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no0nefamous

macrumors regular
Original poster
May 11, 2021
237
210
When recording video with the HDR setting turned on on iPhone, do the resulting video files actually lose image quality if they are converted to a non-HDR file or uploaded to a non-HDR streaming service? (For instance, as far as I know, YouTube doesn't have any HDR capabilities).

In other words, if you convert an HDR video file to non-HDR, is the resulting video worse looking than if you had not shot in HDR in the first place?
 

R S K

macrumors regular
Oct 18, 2022
193
71
Hannover, Germany
They do not lose image quality, they lose color depth i.e. have only a fraction of the dynamic range. They have the dynamic range of SDR, that's all. Otherwise, they would be unwatchable on 99% of screens. SDR or Rec. 709 has a maximum dynamic range of 100 nits, HDR will generally start around 1000 nits and goes up to 10.000 nits depending on which colorspace you are mastering for.

And Youtube has supported HDR for quite some time now. My latest videos for example are in HDR. But they will only be played or identified as HDR if you are in fact watching them on an HDR screen.

Bottom line: if you do not need or intend to output as HDR there is no practical reason to shoot or edit in HDR. I would turn it off.
 
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no0nefamous

macrumors regular
Original poster
May 11, 2021
237
210
I actually just realized that YouTube does HDR after viewing one of my YouTube videos that I uploaded from my phone on YouTube via my iMac screen.

So, let's say I play that same video on a non-HDR screen. Will it look the same as a video that was converted from HDR to SDR? Or is the loss of color depth worse than having shot in SDR in the first place?
 

R S K

macrumors regular
Oct 18, 2022
193
71
Hannover, Germany
Again, it depends on the chosen color space and processing. If done properly you will not see any difference compared to simply outputting the same file in regular SDR.

And how can you lose color depth that you can't even display to begin with? It's already "lost" by not having the display capabilities.

I also don't know how you could know on an iMac whether a clip is in HDR or not since YT will know that you don't have an HDR screen and won't even present it to you as such to begin with. 🤨
 

no0nefamous

macrumors regular
Original poster
May 11, 2021
237
210
I also don't know how you could know on an iMac whether a clip is in HDR or not since YT will know that you don't have an HDR screen and won't even present it to you as such to begin with. 🤨

On my iMac (m1 24"), YouTube videos with HDR capabilities give me the HDR option. 🤷‍♂️
 

R S K

macrumors regular
Oct 18, 2022
193
71
Hannover, Germany
Interesting. Then I guess Apple flags it somehow that it's simply "downgrading" the clip to an appropriately tone-mapped version. Seems nonsensical, since there is no actual advantage, but oh well. 🤷🏼‍♂️
 

jwolf6589

macrumors 601
Dec 15, 2010
4,827
1,590
Colorado
They do not lose image quality, they lose color depth i.e. have only a fraction of the dynamic range. They have the dynamic range of SDR, that's all. Otherwise, they would be unwatchable on 99% of screens. SDR or Rec. 709 has a maximum dynamic range of 100 nits, HDR will generally start around 1000 nits and goes up to 10.000 nits depending on which colorspace you are mastering for.

And Youtube has supported HDR for quite some time now. My latest videos for example are in HDR. But they will only be played or identified as HDR if you are in fact watching them on an HDR screen.

Bottom line: if you do not need or intend to output as HDR there is no practical reason to shoot or edit in HDR. I would turn it off.
Yes especially since it slows down my Mac opening them.
 

R S K

macrumors regular
Oct 18, 2022
193
71
Hannover, Germany
Yes especially since it slows down my Mac opening them.

Certainly not any more or less than a non-HDR clip from an iPhone. The differences as far as datarate etc. is negligible. So if it slows down noticeably in comparison, then it's something with your machine.
 

jwolf6589

macrumors 601
Dec 15, 2010
4,827
1,590
Colorado
Certainly not any more or less than a non-HDR clip from an iPhone. The differences as far as datarate etc. is negligible. So if it slows down noticeably in comparison, then it's something with your machine.
No its because I have a 2020 Intel mac and not an apple silicon mac. Non HDR clips play fast and there is no lag.
 

R S K

macrumors regular
Oct 18, 2022
193
71
Hannover, Germany
Again, other than maybe datarate (i.e. lacking disk I/O) there is no logical reason why they should. Not even on an Intel Mac. And that difference in datarate is merely up to around 10% more with HDR. The image itself does not require more (relevant) resources.

If anything, you're seeing a difference in playback between CODECS, not color spaces.
 

jwolf6589

macrumors 601
Dec 15, 2010
4,827
1,590
Colorado
Again, other than maybe datarate (i.e. lacking disk I/O) there is no logical reason why they should. Not even on an Intel Mac. And that difference in datarate is merely up to around 10% more with HDR. The image itself does not require more (relevant) resources.

If anything, you're seeing a difference in playback between CODECS, not color spaces.
I found a solution. Disable HDR on iPhone has all is well on Mac. Simple….
 
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