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yeohray2
Malaysia
106 Posts |
 Posted - Jul 24 2022 : 03:42:05
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Hi, I need to read only the EXIF details from raw files, so I'm using ParamsFromFile and it works. However, it's rather slow and looking at the Task Manager, the disk where the raw files are stored in is running at 100%. This suggests that almost the entire RAW file, which is ~30 MB each, is being read.
I was hoping that ParamsFromFile would need to read only a portion of the RAW file. Is there any setting that I can use to speed up the process? I'm using ImageEn 10.2, and the ielibx.dll. Using the WIC option is even slower. I've also tried using the thumbnail options like these:
FWorkImage.IO.Params.RAW_GetExifThumbnail := False;
FWorkImage.IO.Params.RAW_GetEmbeddedJpeg := False;
FWorkImage.IO.Params.RAW_HalfSize := True;
FWorkImage.IO.ParamsFromFile(AFileName, True);
but it makes no difference.
Should add that using ParamsFromFile on jpeg files is extremely fast, and doesn't seem to read the entire file (though I might be wrong).
Thanks in advance.
Ray |
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xequte
38608 Posts |
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yeohray2
Malaysia
106 Posts |
Posted - Jul 25 2022 : 03:58:28
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Hi Nigel,
It's using the ielib DLL. I've uploaded some sample image files and the source for a simple test application here - https://drive.google.com/drive/folders/1RB4ZzGKI15BgyLMr9xWbRpLl8cjaYKu_?usp=sharing
The problem with running the test is that the image files might already be cached by Windows when you download and extract the files, so the test completes very fast without touching the disk at all.
This is the result on my PC when newly rebooted:
It averages about 5 - 6 files every second, and you can see the disk reads maxing out in Task Manager.
Thanks in advance.
Ray |
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xequte
38608 Posts |
Posted - Jul 28 2022 : 00:47:56
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Hi Ray
On my test system the all 17 files are processed in a total of 0.5 seconds:
But I am reading from a local hard drive. LibRaw will be reading the whole file into memory to process it (even if it only reads the header data). So this may be slow for files located on a network device.
Nigel
Xequte Software
www.imageen.com
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yeohray2
Malaysia
106 Posts |
Posted - Jul 28 2022 : 02:04:32
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Hi Nigel,
I guess you're using an SSD drive? If libraw has to read the entire file even if I only need the metadata, then processing 6 files/second on my IDE hard disk drive is normal then. Thanks.
Ray |
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xequte
38608 Posts |
Posted - Jul 28 2022 : 02:15:48
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Yes, the speeds above are for an SSD. On a slower WD drive I get about the same speed as you.
Nigel
Xequte Software
www.imageen.com
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ParamsFromFile and raw files
