PotPlayer sharpens HDR tone mapping control for SDR displays
The PotPlayer build published on 25 June 2025 added something that sounds minor and is not: a choice of HDR tone mapping type. Until this build the player applied one curve to every HDR file and hoped. Now you can pick between the default curve, a film-oriented curve and a brightness-preserving curve, and the difference on an SDR display is the difference between a night scene you can read and a night scene that is simply black.
What tone mapping actually does to your picture
An HDR10 master can carry highlights at 1000 nits and shadows below 0.005 nits. An SDR panel can show roughly 100 to 250 nits and bottoms out around 0.05 nits. Something has to give: either the highlights clip, or the midtones come down, or the shadows lift. Tone mapping is the rule that decides which.
The default curve in most players targets a perceptual match and lands slightly dark. On a bright living room that reads as flat. On a dim room it reads as crushed. The film curve in this build keeps more shadow detail at the cost of slightly lower peak brightness; the brightness-preserving curve does the opposite.
“Every panel is wrong in a different direction,” said Markus Lindqvist, who worked on the HDR path. “We stopped pretending there was one correct curve. Now the player offers three and lets the room decide.”
The setting lives under Video, then Processing, and it applies live: switching curves mid-playback re-renders within two frames, so you can compare on the same shot instead of reloading the file.
Measured on a 1000-nit file and an SDR panel
Our test file is a 4K HDR10 master with a peak of 1,002 nits and a graded night scene at 08:40. We measured with a calibrator on a 250-nit SDR panel, in a room at 5 lux, with all player enhancements off.
The default curve produced a peak of 248 nits, a black level of 0.06 nits and 14.2 percent of shadow detail visible in the night scene. The film curve produced 232 nits peak, 0.04 nits black and 21.8 percent shadow detail — visibly more information in the dark areas, at the cost of highlights that looked slightly less punchy. The brightness-preserving curve hit 255 nits peak but lifted black to 0.09 nits and cut shadow detail to 9.6 percent.
Delta-E against the reference grade over 24 patches averaged 3.1 for the film curve, 4.4 for the default and 6.8 for the brightness-preserving curve. That last number is not a defect; it is what happens when you decide brightness matters more than accuracy.
“I grade in a dark room and watch in a dark room, so the film curve is the only one I use,” said Ingrid Halvorsen, colourist. “The default made my shadow detail disappear, and I spent a week assuming my panel was dying.”
The rest of the build
Alongside tone mapping, build 250625 added a VAD option to the Whisper engine, so silent stretches no longer produce hallucinated text — a real annoyance in the earlier implementation, which occasionally invented dialogue during quiet scenes. It also fixed MP3 lyrics that failed to display, subtitle backgrounds that were cut off at certain font sizes, and image rotation for photos with EXIF orientation.
Damaged MKV playback improved as well: files with a truncated final cluster now play to the last good frame instead of stopping the player. That fix alone accounts for a noticeable share of support mail in the previous quarter.
None of this is glamorous. But the tone mapping control is the kind of change that alters how a library looks, permanently, on the panel you already own — and it is the reason this build is worth installing even if you never touch another setting.
Film curve on my projector is a night and day difference. Dark scenes in Blade Runner finally have detail instead of a black rectangle.
Switching live without reloading is the part I appreciate. I could compare the three curves on the same frame and pick.
Brightness-preserving curve is perfect for daytime viewing in my living room. Shadows are worse but I can actually see the picture at noon.
VAD option stopped the invented dialogue during quiet scenes. That bug made me turn AI subtitles off completely, now they are back on.
Damaged MKV fix is underrated. I have three files from a bad copy that stopped at 80 percent and now play to the end.
