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Thread: Batch Conversion - Convert in multiple threads

  1. #1
    IV Newbie
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    Default Batch Conversion - Convert in multiple threads

    Hi,

    I'd like to request to add the feature of processing multiple images at once in batch conversion. Currently trying to convert .cr2 files to .png at highest compression, it always takes ages because this is a single threaded workload; mostly one hour for ~50 files (6000x4000 px). If you need to convert 1000+ files, this will take days.
    If there was a way to specify how many simultaneous threads should be used, or an auto setting (or both), this would speed up things a lot for everyone doing these kinds of conversion.

  2. #2
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    Please edit your forum profile to select your IrfanView version, Windows OS, etc.

    Have you tried using the 64-bit version?

    Have you tried splitting the job into smaller chunks, and running multiple instances of IrfanView?

  3. #3
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    Default

    Thanks for the quick reply. I edited the profile.

    I am running the 64bit version of IrfanView (4.42). Freshly downloaded some hours ago.

    Running 16 instances of IrfanView is not what I really want. Seeing IrfanView calling the program to convert multiple times and processing x photos at once, instead of one after another, would be really nice. I'm seeing this kind of behaviour in other programs for e.g. audio encoding as well, with no trouble. And it really speeds things up a lot.

  4. #4

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    Hello,
    I'm using Irfanview for more than 10 years and I really like it because it knows a wide range of images, is fast, it has resample function AND I really love the batch conversion. Since the pictures are becoming bigger and bigger I think the multithreading batch conversion would be a great feature. Is not about multithreading conversion for one single image but converting multiple images at the same time using one thread for each image. In order to avoid disk usage there can be one single reader and write from/to the disk. I have 16 GB of RAM memory so loading multiple images in memory for conversion wouldn't be a problem.
    I'm on holiday right now and I made my photos by mistake in RAW format (Canon Raw .CR2). I checked on internet for a converter but what I found are crappy or you have to pay for them. I have downloaded an Irfanview plugin and now I can convert them to JPEG/PNG using Irfanview batch conversion function which is great!
    However one image is 20 MBytes (20 MP) and it takes like 5 seconds to convert one file using one single thread (core). I have 4 cores with HT enabled so there could have been 8 simultaneous conversions. I also have SSD and 16 GB of RAM and Irfanview is using only 250 MB... What I'm trying to say is that I have plenty of resources unused .
    I'm a programmer too and I think this multithreading functionality shouldn't be too hard to implement but definitely it would be very useful.
    Thank you!

  5. #5
    Multiple User Jacal's Avatar
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    Default

    If I may go a little off-topic, as long as you have access to the internet on your holiday, I would not recommend IrfanView as a raw photo converter. It can be done - and it is actually fast, 4,3 s per an 18 MP image on my computer -, but the results are very mediocre and one looses all the advantages of shooting in raw formats. One has no control over the process and exported images (only 8-bit per channel even for tiff or png) usually look worse than embedded jpeg preview images.

    An obvious program for Canon's cr2 photos is the free and non-crappy Canon's "Digital Photo Professional", ver. 4.x, a 64-bit program, that understands all the camera settings and can, by default, produce images, that look like the embedded jpeg images, but in higher quality, less compressed. And the photos can be tweaked in many ways before conversion, in batch or individually, what can make resulting images considerably better than out-of-the-camera jpeg photos.

    Powerful and stable open-source raw photo editors are LightZone, darktable and RawTherapee, if I mention only my favourites.

    Conversion includes demosaicing etc. and is never very fast. Canon's program, using CPU very effectively, is approximately three times slower than IrfanView. And the time is well spent.
    Last edited by Jacal; 18.09.2016 at 04:19 AM. Reason: typo

  6. #6
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    Quote Originally Posted by Jacal View Post
    If I may go a little off-topic, as long as you have access to the internet an your holiday, I would not recommend IrfanView as a raw photo converter.
    I think it's an important point. IrfanView is excellent for many tasks, but it will never (IMO) be a replacement for PhotoShop and other dedicated software. One should use the right tool for each job.

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