When retrieving tags, ExifTool seems to use a wrong lookup table when labeling the value for NCLC Transfer Characteristics.
The file is labeled by Apple Finder as 1-4-1. Value 4 for the Transfer function indicates a Gamma 2.2 curve (SMPTE Registered Disclosure Document RDD 36:2015).
ExifTool assigns the label "BT.470 System M (historical)". Which would be the label for Color Primary=4. Not when the Transfer Characteristics=4
MacOS Ventura 13.4; ExifTool 12.60 (via homebrew)
% exiftool '/Users/greendcp/Movies/test/Flavio-test_DS-burnin_GSFF_h264_output-gamma22.mov'
ExifTool Version Number : 12.60
File Name : Flavio-test_DS-burnin_GSFF_h264_output-gamma22.mov
Directory : /Users/greendcp/Movies/test
File Size : 464 MB
File Modification Date/Time : 2023:02:25 09:55:35+01:00
File Access Date/Time : 2023:06:27 12:47:00+02:00
File Inode Change Date/Time : 2023:02:25 10:12:42+01:00
File Permissions : -rw-rw-rw-
File Type : MOV
File Type Extension : mov
MIME Type : video/quicktime
Major Brand : Apple QuickTime (.MOV/QT)
Minor Version : 0.2.0
Compatible Brands : qt
Media Data Size : 463531827
Media Data Offset : 36
Movie Header Version : 0
Create Date : 2023:02:25 08:53:36
Modify Date : 2023:02:25 08:53:36
Time Scale : 12800
Duration : 0:04:17
Preferred Rate : 1
Preferred Volume : 100.00%
Preview Time : 0 s
Preview Duration : 0 s
Poster Time : 0 s
Selection Time : 0 s
Selection Duration : 0 s
Current Time : 0 s
Next Track ID : 4
Track Header Version : 0
Track Create Date : 2023:02:25 08:53:36
Track Modify Date : 2023:02:25 08:53:36
Track ID : 1
Track Duration : 0:04:17
Track Layer : 0
Track Volume : 0.00%
Image Width : 1920
Image Height : 1080
Time Code : 3
Graphics Mode : srcCopy
Op Color : 0 0 0
Compressor ID : avc1
Vendor ID : Unknown ( )
Source Image Width : 1920
Source Image Height : 1080
X Resolution : 72
Y Resolution : 72
Compressor Name : H.264
Bit Depth : 24
Color Profiles : nclc
Color Primaries : BT.709
Transfer Characteristics : BT.470 System M (historical)
Matrix Coefficients : BT.709
Pixel Aspect Ratio : 1:1
Video Frame Rate : 25
Media Language Code : Unknown (32767)
Balance : 0
Audio Format : mp4a
Audio Channels : 3
Audio Bits Per Sample : 16
Audio Sample Rate : 1
Purchase File Format : mp4a
Matrix Structure : 1 0 0 0 1 0 0 0 1
Media Header Version : 0
Media Create Date : 2023:02:25 08:53:36
Media Modify Date : 2023:02:25 08:53:36
Media Time Scale : 12800
Media Duration : 0:04:17
Gen Media Version : 0
Gen Flags : 0 0 0
Gen Graphics Mode : ditherCopy
Gen Op Color : 32768 32768 32768
Gen Balance : 0
Text Font : System
Text Face : Plain
Text Size : 12
Text Color : 0 0 0
Background Color : 65535 65535 65535
Font Name : Lucida Grande
Handler Class : Data Handler
Handler Description : Core Media Data Handler
Other Format : tmcd
Playback Frame Rate : 25
Software Version : Blackmagic Design DaVinci Resolve Studio
Handler Type : Metadata Tags
Image Size : 1920x1080
Megapixels : 2.1
Avg Bitrate : 14.4 Mbps
Rotation : 0
According the source I used (https://aomediacodec.github.io/av1-spec/av1-spec.pdf), this is the correct meaning of the value of 4 for TransferCharacteristics.
MediaInfo also uses the same definition. (https://sourceforge.net/p/mediainfo/discussion/297610/thread/0b6d2fd38f/)
- Phil
Ah, thanx for the swift reply.
My actual source was the manual of Davinci Resolve. It seems like they have their own ideas.
Screenshot 2023-06-27 at 14.33.33.png
Most of those entries are the same as ExifTool. I wonder if Gamma 2.2 is equivalent to BT.470 System M ?
- Phil
It looks like this is true. Also, BT.470 System B, G is Gamma 2.8
Screen Shot 2023-06-27 at 8.56.40 AM.png
- Phil
Great! This explains a lot.
Thnx (also for ExifTool)
J!