe tells us. In fact, the HD color bars that you can generate within Premiere Pro conform to the ARIB STD-B28 standard, and not SMPTE (There are two color bars. To know the differences, read this article).
Secondly, Adobe also shows us. If you generate the HD color bar from within Premiere Pro (Under the Project tab, right click and select New Item > HD Bars and Tone…) and then use the Reference monitor to study the YC Waveform, you get something like this (click to enlarge):
I’m not going into the details of how you read the ARIB bar – for an explanation please reference the article I linked to above. The YC waveform shows the image as both Y (luma) and C (chroma) values. I’ve turned off C (You can see the Chroma box unchecked) because we don’t need it for our purposes.
From left to right is the space of the image, as you can see it. Bottom to top is the IRE range. As we saw in Part One, the range must fall within 0 to 100 IRE. HDTV is standardized at 0 IRE for black and 100 IRE for white.
The concept of PAL or NTSC does not apply to Rec. 709. However, if you’re called upon to deliver in SD PAL or NTSC, the ITU standard changes, and you will have to make changes to your colors (if your footage did not originate from either PAL or NTSC). More later.
As an aside, if you open a sequence with 25 fps as its frame rate, the waveform won’t display IRE, but voltages from 0.3 to 1 V (Read this to know how they relate).
We are only concerned with six parts of the waveform (Refer to the color bars from Part One):
- 1. White (big white box at the bottom) corresponds to 100 IRE. You can see the length of the green line match the proportions of the box in the waveform. Nothing else exists on that line.
- 2. Black, which is the big black box to the left of the white box, corresponds to 0 IRE, and you can see that line matches the proportions of the box as well.
- 3. On the right, you have a few ‘steps’ of black. This is called the Pluge. There are five steps: -2, 0, +2, 0, +4. Look at the color bar. Only the third and fifth bars should ‘stand out’ from amongst the black, because these are slightly over 0 IRE. The third one should be especially faint. If you cannot see the bars, then your monitor needs to be calibrated.
- 4. The colors on the top of the color bar all have a luma of 75 IRE. You also have the option of 100%, but we are not concerned with that at this point.
- 5. This dotted line represents 7.5 IRE. If you check the Setup box, the entire waveform will shift from 0 to this dotted line from the bottom, while the top stays at 100 IRE. You only use this option if you’re grading for NTSC delivery in standard definition. If you’re grading for 30p HDTV or 25p PAL SDTV, you should leave black at 0 IRE.
So, coming back to our initial question. How do we know Adobe Premiere Pro operates under studio swing? Simply because the ARIB color bar is a standard studio swing color bar, and if Premiere Pro represents its black at 0 IRE and white at 100 IRE, you know that’s the space it operates in. RGB and RAW images don’t have a default luma-chroma component or representation, so Premiere Pro will convert all RGB images and video on the fly to studio swing to show you the waveform.
To put it simply, in Premiere Pro, 0 IRE corresponds to 16 and 100 IRE corresponds to 235 by default (for 8-bit. For 10-bit, the corresponding 10-bit values). There’s nothing you need to do at all. How nice.
But I can’t output broadcast-safe colors from Premiere Pro!!
Hold on, stressed-out video editor. PAL and NTSC is not Rec. 709. If you use the ARIB bar and studio swing in Premiere Pro, you’re obviously not going to conform to either PAL or NTSC, unless you tell Premiere Pro that’s what you want.
This situation happens if you shoot in HD in Rec. 709 but want to deliver to SDTV PAL or NTSC.
The first step is to specify the settings of your sequence. But, being Premiere Pro, it does not touch your native footage in any way. To ensure your colors and lumas are broadcast safe, you must use the Broadcast Colors effect:
Let me repeat: You don’t use this effect for HDTV export or 1080p or 720p export. You only use it for PAL or NTSC export.
Here are the settings explained:
- Broadcast Locale – PAL or NTSC. Plain enough.
- How to Make Color Safe – This tells Premiere Pro how you want to ‘bring down’ the colors without wasting time grading each one. There are four options. I suggest you try ‘Reduce Saturation’, since this corresponds to your footage most closely.
- Maximum Signal Amplitude (IRE) – Now this is something that most don’t get. The maximum IRE for Rec. 709 is 100 IRE, we already know that. However, why is the default value 110?? Simple. In the real world, most major broadcast stations allow a 5% variation either way (for chroma). E.g., the BBC specifies -5% to 105% (total range 110 IRE) for RGB components or chroma; and -1% and 103% (total range 104 IRE) for luma. The BBC explicitly states that an error will only be detected if the out of gamut pixels exceed 1% of the total pixels.
This is where having a calibrated broadcast monitor (PAL or NTSC, not HDTV!!) helps. Not only can you see the color bar correctly, but you can also see the impact of keeping the Maximum Signal Amplitude at 110 while adjusting the second option. In plain speak, you try to Reduce Saturation or Reduce Luminance, and only if neither works do you reduce Maximum Signal Amplitude. This is simply not possible with an sRGB monitor.
To recap this section:
- For PAL and NTSC standard definition delivery, use the Broadcast Colors effect, and study the effects on a PAL or NTSC broadcast monitor.
- For HDTV delivery, don’t use Broadcast Colors, and study the effects on an HDTV broadcast monitor.
Warning: Only use the Broadcast Colors effect for minute adjustments. If the changes needed to be made are drastic, you must color correct. The former clips your values, the latter will give you smoother tones and roll-offs.
While making adjustments to your grade (only for PAL or NTSC), you might want to check or uncheck the ‘Setup (7.5 IRE)’ box in the YC waveform. In the case of PAL, nothing needs to be done. In the case of NTSC, you might want to check the Setup (7.5 IRE) box. Mind you, this does not change your footage or signals in any way. It just remaps the YC waveform so you know the relative levels of things. Ultimately, Premiere Pro will automatically conform your timeline on export to the necessary standards.
Now we know that Premiere Pro works in studio swing, under Rec. 709. So, when you work with video shot in Rec. 709, you need not do anything to conform to Rec. 709 as long as your luma falls between 0 IRE and 100 IRE throughout your timeline.
Did I just state the obvious? If you shoot in Rec. 709, shouldn’t the video be between 0 IRE and 100 IRE anyways and always? It should be, but sometimes it isn’t. The usual culprits are those cameras that have a high dynamic range, and record RAW. To pass on the benefits of this extended range also while shooting codecs like Prores, etc., they knowingly allow some ‘extra’ stuff into the image. This means, you have important data that falls outside the studio swing range, but within the full range.
These images look great on sRGB monitors, but are unacceptable for broadcast. When you bring these images into Premiere Pro and study their YC waveforms, you’ll see them extending beyond the 0-100 IRE regions. When you see this happening, you need to grade to bring the video levels back into the acceptable zone. Then carry on. Premiere Pro does the rest. The simplest tool that allows you to get levels within the legal range is ‘Levels’.
- If your footage was shot in Rec. 709, you don’t need to do anything in Premiere Pro as far as settings or effects are concerned.
- Just make sure the video levels stay within the 0-100 IRE range. Use the YC waveform monitor and view the Program Monitor on a calibrated HDTV broadcast monitor to make sure. It’s only studio swing if both agree it is.
But what about full swing? How does Premiere Pro handle that par? That’s what we’ll look at in Part Three, and lay this demon to rest.