I’m aware that Shotcut doesn’t natively work super great with HDR footage from the iPhone, and I’ve looked into the solutions posted previously, most of which ultimately links back to thie “Editing HDR Source Clips” help page.
However, I’ve found that this doesn’t work for me.
After running the conversion (left), with the box checked for “Convert to BT.709”, it still looks very washed out compared to the source clip opened in VLC (right).
I’ve also noticed that the properties dialog lists a “Color Transfer” I haven’t found referenced in any other help topics on the issue: ARIB B67 (HLG).
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HLG is a form of HDR; I updated the documentation page for that. This is what iPhone uses for HDR as well as GoPro HERO13 when you turn that on. The conversion worked, but converting HDR to SDR is inherently lossy, and there is more than one way to do it. Did you compare the unconverted in Shotcut with the converted? If you don’t like Shotcut’s conversion you can either use the LUT filter (see the NBCU LUTs on our Resources web page) on the unconverted file, or use a different tool to convert it.
Here is my example in Shotcut.
Unconverted
Using the NBCU HLG2SDR LUT
Converted to Rec. 709 MP4
I am using Windows 11 with a HDR monitor, and if I view it with VLC it displays in HDR. It looks better as expected since HDR > SDR (at least my opinion, but in reality not everyone agrees!) I am not confident making a screen grab with the Snipping Tool makes a valid comparison since it is in HDR, and the image format is not HDR in the same sense as video (PNG is sRGB). Anyways, I tried but it came out weird
Then, I used Video > Take Snapshot in VLC, and it produced the unconverted image (PNG)
Now, which do I think looks closest to viewing the HDR video on HDR display with HDR-capable player? Probably the LUT. I just learned about these LUTs, and some will prefer the more saturated look of the converted.
P.S. When playing a HDR video on a SDR system, VLC is doing a conversion to SDR in realtime using a display technology (shader), which again, is only one of many ways to convert it as there is no standard formula to fit a square peg into a round hole.
Appreciate the in-depth reply. I’ll give the LUT a try and see if that gets me closer to my expectation. I might, going forward, perhaps eschew HDR when filming on the iphone – maybe that will be a better way about.
The LUT I used is named 3-NBCU_HLG2SDR_DL_Adobe_v1.2.cube
