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Thread: RAW format import / alpha channel handling

  1. #1
    IV Newbie Wisblade's Avatar
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    Lightbulb RAW format import / alpha channel handling

    Hello.

    I've just hit two missing modes in RAW format import.
    • YUV formats: I was attempting to read a raw HD-SDI frame, encoded in YUV 4:2:2 format (16 BPP). No option is suitable in RAW open parameters dialog.
      By the way, only YUV 4:2:0 is available, missing encodings are 4:4:4, 4:2:2, 4:1:1, 4:2:1, 3:1.5:1.5; 3:1.5:0, 3:1:1. Due to the numerous missing encoding, I think a whole block for YUV would be a perfect idea (like the one for RGB 24/32).
    • 32 BPP RGB images: again from a HD-SDI camera, the image is sent in TRGB ("Transparency", not "Alpha"), meaning that all "A" bytes are set to 0x00 (opaque) and not 0xFF: the imported image is then entirely black (due to an invalid alpha plane where all values are zero).
      An option for alpha channel should be added ("Alpha" [current mode], "Transparency" [A=255-T], "Ignore" [allow to load 24 BPP images encoded on 32 BPP], "Force" [alpha=arbitrary value set by user]).
      All options but the current alpha handling could have solved my problem.


    For the first problem, I didn't find any suitable solution to properly load image: IrfanView do not handle YUV once image is loaded.

    Note that for the second problem, it reveals another problem: once image is loaded (and obviously black), then "Image->Show channel->Alpha" is DISABLED, despite the image was loaded WITH an alpha channel (but a full transparent one). Worst, the "Image->Negative" menu do NOT show the alpha channel, so there is absolutely NO option to display properly the image, even with a post-process.

    Why do I need these options? Simply in order to do a batch conversion of raw frames (a LOT of raw frames...) to PNG files. Since IrfanView cannot do it, I was forced to write converters in C++/Qt to do so, but obviously it requires maintenance -while IrfanView is regularly updated- and also Qt's QFile/QImage seems to be WAY slower than IrfanView...

    Thanks for reading, I hope these features could be added soon in my favorite image viewer.

  2. #2
    IV Newbie Wisblade's Avatar
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    Oooops... Forgot to say: in batch conversion mode, the RAW options are severly reduced compared to the "normal" RAW open options. It would be great if the two modes could share the same options/features...

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    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    I suggest emailing Irfan Skiljan with your suggestions. See Help, About IrfanView for his email.

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    IV Newbie Wisblade's Avatar
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    Quote Originally Posted by Bhikkhu Pesala View Post
    I suggest emailing Irfan Skiljan with your suggestions. See Help, About IrfanView for his email.
    Hi Bhikku.

    I thought that suggestions were ”cleaned”, then transmitted to Irfan if suitable... Was I wrong?

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    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    No one else commented. I have no knowledge of the issue.
    Let us know what Irfan says and I will update the thread.

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    IV Newbie Wisblade's Avatar
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    Quote Originally Posted by Bhikkhu Pesala View Post
    No one else commented. I have no knowledge of the issue.
    Let us know what Irfan says and I will update the thread.
    Done, waiting his answer. Thanks.

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