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  1. hi there

    are all rastor image formats the same ? for instance is bmp better or worse than say dpx for in terms of quality etc. ?

    is bmp that uses rgb24 as pixel format i n any way different to dpx that uses rgb 24 pixel format in terms of quality? i f i were to choose between these two for working with image sequences inside blender which one would be better to preserve quality?

    is there quality loss when converting dpx to dpx or bmp to bmp inside blender?


    thank you
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  2. Member DB83's Avatar
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    AFAIK ( and that counts for little) both BMP and dpx are uncompressed formats so you get a bit for bit image from both (sure that someone will correct me here).

    Yet BMP is a basic standard, supported for viewing on standard platforms without the need for a dedicated viewer. From what I read, and it does have its qualities, dpx does not meet this.

    If I read correctly, dpx is an intermediate platform whereas BMP is a delivery platform.
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  3. Member Cornucopia's Avatar
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    You need to compare apples to apples.

    Uncompressed or Losslessly compressed is always going to be "better" in quality than the equivalent sampling done with lossy compression.
    But you also have to consider:
    1. Bit Depth (8 vs. 10 vs. 12 vs. 16... bits per pixel per color, or even using Float vs. Integer)
    2. Color System (HDR vs. SDR, sRGB vs. NTSC/601 vs. 709 vs. 2020 vs. P2...)
    3. Color Subsampling & # of Primaries (RGB vs. YUV, 4:4:4 vs. 4:2:2 vs. 4:2:0 vs. 4.1.1...)
    4. The presence of Alpha, Depth, or other specialty channels

    Example: assuming you had an image that was:
    Uncompressed, 8bit/color/pixel, SDR, sRGB, RGB 4:4:4, 1920x1080

    ...it wouldn't matter if it was BMP, DPX, PNG, TIFF, TGA, etc as far as quality, as they would all be the same (if from the same source). It might matter which is used if regarding OTHER concerns: load time, data ordering (planar vs. packed), support for certain features, backward compatibility. In that respect, these days I agree with pandy, PNG is probably preferred. But BMP is a good lowest common denominator, due to its age.

    Scott
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  4. ok thanks a lot
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  5. Scott's answer, as usual, is spot on. The one thing I'd add is that, in between PNG (probably the best modern lossless format) and BMP (the original, but very dated format) is TIFF. There are quite a few flavors of this, but it is a format that has been used for decades by the photo editing crowd. They probably don't use it as much today, but you may find that some applications are "happier" with TIFF than with most other formats.
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  6. Member Cornucopia's Avatar
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    Hahaha! I was gonna mention TIFF, but thought I was already being too wordy, so I stopped and left it at that.
    Thanks.

    Scott
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  7. Originally Posted by Cornucopia View Post
    Hahaha! I was gonna mention TIFF, but thought I was already being too wordy, so I stopped and left it at that.
    Thanks.

    Scott
    As some have found, I never have a problem being too wordy, so just call on me when you want to make your posts longer.
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  8. IMHO TIFF is poor standard (supported mostly on pre x86 Apple products and derived x86 applications) due many closed and proprietary extensions. PNG support high bitdepth, lossless compression and it is open thus my favourite.
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  9. Originally Posted by pandy View Post
    IMHO TIFF is poor standard (supported mostly on pre x86 Apple products and derived x86 applications) due many closed and proprietary extensions. PNG support high bitdepth, lossless compression and it is open thus my favourite.
    No argument. TIFF is actually quite old, having been developed back in the late 1980s during the desktop publishing era by my arch-rival, Aldus (I had some involvement in desktop publishing back then). Aldus got bought by Adobe who was tied at the hip with Apple, and even before that, Apple was heavily involved because desktop publishing is the thing that save the Macintosh from being as lame a product as its predecessor, the Lisa, had been.
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  10. Originally Posted by johnmeyer View Post
    Originally Posted by pandy View Post
    IMHO TIFF is poor standard (supported mostly on pre x86 Apple products and derived x86 applications) due many closed and proprietary extensions. PNG support high bitdepth, lossless compression and it is open thus my favourite.
    No argument. TIFF is actually quite old, having been developed back in the late 1980s during the desktop publishing era by my arch-rival, Aldus (I had some involvement in desktop publishing back then). Aldus got bought by Adobe who was tied at the hip with Apple, and even before that, Apple was heavily involved because desktop publishing is the thing that save the Macintosh from being as lame a product as its predecessor, the Lisa, had been.
    Well... once again - IMHO TIFF is a poor format as there is plenty of closed and proprietary extensions... i'm aware of the TIFF history, always had difficulties with TIFF (unless same ecosystem used), dealing with many issues related to closed and proprietary extensions... that's all. IMHO there are better formats than TIFF especially for video/raster image.
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  11. Member Cornucopia's Avatar
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    Never had difficulty with the extensions to TIFF, though I heard about it. It was certainly more extensible/versatile than BMP was, back in the day, and more recommended as a cross-platform/archival/sharing format. But, yeah, when PNG came along, I switched, and haven't looked back.

    Scott
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  12. TIFF can be raster OR vector OR vector+raster, it may have many pages, Little Endian vs Big Endian, you can have CMYK TIFF, add to this proprietary compression and extensions... one format to rule them all... as pointed before - TIFF not my favourite... prefer open formats - this is beneficial to everyone.
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