1 00:00:00,000 --> 00:00:06,400 HDMI made the entire internet mad recently by introducing a confusing new branding scheme 2 00:00:06,400 --> 00:00:11,200 when the old one was serving everyone just fine. But hold on, there's more because it's about to 3 00:00:11,200 --> 00:00:18,080 get more confusing with the introduction of HDMI 2.1a. There's an A. So let's talk about what's new 4 00:00:18,080 --> 00:00:24,720 in the HDMI 2.1a spec. And as you may have gathered from the fact that it's called 2.1a instead of 5 00:00:24,720 --> 00:00:31,920 2.2, the list of changes is rather short. In fact, there's only one new feature and it's called 6 00:00:31,920 --> 00:00:36,640 source-based tone mapping. That might sound like some kind of gimmick you'd pay extra for at a 7 00:00:36,640 --> 00:00:42,160 tanning salon, but it actually has to do with the way devices handle HDR. Tone mapping is the 8 00:00:42,160 --> 00:00:48,160 process of taking an HDR signal and adjusting it to match the capabilities of whichever display you 9 00:00:48,480 --> 00:00:55,760 be watching that content on. You see, many HDR-capable TVs actually are not able to show an 10 00:00:55,760 --> 00:01:01,600 HDR image as it's originally mastered. Oftentimes, the original video is mastered at 1,000 nits of 11 00:01:01,600 --> 00:01:06,720 brightness or even higher, but most consumer displays, even many that are marketed as HDR, 12 00:01:07,280 --> 00:01:13,840 cannot get that right. Additionally, HDR content is often mastered for a wider color gamut than 13 00:01:13,840 --> 00:01:20,320 many TVs can show, meaning they can't display as many colors as are contained in the source material. 14 00:01:20,320 --> 00:01:25,920 Without tone mapping, the TV would clip the image. That is, it would simply discard the information 15 00:01:25,920 --> 00:01:31,760 it can't display from the video signal, and the image would instead have very incorrect colors, 16 00:01:31,760 --> 00:01:36,880 or just parts with no information, and portions that would be blown out to absolute crap so you 17 00:01:36,880 --> 00:01:41,520 can't even see them at all. So tone mapping effectively takes color and brightness information 18 00:01:41,520 --> 00:01:47,760 and maps it to a value that the TV can actually show. This allows the TV to approximate the original 19 00:01:47,760 --> 00:01:53,280 image accurately enough so that it looks okay on your screen instead of a distorted mess. 20 00:01:53,280 --> 00:01:58,000 So for example, a signal with 1,000 nits peak brightness can be reduced so that the brightest 21 00:01:58,000 --> 00:02:03,600 parts of the image are now, say, 400 nits. Everything goes in line with that. 22 00:02:04,240 --> 00:02:10,080 Now back to HMAT 2.18. Traditionally, tone mapping is handled by the display itself, 23 00:02:10,080 --> 00:02:16,400 but the source-based tone mapping in HDMI 2.1a offloads some of this responsibility from the 24 00:02:16,400 --> 00:02:22,160 display and moves it to the source, whether the source is a GPU, a streaming box like an NVIDIA 25 00:02:22,160 --> 00:02:30,000 Shield, or a Blu-ray player. But why exactly would we want this? Dolby Vision HDR actually already has 26 00:02:30,000 --> 00:02:35,920 a proprietary option where you can select either TV-led or player-led tone mapping, 27 00:02:35,920 --> 00:02:41,040 and tests have shown that tone mapping looks better when it's handled by the display itself, 28 00:02:41,040 --> 00:02:47,440 as the TV is adapting to its own characteristics, as well as data from its ambient light sensor if 29 00:02:47,440 --> 00:02:52,000 it has one of those built in. Having the source handle tone mapping means that it's doing the 30 00:02:52,000 --> 00:02:57,040 mapping based simply on what the TV reports its capabilities to be, meaning the adjustments the 31 00:02:57,040 --> 00:03:04,240 source makes may not be as accurate. So why do we want this? Well, it's because there is a big plus 32 00:03:04,240 --> 00:03:11,440 to source-based tone mapping, lower latency. Even if something might look a bit better if the TV 33 00:03:11,440 --> 00:03:17,280 is handling the tone mapping, this additional processing that the TV has to do adds latency, 34 00:03:17,280 --> 00:03:22,720 which can be a significant drawback for gamers who want as small of a delay between pressing a 35 00:03:22,720 --> 00:03:28,480 button on the controller and seeing an action happen on the screen as possible. So source-based 36 00:03:28,560 --> 00:03:35,280 tone mapping, or SBTM, is a sensible addition to HDMI's increasingly gamer-focused feature set. 37 00:03:35,280 --> 00:03:40,320 Additionally, source-based tone mapping does allow more of a plug-and-play experience for the user, 38 00:03:40,320 --> 00:03:44,480 as since it allows the source to read and understand the display's capability, 39 00:03:44,480 --> 00:03:50,400 the user won't have to spend as much time adjusting picture settings to get their HDR content to look 40 00:03:50,400 --> 00:03:56,640 right. For now, it sounds like SBTM support can be added to existing devices via firmware updates, 41 00:03:56,640 --> 00:04:01,680 but that'll be up to device manufacturers. So if you want the feature without spending 42 00:04:01,680 --> 00:04:07,920 extra on new equipment, your mileage may vary as AV manufacturers have a track record, let's say, 43 00:04:07,920 --> 00:04:14,560 of being very slow with updates. Additionally, HDMI 2.1a is going to suffer from the same stupid 44 00:04:14,560 --> 00:04:21,440 naming issues we saw with the original HDMI 2.1. All current HDMI devices will transition over to 45 00:04:21,440 --> 00:04:28,880 the HDMI 2.1a name, but they don't all have to support every new feature of HDMI 2.1 or 2.1a, 46 00:04:28,880 --> 00:04:33,920 so make sure you read the spec sheet to see if the features you care about are actually present. 47 00:04:34,480 --> 00:04:37,920 I mean, you never spend money without reading the fine print first, right? 48 00:04:39,040 --> 00:04:43,360 Right? So thanks for watching guys, if you liked this video, hit like, hit subscribe, 49 00:04:43,360 --> 00:04:48,080 and hit us up in the comment section with your ideas for topics that we should cover in the future.