SDR vs HDR, what does it all mean and when does it matter? SDR stands for Standard dynamic range and HDR means High dynamic range. Blu-ray and 1080P streaming is limited to SDR while 4K UHD disc and 4k streaming uses HDR.
This picture below gives an example of what can be achieved with HDR, Its a mock-up that simulates the effect of HDR by reducing the color gamut on one side. But you cannot really see a SDR vs HDR difference unless you are viewing HDR content on a HDR tv or projector. But you get the idea of what can be achieved.
HDR – Metadata
HDR video is a combination of 3 things: Wider Color Gamut, Color Depth and Dynamic range. This metadata is additional information that is sent with the video signal that tells the display how to display the content properly. More on this below.
HDR – Wider Color Gamut
A Tv with HDR can display a wider color gamut than a standard tv, which means it can display more more saturated colors resulting in a more life like image. But to really see a huge difference you need to have a higher end TV that uses the HDR capabilities at a maximum. There is not much difference between a high end SDR tv and a cheap HDR tv. With a more premium HDR tv the difference is bigger. See for yourself below.
High-End TV with HDR ( Sony X930D )
High-End TV with SDR
Low-End TV with HDR
Color depth means how how many colors can be displayed so this is similar to wide color gamut. A low color depth can results in color banding like this one below. This is usually seen in a complex scene where the color spectrum is very wide. A standard SDR TV can display 8-bit color which means 16.7 million colors which may seem like a lot but a HDR tv can display more than 1 billion colors. In this case there is not a lot of difference between a high end and low end HDR tv.
Dynamic range is the third component of HDR which is where a good TV will shine. A tv that can get very bright can show details in dark areas and display finer details within bright areas. Compare the 2 pictures below, As you can see in the HDR image the clouds on the mountain is more defined while the SDR picture they are almost not visibly. Details in the shadows below the cars are also a little more defined. This difference might seem small by looking at these pictures but remember that to truly see a difference you need to view it in a good HDR TV.
HDR TV ( Sony X930D )
Bluray vs 4K Ultra HD discs
The video below is a comparison between a standard blu-ray disc vs a 4K UHD disc, it compares
still images from the movie. You can see there is a difference in color and detail, in some scenes the difference is more profound, but to really see a difference you need to have an actual 4K Blu-ray player ( or 4K streaming ), a 4k UHD disc and a 4K TV that has high enough brightness levels that can take advantage of the increased color gamut, color depth and dynamics range. Comparing youtube videos like the one below does can not be a true SDR vs HDR comparison. You really need to see a 4K HDR Tv or Projector in person.
Dolby Vision vs HDR10 vs HDR10+
There a also 3 different HDR formats. Dolby Vision, HDR 10, HDR 10+ which each has different approaches on how they handles HDR content. There are not a lot of differences between the formats but there are some that is good to know.
This is an open standard HDR format. I uses 10 bit colors and 1.07 billion colors just like the other 2 standards. This is the most widely accepted format that is compatible with most TV´s, players and streaming services. The drawback of this format is that is uses static metadata which means that brightness and other picture settings can’t be changed automatically on a scene by scenes basis. This can lead to some scenes behind too dark or too bright, and you will miss out on HDR highlights.
HDR 10 +
This format is supported by Samsung and some other TV´s. It also uses 10 bit, 1.07 billion colors but has dynamic metadata which means it can change the picture settings one a scene by scene basis which fixes the problem of some scenes being too dark or too bright. Keep in mind that HDR 10+ is not supported by Netflix, so if you are watching on a Samsung tv it will default to HDR10, this is something to keep in mind.
This format is similar to HDR 10+, which also uses dynamic metadata. But this format is not supported by Samsung TV´s. But is supported by Sony, LG, Vizio, Hisense and TCL. If you are a heavy Netflix user its a good idea to avoid the Samsung tv. The Apple TV4K box also only support Dolby Vision. Dolby vision can also use 12-bit color although no TV´s is currently capable of supporting that format.
HDR 10 vs Dolby Vision
So how does dynamic metadata compare to static metadata, this is a comparison video between HDR 10 and Dolby Vision, both are in 4K. Judge for yourself.
HDR in TV vs Projectors
What about HDR when using a projector, how does that work?, Well a projector works very differently than a TV. An lcd tv can dim individual areas in the image and an oled tv can even turn of the light of specific pixels. A projector can only dim the entire image which is why it can never achieve the same level of HDR capabilities like a TV. The same is true for highlights. A projector can’t highlight specific areas in the image whit out affecting other areas.
Tone Mapping, can it fix the HDR?
Most projectors struggles to take advantage of HDR because of the limitation of the projector technology. Projectors can’t use HDR10+ or Dolby Vision, but are limited to HDR10. Tone mapping is a process where the HDR signal is adapted to fit the limitations of the display. It is a static process that applies a single tone map curve to the content being watched, but its incapable of changing the curve on a scene by scene basis. ( like HDR+ or Dolby Vision ) This can be annoying when watching a movie when some scenes are to dim or washed out while others look good. You might have to change the HDR setting in the projector every time you view a different movies.
JVC projectors have a mode in their projectors called Frame adapt HDR that tries to solve the above problem. It has 3 settings, low medium and high. Low will tame the brightest content while high will brighten the dimmest. Auto analyses HDR metadata when available much like HDR+ and dolby vision. This does not work as well as those 2 other but Its the best that current projectors can offer. Here the guys behind the JVC projectors explain it further:
Tips for improvements
To take full advantage of the HDR in Projectors make sure you don’t have any ambient light coming into your room that can wash out the picture. Its also a good idea to use a projector that have a high light output. Many 4k projectors have different modes for HDR depending on lightning conditions and the type of movie you are watching. You might have to tweak the HDR settings in the projector each time you watch a different movie.
SDR vs HDR Projectors
If you are thinking of buying a new 4K HDR projector you might consider going for a premium 1080P SDR projector instead. The SONY VPL-HW65ES offers great contrast ratio, color and great black levels that can rival a 4K projector with HDR. The only downside are that its not 4K so you loose a little resolution, and its can not display HDR but as you know that is something projectors struggles with anyway.
4K Streaming vs 4K UHD Blu-ray
What about when comparing 4K streaming vs a 4K UHD disc, is there a lot of difference in the SDR vs HDR experience? Well lets compare, a Blu-ray 4K disc sends data through your hdmi cable from 82 to 128 megabits per second. For a Netflix 4K streaming subscription this number is only 25 megabits. So the Blu-ray can send 3-5 times more data compared to streaming, but is this differences enough to see a difference in HDR detail. Below is a great comparison video between these. Judge for yourself.
There you have it. As you can see there can be a huge difference when comparing SDR vs HDR in some scenes while in others the difference is negligible. When comparing the differences in the HDR formats it can be tough to spot a difference. But then again trying to spot differences in youtube videos watching through your SDR screen is a limiting factor. If you are thinking of buying a new TV the best thing you can do is to visit a store, and choose one that fits your need. Visit my OLED vs LCD post for more info.