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I have a raw file but I don't know the pixel format or the width of the image. I need a tool that can quickly display the data and allow me to try different formats easily. An example of such a tool for Windows would be 7yuv. What software exists for this task on Linux?

Note: This has nothing to do with digital camera raws, which is frustrating my attempts to use Google to answer this question.

7yuv

guntbert
  • 13,475
Alistair Buxton
  • 6,852

3 Answers3

12

Turns out Gimp can do this. Just open the file as raw, and you get this helpful dialog that allows you to preview the image:

enter image description here

Alistair Buxton
  • 6,852
7

convert from ImageMagick

E.g., an 8-bit 2x3 grayscale:

printf '\x00\xFF\x88\xFF\x00\xFF' > in.bin

Then:

convert -depth 8 -size 3x2+0 gray:in.bin out.png

Output (once you scale it up somehow, see section below for details):

enter image description here

Command explanation:

  • -depth 8: each color has 8 bits
  • -size 2x3+0: 2x3 image. +0 means starting at offset 0 in the file. If there are metadata headers, you can skip them with the offset.
  • gray:in.bin: the input file is in.bin, and the format is gray, as defined at http://www.imagemagick.org/script/formats.php This weird notation is used because ImageMagick usually determines the format from the extension, but here there is no extension.

How to view such tiny outputs like this example

The problem now is how to view the such a tiny 3x2 output accurately. A direct eog:

eog out.png

is not very good because the image is too small, and if you zoom in a lot eog uses a display algorithm that mixes up pixels continuously, which is better for most pictures, but not for such a tiny image.

One good possibility is to run:

convert out.png -scale 300x out2.png

or directly in one go with:

convert -depth 8 -size 3x2+0 gray:in.bin -scale 300x out.png

-scale is needed instead of -resize, since -resize mixes pixel colors continuously up much like eog by default.

Anther option is to view it in Gimp:

gimp out.png

Image editors such as Gimp must show every single pixel separately if you zoom in enough.

RGB example

printf '\xFF\x00\x00\x00\xFF\x00\x00\x00\xFF' > in.bin
convert -depth 8 -size 3x1+0 rgb:in.bin out.png

or with the -scale to make it more viewable:

convert -depth 8 -size 3x1+0 rgb:in.bin -scale 300x out.png

enter image description here

Related:

Tested on Ubuntu 16.04, ImageMagick 6.8.9.

Ciro Santilli OurBigBook.com
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1

this python snippet does it:

from PIL import Image
import numpy as np

raw_img = np.fromfile("image",  dtype=np.uint8)
l = int(np.sqrt(raw_img.shape[0]/4))  # for a l x l square image
Image.frombytes(mode='RGBA', size=(l, l), data=raw_img).show()
roberto
  • 111