Does --hdr-compute-peak make HDR videos brighter?

[laichiaheng]

From what I understand, --hdr-compute-peak=auto works when the video peak brightness is higher than your monitor peak brightness, so the videos usually look darker with --hdr-compute-peak=auto. However, some of my videos look brighter when --hdr-compute-peak is enabled, it turns darker if I disable --hdr-compute-peak.

General
Complete name                            : ***.mp4
Format                                   : MPEG-4
Format profile                           : Base Media / Version 2
Codec ID                                 : mp42 (isom/mp42)
File size                                : 20.4 MiB
Duration                                 : 8 s 85 ms
Overall bit rate                         : 21.2 Mb/s
Frame rate                               : 30.000 FPS
Encoded date                             : 2024-04-08 14:43:08 UTC
Tagged date                              : 2024-04-08 14:43:08 UTC
Writing operating system                 : Google Android 14
Writing hardware                         : Samsung Galaxy S23 Ultra (SM-S9180)

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L1@Main
HDR format                               : SMPTE ST 2094 App 4, Version 1, HDR10+ Profile B compatible
Codec ID                                 : hvc1
Codec ID/Info                            : High Efficiency Video Coding
Duration                                 : 8 s 1 ms
Bit rate                                 : 21.2 Mb/s
Width                                    : 1 080 pixels
Height                                   : 1 920 pixels
Display aspect ratio                     : 9:16
Frame rate mode                          : Variable
Frame rate                               : 30.000 FPS
Minimum frame rate                       : 29.412 FPS
Maximum frame rate                       : 30.303 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.340
Stream size                              : 20.2 MiB (99%)
Title                                    : VideoHandle
Language                                 : English
Encoded date                             : 2024-04-12 11:10:36 UTC
Tagged date                              : 2024-04-12 11:10:36 UTC
Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : PQ
Matrix coefficients                      : BT.2020 non-constant
Mastering display color primaries        : Display P3
Mastering display luminance              : min: 0.0050 cd/m2, max: 1000 cd/m2
Maximum Content Light Level              : 1000 cd/m2
Maximum Frame-Average Light Level        : 200 cd/m2
Codec configuration box                  : hvcC

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 8 s 85 ms
Bit rate mode                            : Constant
Bit rate                                 : 256 kb/s
Nominal bit rate                         : 128 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 253 KiB (1%)
Title                                    : SoundHandle
Language                                 : English
Encoded date                             : 2024-04-12 11:10:36 UTC
Tagged date                              : 2024-04-12 11:10:36 UTC

[kasper93]

Yes, defectively it will make it "brighter", if otherwise dynamic range would be compressed too much.

Without dynamic detection. You get 0-1000 compressed to your target, with peak detection you get 0-real peak compressed to your target.

[laichiaheng]

The target-peak of my monitor is 1400nits, I mean in HDR mode, the video is much brighter with --hdr-compute-peak=yes

[kasper93]

Show stats from mpv. mediainfo doesn't show HDR10+ parameters.

[laichiaheng]

Show stats from mpv. mediainfo doesn't show HDR10+ parameters.

[kasper93]

As you can see, your file has metadata that indicate MaxRGB to be 10000 nits, which is used as a tonemapping information. So 0-10000 is mapped to your display.

I don't know if this is parser issue or this is real value of MaxRGB, for this we would need a sample file to test.