Speaker 1: When you go to watch a movie in a traditional theater, how do you think that movie is encoded and displayed? Did they stream it from some top secret encrypted website? Is it encoded using a standard delivery format, like H.264 or ProRes? Or is it a completely uncompressed video stream? Well, actually, it's none of those things. Ever since the rise of digital projection systems, the format of choice for theaters has been the Digital Cinema Package, or DCP. So what is a DCP? Well, in short, a Digital Cinema Package is a standardized delivery format designed for use in theaters. A DCP isn't a codec, exactly. Your camera can't record a DCP. Instead, it's sort of like a DVD or Blu-ray, a set of industry standards for delivering and then playing back content. When a new film is released, the studio will ship each theater a hard drive containing one or multiple DCPs. The theater will then load these DCPs onto a special computer called a DCP server. The DCP server is basically like an overpowered media player. It will typically have enough internal capacity to store multiple movies at once, as well as video and audio outputs for connecting to the projector and sound system. The DCP server's operating system allows the technician to build a schedule of which DCPs should be played and when. Each show usually involves playing back a few small DCPs for advertisements and various other graphics, followed by one big DCP for the movie itself. That's right, almost everything you see on the theater screen, even the previews, are DCPs. Now that's all well and good, but what's in one of these DCPs anyway? Well, a DCP usually consists of a folder containing several files. First, there are XML files describing the contents of the DCP and telling the DCP player where to look for all the data. Next, there are two separate files for the video and audio tracks of the film. These obviously make up the majority of the DCP's contents. Finally, there is the optional subtitle track, which varies depending on the region and type of screening. Let's look at each of these in a bit more detail, starting with the video track. It's a common misconception that movies in the theater are either uncompressed or losslessly compressed. In reality, the video track of a DCP uses a codec called JPEG 2000. JPEG 2000 is different from ordinary JPEG compression, but the concept is fairly similar. It's an all-intra, lossy codec wrapped in an MXF container. The bitrate of a DCP varies from around 150 to 250 Mbps, which is quite a bit higher than online streaming or Blu-rays, but we also need to keep in mind that the JPEG 2000 codec is less efficient than something like H.264. So while it would be fair to say that DCPs aren't compressed as heavily as other delivery formats, the quality isn't as outstanding as you might expect. It's certainly worse than something like ProRes. However, results speak for themselves, and I think you'd be hard-pressed to notice any significant compression artifact in a DCP, even if you go out of your way to look for them. Curiously though, the bitrate is generally the same regardless of whether a DCP is rendered at 2K or 4K, so a higher-resolution DCP is actually compressed much more heavily than a lower-resolution one. However, again, I think in practice, most people will still prefer the higher-resolution version. Speaking of resolution, this is one area where DCPs are actually fairly strict. While DCPs can be encoded at several different resolutions, they all fall under the umbrella of either DCI-2K or DCI-4K. I've discussed these two standards at length in a previous video, but I'll recap here. Basically, there are two container resolutions, either 2048x1080 or 4096x2160. These container resolutions can then be cropped depending on the aspect ratio of the film. There are two main aspect ratios which are universally accepted, and then a few others which are a bit more inconsistent. First there is 1.85 to 1, or flat, which translates to a resolution of either 1998x1080 or 3996x2160. Then there's 2.39 to 1, or scope, which translates to either 2048x858 or 4096x1716. These four resolutions are by far the most common for encoding DCPs, and their compatibility is essentially universal. But there are technically two other options. Per the DCP specifications, it is technically permissible to use the full container resolution. You can also use a 16x9 crop to create the more familiar resolutions of 1920x1080 or 3840x2160. However, at this point we need to acknowledge the unfortunate reality that this delivery standard isn't quite as standardized as you might hope. While these less common resolutions are technically allowed, there's a good chance that a typical theater might not handle them correctly. Every theater is a little bit different, and the technicians may not be thoroughly versed in the ins and outs of the DCP specifications. As an example, most theater screens use matting to change the shape of the screen depending on the aspect ratio of the film being shown. Most theaters have presets set up for 1.85 to 1 and 2.39 to 1 ratios, but might not mat the screen correctly if the aspect ratio isn't one of those two. Heck, sometimes they don't even mat the screen correctly when the film is a common aspect ratio. I once went to see a Marvel movie, and the projector was angled like this the whole time. So if your film uses an aspect ratio other than flat or scope, it's usually best to scale the film to fit one of the more common aspect ratios, and then just accept that the screen shape won't match perfectly. For example, Jurassic World was produced in an aspect ratio of 2 to 1, but its DCP was encoded as 1.85 to 1 with letterboxing on the top and bottom. As for the decision between 2K and 4K, it really just depends on what the theater asks for. Some theaters have upgraded to 4K projectors, while many have not. So it's not a bad idea to export both 2K and 4K DCPs, and send whichever one the client requests. Now what about framerate? Well, the story here is pretty similar. By far, the most common and reliable framerate for a DCP is 24 frames per second. Not 23.976, 24 exactly. This has been the standard since the silent film era, and it isn't going anywhere anytime soon. If your film was produced at 23.976, don't worry too much because both of the DCP export tools we'll discuss later on will automatically convert your film to 24p. But what if your film uses a framerate like 25 or 29.97? Once again, this is where things get a bit tricky. First of all, it depends on which type of DCP you're delivering. At the time of writing, there are two main standards, Interop and SMPTE. The Interop DCP standard is older and more restrictive, but its compatibility is nearly universal. On the other hand, the SMPTE DCP standard allows a much wider range of formats, but it isn't supported by all theaters. So if you need to deliver an Interop DCP, then unfortunately 24p is pretty much your only option. 48p is also supported, but only for 2K compositions which aren't 3D. In contrast, SMPTE DCPs can have a much wider range of framerates. The standard allows for framerates of 24, 25, 30, 48, or 60fps at 2K, and 24, 25, or 30fps at 4K. So if you know for sure that a theater supports SMPTE, then you can probably get away with encoding your DCP at a different framerate. But if you aren't sure, 24p is by far the safest option. We're almost done talking about the video track, but before we move on, there's one more important aspect we need to discuss. Color. Which gamma curve, color space, and bit depth should we use for encoding our DCP? DCI projectors sort of occupy a space in between SDR and HDR. First of all, their contrast and brightness characteristics are decidedly SDR. Projectors have never been as good at contrast as LCD and OLED displays, and theater projectors are no exception. Most DCI projectors produce a peak brightness of only around 50 nits, and they don't have any local dimming technology to enhance contrast further. The only reason these projectors don't look dim and washed out is because there's so little ambient light. HDR, this is not. However, in spite of their lackluster dynamic range, DCI projectors do have some advantages over typical SDR screens. For one thing, they typically use the DCI-P3 color space, which is a bit wider than the typical Rec.709. Additionally, they use 12 bits per channel of precision, which means that color banding is nearly imperceptible. In turn, the DCP standard is designed to take maximum advantage of the projector's strengths and weaknesses. DCPs are typically encoded with a standard gamma, 12 bits per channel of precision, and the XYZ color space. If you haven't heard of XYZ, it's a system where colors are represented by their X, Y, and Z coordinates on the chromaticity diagram. While this standard theoretically encompasses the entire visible spectrum, as well as many colors outside of it, in practice, the DCP is typically limited to colors that also exist in the DCI-P3 color space. One last thing I want to address is the existence of Dolby Cinema. You might have seen advertisements for this claiming that it provides an HDR experience in the cinema. This is sort of true, but it's also a bit misleading. Dolby Cinema DCPs do use the same PQ gamma curve as Dolby Vision HDR. However, that doesn't mean you're seeing the same dynamic range as a typical HDR TV. While Dolby Cinema projectors do have superior dynamic range to a typical projector, the improvement is only about one stop, and a far cry from the capabilities of a true HDR display. So yes, some DCPs are encoded as HDR, but the results aren't as stunning as you might expect. Okay, so that's pretty much it for video. Now what about audio? Well, unlike the video track, the standards for the audio track seem to be much less specific. The sound is encoded as 24-bit linear PCM at a sample rate of either 48 or 96 kHz. That's pretty standard. But how many channels should the audio have? Well, if you're producing content for social media, odds are you're working in either mono or stereo sound. But higher-end productions often mix for surround sound standards like 5.1, 7.1, or Dolby Atmos. And the thing is, the DCP standard doesn't actually specify how many channels the audio track should have. It only specifies a maximum of 16. So then, is an ordinary stereo mix allowed? Well, technically, yeah. The standard doesn't specify a minimum number of tracks. However, in practice, almost all theaters employ some sort of surround sound. While you can theoretically encode a DCP in stereo, that mix won't take advantage of the theater's full capabilities, and will likely only play out of the left and right speakers. This isn't wrong, exactly, but it probably won't sound the way you expect a movie to sound. So for practical purposes, I would recommend mixing your film using 5.1 surround sound as a minimum. Some theaters employ more robust speaker configurations, but 5.1 is a fairly safe bet. Now, I'm not an expert in mixing for surround by any means, but I have started doing it on some projects, and it really isn't that bad once you learn the basics. Alright, so with the video and audio out of the way, there's only one more track to worry about, the subtitles. You might think that subtitles are only used for films produced in foreign languages, but this is actually not the case. Sometimes, theaters will offer special screenings of movies with native language subtitles across the whole film. Some people need these subtitles for accessibility reasons, and some just prefer watching movies that way. Subtitles are also used if a particular bit of dialogue is in a foreign or fictional language, and the director wants the audience to understand what's being said. These subtitles actually aren't baked into the video track like you might expect. While ordinary titles are often baked in, subtitles are not. The video track is completely clean. Instead, the subtitles are stored as a separate text file, and the DCP player will dynamically render the text and overlay it on top of the video track. The subtitle track also includes metadata for the formatting, duration, position, and font of the text. And that's pretty much it as far as DCP contents are concerned. Metadata, video, audio, and subtitles. So with that in mind, how can we actually make one? Well, for a very long time, the only real option was to hire a post-production house to do it for you. When it came time to deliver a film, the studio would create what's called a Digital Cinema Distribution Master, or DCDM. This is basically a collection of rendered files which are ready to be compiled into a DCP by the finishing house. For example, a DCDM often includes the video track with your compression and color science applied, but wrapped into individual TIFF files rather than an MXF container. From there, a dedicated finishing house would take the studio's DCDM and manually format it into a DCP. This remains the most reliable method for creating a DCP, since humans are involved in every step of the process for quality control. However, while major studios will still use this approach, the fees charged by post-production houses are often prohibitively expensive for independent filmmakers. So a better question is, how can we make a DCP on a budget? Well, on this front, there's actually some really good news. While commercial DCP authoring tools have existed for a while, they're still quite pricey for what they are, but thankfully we don't have to use them, because DCP authoring capabilities have now been integrated into several popular video editing programs. Both Adobe Premiere and DaVinci Resolve Studio are now capable of exporting DCPs at no additional cost. While these are both paid programs, I think it's fair to say that if you're in a position where you need to create a DCP, you probably already have either Premiere or Resolve. So let's create a DCP. To start, let's go over some basic steps that you should take regardless of which software you're using, and then I'll go over the specifics for both Premiere and Resolve. The first thing you're going to want to do is figure out how you want to make your resolution and framerate DCP friendly. As I stated earlier, DCPs are quite picky about which resolutions and framerates are allowed, so if your timeline doesn't match these specifications perfectly, you're going to have to conform it somehow. You could do this by changing the timeline settings and then tweaking the scaling of your clips, or you can leave the timeline as is and change the automatic scaling options in the export settings. If your timeline's aspect ratio isn't either flat or scope, you'll have to choose whether you want to scale it to fill or scale it to fit. If you scale the timeline to fill, then some parts of the image will be chopped off and lost, but the final result will fit a theater screen perfectly. However, most filmmakers instead opt to scale their timeline to fit one of the DCI aspect ratios. This way the original shape of the film will be preserved, just with a bit of letterboxing. As for framerate, your DCP is almost certainly going to run at 24 frames per second, so if your timeline framerate is significantly different from that, then you're going to have to do some work to conform all of the footage to a different speed. However, if your timeline runs at 23.976 FPS, you actually don't have to worry about this. Both Premiere and Resolve will automatically recognize this framerate and conform it to 24p for you. Alright, so with our film formatted and ready, let's take a look at how to export a DCP in Premiere. So we're going to go ahead and open the export window as usual, and then we're going to change the format to Raptor DCP. Under our video export settings, we can choose from a few different options for formatting our DCP. Now unfortunately, at the time of writing this video, Premiere only supports 2K DCPs, with a framerate of either 24 or 25p. Additionally, Premiere's lack of color management support means that we won't be able to take advantage of the full DCI-P3 color space. Premiere is going to simply assume that our timeline is Rec.709, and perform the conversion to XYZ based on that assumption. The results should look correct in the theater, but your color gamut will be effectively limited to Rec.709. Anyway, for our resolution, we only have three options, full, flat, or scope in 2K. So we're going to choose whichever is most appropriate, and then we're going to make sure that our scaling settings up here are correct. Now in this case, it doesn't matter because the timeline aspect ratio is the same as DCI scope, so we're just going to leave it as is. But for example, if we were going to deliver to flat, then you can see we have it set to scale to fill, so the sides are being cut off, but we could also do scale to fit, for example. But we're going to go with scope. And then we also want to choose our framerate, of course, so this is going to be 24, then we could also go 25 if we had a PAL project for whatever reason. Now under the audio tab, we can choose whether we want to deliver our sound mix as either stereo or 5.1, and everything else is set for us. Again, I'd recommend delivering 5.1 if at all possible, though in this case I only have a stereo mix of the project, so we're going to be delivering stereo. So then finally, all you have to do is choose an output file name, just like always, and hit export. Premiere's DCP support is still fairly rudimentary, but it's better than nothing. Alright, so now let's take a look at Resolve. So we're going to make sure we're on the Deliver tab here, and we're going to switch the format to DCP. So now we're going to go ahead and leave the codec here at its default setting, and then we're going to choose our desired resolution. Now we have the same three aspect ratios to choose from here, however Resolve does allow us to export 4K DCPs as well, so in this case I'm going to choose 4K DCI Scope. Now below this we can choose whether we want our DCP to be exported as HDR. This could be useful for delivering for something like Dolby Cinema, but the vast majority of the time you'll just want to leave this turned off. And below that we can choose whether we want to package our DCP as Interop or SMPTE. And again, Interop is a safer bet because it's more widely supported by theaters, and we don't really need any of the SMPTE features in this particular case. And next we can go ahead and choose our maximum bitrate. The default here is usually fine, though if you really wanted to you could go lower to something like 150, but for the most part just leave it as is. And next we're going to go ahead and go over to our Audio tab. So in the Audio tab we're going to want to make sure that we have the correct sound mix selected. So in this project I've set up several different main outputs for different surround sound standards, but in this case I'm just going to go ahead and select my 5.1 mix for the sake of simplicity. And finally we're going to go back to the Video tab, and we're going to scroll all the way down to Composition Settings. So DCPs have a standardized filenaming scheme, and this window is going to allow you to generate the appropriate filename for your project. So you can enter in your film's title, its type, information about the format and distributor, etc. And you don't actually have to use this as your DCP's filename, but it is recommended. Now as for color management, we want our DCP to be encoded with a standard gamma and the XYZ color space. However, Resolve will just handle this conversion for you. If your project doesn't have color management enabled, then Resolve will automatically convert from the timeline color space to XYZ during the DCP export. And if you do have color management set up like I do here, then Resolve will automatically override the output transform to the appropriate value. So you don't need to worry about choosing the correct one. Resolve will do it for you when you choose DCP as your delivery format. If you're curious though, the appropriate transform is called DCI XYZ in RCM, and DCDM in ACES. Okay, so now we have a DCP on our computer, but how can we make sure that everything's correct? Well, ideally we would do a quality control check using an actual theater with a DCP server. But if that isn't an option, there are a few publicly available DCP players we can use. My preferred way to playback a DCP is to just use Resolve. That's right, in Resolve you can actually just import a DCP like you would any other media file. You will need to use a color space transform to convert XYZ to Rec. 709, but aside from that, everything just kind of works. So at the end of the day, why should you care about DCPs? Well if you're just making content for social media, then you probably won't have to deliver one anytime soon. But it can't hurt to learn how the process works in case you end up submitting your projects to film festivals or something like that. And even if you aren't a content creator, it can still be a lot of fun to learn how the technology behind your favorite movies works. Anyways, I hope you all enjoyed this video. My name is Cayman Crocker, signing off.