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Make Cinema DNG frames export multithread#297

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ilia3101:masterfrom
Gabboxl:cdng_parallel_export
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Make Cinema DNG frames export multithread#297
Gabboxl wants to merge 1 commit into
ilia3101:masterfrom
Gabboxl:cdng_parallel_export

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@Gabboxl Gabboxl commented Aug 17, 2025 •
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  • made CDNG export thread safe (dngObject_t struct must be created for each frame)
  • Cinema DNG export takes at least 50% less time (at least 2X faster, depending on CPU speed & core number. Sometimes it took even 70% less time on my PCs); the result is the same without differences

Fixes #86

@Gabboxl
Make Cinema DNG frames export multithread
7dca42b 
- made CDNG export thread safe (dngObject_t struct must be created for each frame)
@masc4ii
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masc4ii commented Aug 24, 2025 •
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This is much faster than before! Cool. Unfortunately the Progress (Status) Dialog doesn't work with this. Any chance to fix it?

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Gabboxl commented Aug 25, 2025

This is much faster than before! Cool. Unfortunately the Progress (Status) Dialog doesn't work with this. Any chance to fix it?

Hi, thanks for testing! The progress dialog works, but at a very slow rate of refresh, only when the qApp->processEvents(); line gets hit, the dialog processes all the user input.
To fix this, the main thread must execute the processEvents() method continuously, leaving the other threads rendering all the frames. This is not happening right now because of OpenMP, which includes the main thread in the same team as all other threads.
By using OpenMP it is not really pretty to fix this, but I will look into refactoring this method without using OpenMP to fix the issue.

I would suggest merging this PR in the meantime, as refactoring this method will take me some time, which I think I won't have for at least a few weeks.

fijha added a commit to fijha/MLV-App that referenced this pull request Feb 25, 2026
@fijha
Parallel CinemaDNG export
20e914e 
Based on this 2 pull requests:

ilia3101#312
ilia3101#297
@fijha fijha mentioned this pull request Feb 25, 2026
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Dual iso rendering/export very slow

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@Gabboxl @masc4ii