I was wondering if it's possible to batch adjust the embed fast load data option that is available in Bridge when you go to change DNG preview settings. Not sure if this is something that ExifTool can do or needs to be a CameraRaw process.
Thanks Kindly,
Caleb
A quick google search seems to indicate that the "fast load" is actual just a preview image.
Find a file that doesn't have the fast load and one that does. Then run this command on them and copy/paste the results here
exiftool -Preview:all /path/to/files/
Quote from: StarGeek on May 02, 2023, 11:52:47 AMA quick google search seems to indicate that the "fast load" is actual just a preview image.
Find a file that doesn't have the fast load and one that does. Then run this command on them and copy/paste the results here
exiftool -Preview:all /path/to/files/
This is from a file that has fast load:
Preview Image : (Binary data 84309 bytes, use -b option to extract)
Thumbnail TIFF : (Binary data 131544 bytes, use -b option to extract)
This is from a file that does
not:
Preview Image : (Binary data 76088 bytes, use -b option to extract)
Thumbnail TIFF : (Binary data 131544 bytes, use -b option to extract)
They do seem very similar to me. The fast load option seems to a bit larger of a preview image.
I found this in the source code:
0xc7aa => { #31 undocumented DNG tag written by LR4 (val=256, related to fast load data?)
Name => 'CacheVersion',
[...]
So looking at CacheVersion may help to tell if the image has fast load data, but I don't know what other information is related to this feature.
- Phil
Where do I find if a DNG has Fast Load set or not?
OK. Here are the metadata differences between a DNG created with the fast load option and one without (DNG Converter version 13.4):
> ls tmp
NikonD5-fastload.dng NikonD5-without.dng
> exiftool tmp -w txt -a -u -G1
1 directories scanned
2 image files read
2 output files created
> diff tmp/*.txt
3c3
< [System] File Name : NikonD5-fastload.dng
---
> [System] File Name : NikonD5-without.dng
22c22
< [IFD0] Strip Offsets : 327802
---
> [IFD0] Strip Offsets : 326128
29c29
< [IFD0] Modify Date : 2023:05:02 15:40:58
---
> [IFD0] Modify Date : 2023:05:02 15:40:21
65c65
< [IFD0] Preview Date Time : 2023:05:02 15:40:58-04:00
---
> [IFD0] Preview Date Time : 2023:05:02 15:40:21-04:00
81c81
< [SubIFD] Tile Offsets : (Binary data 2852 bytes, use -b option to extract)
---
> [SubIFD] Tile Offsets : (Binary data 2839 bytes, use -b option to extract)
104c104
< [SubIFD1] Preview Image Start : 459130
---
> [SubIFD1] Preview Image Start : 457456
117c117
< [SubIFD1] Preview Date Time : 2023:05:02 15:40:58-04:00
---
> [SubIFD1] Preview Date Time : 2023:05:02 15:40:21-04:00
119,169d118
< [SubIFD2] Subfile Type : Reduced-resolution image
< [SubIFD2] Image Width : 1856
< [SubIFD2] Image Height : 1238
< [SubIFD2] Bits Per Sample : 8 8 8
< [SubIFD2] Compression : Lossy JPEG
< [SubIFD2] Photometric Interpretation : Linear Raw
< [SubIFD2] Samples Per Pixel : 3
< [SubIFD2] Planar Configuration : Chunky
< [SubIFD2] Tile Width : 464
< [SubIFD2] Tile Length : 416
< [SubIFD2] Tile Offsets : (Binary data 83 bytes, use -b option to extract)
< [SubIFD2] Tile Byte Counts : (Binary data 71 bytes, use -b option to extract)
< [SubIFD2] Black Level : 18 0 25
< [SubIFD2] Preview Application Name : Adobe DNG Converter
< [SubIFD2] Preview Application Version : 13.4
< [SubIFD2] Opcode List 2 : MapPolynomial, MapPolynomial, MapPolynomial
< [SubIFD2] Cache Version : 0.1.0.0
< [SubIFD3] Subfile Type : Reduced-resolution image
< [SubIFD3] Image Width : 512
< [SubIFD3] Image Height : 341
< [SubIFD3] Bits Per Sample : 8 8 8
< [SubIFD3] Compression : Lossy JPEG
< [SubIFD3] Photometric Interpretation : Linear Raw
< [SubIFD3] Samples Per Pixel : 3
< [SubIFD3] Planar Configuration : Chunky
< [SubIFD3] Tile Width : 512
< [SubIFD3] Tile Length : 352
< [SubIFD3] Tile Offsets : 974280
< [SubIFD3] Tile Byte Counts : 45639
< [SubIFD3] Black Level : 31 34 37
< [SubIFD3] Preview Application Name : Adobe DNG Converter
< [SubIFD3] Preview Application Version : 13.4
< [SubIFD3] Opcode List 2 : MapPolynomial, MapPolynomial, MapPolynomial
< [SubIFD3] Cache Version : 0.1.0.0
< [SubIFD4] Subfile Type : Reduced-resolution image
< [SubIFD4] Image Width : 256
< [SubIFD4] Image Height : 171
< [SubIFD4] Bits Per Sample : 8 8 8
< [SubIFD4] Compression : Lossy JPEG
< [SubIFD4] Photometric Interpretation : Linear Raw
< [SubIFD4] Samples Per Pixel : 3
< [SubIFD4] Planar Configuration : Chunky
< [SubIFD4] Tile Width : 256
< [SubIFD4] Tile Length : 176
< [SubIFD4] Tile Offsets : 1019920
< [SubIFD4] Tile Byte Counts : 14268
< [SubIFD4] Black Level : 47 49 45
< [SubIFD4] Preview Application Name : Adobe DNG Converter
< [SubIFD4] Preview Application Version : 13.4
< [SubIFD4] Opcode List 2 : MapPolynomial, MapPolynomial, MapPolynomial
< [SubIFD4] Cache Version : 0.1.0.0
173,174c122,123
< [XMP-xmp] Modify Date : 2023:05:02 15:40:58-04:00
< [XMP-xmp] Metadata Date : 2023:05:02 15:40:58-04:00
---
> [XMP-xmp] Modify Date : 2023:05:02 15:40:21-04:00
> [XMP-xmp] Metadata Date : 2023:05:02 15:40:21-04:00
182c131
< [XMP-xmpMM] Document ID : xmp.did:fe0abc40-f722-4ed4-a799-72a24ecee39f
---
> [XMP-xmpMM] Document ID : xmp.did:0d0bfb55-ead8-4c99-a34e-b9590812f86e
184c133
< [XMP-xmpMM] Instance ID : xmp.iid:fe0abc40-f722-4ed4-a799-72a24ecee39f
---
> [XMP-xmpMM] Instance ID : xmp.iid:0d0bfb55-ead8-4c99-a34e-b9590812f86e
187,188c136,137
< [XMP-xmpMM] History Instance ID : xmp.iid:fe0abc40-f722-4ed4-a799-72a24ecee39f
< [XMP-xmpMM] History When : 2023:05:02 15:40:58-04:00
---
> [XMP-xmpMM] History Instance ID : xmp.iid:0d0bfb55-ead8-4c99-a34e-b9590812f86e
> [XMP-xmpMM] History When : 2023:05:02 15:40:21-04:00
384c333
< [PreviewIFD] Preview Image Start : 46250
---
> [PreviewIFD] Preview Image Start : 46238
484c433
< [Composite] Modify Date : 2023:05:02 15:40:58-04:00
---
> [Composite] Modify Date : 2023:05:02 15:40:21-04:000
(note no CacheVersion difference)
- Phil
Quote from: StarGeek on May 02, 2023, 03:37:31 PMWhere in Brdige do I find if a DNG has Fast Load set or not?
Quote from: StarGeek on May 02, 2023, 05:20:44 PMQuote from: StarGeek on May 02, 2023, 03:37:31 PMWhere in Brdige do I find if a DNG has Fast Load set or not?
It is set in Camera RAW: ellipses icon -> update DNG preview. It can be verified in File Info -> Raw Data.